rlr 1 II

"^ -* J " -^ -T

REPORTS ON RESEARCH FROM WOODS HOLE OCEANOGRAPHIC INSTITUTION

'. ' *.-

•^ -*>--•-

Contents

A At the Coast— Where Air, Sea, Land, and People Meet

— Donald Anderson

Dynamic Waters:

Change is constant at the border of land and sea

L Rising Sea Levels and Moving Shorelines

New tools show promise for better predictions and
decisions about coastline change — Rob Evans

1 ") Shaping the Beach, One Wave at a Time

New research is deciphering how currents, waves, and
sands change our shorelines — Britt Raubenheimer

1 C. The New Wave of Coastal Ocean Observing

Shore stations and seafloor nodes provide connections for
long-term studies of coastal processes — Mike Carlowicz

Fertile Waters:

A crossroads of currents, chemistry, and abundant life

19

22

26

29

The Grass is Greener in the Coastal Ocean

Coastal waters teem with life, but sometimes scientists
can't explain why — Kenneth Brink

Where the Rivers Meet the Sea

The transition from salt to fresh water is turbulent,
vulnerable, and incredibly bountiful — Rocky Geyer

Rites of Passage for Juvenile Marine Life

Learning from the life-or-death journeys of barnacle,
lobster, and clam larvae — Jesus Pineda

Water Flowing Underground

New techniques reveal importance ofgroundwater seeping
into the sea — Matthew Charette and Ann Mulligan

Troubled Waters:

Life and death issues of chemical and nutrient pollution

~)A The Growing Problem of Harmful Algae

Tiny plants pose a potent threat to those who live in
and eat from the sea — Donald Anderson

A~)

A Fatal Attraction for Harmful Algae

Clay sticks to algae and sinks, offering a potential
solution to a deadly problem — Mario Sengco

Red Tides and Dead Zones

The coastal ocean is suffering from an overload of
nutrients — Andrew Solow

A £. Mixing Oil and Water

Tracking sources and impacts of oil pollution in marine
environments — John Farrington and Judith McDowell

rn Oil in Our Coastal Back Yard

Spills on WHOI's shores set the stage for advances in
mitigating and remediating oil spills — Christopher Reddy

FRONT COVER: Tracy Pugh, a former WHOI research assistant,
records the growth of barnacles in Buzzards Bay on Cape Cod, Mass.
Photo by Jesus Pineda, WHOI Biology Department.

BACK COVER: The high-speed coastal research vessel Tiogn departs
Woods Hole for a day trip of testing oceanographic equipment.
Research Associate Marshall Swartz of the Physical Oceanography
Department visually inspects a conductivity-temperature-depth
profiler (black bottles) that will be used to study the Hudson River
estuary. On the fantail, the yellow robotic vehicle SeaBED awaits tests
of navigation and imaging systems for underwater surveys on the
continental sheif. Photo by Tom Kleindinst, WHOI Graphic Services.

2 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

Strategic Waters:

Tapping coastal ocean resources

56

60
62
63
64
65

Which Way Will the Wind Blow?

Marine scientists have a key role to play in the debate
over wind farms in the coastal ocean — Porter Hoagland

For the Navy, the Coast Isn't Clear

Oceanographers mobilize to help the Navy operate effec-
tively in complex, shallow waters — Richard Pittenger

Where Are Mines Hiding on the Seafloor?

New research reveals how waves, currents, and swirling
sands can bury mines — Lonny Lippsett

New Instrument Sheds Light on Bioluminescence

A WHOI engineer invents a device to measure a critical
but elusive phenomenon — Lonny Lippsett

The Cacophony on the Coast

The Navy's traditional acoustic detection methods don't
apply in complex, shallow waters — Lonny Lippsett

Robo-Sailors

Navy-sponsored research spawns a new generation of
underwater vehicles

££ Down on the Farm... Raising Fish

Aquaculture offers more sustainable seafood sources, but
raises its own set oj problems — Hauke Kite- Powell

1930

EDITOR: Mike Carlowicz

OCEAN INSTITUTE SERIES EDITOR: Lonny Lippsett

CONTRIBUTING EDITORS: Kate Madin, Amy E. Nevala, and Mildred Teal

DESIGNER: Jim Canavan, WHOI Graphic Services

CONTRIBUTING DESIGNERS: Katherine Joyce and Jeannine Pires

WHOI PRESIDENT AND DIRECTOR: Robert B. Gagosian

CHAIRMAN OF THE BOARD OF TRUSTEES: James E. Moltz

CHAIRMAN OF THE CORPORATION: Thomas Wheeler

DIRECTOR OF COMMUNICATIONS: James M. Kent

Oceanus is printed by Woods Hole Oceanographic Institution and up-
dated online at www.oceanusmag.whoi.edu

Shipping and handling for two issues per year is $15 in the U.S., $20 in
Canada, and $25 elsewhere. To receive the print publication, visit www.
oceanusmag.com or call (toll-free in North America) 1-800-291-6458;
outside North America call 508-966-2039, fax 508-992-4556, or write:
WHOI Publication Services, P.O. Box 50145, New Bedford, MA 02745-
0005. Checks should be drawn on a U.S. bank in U.S. dollars and made
payable to: Woods Hole Oceanographic Institution.

For single back issues, visit the online store: shop.whoi.edu. For bulk
issues or back issues, contact [ane Hopewood, WHOI, Woods Hole, MA
02543; jhopewood@iwhoi.edu; phone: 508-289-3516; fax: 508-457-2182.

When sending change of address, please include mailing label. Claims
from the U.S. for missing issues will be honored within three months of
publication; from overseas, six months.

Permission to photocopy for internal or personal use or the internal or
personal use of specific clients is granted by Oceanus to libraries and oth-
er users registered with the Copyright Clearance Center (CCC), provided
that the base fee of $2 per copy of the article is paid directly to: CCC, 222
Rosewood Drive, Danvers, MA 01923. Address letters to the editor to
oceanuseditor@whoi.edu

Woods Hole Oceanographic Institution is an Equal Employment Op-
portunity and Affirmative Action Employer.

Oceanus and its logo are Registered Trademarks of the Woods Hole
Oceanographic Institution.

Copyright ©2004 by Woods Hole Oceanographic Institution. All Rights
Reserved. Printed on recycled paper.

Woods Hole Oceanographic Institute

At the coast — where air, sea, land, and people meet

We are all stewards of the coast-
al ocean. For some of us, the
connection to the sea is clear
and immediate; for others, it is subtle and
distant. But whether you live on water-
front property or in a land-locked hamlet,
your everyday activities attect this most
sensitive and most threatened portion of
the world's oceans.

Oil slicks in our harbors, sewage in our
bays, and trash on our beaches provide ob-
vious testimony to our links to the coast.
So do the shrimp, salmon, and scallops on
our dinner plates, and the money in the
wallets of the millions of business owners
and employees who make their living on
the water's edge. Hundreds ot thousands
of buildings stand within reach ot a storm
surge from the ocean.

The subtle connections to the sea reach
hundreds of miles inland. Air pollution
from cars, trucks, and factories eventu-
ally precipitates into the ocean. Pesticides
sprayed on lawns and golf courses run off
into rivers, get ingested by fish downstream,
and eventually poison shorebirds that never

fly near those lawns or golf courses.

Few farmers in Midwestern states think
of how their activities affect the ocean, but
they should. Ever since Fritz Haber dis-
covered in 1908 how to remove nitrogen
gas from the atmosphere and turn it into
fertilizer, the amount of nutrients applied
to farmlands has increased dramatically.
Perhaps two-fifths of the world's popula-
tion would not exist were it not for this af-
fordable and inexhaustible supply.

The downside is that much of this
nitrogen runs off the farms and finds its
way into the coastal ocean. Nitrogen and
other nutrients stimulate the growth ot
microscopic marine plants, which in turn
feed marine animals. But sometimes the
fertilizer promotes too much plant growth,
crowding out many species and suffocat-
ing others. The headline from a recent
series in The Baltimore Sun says it all: "Ni-
trogen's deadly harvest: feeding the world,
but poisoning the oceans."

The coastal ocean is a precious, narrow
strip of water extending from the edge of
the continental shelf to the estuaries where

salt water and fresh water meet. It is the
most biologically productive part ot the
ocean, and this wealth of activity influ-
ences, and gets influenced by, the cycles
of carbon and other elements that govern
climate and human lite itself.

The growth of the human popula-
tion—and the means used to achieve that
growth — increasingly threaten nearshore
waters. We have heard the statistics. Half
of Earth's population lives within 50 miles
of a coast. Coastal areas supply 90 per-
cent of the world's fish catch and 25 per-
cent of U.S. oil. More than 80 percent ot
U.S. global trade passes by ship through
our harbors. Beaches and coastal water-
ways are fertile territory for tourism and
recreation, the largest sector of the U.S.
service industry.

Other statistics are less known but
more worrisome:

• Eleven of the world's 15 most produc-
tive fishing grounds— and 70 percent of
the major fish species in them — have been
or will soon be overexploited.

. Within 60 years, one of every four

4 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

Chatham, Mass., photo by Steve Heaslip, Cope Cod Times

houses within 500 feet of the shoreline
could be destroyed due to sea-level rise
and inappropriate coastal development.

• The bottom of all the oceans' conti-
nental shelves are trawled by fishermen
at least once every two years, with some
areas scarred by nets and chains several
times a season.

• At any given time, several thousand
species are being

carried from one
location to an-
other in ship bal-
last tanks, ready to
invade and colonize
distant habitats. In
San Francisco Bay
alone, 234 inva-
sive species have
become established,
and a new species
successfully invades
every 14 weeks.

The news is not
all bad. Coastal
waters in some re-
gions are cleaner

than they've been for decades, thanks to
efforts to reduce chemical and nutrient
pollution. Marine aquaculture operations

Donald Anderson, Director of the WHOI
Coastal Ocean Institute and Rinehart Coastal
Research Center.

are reducing the pressure on wild-capture
fisheries. Some states are creating no-
build zones in sensitive coastal areas, pre-
venting development that is incompatible
with the dynamic nature of the shoreline.

This issue of Oceanus provides back-
ground on many of these problems and
promising developments. The articles that
follow highlight the role that science must
play in society's
approach to ev-
erything from oil
pollution and algal
blooms to wind
power and shifting
shorelines.

New tech-
nologies, new
approaches to
coastal research,
and new collabora-
tions among scien-
tists from differ-
ent disciplines are
setting the stage
for scientifically
based management

of the coastal zone. Resource managers
and elected leaders are desperate for ideas
and guidance about how to manage our

relationship with the ocean. Many of the
answers they need require new scientific
inquiry, as well as better explanation of
what we already know.

This is the mandate of the Coastal
Ocean Institute (COI). Through research
grants, scientific gatherings, and the
development of state-of-the-art facili-
ties, the Institute encourages innovative,
interdisciplinary research and technology
development that can improve our un-
derstanding of the processes at work
along our shores. COI also fosters com-
munication efforts to help civic leaders,
students, and citizens become better in-
formed about the complexities of this dy-
namic environment and the possibilities
for sustaining and restoring it.

Coastal waters are the ocean's first
line of defense, and that line is show-
ing many signs of stress. The first step
in promoting effective stewardship is to
recognize and document the problems;
as you will read, we are far along in that
regard. The challenge now is to move
our scientific understanding forward to
a point where we can reduce or eliminate
some of these problems.

— Donald M. Anderson

Woods Hole Oceanographic Institution

Rising Sea Levels and Moving Shorelines

New tools and techniques show promise for better predictions and decisions about coastline change

Breaching the beach

The shoreline of Chatham, Mass., has been battered and reshaped by potent Atlantic
winds and waves for centuries. This series of photos shows the barrier beach in 1 985,
7 986, and 7 995, before and after a winter nor'easter created a new inlet. Improved
understanding of how shorelines change over time can help coastal managers to better
in development and respond to recurrent or episodic threats.

By Rob L. Evans, Associate Scientist
Geology and Geophysics Department
Woods Hole Oceanographic Institution

Nae man can tether time or tide.

—Robert Burns

For the past century, the pace and den-
sity of development near the ocean
has been unprecedented, and much of it
is incompatible with the dynamic nature
of the shoreline. More than S3 trillion are
invested in dwellings, resorts, infrastruc-
ture, and other real estate along the Atlan-
tic and Gulf coasts of the United States,
and more than 155 million people live in
coastal counties. The coastal population is
estimated to rise by 3,500 people per day.

Yet, as the devastating hurricane season
of 2004 showed, there is a price to be paid
for living at sea level and building on sand.
Even without extreme storms, the shore-
line naturally advances and retreats on
scales ranging from seconds to millennia.

As a growing population hugs the
coast, understanding the complex process-
es by which coastlines change has never
been more relevant and more important to
our well-being.

A rising tide

Changes to the shoreline are inevita-
ble and inescapable. Shoals and sandbars
become islands and then sandbars again.
Ice sheets grow and shrink, causing sea
level to fall and rise as water moves from
the oceans to the ice caps and back to the
oceans. Barrier islands rise from the sea-
floor, are chopped by inlets, and retreat
toward the mainland. Even the calmest of
seas are constantly moving water, sand,

6 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

and mud toward and away from the shore,
and establishing new shorelines.

Coastal changes have accelerated in the
past century. Although sea level has been
rising since the end ot the last glaciation
(nearly 1 1,000 years), the rate of sea-level
rise has increased over the past 200 years
as average temperatures have increased.
Global warming has added water to the
oceans by melting ice in the polar regions.
But the greater contributor is thought to
be thermal expansion of the oceans — a
rise in sea level due to rising water tem-
perature. Sea level has risen 10 to 25 centi-
meters in the past 100 years, and it is
predicted to rise another 50 centimeters
over the next century (with some esti-
mates as high as 90 centimeters). Whether
or not human activities have contributed
to the change, the sea is definitely rising,
and it jeopardizes our rapidly growing
coastal communities.

Coastal erosion accelerates as sea
level rises. Erosion decreases the value ot
coastal properties because it decreases "the
expected number of years away from the
shoreline," as researchers and underwrit-
ers put it. This quiet loss of U.S. property
value amounts to $3 to $5 billion per year.
Then there is the actual loss of property,
including structures, which amounts to as
much as $500 million a year.

Eroding coastlines are also at greater
risk from storm damage. Property damage
from hurricanes along the eastern U.S. is
estimated to average $5 billion per year,
with the cost in 2004 alone estimated at
more than $21 billion. Such calculations
rarely account for the long-term costs of
flooding and erosion, damage to natural
landforms or ecosystems, and lost recre-
ation and tourism opportunities.

There is significant debate about how
to best manage coastal resources to cope
with the changing shoreline. When and
where will the coast change? And what, if
anything, should we do about it?

Billions of tax dollars are being spent to
restore and protect our wetlands, maintain
our beaches and waterways, and rebuild
coastal infrastructure. For example, the

State of Louisiana is proposing to spend
$14 billion over the next 40 years to re-
store coastal barriers along the Missis-
sippi River delta. Despite these vast sums
of money, very little is being invested in
basic research that can improve our ability
to predict shoreline change, inform coastal
managers in their decision-making, or
provide more accurate risk assessment.

More than just a beach problem

The coast is an incredibly complex sys-
tem, of which beaches are only one part.
All aspects of the system— rivers, estuar-
ies, dunes, marshes, beaches, headlands,

the surf zone, and the seafloor — influence
and respond to the others. But many parts
of the system have yet to be studied in
sufficient detail to fully understand their
roles in shoreline change.

Beach erosion threatens property near
the shoreline, but it also profoundly influ-
ences a critical part of our coastal ecosys-
tem: the marshes. Tidal marshes in estu-
aries and behind barrier islands are the
dominant habitat along the Atlantic Coast
of the U.S., and they are particularly vul-
nerable to rising sea level.

Marshes are ecologically and economi-
cally important because they regulate the

A rising tide along the coast

:

Never before has coastal research been more relevant and more important to
society's well-being. The numbers are staggering:

More than 155 million people (53 percent of the population) live in U.S. coastal
counties which comprise less than 1 1 percent of the land area of the lower 48 states.
Roughly 1,500 homes are lost to erosion each year.

Nearly 180 million people visit the U.S. coast every year, and coastal states account
for 85 percent of U.S. tourism revenues. The tourism industry is the nation's largest
employer and second largest contributor to gross domestic product.
71 percent of annual U.S. disaster losses are the result of coastal storms.
Close to 350,000 homes and buildings are located within 150 meters of the ocean.
Within 60 years, one out of every four of those structures will be destroyed.

Light detection and ranging (LIDAR) images gathered by airplane reveal extensive beach
changes and dune erosion on Hatteras Island, N.C., which was breached by the storm
surge from Hurricane Isabel in September 2003. The images show elevation above sea
level, with reds signifying the highest elevations and blues representing the water line.
The breach occurred where the island was narrowest and the dune heights were lowest.

Woods Hole Oceanographic Institution

, "it

DIGGING FOR EVIDENCE — Scientists from the WHOI Department of Geology and Geophysics are applying numerous techniques to understand
how the shoreline is changing in response to rising sea level. Left: Assistant Scientist Liviu Giosan (tan shirt) and Graduate Student Jonathan
Woodruff extract sediments from the beach using a vibracorer. Middle: Assistant Scientist Jeff Donnelly holds a core of mud and sediment pulled
up from a marsh. Right: Giosan prepares sediments from a split core for laboratory study.

exchange of water, nutrients, and waste be-
tween dry land and the open ocean. They
filter and absorb nutrients and pollutants,
and buffer coastlines from wave stress
and erosion. And tidal marshes provide
nursery grounds for countless species of
fish and invertebrates. They are among the
most biologically productive ecosystems
in the world, producing more biomass per
area than most other ecosystems.

Whereas researchers have been
studying the fertility and biologic
productivity of marshes for many years,
they have only recently started to
determine how these coastal wetlands
grow and erode. As sea level rises, we
need to know the threshold at which
marshes can no longer grow fast enough
to keep pace with rising waters. If the
rate of sea-level rise doubles over the
next 100 years — or quadruples, as some
more extreme models project— tidal
marshes and coastal ecosystems will
likely experience unprecedented changes.
Some may disappear altogether. Our
coast may return to its condition at the
end of the last glaciation, 1 1,000 years
ago, when sea level was rising too fast for
marshes to be established.

New toys for the sandbox

Although there has been progress in
many areas of coastal geology, our under-
standing of the fundamentals of shoreline
change has been limited by the lack of a
broad and integrated scientific focus and
a lack of resources. In many locations, we
cannot answer simple questions, such as
where sand goes after it is eroded from the
beaches, or what role underwater forma-
tions play in determining which areas of
the coast will erode and accrete.

Recent advances in technology make
this an ideal time to tackle some of these
science problems. Our ability to map,
measure, model, and understand the fun-
damental processes shaping the shoreline
has never been better. We can gather a
more precise record ot long-term trends
in shoreline motion, which were previ-
ously identifiable only through historical
records, such as by comparing old nautical
charts with modern ones.

Several instruments have allowed us
to make dramatic improvements in our
ability to map the beach and seafloor, and
what lies beneath.

• Light detection and ranging (LIDAR)
allows researchers to use radar-like pulses

of light to map beaches and the bottom of
clear, shallow waters. It provides maps that
are precise to within 10 centimeters.

• Global Positioning System receivers
and monuments use satellites to track the
movement of shoreline features trom day
to day in three dimensions. These devices
allow positions to be obtained accurately
to within a tew centimeters.

• High-resolution seismic imaging,
ground-penetrating radar, and electro-
magnetic resistivity instruments em-
ploy sound and electrical signals and the
properties of rocks and sediments to "see"
the layers beneath the beach surface and
seafloor. They can probe to depths of tens
ot meters.

The processes that shape our coasts
occur on a variety of time and space
scales. Linking these diverse processes is
a challenge that requires a system-wide,
multidisciplinary approach. It also re-
quires the willingness of policymakers
and coastal managers to support basic
research and to pay more attention to its
results. There are several clear, process-
based science problems that need to be
addressed before we can accurately pre-
dict shoreline change.

8 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

How is the shoreline changing with
time and geography?

Many studies ot nearshore processes
have been conducted on long, straight
shorelines, and scientists have made some
progress in understanding how waves,
sandbars, and currents interact in sim-
plified situations. But the mechanisms
driving shoreline change are not well un-
derstood in regions where the nearshore
region has complicated seafloor topogra-
phy, inlets, or headlands — which means
most beaches.

Waves traveling across the continen-
tal shelf are reflected, refracted, amplified,
and scattered by underwater topography,
and research has suggested that erosional
hotspots along the coast are often the re-
sult ot these seafloor formations. Banks,
shoals, canyons, and even different types
of sediment cause waves to decay and
break differently. Wave-induced currents
cause sediments to erode and accrete and
reshape the seafloor near the coast, chang-
ing how future waves will evolve.

The complex dynamics between
waves and seafloor evolution need to be
unraveled before we can make predictions
about changes to the shoreline. We need to
build a network of wave-measuring
instruments along different coastlines and
feed those measurements into computer
models of how the shoreline reacts to
waves and currents. These models will
help us make predictions about how water
might circulate and how sediment might
move in response to those different
underwater formations. (See "Shaping the
Beach, One Wave at a Time," page 12.)

How will barrier islands respond to
sea level rise?

Barrier islands account for approxi-
mately 15 percent of the world's shoreline,
and they dominate the Atlantic and Gulf
coasts of the United States. Built by the ac-
tion of waves and currents, these narrow
ridges ot sand usually run parallel to the
mainland, protecting the coast from ero-
sion. These natural barriers are bisected by
tidal inlets and channels, and they shelter

Trouble in paradise

This sequence shows how the seas advanced and property was destroyed in Floralton
Beach, Fla. Vegetation and dune lines were completely wiped away after Hurricane
Frances (middle photo), leaving shoreline properties directly exposed to coastal surges
from Hurricane Jeanne (bottom photo).

Woods Hole Oceanographic Institution

ELECTRIC IDEAS— WHOI Associate Scientist Rob Evans (left) works with Engineering Assistant
Matthew Gould to test a seafloor electromagnetic surveying instrument, one of many new
technologies developed to better map and monitor the coastal system.

back-barrier salt marshes, tidal flats and
deltas, and mangroves. Though usually no
more than a few meters above sea level,
these islands are often covered with hu-
man developments.

The long-term late of today's barrier is-
lands is dependent on future sea-level rise.
The latest report of the Intergovernmen-
tal Panel on Climate Change predicts that
global warming will cause sea level to rise
by 50 to 90 centimeters in the next 100
years. At the higher end of these estimates,
many back-barrier marshes will struggle
to keep up with the inundation.

Sand will move from barrier beaches to
the nearshore underwater regions in order
to re-establish equilibrium between the
slope of the beach and the higher tides and
waves. The water levels and topography
behind these barriers could gradually or
catastrophically change. Inlets will become
more dynamic, while deltas will enlarge.
Whole marshlands might disappear, being
converted to tidal lagoons or bays. Cata-
strophic amounts of sand could be lost
from some beaches.

To properly protect barrier beaches —

or learn when to abandon them — we need
to map and monitor them regularly. We
also need to dig into the sediments of the
coast to piece together the history of past
changes. Such efforts will allow us to mod-
el how tidal systems are likely to respond
to rising ocean waters.

What is the impact of storms?

Intense storms such as hurricanes,
noreasters, and typhoons often result in
substantial loss ot life and resources, yet
we know little about the processes that
govern their formation, intensity, and
movement. Nor do we know much about
their history, due to the relatively short
history of reliable weather observations.
With little data on how coastal systems
have responded to storms in the past, we
have been ill-equipped to model and proj-
ect how climate and sea-level change will
affect future storm trends.

Geological investigations of coastal en-
vironments can provide long-term records
of environmental change. Evidence of past
storms can be found in back-barrier sedi-
ments: When a storm washes sand over
the dunes and into back bays and marsh-
es, it forms dateable layers in the muddy
sediments. Mapping regional occurrences
of these "overwash" deposits can allow
researchers to estimate the storminess of
years past and help improve models ot the
probability of future storm strikes.

How is the shore linked to the shelf?

In the past, studies ot the beach and
surf zone were usually separated and stud-
ied independently from what was happen -

MAPPING THE SEAFLOOR BY LASER— Researchers used LIDAR instruments to generate this
seafloor map of the Piscataqua River inlet between Kittery Point and New Castle Island on the
border between New Hampshire and Maine. New imaging techniques are allowing coastal
scientists to visualize the geologic framework of the coastline, track major movements of
sediment, and project how the shoreline might change with time.

1 0 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

ing farther out on the continental shelf. It
has largely been a logistical problem, as
the region trom 0 to 10 meters of water
depth can present some of the most dif-
ficult areas to sample. These areas are too
shallow for most ships, and too deep or
turbulent for researchers on foot. Howev-
er, the zone from 10 meters above sea level
to 10 meters below is perhaps the most
physically dynamic and ecologically vul-
nerable. It we are to fully understand the
coastal system, we have to eliminate the
imaginary barrier between the shallows
and the deep.

What can the past tell us about
the future of the shoreline?

Natural records from a variety of
sources — deep-sea sediments, ice sheets,
corals, calcium carbonate formations in
caves — show that abrupt environmen-
tal changes are common in Earth's his-
tory. Sea level rise rates during the past
1 1,000 years have been uncharacteristi-
cally steady, and may be ripe for change.
That our coastlines have developed such
remarkable diversity during these stable
times (environmental stress usually pro-
motes diversity; calm promotes homoge-
neity) suggests the shape of the shore is
affected by a lot more than sea level.

Coasts are complex, transitional envi-
ronments that respond to changes in both
continental and deep-ocean processes.
The sediments onshore and offshore are
great recorders of this variability, yet these
archives have yet to be systematically
studied and compared with what we have
learned from inland and deep-sea envi-
ronmental proxies for climate.

The high stakes of high water

Resource managers and civic leaders
have a great responsibility for managing
the coast and human use of it, but they
have not always had the best information
available to make scientifically sound deci-
sions. The link between sea-level rise and
shoreline change, while undoubtedly pres-
ent, remains controversial.

For this reason, coastal managers want

BURIED CLUES — WHOI Assistant Scientist llya Buynevich demonstrates a ground-penetrating
radar instrument on a beach in Cotuit, Mass. By bouncing radar waves off buried rocks and
sediments, he can create maps of subterranean layers and extrapolate past sea level.

more reliable data on sea-level rise. They
need studies that apply our knowledge ot
basic processes to more complex, human-
altered shorelines (seawalls, bulkheads,
jetties, groins). They need scientific analy-
ses of the effects of adding and removing
sediments from the shoreline.

There is no doubt that sea level is ris-
ing. It's not the first time, and the rate at
which it is changing may or may not be
unusual. What is different this time is that
humans have congregated along the shore-

line without much awareness of how much
or how soon the sands might shift. We
have the ability to make better decisions
about our lives along the coast. We just
have to start making the measurements
that can provide the right answers.

— This article is the result of a workshop

held at WHOI in April 2004. Many

colleagues who attended that meeting —

too numerous to list — contributed to

this article. I'd like to thank them.

Rob Evans was an undergraduate in the Physics Department at the Uni-
versity ot Bristol in England when he saw an advertisement tor a Ph.D.
project that involved a cruise to a mid-ocean ridge known as the East
Pacific Rise. Undeterred by the fact that he knew next to nothing about
mid-ocean ridges, he applied for the studentship at Cambridge University
and the cruise to a sunny location. Since then, Evans has collaborated with
most of the research groups in the world that carry out electromagnetic
studies of the seafloor. He was a postdoctoral scholar in Toronto, before
coming to the Woods Hole Oceanographic Institution as an Assistant Sci-
entist in 1994. More recently he has started working closer to shore. His
lack of hair is a result of the stress of doing marine science and has no rela-
tionship to his heavy use ot electromagnetic fields.

Woods Hole Oceanographic Institution 1 1

Shaping the Beach, One Wave at a Time

New research is deciphering how currents, waves, and sands change our shorelines

By Britt Raubenheimer, Associate Scientist
Applied Ocean Physics & Engineering Department
Woods Hole Oceanographic Institution

For years, scientists who study the
shoreline have wondered at the appar-
ent fickleness of storms, which can dev-
astate one part of a coastline, yet leave an
adjacent part untouched. One beach may
wash away, with houses tumbling into the
sea, while a nearby beach weathers a storm
without a scratch. How can this be?
The answers lie in the physics of the

nearshore region — the stretch ot sand,
rock, and water between the dry land be-
hind the beach and the beginning of deep
water far from shore. To comprehend and
predict how shorelines will change from
day to day and year to year, we have to:

• decipher how waves evolve;

• determine where currents torm and why;

• learn where sand comes from and where
it goes;

• understand when conditions are right for
a beach to erode or build up.

Understanding beaches and the adja-
cent nearshore ocean is critical because
nearly half of the U.S. population lives
within a day's drive of a coast. Shoreline
recreation is also a significant part of the
economy of many states. (See "Rising Sea
Levels and Moving Shorelines" page 6.)

For more than a decade, I have been
working with WHOI Senior Scientist
Steve Elgar and colleagues across the
country to decipher patterns and pro-
cesses in this environment. Most ot our

A mess of physics near the shore

Many forces intersect and interact in the surf and swash zones of the coastal ocean, pushing sand and water up, down, and along the
coast. Variations in the height and direction of waves, as well as the shape of the seafloor, drive currents that rearrange the system.

When waves approach the beach
at an angle, they drive along-
shore currents (blue arrows).

When alongshore
currents converge, rip
currents can form.

Breaking

waves cause turbulence

in the water column. In shallow water,

this turbulence can stir up the sand bed,

suspending sediments.

Breaking
waves create un-
dertow. Variations in the strength
of the waves and undertow drive the
transport of sediment, causing sandbars
o move offshore or onshore.

Different wave heights lead to different
water levels in the nearshore. That drives
flows "downhill" (green arrows) from
high to low-water areas.

1 2 Oceani - Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

ars and ripples move
ard or away from shore

• if i«l n-l» i l •JH

SWIRLING CURRENTS AND SEDIMENTS — Waves approach the beach from different directions in Haleiwa, Hawaii, driving alongshore currents of
different strengths. As waves break, they generate turbulence that suspends sand and drives undertows.

work takes place in the breaking waves
of the surf and swash zones: the region
that begins where waves crest and ends
where the foamy white water barely cov-
ers our feet.

Our goal is to understand and model
waves, currents, and sand movement in
the nearshore. Given weather conditions
(winds, offshore waves), a map (islands,
canyons, shoals, sandbars, the slope of the
beach face), and sediment characteristics,
we want to be able to model and predict
how waves might change, and how those
changes might affect currents and the ero-
sion or accretion of sand on the beaches.
To do this, we have to get into the water,
making observations in the middle ot the
breaking surf.

If we are successful, we can help coastal
policymakers and managers under-
stand how the movement of water affects
the evolution of coastlines, the safety of
beachgoers, and the dispersal of runoff
and pollutants.

What lies beneath

As storms and winds churn the ocean,
waves roll across the continental shelf and
into shallow water near the shore. They
pitch forward and break, spraying foam
and running up onto the beach. As the
waves break, they drive currents that flow
both offshore and along the coast.

Such is the view that most of us get
when we stand on the shore. But what lies
beneath the waves can make all the differ-
ence between 20-foot breakers and gently
lapping rollers.

As waves move from deep water to-
ward the shoreline, the ocean bottom
alters their direction and strength, just as
a lens bends and reflects rays ot light. Fea-
tures such as submarine ridges, canyons,
and sandbars influence the propagation of
waves, just as winds are directed and fo-
cused by mountains and valleys.

The breaking waves and resulting
currents pick up and move sand, making
beaches dynamic, perpetually in motion.

This subtle but steadily flowing river
of sand moves laterally up and down the
shoreline, as well as offshore during storms
and back toward land between storms.

Waves and currents affect this move-
ment of sediment, but changes in sedi-
ment levels, in turn, affect the waves and
currents. For example, sand eroded from
the beach during winter storms may move
offshore to form a sandbar. That causes
waves to break farther offshore, protecting
the beach from further erosion.

To avoid the complicated physics as-
sociated with along-coast changes in wave
height and direction, most scientific stud-
ies of the nearshore have historically been
conducted on smoothly sloping beaches
with long, straight shorelines. The rela-
tively simple shores of the Outer Banks ot
North Carolina have been a frequent focus
for nearshore research. It was assumed
that waves, currents, and sand levels were
uniform up and down these beaches.

However, recent studies by (eft List of

Woods Hole Oceanographic Institution 1 3

the U.S. Geological Survey have shown
that even on these long, straight coast-
lines, one section of beach may recede
shoreward by tens of yards during a storm,
while a few miles down the coast the
beach may be unaltered. Most of the erod-
ed sand eventually returns after the storm,
but that is no consolation to the owners
of homes and structures destroyed by the
shifting shoreline.

Stepping up to the bar

Several hypotheses explain the diver-
gent erosion rates along the same coast.
Perhaps there are differences in the un-
derlying geology of the region or in the
flow of groundwater to the ocean. Maybe
something as subtle as the size of sand
grains makes a difference. Or perhaps
these seemingly "simple" and similar sea-
floors produce more changes in offshore
waves than we think.

My research group is intrigued by a dif-
ferent theory: The location of underwater
sandbars in the surf may cause variable
erosion along the coast. Sandbars appear
to protect beaches by causing increased
breaking and dissipation ot wave energy

before the waves can attack the shoreline.

To test the sandbar hypothesis we used
observations of waves and mean water
levels collected at the U.S. Army Corps of
Engineers' Field Research Facility in Duck,
N.C. We found that sandbars affect coastal
water levels and flooding during storms.
When a sandbar is near the beach, waves
break in shallow water and drive more wa-
ter onto the shore. This causes flooding and
allows the surf to reach dunes and man-
made structures. We believe that shallow
sandbars may lead to increased erosion.

Sandbar locations can be variable along
straight coasts, which may explain Jeff
List's findings. And recent aerial observa-
tions collected by Tom Lippmann ot Ohio
State University show that the numbers
and locations of sandbars influence a
storm's effect on a beach. But further re-
search is needed to determine whether the
feedback between sandbars and coastal
water levels is important during storms.

Current events in the surf

In contrast to much of the East Coast
of the United States, many continental
shelves have abrupt, irregular changes in

STORM SURGE — The ocean rushes onto the streets of South Nags Head, N.C, wiping out dunes
and damaging houses during the "perfect storm" of 1991. Ocean waters wash over barrier
islands during storms because winds push water against the shore, low atmospheric pressure
allows water levels to bulge upward, and breaking waves force water toward the shore.

the seafloor that cause large changes in the
waves beyond the surf zone.

For instance, the steep topography of
Scripps and La lolla submarine canyons
in Southern California produces dramatic
changes in wave energy over distances of
a few hundred meters. As waves pass over
the canyons, the seafloor acts like a mag-
nifying glass, concentrating ocean wave
energy into hot spots. This makes Black's
Beach a world-famous surf spot, where-
as La lolla Shores (just two miles to the
south) is well known to novice sea kayak-
ers and scuba divers for its gentle waves.

These changes in wave heights along
the coast result in complex flows of water
and changes to sand levels on the beach.
Water that piles up on the shore near the
large breaking waves at Black's Beach
tends to flow south toward La Jolla
Shores and north toward Del Mar.
When these currents intersect with oppos-
ing currents — perhaps between the heads
of the two canyons — strong offshore-di-
rected flows, called rip currents, can
form. Rip currents are a danger to
swimmers and have been observed
to carry huge plumes of sand and pollut-
ants offshore.

Scientists from WHOI and 10 other in-
stitutions recently conducted a major field
program in those complicated Southern
California waters to determine how abrupt
coastal seafloor topography affects waves,
currents, and changes to sand levels. The
team of more than three dozen scientists,
engineers, students, and research assis-
tants deployed instruments to measure the
effect of the canyons on waves and the re-
sulting changes in the flows onshore.

In the Nearshore Canyon Experiment
(NCEX), sponsored by the Office of Naval
Research and the National Science Foun-
dation, my colleagues and I deployed pres-
sure gauges and current meters in the surf
and swash zones to measure wave heights
and directions, and the resulting move-
ment of water and sand. "Drifters" de-
signed to operate in the breaking waves of
the surf zone were used to determine the
locations and speeds ot rip currents. Beach

1 4 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

dn extremely rapid dro,
Canyon changes the direction of:
arriving from the northwest, redirectin
(curved large arrow) toward Black's Beat
The exceptionally high waves at Black's occu
because wave energy also arrives diret

CHANNELING THE WAVES — The bottom topography of the Scripps and La Jolla submarine canyons directs and focuses wave energy near
San Diego. Red dots show the placement of wave-measuring instruments from the Nearshore Canyon Experiment.

surveys were conducted frequently to see
how the seafloor and sand levels evolved
under changing surt conditions.

Other scientists bounced radar sig-
nals off the water surface to determine
its speed, just as police use radar guns to
track moving cars. Video cameras chron-
icled sea foam as it was carried along the
coast by the complex currents.

We have only begun to analyze our
observations, but eventually we will be
able to update and improve numerical
models of the important physical pro-
cesses and test the model predictions
with real-world measurements.

Beach forecasts

Our long-term goal is to predict coastal
wave heights and directions, nearshore
currents, and changes to beach sand lev-
els. We may not achieve this goal until we
can study nearshore processes on a wide
range of coasts (for instance, rocky shore-
lines, peninsulas, and large bays), but it is

achievable within our lifetime.

Surfers, sport-fishermen, and recre-
ational boaters frequently use predic-
tions of wave heights along the coast of
Southern California, as generated by our
colleagues from the Scripps Institution of
Oceanography. The new NCEX measure-
ments will improve the prediction models,
helping not only those who play at the
beach for the day, but also civic leaders

who must manage our beaches and coasts
for the long term.

One hundred years ago, we could not
predict whether it would be sunny or rainy
the day after tomorrow. Now we can pre-
dict the weather as much as 10 days in ad-
vance. By the middle of the 21st century,
we ought to be able to predict the weather
at the beach... both above and below the
water line.

T) ritt Raubenheimer decided to study physics during the ninth grade,
.Dwhen she had a choice between taking either physics or biology (which
'C included cutting up cute little frogs). She fell in love with research while
\ attending Middlebury College, as she worked with astronomers at an ob-
2 servatory in the Canary Islands to collect observations of a supernova
g remnant. Raubenheimer spent the vacations of her youth backpacking,

handgliding, rock climbing, canoe camping, and backcountry skiing, so she
1 knew she wanted to take her physics skills outdoors. She became interested

'

? in nearshore oceanography while studying coastal overwash during her
E ^ first job, at the U.S. Geological Survey's office in Saint Petersburg, Fla. She
completed her training with a doctorate in oceanography from the Scripps Institution of Ocean-
ography. Now her job requires her to go to the beach and to scuba dive to deploy instruments.
Raubenheimer recently received a Young Investigator Award from the Office of Naval Research and
a Career Award from the National Science Foundation. As part of the latter award, she developed a
program offering six-month undergraduate fellowships to expose students to scientific research.

Woods Hole Oceanographic Institution "\ 5

The New Wave of Coastal Ocean Observing

Shore stations and seaf loor nodes provide connections for long-term studies of coastal processes

Most traditional means of observing
the ocean have their limits. Research
ships and submarines must return to port.
Robots and moored instruments run out
of battery power. Satellites have stamina
but their view does not penetrate into the
depths. Ships and subs can carry only a few
scientists at a time, and never into danger-
ous but scientifically interesting conditions
such as hurricanes. Consequently, scientists
have had to be satisfied with intermittent
glimpses ot the environment.

The next wave of ocean science
will be done full time, and in
real time. In recent years,
ocean scientists and
engineers have
been devel-
oping new

ways to go to sea — and stay out there —
without getting seasick. They have been
plugging instruments into seafloor nodes
connected directly to shore-based labs,
and using electro-optic-power cables to
transmit steady streams of power and data.

At locations such as the Martha's
Vineyard Coastal Observatory (MVCO)
operated by Woods Hole Oceanographic
Institution, researchers have staked out a
parcel of ocean and are observing it with

Satellite
Imaging

Shore Lab

• Power Interface

• Telemetry

• Computer Control

• Rain Gauge

' Radiation Sensors

Meteorological Mast

• Sonic Anemometer

• Temperature/RH
Pressure Sensors

•H 20 Sensor

• CDs Sensor
•Surf Camera

24/7 vigilance, with the potential to do so
for years. They can continuously measure
what is happening on the sandy ocean bot-
tom, in the water column from the seafloor
to the surface, and in the air above it. And
they can do it while sitting at their desks.
Thanks to the cables, data from the sea are
freely available on the Internet in real time
to an unlimited number of scientists.

Unconstrained by time, space, and
foul weather, scientists are starting to use
coastal observatories to move past the

snapshots of ocean processes, the re-
stricting "befores" and "afters"
that do not allow them
to learn what

happened in
Aircraft
Measurements between.

Now they

Ship-based
Measurements

Undersea Node -

•Data and Power Transmission

• Currents, Pressure, Waves

• Salinity, Temperature, Oxygen, CO2

• Turbidity and Fluorescence

Offshore Flux Tower -

•Data and Power Transmission

• Wind, Temperature, Pressure, Humidity

• Solar/IR Radiation
•Currents, Waves

• Temperature, Salinity

• Heat. Mass, Momentum Fluxes

MICROSCOPE AND TELESCOPE—

The Martha's Vineyard Coastal Observatory (MVCO)

allows scientists to measure small details of ocean process with

minute-by-minute resolution, while also affording the opportunity to paint broader pictures

of what is happening in the northwestern Atlantic over the longer term. MVCO includes a shore-based lab and

meteorological mast, an underwater node, and a tower wired for instrumentation above and below the water line.

16 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.ee

can illuminate processes. How
do storms rearrange shorelines
and seafloor sediments? What
is exchanged at the interface
between air and water, and how
does it affect coastal weather?
Why do currents change season-
ally? How do environmental
changes affect plankton at the
base of the marine food chain?

New window on the Atlantic

Built in stages since 2000 on
the south shore of Martha's Vine-
yard, MVCO provides a natural
laboratory to study key coastal
processes in the North Atlantic.
Permanent and project-specific
instruments have measured the
motion and strength ot currents,
the movement of sediments, the
cycles of microscopic plants and
animals and the bottom-dwell-
ing creatures that eat them, the
exchange of gases and aerosols
between the ocean and atmo-
sphere, and coastal meteorology.

fust 90 minutes from Woods
Hole on WHOI's coastal research
vessel Tioga, MVCO is exposed to the
open ocean and a wide range of condi-
tions, including energetic tides and sur-
face waves, and winds ranging from dead
calm in summer to intense storms in fall
and winter. In a seasonal rhythm, offshore
waters become stratified in summer, with
warmer surface waters atop denser, colder
waters; in winter, the water column be-
comes homogeneous again.

The National Science Foundation
(NSF) and Woods Hole Oceanographic
Institution shared the costs to build a
small, inland shore lab, a 10-meter mast
with meteorological instruments at the
ocean's edge, and a seafloor node 12
meters below the sea surface and 1.5 ki-
lometers from the shore. Cables connect
the sensors at the mast and sea node to
computers and communications devices
in the shore lab.

In 2002, the Office of Naval Research

STANDING TALL — The Air-Sea Interaction Tower, built as part of
an experiment sponsored by the Office of Naval Research, allows
scientists to deploy instruments that monitor the relationship
between winds and waves in all weather conditions.

previously difficult to study.

For instance, scientists have
spent decades making shipboard
expeditions to measure how the
air and sea exchange heat, wa-
ter, gases, and momentum. But
they have learned little about
what happens when wind speeds
exceed 40 to 50 knots because
no ship captain will intention-
ally cruise into a hurricane and
risk lives to make such measure-
ments. Even in less extreme cir-
cumstances, the natural move-
ment of a research vessel leaves
scientists wondering how much
a- of what they measure is real and
r how much of it is "ship noise."

Coastal observatories also can
help engineers who are develop-
": ing and testing new instruments.
For instance, researchers working
^ on power-hungry, advanced sen-
5 sors have plugged into MVCO
to test the effectiveness of their
instruments without the power
limits of batteries or the time lim-
its of ship-based expeditions.

(ONR) provided support for the design,
construction, and deployment of an Air-
Sea Interaction Tower (ASIT) about 3 kilo-
meters from Martha's Vineyard. The tower
stands in 15 meters of water and extends
22 meters above the water line into the at-
mosphere. It is connected through its own
fiber-optic cable to the shore lab.

The node and tower act as scaffolding
and "extension cords," allowing scientists to
install instruments in the coastal environ-
ment, then return home to collect data over
the Internet. If equipment fails, they can
quickly detect the problem and go fix it.

Wind, rain, or dark of night

In addition to long-term, continu-
ous, and easily accessible streams of data,
coastal observatories provide other ad-
vantages. Structures such as MVCO can
allow scientists to chronicle the processes
at work during extreme events that were

Getting down to business

Today, WHOI scientists and engineers
are working with colleagues from around
the country, using MVCO for a variety ot
interdisciplinary and multi-institutional
research projects. These have included:

• The Coupled Boundary Layers and
Air-Sea Transfer (CBLAST) program,
supported by ONR. This experiment, con-
ducted in the summer of 2003, focused on
the dynamic interaction between winds,
waves, and ocean-mixing processes as they
exchange heat, water, energy, and gases
(such as carbon dioxide) between the
ocean and atmosphere. These exchanges
are fundamental processes that determine
coastal weather and play a critical but ott-
unappreciated role in global climate.

. Surface Processes and Acoustic
Communications (SPACE), and Optics,
Acoustics, and Stress In Situ (OASIS), sup-
ported by ONR. Investigators are evaluat-

Woods Hole Oceanographic Institution 1 7

UNDERWATER POWER STRIP — Left: The seafloor node of the Martha's Vineyard Coastal Observatory, shown here being lowered into the water,
supports experiments but it is also an experimental technology itself. Scientists plug into the node's power supply and data cables to study
everything from shifting sands to blooming plankton. Right: New robotic technologies and cutting-edge instruments — such as the plankton-
observing FlowCytobot — are tested at MVCO before heading off to projects in other regions.

ing how bubbles near the sea surface and
suspended sediments in the water column
affect the propagation ot sound and light
underwater. Bubbles, turbulence, and
sediments accumulate and behave differ-
ently in shallow water— where the Navy
is primarily working today — than in deep
water— the region of most naval interest
during the Cold War. The Navy relies on
the accurate transmission and reception
of sound and light signals for underwater
communication and remote sensing.

• Plankton dynamics experiments, sup-
ported by NSF and the National Aeronau-
tics and Space Administration. Long-term
studies ot plankton dynamics — to learn
how, when, where, and why microscopic
marine plants and animals flourish— take
advantage of two newly developed instru-
ments: the FlowCytobot and the Au-
tonomous Vertically Profiling Plankton
Observatory (AVPPO). FlowCytobot is a
laser-based system to monitor and identify
microscopic plankton down to individual
cells. The AVPPO repeatedly records imag-
es ot plankton scattered throughout the wa-
ter column. Long-term deployment of such
power-hungry instruments is only possible
with the type ot infrastructure at MVCO.

• Sediment transport experiments, sup-
ported by ONR. Researchers have been

investigating the processes and factors —
including winds, waves, currents, tides,
and seafloor topography — that move sand
and shape the seafloor around MVCO. In
a related project, researchers have investi-
gated the processes that bury objects such
as military mines in seafloor sediments.
(See "Where are Mines Hiding on the Sea-
floor?" page 62.)

• Ozone chemistry experiments, sup-
ported by NSF. Researchers have deployed
instruments on the ASIT to quantify how
much ozone pollution is being removed
from the atmosphere and deposited into
the ocean.

• Ocean Horizontal Array Turbulence
Study (OHATS), supported by NSF. An
air-sea interaction experiment is using
18 closely spaced sonic anemometers,

or wind gauges, to examine the effect of
ocean waves on air turbulence and ed-
dies. The observations, begun in August
2004, should allow researchers to improve
weather prediction models.

Building for today and tomorrow

With initial experiments underway and
some lessons already learned at MVCO,
WHOI scientists and engineers are making
plans to improve and expand the facility.

Autonomous underwater vehicles

(AUVs) and other robotic vehicles will
likely play an important role in future
studies at MVCO and other ocean obser-
vatories. Researchers can use observato-
ries as remote ports from which they can
launch these vehicles into inaccessible re-
gions and extreme conditions. Equipment
is already being tested to allow AUVs to
download data and recharge their batteries
at underwater nodes.

WHOI researchers are also working
with colleagues at other institutions to cre-
ate a network of coastal observing systems
extending from the Gulf of Maine to Flor-
ida. By linking observations of several ob-
servatories along the East Coast, research-
ers will be able to develop a clearer picture
of the long-term cycles and processes at
work in the northwestern Atlantic. From
hurricanes to migrating marine life to ed-
dies spinning off from the Gulf Stream,
coastal observers will be able to track de-
velopments in the ocean from start to fin-
ish and season to season. The result will be
a more precise view of everyday lite in one
of the world's oceans.

— Written by Mike Carlowicz, WHOI

Science Writer, with WHOI Senior Scientist

John Trowbridge and Associate Scientists

James Edson and Heidi Sosik.

18 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edi

The Grass is Greener in the Coastal Ocean

Coastal waters teem with life, but sometimes scientists can't explain why

By Kenneth H. Brink, Senior Scientist
Physical Oceanography Department
Former Director, Coastal Ocean Institute
Woods Hole Oceanographic Institution

Stretching from inland rivers and
bays to the edge of the continen-
tal shelf, the coastal ocean accounts
for about 10 percent of the oceans sur-
face area. Yet this relatively small sliver of
ocean contains about halt of all the micro-
scopic plants adrift in our seas.

With satellites we can see what fisher-
men find with their nets: coastal waters
are the most biologically productive por-
tions of the world's oceans. Acre for acre,

the coastal ocean is as productive as a
prosperous Midwestern farm.

This is not necessarily a surprise. Mi-
croscopic plants, or phytoplankton, form
the base of most of the food webs in the
ocean. Microscopic animals (zooplankton)
eat the phytoplankton, and are in turn
eaten by other, larger animals. Increased
biological activity by plants enhances ani-
mal activity.

Most of the world's great fisheries lie
within coastal waters. But why is this area
so much more productive than the rest of
the ocean? Growing microscopic plants
is like growing a lawn: both nutrients and

light have to be available in the right quan-
tities to allow photosynthesis to take place.
Since light typically penetrates just the top
50 to 100 meters ( 150 to 300 feet) of the
ocean, the problem comes down to having
a sustained supply of nutrients in the up-
per layers ot the water.

In the deep, open ocean, when nutri-
ents become available near the surface,
plants bloom, die, decay, and sink, often
to a depth where there is no light. Instead
of being recycled, the nutrients consumed
by these plants accumulate in the depths,
out of the reach of new plants. So while
the open ocean can experience transient

Hot spots along the coast

Using satellite data, scientists can estimate how quickly microscopic plants are growing in the ocean. Red and yellow colors indicate
regions of fastest growth, revealing the fertility of coastal waters. Tiny plants known as phytoplankton form the base of the food web,
providing food for microscopic animals that in turn provide food for larger animals.

Woods Hole Oceanographic Institution 1 9

NUTRIENTS FROM THE DEEP— Strong winds blowing along the coast can promote a
phenomenon known as upwelling. The waters off California, Peru, and western Africa — where
upwelling provides abundant nutrients — include some of the world's most productive fisheries.

blooms, there is usually not a sustained
supply of nutrients in the upper ocean to
promote plant activity.

Mighty winds and lazy rivers

The coastal ocean teems with lite
because there are mechanisms tor tap-
ping this store of deep nutrients and for
drawing plant food from other marine
environments. There is no one mecha-
nism at work on every coast, but different
processes at work in different places. Some
are well understood, while others remain
a mystery.

One well-understood example is wind-
driven coastal upwelling, a process that
taps into the store of nutrients stockpiled
in the deep. Along some coastlines, strong
winds blow parallel to the coast during
certain seasons. These persistent breezes
push water downwind, while the force of
Earth's rotation (called the Coriolis force)
deflects water to the right of the winds
(left in the southern hemisphere). As a
result, the waters in the turbulent upper
10 to 30 meters of the ocean are blown off-
shore, drawing colder, nutrient-laden wa-
ters from the depths to replace them.

The surface waters in regions of coastal
upwelling are cold and nutrient-rich,
promoting robust growth of plants and

the animals that feed on them. But this
mechanism can only be effective in places
where the winds blow in the right direction.

These special places— coastal
California, the Iberian-Canary system
off Spain and Portugal, coastal Peru
and Chile, and the Benguela system
off southwestern Africa — are home to

some of the world's most important
fisheries. As much as 40 to 50 percent ot
the world's commercial tish catch comes
from upwelling areas that comprise just
1 percent of the global ocean.

Another well-known mechanism
for coastal productivity is river outflow.
Natural and manmade nutrients —
principally nitrates and phosphates— run
off the land and fertilize marine plants.
River outflow is best known for building
productive regions in the North Sea and
in the Gulf of Mexico. (See "Where the
Rivers Meet the Sea," page 22.)

This fertilizer can be a mixed blessing.
When too many nutrients are released into
seas, bays, and estuaries, they can create
an overabundance of decaying plants and
animals, depleting oxygen from the water.
These nutrient-rich, oxygen-poor waters
become dead zones, driving animals to mi-
grate or die. This may be the greatest threat
to the health of our marine environment.
(See "Red Tides and Dead Zones," page 43.)

Unsolved mysteries

While the fuel for some productive
coastal zones is well understood, it is sur-

THE BIG MUDDY — A satellite image shows the flood of sediment pouring out of the Mississippi
River into the Gulf of Mexico (more than 500 million tons per year). The torrent of nutrients
feeds blooms of marine plants, creating one of the ocean's most biologically productive regions.
But an overabundance can cause microscopic plants to grow, die, and decay so fast that they
create "dead zones" (blackened waters) that can linger for months.

20 Oeeanus Magazine • Vol. 43, No. 1 • 2004 • ocean usmag.v

prising how little we understand about
other historically important regions.

Georges Bank off the New England
coast is one of the world's most produc-
tive fisheries and known to sustain high
production of microscopic marine plants.
Wind-driven upwelling cannot be a factor
here and the region is too tar from land
tor runoff to be important.

The Georges Bank system is dominated
by extremely strong tides and sharp fronts,
where water masses with stark differences
in temperature or salt content intersect.
There are several similar systems around
the world — including the Yellow Sea and
the Grand Banks — but no one has directly
observed a means tor providing nutrients
in these areas. In the past tew years, re-
searchers have proposed some sound hy-
potheses and theoretical models involving
the interplay of tidal pumping and ocean
mixing. But none of those theories has
been tested in nature.

While there is no solution to the
Georges Bank enigma, at least there are
some promising hypotheses. In the Gulf of
Alaska, we don't have a clue. None of the
well-understood mechanisms work in this
incredibly productive region. The winds
blow in the wrong direction and the coast-
al runoff is pure, low-nutrient water. There
is no strong hypothesis to account tor the
productivity ot the area, though that does
not stop the fishing boats from proving
the waters are rich.

Fishing for answers

How could we still have such gaps in
our fundamental knowledge as we be-
gin the 21st century? Perhaps the biggest
reason is the cost and difficulty of mak-
ing observations in the ocean. We just
don't have good factual descriptions and
observations of some regions, although
coverage is rapidly improving around the
United States.

It is only through direct observations
that we can detect nutrient pathways or
at least gather enough clues to allow the
formulation of strong hypotheses based
on computer models. Our biggest chal-

A FINE KETTLE OF FISH — Most of the world's great fisheries lie in coastal waters. Scientists can
explain why many areas are teeming with life, but other productive regions defy explanation.

lenge is to develop and improve our ability
to make these observations — of nutrients,
currents, and the abundance of phyto-
plankton — in the right places, at the right
times, and at rates and scales that can be
compared. This means collecting data over
months and years, rather than through
isolated, intermittent expeditions.

We are at a wonderful juncture where
critical new ocean technologies are in
sight, and we have the right sort of ques-
tions and problems to solve with them.
Some tools are emerging— particularly
autonomous underwater vehicles, remote
sensors, and coastal observatories — that
promise to make our observations more
specific and more quantitative. At the
same time, our numerical models are be-
coming increasingly realistic and useful.
This interplay of models and observations
is proving extremely productive, as in the
case of Georges Bank, where we now have
a specific hypothesis to test.

The reasons for understanding pro-
ductivity in the coastal ocean extend well
beyond the curiosities of pure science
and the livelihood of fishermen. The bio-
logical activity along our coasts has im-
portant implications for human activity
on the land.

For instance, toxic blooms caused by
polluted and excessively fertilized waters
can hamper recreation and sicken humans
and marine life. Also, as marine creatures
generate wastes, decompose, and sink,
they provide a means tor removing carbon
from the upper layers of the ocean and, in
turn, removing greenhouse gases from the
atmosphere.

The coastal environment is the most
familiar and most connected with hu-
man life. It is also most affected by human
activity. Understanding the reasons for
the marvelous abundance of life in these
regions will give us a means to ensure our
own life along the water's edge.

Ken Brink was educated at Cornell and Yale Universities, and has
conducted research at WHOI since 1971. From 1996-2001, he
served as chair of the Ocean Studies Board of the National Research
Council. Brink also has served as president of The Oceanography Soci-
ety and as a member of the Science Advisory Panel of the U.S. Commis-
sion on Ocean Policy. From 2001 to 2004, he was director of the WHOI
Coastal Ocean Institute. He is now the science director of the national
Ocean Research Interactive Observatory Network. In his spare time,
Ken enjoys travel and historic railroads.

Woods Hole Oceanographic Institution 21

Where the Rivers Meet the Sea

The transition from salt to fresh water is turbulent, vulnerable, and incredibly bountiful

By Rock)- Geyer, Senior Scientist and Chair
Applied Ocean Physics & Engineering Department
Woods Hole Oceanographic Institution

The sea lions stop bellowing and slip,
one by one, off the jetty into the mo-
cha-brown water of the Fraser River near
Vancouver, British Columbia. The surface
of the water is smooth, except for a line
of ripples moving slowly upriver. The sea
lions seem to know that the calm surface
belies turmoil beneath.

The tide has just turned, and a tongue
of salt water is first creeping, then gallop-
ing, back into the Fraser just a few hours

after being expelled by a strong outflow
during the previous ebb. Although the
surface appears calm, the underwater
intersection of fresh and salt water roils
with turbulent eddies as strong as any in
the ocean. The confusion of swirling wa-
ter and suspended sediments disorients
homeward-bound salmon, providing an
easy feast for the sea lions.

Not all rivers end as dramatically as
the Fraser. But the mixing of freshwater
streams and rivers with salty ocean tides
in a partly enclosed body of water — scien-
tists call it an estuary — fuels some of the

most productive ecosystems on Earth, and
also some of the most vulnerable.

Long before the advent of civilization,
early humans recognized the bounty ot
the estuary and made these regions a focal
point for human habitation. Unfortunate-
ly, overdevelopment, poor land use, and
centuries of industrial contamination have
taken a toll on most estuaries. Boston Har-
bor, San Francisco Bay, and the Hudson
River are poster children for environmen-
tal degradation.

Yet there is hope. Estuaries are the
borderlands between salt- and freshwater

MIXING IT UP IN GOTHAM — WHOI Senior Research Assistant Jay Sisson (left) and Engineer Craig Marquette maneuver a box corer after plucking
a 30-centimeter-deep sample of sediment from the bottom of the Hudson River in June 2001. Within sight of Manhattan, the researchers
measured the rate at which sediment accumulates along this intersection between salty ocean water and fresh river water.

22 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

environments, and they are incredibly
diverse both biologically and physically.
The diversity and the high energy of the
txosvstem make estuaries remarkably
resilient. \Vith a better understanding ot
these systems, \ve can reverse their decline
and restore the ecological richness of these
valuable, albeit muddy, environments.

How does an estuary work?

From a physicist's point of view, the
density difference between fresh and salt
water makes estuaries interesting. When
river water meets sea water, the lighter
fresh water rises up and over the denser
salt water. Sea water noses into the estuary
beneath the outflowing river water, push-
ing its way upstream along the bottom.

Often, as in the Fraser River, this oc-
curs at an abrupt salt front. Across such a
front, the salt content (salinity) and den-
sity may change from oceanic to fresh in
just a few tens of meters horizontally and
as little as a meter vertically.

Accompanying these strong salinity
and density gradients are large vertical
changes in current direction and strength.
You can't see these swirling waters from
the surface, but a fisherman may find that
his net takes on a life of its own when he
lowers it into seemingly placid water.

Pliny the Elder, the noted Roman
naturalist, senator, and commander ot
the Imperial Fleet in the 1st century A.D.,

FLOOD OF ACTIVITY — A satellite image shows plumes of sediment suspended in the waters
of the Fraser River as they pour into the Strait of Georgia in June 2003. The mixing of Rocky
Mountain and Pacific waters creates one of the world's most productive estuaries.

observed this peculiar behavior of fisher-
mens' nets in the Strait of Bosphorus, near
Istanbul. Pliny deduced that surface and
bottom currents were flowing in opposite
directions, and he provided the first writ-
ten documentation of what we now call
the "estuarine circulation."

Saltwater intrusion

The opposing fresh and saltwater
streams sometimes flow smoothly, one
above the other. But when the velocity
difference reaches a certain threshold,

vigorous turbulence results, and the salt
and fresh water are mixed. Tidal currents,
which act independently of estuarine cir-
culation, also add to the turbulence, mix-
ing the salt and fresh waters to produce
brackish water in the estuary.

In the Fraser River, this circulation
is confined to a very short and energetic
frontal zone near the mouth, sometimes
only several hundred meters long. In other
estuaries, such as San Francisco Bay, the
Chesapeake Bay, or the Hudson River, the
salt front and accompanying estuarine

Strait of Georgia

SALTY

-200 meters depth

Ocean Floor

Fraser River FRESH -12 meters

fer Bottom

H — 1 kilometer-

A COASTAL MIXING BOWL — Nutrient- and sediment-laden fresh water from the Fraser River in British Columbia rides up and over salty ocean
waters, which are beginning to march upriver during flood tide. The interaction of the two water masses of different salinities and densities in the
estuary creates underwater turbulence and mixing that naturally flushes and energizes the coastal system.

Woods Hole Oceanographic Institution 23

circulation extend inland for many miles.
The landward intrusion of salt is care-
fully monitored by engineers because of
the potential consequences to water sup-
plies if the salt intrusion extends too far.
For instance, the city of Poughkeepsie,
N.Y., 60 miles north of the mouth of the
Hudson River, depends on the river for its
drinking water. Roughly once per decade,
drought conditions cause the salt intru-
sion to approach the Poughkeepsie fresh-
water intake. The last time this happened,
in 1995, extra water had to be spilled from
dams upstream to keep the salt front from
becoming a public health hazard.

The lifeblood of estuaries

Estuarine circulation serves a valuable,
ecological function. The continual bot-
tom flow provides an ettective ventilation
system, drawing in new oceanic water and
expelling brackish water. If it weren't for
this natural "flushing" process, the waters
of the estuary would become stagnant,
pollution would accumulate, and oxygen
would be depleted.

This circulation system leads to incred-
ible ecological productivity. Nutrients and
dissolved oxygen are continually resup-
plied from the ocean, and wastes are ex-
pelled in the surface waters. This pumping
action leads to some of the highest growth
rates of microscopic plants (researchers
call it "primary production") in any ma-

rine environment. This teeming popula-
tion of plankton provides a base for di-
verse and valuable food webs, fueling the
growth of some of our most prized fish,
birds, and mammals— salmon, striped
bass, great blue heron, bald eagles, seals,
and otters, to name a few.

The vigor ot the circulation depends in
part on the supply of river water to push
the salt water back. The San Francisco Bay
area has become a center of controversy in
recent years because there are many inter-
ests competing for the fresh water flowing
into the Bay — principally agriculture and
urban water supplies extending to Southern
Calitornia. Environmentalists are deter-
mined that San Francisco Bay should get
"its share" of the fresh water coming from
the Sacramento-San Joachim delta because
the vast freshwater habitats in the region
are particularly vulnerable to salt intrusion.

Estuarine circulation is also affected by
the tides; stronger tides generally enhance
the exchange and improve the ecological
function of the system. The Hudson estu-
ary, for example, is tidal for 153 miles in-
land to Troy, N.Y. The Algonquin Indians
called the river Mohicanituk, "the river
that flows both ways."

Mucking up the system

Estuaries have their problems. Some
are self-inflicted; some are caused by the
abuses ot human habitation.

SEEING THROUGH MUD — Photograph (left) and x-ray image (right) of sediments from a region
of rapid deposition in the Hudson River estuary. The sharp change in color (left) indicates a
change from fresh, oxidized sediment to older, anoxic mud. X rays reveal laminations of silt
(light colors) and mud (dark) formed by repeated deposition and erosion over tidal cycles.

An estuary, with all of its dynamic stir-
rings, has one attribute that promotes its
own destruction: It traps sediment. When
suspended mud and solids from a river
enter the estuary, they encounter the salt
front. Unlike fresh water, which rides up
and over the saline layer, the sediment falls
out of the surface layer into the denser,
saltier layer of water moving into the estu-
ary. As it drops, it gets trapped and accu-
mulates on the bottom. Slowly, the estuary
grows muddier and shallower.

Occasionally a major flood will push
the salt out of the estuary, carrying the
muddy sediment along with it. Sediment
cores in the Hudson River indicate that
sediment may accumulate tor 10, 20, or
even 50 years, laying down layers every
year like tree rings. But then a hurricane
or big snowmelt floods the river, wipes out
the layers of sediment, and sends the mud
out to sea.

The "episodic" behavior ot sediment
deposition is good news and bad news. It
is good because a big storm can keep an
estuary from getting too shallow too fast.
In fact, it appears that over the last 6,000
years, the natural dredging by large storms
has maintained nearly constant water
depth in the Hudson estuary.

The bad news is that the sediment re-
tains a "memory" of all ot the contami-
nants that have passed through it over the
years. Environmental regulations are far
stricter now than they were 50 years ago,
and we have stopped using many chemi-
cals that play havoc with the environment.
For instance, polychlorinated biphenyls
(PCBs) were banned in the 1970s because
they were shown to be toxic to fish and
wildlife, and to the humans who consume
them. Yet we still have a contamination
problem in the Hudson and other rivers
because PCBs are slow to decay and each
new flood remobilizes these "legacy" con-
taminants and prolongs our exposure.

Trickle-down effects

Billions of dollars are now being spent
to clean up American estuaries contami-
nated by industrial pollution. In Boston,

24 Oceanus Magazine- Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

1

w

GETTING DIRTY AT WORK—WHOI Assistant Scientist Peter Traykovski (left), Senior Research
Assistant Jay Sisson, and a professional diver examine an instrument tripod covered with hydroids
and mud after six months on the bottom of the Hudson River. Researchers chronicled currents, the
flow of sediments, and changes in river bed elevation due to erosion and deposition.

for instance, the new sewage system creat-
ed to clean up Boston Harbor cost taxpay-
ers about $5 billion. The Superfund pro-
gram of the U.S. Environmental Protection
Agency collects and spends billions of dol-
lars more to remediate estuaries.

Often the remediation strategies are
complex and controversial. In the case
of Hudson River, there is a heated debate
about whether PCB-contaminated sedi-
ments should be removed — dredged with
high-tech methods that theoretically mini-
mize environmental harm — or left undis-
turbed. That debate pivots on the episodic
storm phenomenon: Are the contaminated
sediments there to stay, or could they get
stirred up when the next hurricane washes
through the Hudson Valley?

Aside from cleanup initiatives, parts of
the Hudson need to be dredged for navi-
gational purposes. Dredging is not that
costly or difficult, but finding a place to
put contaminated sediments is a problem.
The Port of New York has been filling up
abandoned Pennsylvania coal mines with
its contaminated mud, but that is not a
long-term solution.

While the problems of American estu-
aries are complicated and expensive, they
pale in comparison to Asian estuaries. The
entire nation of Bangladesh lies within the

estuary and lower floodplain of the Ganges-
Brahmaputra River. Other Asian rivers such
as the Mekong, Chiang Jiang (or Yangtze),
and Huang Ho (or Yellow River) are crowd-
ed and strained by concentrated human
settlements. Global sea-level rise is causing
a loss of land, increased flooding, and in-
creased salt intrusion in these estuaries.
The demand tor water upstream for
irrigation and domestic use significantly
reduces freshwater flow through these
systems. The Indus River and Huang Ho
estuaries have suffered trom drastic re-
ductions of freshwater flow over the past
several decades, and the impact of these
human alterations is just now being recog-
nized. New policies about land use, water
diversion, and even global carbon dioxide

production (which affects global warming
and sea level rise) will be needed to pro-
tect these vulnerable estuarine environ-
ments and their human inhabitants.

Stirring up new ideas

One of the challenges of estuarine
research is that most ot the significant
problems are interdisciplinary, involving
physics, biology, chemistry, geology, and
often public policy and economics. Estu-
aries are also incredibly diverse, coming in
all shapes and sizes. Yet scientists are con-
tinually challenged by public policymakers
to generalize our results from studies of
one estuary and apply them to the rest of
the worlds estuaries.

As scientists, one of our roles is to pre-
dict changes in the environment, given
different natural and human-induced in-
fluences. To foresee the health of estuaries
in the future, we have some fundamental
questions to answer about the present and
the past. How far will salt intrude if river
flow is cut in half? Do changes in river
flow increase or decrease the rate at which
sediments shoal the estuary? What ef-
fect do such changes have on the fish that
spawn in fresh water?

What we learn will be critical tor a hu-
man population that increasingly values
coastal waters. We need sound public
policy to reduce vulnerability to coastal
flooding and to protect drinking water,
food supplies, and some ot the world's
most important habitats. We will develop
better policies only if we can ground them
in better science.

T) ocky Geyer is the former director of WHOI's Rinehart Coastal
XYRe

Research Center. He earned a bachelor's degree in geology from
Dartmouth College and master's and doctoral degrees in physical ocean-
ography from the University ot Washington. Geyer was a sailor before he
was a scientist, and he was long baffled by the complex swirls of currents
I that often wrecked havoc with his attempts at precision navigation. He had
| the good fortune to turn this fascination into a vocation, and has subse-
ts quently worked in many estuarine and coastal environments, including
I 5 the Amazon outflow, the Po River outflow in Italy, the fjords and estuaries
of the Pacific Northwest, the tidal channels of New England and Singapore, the Hudson River, the
Eel River piume in northern California, and the western Gulf of Maine. Geyer's research includes
a blend of observational process-studies and numerical modeling, directed both at basic research
questions and applied problems of societal concern, such as harmful algal blooms and contaminant
transport. Geyer has served on the National Research Council's Panel on Environmental Processes:
Source, Fate and Transport, and is a member of the Ocean Studies Board.

Woods Hole Oceanographic Institutic

Rites of Passage for Juvenile Marine Life

Learning from the life-or-death journeys of barnacle, lobster, and clam larvae

By Jesus Pineda, Associate Scientist

Biology Department

Woods Hole Oceanographic Institution

The childhood of a barnacle is fraught
with challenges. It hatches in shal-
low waters close to shore as a tiny larva,
no bigger than a speck ot dust. Currents
sweep it to deeper, choppy waters, some-
times miles offshore. In these proving
grounds each larva floats, at the mercy of
hungry fish and swift ocean currents.

Billions of larvae — including fish, lob-
sters, clams, starfish, and sea cucumbers —
begin life this way. Only a few survive and

return to shore, where they settle on rocks
or sandy seafloor to become adults.

Why larvae make their offshore jour-
ney remains unclear, but we are beginning
to uncover the intricacies of their return
trip — learning how waves, currents, ed-
dies, tides, and other phenomena bring
larvae back toward the shore. With more
insight into the ocean's role in this essen-
tial phase in the life cycle of these species,
natural resource managers can devise bet-
ter strategies to sustain healthy, vibrant
habitats for marine life.

For example, ocean circulation may ex-

plain why populations of lobsters or clams
are sparse in some rocky coastal habitats
that appear ideal. Prevailing ocean currents
may never deliver larvae to their prom-
ised land. Similarly, it would be futile for
coastal managers to create marine reserves
or shellfish beds in areas where larvae are
doomed by currents to be carried so far
offshore that they cannot return.

Telltale clues in murky waters

My interest in larval research was
sparked in 1988 during a scuba diving
class in La Jolla, Calif, where I had just be-

A CLOSE LOOK AT BARNACLES — Tracy Pugh, a former research assistant in the WHOI Biology Department, records the growth of barnacles in
Buzzards Bay on Cape Cod, Mass. Understanding how juvenile barnacles and other marine invertebrates are transported by waves, currents,
eddies, tides, and other phenomena helps researchers devise strategies to sustain vibrant habitats.

26 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

LIFE WITH LARVAE — LEFT: Hair-like appendages on this two-week-old barnacle larva churn the water to aid in feeding. CENTER: After four to seven
weeks, juvenile larvae settle along the shore and develop a hard white shell. RIGHT: Adult barnacles, about one year old, form plates to hold their
body together and for protection.

gun my doctoral studies at Scripps Institu-
tion of Oceanography. During a dive close
to shore, I spotted a layer of brown water
about 10 meters (33 feet) down. When I
swam into it, the water felt very cold.

The next day I returned and swept
a net through this brown water. When
I analyzed my catch in the lab, I found
the color came from patches of maturing
larvae ready to settle near the shore. These
observations hinted at a mechanism tor
transporting larvae toward the beach.

Near the coast, warm fresh water often
collides with colder, saltier water. These
different bodies of water have different
densities, so they tend to remain relatively
distinct. In many ways, the boundary be-
tween these water masses behaves like the
boundary between two other "fluids"— the
sea surface and the atmosphere. Just as
waves form and propagate on the ocean
surface, waves also form within the ocean,
along the boundaries between warm, light
water and cold, dense water.

My observations in scuba diving class
suggested that larvae were being trans-
ported toward shore in cold-water waves
moving below the sea surface. But these
waves, called internal bores, told only halt
of the story.

Coastal fronts

I spotted evidence for the other half of
the puzzle on my way home from a seaside
party. Looking at the Pacific Ocean, I saw
lines of foam, seaweed, and plastic debris
forming parallel to the shore and stretch-

ing several hundred feet across the sea sur-
face. Most beachgoers have probably seen
these features, which form at the intersec-
tion where warm and cold water masses
meet. Scientists call them coastal fronts.

The full picture ot the larval transport
process tell into place. As ebbing tides
move water over seafloor obstacles, they
create internal bores, which transport
large volumes of cold water from deep
offshore areas toward the shore. The in-
coming wave of cold water pushes warmer
nearshore waters out to sea. A few hours
later, the heavier cold water sinks and re-
cedes offshore. Warmer, lighter water near
the surface surges inshore and over the
receding cold water, led by a vanguard ot
coastal fronts. Along with kelp and debris,
the coastal fronts carry larvae ashore.

A rare wave within the ocean

In the years since those observations,
I have studied various phenomena in-
volved in larval transport along the coasts
of southern California, northwestern
Mexico, and Massachusetts. With funding
from the National Science Foundation and
the Office of Naval Research, I have inves-
tigated why some types of larvae accumu-
late in fronts, while others do not. I also
have examined whether periodic ocean
circulation changes such as El Nino have
an impact on larval transport.

Many puzzles remain. For example,
we know little about how currents in the
nearshore environment connect with
larger oceanic currents. If larvae are

swept far from the shore of their birth, do
they grow up somewhere else or are they
lost altogether?

And while our work on internal bores
has focused on larvae, other researchers
have been interested in whether this pro-
cess transports offshore deposits of sewage
and nutrients back onto the beach.

Recent research has shown that inter-
nal waves come in various flavors with
varying impacts on larvae. (Internal bores
are but one flavor.) I am currently collabo-
rating with Alberto Scotti, who studies
fluid dynamics at the University of North
Carolina, to investigate a rare type of in-
ternal wave in the ocean called a "wave
of elevation." As the name suggests, these
waves have taller crests than others around
them. Within each wave of elevation a
strong circular flow of water moves hori-
zontally, spinning any trapped particles
like clothes in a washing machine.

These waves are rarely observed in na-
ture, but we identified some in Massachu-
setts Bay. We suspect they may influence
how larvae move to their adult settle-
ments. As the wave moves toward land,
larvae may become caught up in this rota-
tion and concentrate together.

To test this, we are planning to con-
duct an experiment where we will deploy
plastic-covered electronic drifters (about
the size of soda cans) in areas with waves
of elevation. We will record information
about buoyancy and particle accumula-
tion in the hope of finding out what larvae
must do to catch a ride on these waves.

Woods Hole Oceanographic Institution

Surfing to turf

I have also conducted experiments in
the controlled environment of the labora-
tory to mimic what I saw in the sea. With
funding from the WHOI Rinehart Coastal
Research Center, I collaborated with
WHOI physical oceanographer Karl Hel-
frich, who studies the mechanics and fluid
dynamics of the coastal ocean.

We used a rectangular tank bisected
with a Plexiglas dam, filling one side with
lighter fresh water, dyed blue, and the
other side with heavier, saltier water. We
added buoyant, peppercorn-sized nylon
beads (representing larvae) to the fresh
water. When we lifted the dam, a tongue
ot blue-dyed fresh water surged across the
surface of the salty water. We watched as
the beads accumulated behind this fresh-
water tongue.

Applied to the coastal zone, this ex-
periment suggests that some species of
larvae may accumulate behind — not in
front of— coastal fronts and internal bores.
These larvae surf the waves toward shore.
However, we also found that the larvae of
other species may be pushed ahead of an
incoming front, like the dirt piled up in
front ot a bulldozer.

MIT/WHOIJoint Program
student Fabian Tapia (left) and
WHOI Postdoctoral Scholar
Claudia DiBacco use fine nets
to sample patches ofcyprid
barnacle larvae floating in
Narragansett Bay, R.I. Larvae
ride internal bores — wave fronts
beneath the surface of the
ocean — toward the shore when
they are mature enough to settle
on rocks and coastal structures.

Swimming against the current

Whether larvae are pushed or pulled
onshore turns out to make a difference.
The collision of water masses of differ-
ent densities creates powerful downward-
flowing currents that threaten to sweep
larvae into the depths. The larvae must
resist this downward pull and continue
moving forward.

They do this by swimming. Several
weeks into their growth cycle, larvae
develop appendages to swim. Some or-
ganisms, such as sea anemones, develop
cilia — wiggly, hair-like protrusions that
work like oars. Other species such as
barnacles grow a single strong leg that
functions like a flipper.

With Karl Heltrich and Claudio DiBac-
co, a larval ecologist at the University of

British Columbia, I am now using a spe-
cially designed experimental chamber to
determine how larvae swim when down-
ward currents flow against them. We are
interested because those larvae that do not
swim fast enough will be left behind by
the traveling front and will not reach the
shore. Karl and I also have found that in
order to resist the downward drag, larvae
swimming ahead of a front have to swim
faster than those swimming behind.

The challenges confronted by larvae do
not end near land. We are also interested
in what happens to them once they arrive
close to shore. Frequently my colleagues
and I leave our microscopes and laborato-
ries and head to beaches, coastal lagoons,
and rocky coastlines to study how larvae
accumulate and mature. Some areas host
thick carpets of juvenile organisms. Others
have none at all.

In 2003, 1 visited a new research facility
along the Pacific coast of Panama known
as the Liquid Jungle Lab. While exploring
a nearby estuary, I examined a clump of
mangrove roots. The rocky, remote, and
relatively pristine sanctuary is a habitat
rich with food, so I suspected it would
be equally rich with marine species. Yet I
found surprisingly tew organisms.

Very tew people live near the lab, so it's
unlikely that pollution prevented coloni-
zation of the mangrove roots. I suspect
that as rainforest leaves fall and rot, they
leach naturally occurring chemicals into
the coastal zone and kill any larvae. I plan
to return and test this hypothesis because,
despite their small size, larvae teach me a
lot about life in our oceans.

— WHOI Science Writer Amy E. Nevala
contributed to this article.

As a boy, Jesus Pineda traveled each summer from his home in
Mexico City to his grandmother's ranch in central Mexico, where
he fished for catfish from a local river. That interest spurred a biology
and oceanography career, and he quickly found barnacles, sea anemo-
nes, clams, and other creatures without backbones more intriguing
than fish. After earning degrees in biological oceanography and ma-
rine ecology at Escuela Superior de Ciencias Marinas and at Centre
de Investigation Cientihca y de Educacion Superior de Ensenada in Mexico, he completed doctoral
studies in oceanography at the Scripps Institution of Oceanography. He joined WHOI as a postdoc-
toral scholar before becoming an associate scientist in 1998. For his research, he has explored coast-
lines in the United States, as well as Mexico, Chile, and Panama.

28 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

Water Flowing Underground

New techniques reveal the importance of groundwater seeping into the sea

By Matthew Charette, Associate Scientist

Marine Chemistry and Geochemistry Department

and Ann Mulligan, Assistant Scientist

Marine Policy Center

Woods Hole Oceanographic Institution

T Tp in the cliffs, Nickerson had noticed
\^/ the. . . display of 'extraordinary spirit
and activity' and soon became part of a
general rush for the beach. The men had,
in fact, found a spring bubbling up from a
hole in a large flat rock... once everyone had
been given a chance to drink, they began
to marvel at their good fortune. Tlie spring
was so far below the tide line that it was
exposed for just a half-hour at dead low; at

high tide it was as much as six feet under-
water. They had time to fill only two small
kegs before the rock once again disappeared
below the surf.

—In the Heart of the Sea: The Tragcdv of the
\\'lhile Ship Essex by Nathaniel Philhrick

The story of the 1820 sinking of the
whaler Essex, which was rammed by a
sperm whale, inspired Herman Melville's
Moby Dick. It also provides an inspiration-
al story of how geology came to the rescue
of shipwrecked men.

Cut adrift in longboats in the middle
of the Pacific, the eight survivors of the

disaster— including 14-year-old Thomas
Nickerson — headed toward South America.
When they finally reached land, the dehy-
drated sailors had the good fortune to find
fresh groundwater pouring out of the beach
face at low tide. That water saved their lives.

It turns out that Nickerson's fortunate
observation is not that unusual. Nearly
97 percent of the worlds usable freshwa-
ter lies underground, and the contents of
that vast underground reservoir some-
times seep into the ocean. In fact, wher-
ever aquifers are hydraulically connected
to the ocean, submarine groundwater can
discharge into the sea and saltwater can

FINDING WATER BENEATH THE WATER— WHOI Postdoctoral Scholar Kevin Kroeger and Guest Student Kayla Halloran install a well in Eastham,
Mass., to sample groundwater seeping into a salt pond. Between 5 and 10 percent of the fresh water in the ocean comes from groundwater.

Woods Hole Oceanographic Institution .

intrude landward into tresh aquifers.

Because most humans have a predilec-
tion for living along the coast, ground-
water-seawater interactions have become
increasingly important to understand.
Pertinent questions include: How much
groundwater is flowing from land to sea?
What is that water carrying with it? How
do human activities attect groundwater
quality and the coastal ecosystem?

Historically, coastal groundwater stud-

Precipitation

ies were focused on saltwater intrusion
into inland freshwater aquifers, which
can have dire consequences for drinking
water supplies. Little attention was paid to
submarine groundwater discharge to the
coastal ocean because scientists thought
it was insignificant compared to the dis-
charge from rivers and other surface wa-
ters. Statistically, they were right: Ground-
water represents about 5 to 10 percent of
the freshwater input to the ocean.

Evaporation

HYDROLOGIC CYCLE IN COASTAL ZONES— Precipitation either evaporates into the atmosphere,
gets taken up by plants, flows into streams, or infiltrates the ground and recharges aquifers.
Groundwater flows from inland locations to lakes, streams, or coastal waters. On the seaward
side, denser salt water enters sediments and establishes equilibrium with fresh groundwater.
Tides and mixing along the freshwater-saltwater interface results in seawater circulation
through the sediments.

In recent years, however, submarine
groundwater discharge has received more
attention because new research shows that
it is more than just a simple exchange of
water between land and sea. The flow of
groundwater into the ocean is critical be-
cause those fluids often carry a substantial
amount of dissolved nutrients and pollut-
ants. The appearance of cloudy, algae-filled
water in some harbors and bays may be the
result of this out-of-sight nutrient input.

Water dissolving, water removing

Groundwater discharge appears to be
an important factor for determining the
chemistry of the coastal ocean. As fresh
groundwater flows toward the sea, it rises
up over denser, salty water. The fresh and
salty water mix along the interface, and
the resulting fluid discharges at the shore-
line. This interface between underground
water masses has recently been described
as a "subterranean estuary," a mixing zone
between fresh and salty water analogous to
the region where a river meets the ocean.
(See "Where the Rivers Meet the Sea,"
page 22.)

A variety of reactions and transforma-
tions both inland and near the coast can
influence the amount of dissolved chemi-
cals passing through this underground
estuary. Nitrogen, phosphorous, and other
contaminants may be introduced into
groundwater through a variety of mecha-
nisms. Wastes and nutrients leach from

30 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

septic systems. Rainfall carries atmo-
spheric pollutants and ground spills down
through the soil. Eventually, these chemi-
cals flow underground toward the ocean
just as they do in surface tributaries.

Once these dissolved chemicals reach
coastal waters, they can influence the
abundance of plants and other living spe-
cies. It is not unusual, for instance, for
groundwater to contain dissolved nitro-
gen in concentrations 100 to 1,000 times
greater than in seawater. Nitrogen from
human sources, for instance, has led to the
over-enrichment (eutrophication) ot many
coastal bays and waterways. (See "Red
Tides and Dead Zones," page 43.)

Under the rocks and stones

Groundwater often flows for long dis-
tances and time scales. Unlike surface
estuaries, in which water is restricted hori-
zontally by topography— for instance, hills
and banks restrict water to channels or
streams— groundwater flows throughout
Earths crust. Soil and subsurface geology
play a vital role in influencing the direc-
tion and rate at which groundwater flows.

The patterns of submarine ground-
water discharge are the result of complex
interactions between hydrologic, chemical,
geologic, and human influences. A variety
of disparate techniques have been devel-
oped for accurately assessing and predict-
ing these flows. Unraveling this knot of in-
terwoven influences requires scientists to

work across disciplines, bringing chemists
together with geologists, hydrologists with
mathematical modelers.

For instance, models are useful for in-
vestigating and integrating the complexi-
ties of the groundwater discharge system,
and for predicting the effect of human
activities. Models offer idealized mathe-
matical descriptions of how hydrology and
underground geology can affect flow. But
grounding these models in reality requires
a reasonably accurate three-dimensional

map of the underground geology.

Such maps require field sampling and
the drilling of boreholes into the ground,
which can be invasive and expensive. Data
from boreholes are high in resolution — sci-
entists can "see" features in the subsurface
that are as small as a centimeter— but each
hole in the Earth represents a very small
sample of sediment at only one location.

Researchers also use geophysical tech-
niques such as ground-penetrating radar,
electromagnetic resistivity, and seismic

Cool groundwater seeping
into surface water

COOL VIEW OF GROUNDWATER— Infrared images shot by airplane in September 2002 reveal the
extent of groundwater seeping into Waquoit Bay, Mass. Bright yellows indicate locations where
cool groundwater is emerging from the sandy bottom into the salty, warm waters of the bay.

Woods Hole Oceanographic Institution ;

GO WITH THE FLOW — WHOI Assistant Scientist Ann Mulligan (foreground), Research Assistant Meagan Gonneea (blue shirt), and visiting student
Claudette Spiteri collect data about groundwater discharge into Waquoit Bay, Mass. By measuring water pressure, temperature, and conductivity,
they can monitor how fast groundwater is flowing and how the interface between fresh water and salt water changes over time.

studies, which use the magnetic and
sound-propagating properties of rocks and
sediments to survey broad areas beneath
the surface. Such technological approaches
are now less expensive, less invasive ot the
environment, and more likely to map large
areas quickly.

But these tools only provide knowl-
edge ot specific physical properties of the
underground geology; they do not tell us
what types of sediments are below the sur-
face. For that, we must have direct samples
(as obtained by drilling) that we can then
correlate to the geophysical data.

The best way to map the subterranean
environment and its effect on groundwater
flow is to combine techniques. By drill-
ing boreholes and conducting geophysical
surveys, we can amass enough data to draw
realistic maps of the subsurface, which, in
turn, make our models more realistic.

Water at the bottom of the ocean

As we develop maps of the under-
ground landscape, we can also gain insight
about the groundwater system if we can
see precisely where the groundwater is

entering the sea, how much is flowing out,
and how fast the groundwater is mov-
ing. Airborne thermal imaging — which
exploits the temperature contrast between
groundwater and surface water— is prov-
ing to be an especially useful tool for lo-
cating groundwater discharge.

On Cape Cod, for example, ground-
water maintains a temperature between
10° to 15°C throughout the year; ocean
surface water varies from 25°C in summer
to 0°C in winter. Through the use of infra-
red cameras on planes and blimps, we can
detect this thermal contrast and see where
groundwater is discharging (see image on
page 31 ). With this information, we can
correlate the groundwater discharge pat-
tern with what we know about hydrologic
and geologic features. The combination of
observations offers clues about what might
be controlling the discharge and provides
targets for future sampling locations dur-
ing fieldwork.

Thermal imagery tells the location of
submarine groundwater discharge, but not
the rate of the flow. To quantity that, re-
searchers have turned to chemical tracers.

The concept is relatively simple: In zones
of groundwater discharge, we detect and
track a chemical in the groundwater that
has a different signature or higher concen-
tration than can be found in surface waters.
By knowing the concentration of natural
tracers in the groundwater, we can estimate
how much fluid is required to account for
the excess levels observed in the ocean.

The naturally occurring isotopes ot ra-
dium and radon in Earth's crust have prov-
en to be useful indicators of groundwater
discharge. Radium and radon are leached
from the rocks and sediments that sur-
round and host groundwater aquifers, and
they often become concentrated because
they are not cycled or decayed as much as
they would be in exposed seawater.

Remove the water, carry the water

There is an old, well-established me-
chanical approach to measuring ground-
water that has recently been given new life:
the seepage meter. First conceived in the
1970s, a seepage meter is essentially the
top half of a 55-gallon drum placed over
the interface where groundwater seeps out

32 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

of sediments into the ocean. The seeping
groundwater fills a plastic bag connected
to the top of the drum, and the amount of
fluid captured per unit of time provides an
estimate of the flow.

The problem with old-fashioned seep-
age meters is that they are time- and labor-
intensive: If you want to measure flow
for 24 hours, you need to sit with your
equipment for 24 hours. Longer observa-
tions can become tedious, not to mention
wasteful when precious research time is
spent baby-sitting equipment.

In recent years, we have developed
automated seepage meters that allow re-
searchers to track the flow ot groundwa-
ter continuously for up to a week, even in
remote areas. It is now possible to obtain
high-resolution, long-term records of
submarine groundwater discharge from
an unattended, automated meter while
we are back in the laboratory working on
other parts of the groundwater puzzle. We
recently worked with the U.S. Geologi-
cal Survey to make such measurements as
part of their long-term ecosystem rehabili-
tation program in the Florida Everglades.

Into the blue again

Coastal groundwater-seawater inter-
actions have been studied in many parts
of the world, including the southeastern
coast of the United States, the Mediter-
ranean Sea, Australia, and Cape Cod. In
nearly all of those locations, new lines of
evidence suggest that submarine ground-
water discharge is an important source of
dissolved elements to the ocean. However,
few comprehensive geochemical studies of
such environments have been undertaken.

AUTOMATED MEASUREMENTS— Research Assistant Matt Allen sits on an airboat and sets up a
WHOI-designed automated seepage meter for a three-week deployment in Florida's Everglades.

That is why we are working together
as a groundwater hydrologist and a ma-
rine chemist. Through interdisciplinary
collaboration, we will be able to see a big
picture that can get lost in the details of
a limited scientific focus. In the com-
ing years, we are planning work with
other WHOI geologists, geophysicists,
and chemists to broaden our view of the
problem by conducting a comprehensive
study of an entire groundwater discharge
system from offshore to inland.

To advance our understanding of the

importance of groundwater to our coastal
environment, we must take an interdis-
ciplinary approach. Proper management
of coastal water resources— which are be-
coming overrun by natural and man-made
forms of pollution — requires that we learn
more about the quantity and quality of
these inputs.

The National Science Foundation, the
WHOI Coastal Ocean Institute, the Cove
Point Foundation, and the National Oceanic
and Atmospheric Administration provide
funding for this research.

Matt Charette was born in Boston, raised in Lynn, Mass., and spent his summers on the beaches of Truro on
Cape Cod (a place he now visits for his groundwater research). Charette earned a bachelor's degree in chemi-
cal oceanography from the Florida Institute ot Technology and a doctorate in chemical oceanography from the
University of Rhode Island. He came to WHOI as a Postdoctoral Fellow in 1998 and was named an Assistant Sci-
', entist in 2000. His research focuses on geochemical processes in coastal groundwater and their implications for
^ chemical fluxes to the coastal ocean.

Ann Mulligan earned her bachelor's degree in geological sciences at Brown University, a master's in civil and
environmental engineering from Tufts University, and a doctorate in environmental engineering from the
~ University of Connecticut. Her research focuses on water resource management and modeling of groundwater flow
1 and transport. In graduate school, Mulligan concluded that coastal water resources would become an increasingly
? important issue as development along the coast continues to occur at a rapid pace. She decided to come to WHOI
5 to focus on coastal water resource problems.

Woods Hole Oceanographic Institution 33

\

The Growing Problem of Harmful Algae

Tiny plants pose a potent threat to those who live in and eat from the sea

By Donald M. Anderson
Director, Coastal Ocean Institute
Senior Scientist, Biology Department
Woods Hole Oceanographic Institution

/:</)' and August 2004 — At the height of
'he summer season, when New England-
ers and thousands of tourists open their
wallets to buy fresh "steamers" and fried
clam strips, Maine's shellfish beds are shut
down. Concerned by the worst bloom of
toxic algae in 23 years, resource managers

closed the flats for fear of paralytic shellfish
poisoning. Hundreds of shellfishermen went
without income for nearly two months at
a time when they typically fill their bushel
baskets and wallets. From Nova Scotia to
Cape Cod, restaurateurs watched the price
of clams jump by 200 percent. All of this
was caused by a tiny microscopic organism,
Alexandrium, which does not harm the
clams but can sicken or kill humans who
eat the shellfish.

Millions of microscopic plant cells
thrive in nearly every drop of coastal
seawater. Algae (phytoplankton) are the
primary energy producers in the ocean,
forming the base of the marine food chain.
In the presence of sunlight and a sufficient
bath of nutrients, these single-celled plants
photosynthesize and multiply, creating a
"bloom" that feeds everything from fellow
microbes to great fishes.

Among the thousands of species of

SEEING RED ALONG THE COAST— A massive "red tide" of blooming algae (the dlnoflagellate Noctiluca scintillansj stretched more than
20 miles near LaJolla, California, in the spring of 7 995. Such blooms can have devastating effects on human health, coastal economies, and
marine ecosystems. Algal blooms occur naturally, but they have become more common in recent years, some due to human activities that put
excess nutrients into the water.

34 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

ith abundant nutri
itimal conditions, c
sduce exponentiall
-II can divide into
undred cells within weeks
If enough cells bloom, shellfish can
1 contaminated, poisoning
, and humans who eat them.

2: Warmer temperatures and increased light at certain times of year can stimulate
cysts to germinate. The cysts break open and a swimming cell emerges. Within a few
davs of "hatchina." the cell reoroduces bv simple division.

1:Cysts of Alexandrium lay dormant on the ocean floor, buried in
sediment. Left undisturbed, they can stay in this state for years. When
oxygen is present and conditions are right, germination may begin.

4 and S: When the nutrients are gone,
growth stops and gametes are formed.
Two gametes join to form one cell,
evelops into a zygote and
cyst. The dormant cyst falls to
: ocean bottom for germination
in subsequent years.

1

LIFE CYCLE OF A HARMFUL ALGA— Certain species of toxic algae— in this case, Alexandrium— have evolved a cyst stage in their life cycle that
promotes wide dispersal through the coastal ocean and long-term survival through difficult environmental circumstances.

algae in the sea, a few dozen produce tox-
ins and pose a formidable natural hazard.
Sometimes they reproduce prolifically,
discolor the water, and foul beaches with
foam from their prodigious population
explosions. Other times these harm-
ful algae are dilute and invisible, nearly
inconspicuous if not tor the destruction
they cause. A bloom ot harmful algae can
completely and permanently alter the
structure of a food chain, causing massive
die-offs of shellfish, marine mammals,
fish, seabirds, and other animals that con-
sume them. They can sicken, disable, or
kill humans.

Researchers estimate that blooms of
harmful algae cost the United States at
least $50 million per year. The economic
damage arises from:

• the death of wild and farmed fish,
shellfish, submerged aquatic vegeta-
tion, and coral reefs

• short- and long-term closure of har-
vestable shellfish and fish stocks

• reductions in seafood sales, including
the avoidance of "safe" seafood due to
over-reaction to health advisories

• the costs of conducting monitoring

programs to detect and quarantine
toxic shellfish and other affected
resources

• impacts on tourism and related
businesses

• medical treatment of exposed
populations.

Harmful algal blooms are natural and
they are not new. But ocean scientists are
growing concerned that they are now all
too common. The unprecedented growth
of human activities in coastal water-
sheds— including agriculture, aquaculture,
industry, housing, and recreation — has
drastically increased the amount of fertil-
izer flowing into coastal waters and fueled
unwanted algal growth.

A growing plague

And Moses. ..lifted up the rod, and smote
the waters that were in the river, in the sight
of Pharaoh, and in the sight of the servants;
and all the waters that were in the river
turned to blood. And the fish that were in
the river died; and the river stank, and the
Egyptians could not drink of the water of
the river; and there was blood throughout
the land of Egypt. — Exodus 7:20-21

Red tides have been known through-
out recorded history, but the nature of the
global problem in estuaries and coastal
waters has changed considerably over the
last several decades, both in extent and in
public perception.

Virtually every coastal country is
threatened by multiple harmful or toxic
algal species. Bloom events can cover
areas as small as a coastal pond or as large
as one million football fields (more than
1,000 square miles).

These blooms of algae are popularly
known as "red tides," since the tiny plants
can sometimes increase in such abun-
dance that they change the color of the
water with their pigments. The term is
misleading because non-toxic species also
can bloom and discolor the water, and
other species are incredibly toxic even
when concentrations are low and the wa-
ter seems clear. Given the confusion sur-
rounding the meaning of "red tide," the
scientific community prefers the term
harmful algal bloom, or HAB.

One cause for the increasing frequency
of HAB events seems to be nutrient enrich-
ment—that is, too much "food" for the

Woods Hole Oceanographic Institution 35

algae. Just as the application ot fertilizer to
lawns can enhance grass growth, marine
algae grow in response to nutrient inputs
from domestic, agricultural, and industrial
runoff. Nutrient enrichment leads to exces-
sive production of organic matter (includ-
ing HABs) and a reduction in the amount
ot lite-giving oxygen dissolved in the water,
a process known as eutrophication.

Life cycle of a bloom

Fall 1 972 — Over Labor Day week-
end, Tropical Storm Carrie blows into
New England and becomes a Nor'easter,
battering the coast with heavy winds and
rain. Unbeknownst to scientists, cells of
Alexandrium fundyense (algae native to
the Bay of Fundy) are washed south and
west by currents stirred by the storm. Sev-
eral weeks after Carrie, a massive bloom of
shellfish-poisoning algae blankets the wa-
ters of New England. Before 1972, toxins
associated with A. fundyense had not been
recorded in western New England waters;
since then, that species has bloomed nearly
every year.

Algae usually reproduce by asexual
fission: One cell grows and then divides

into two cells, then two into four, four into
eight, and so on. When growth is un-
checked by environmental conditions —
such as grazing by animals or a shortage ot
nutrients or light — harmful algae popula-
tions can accumulate to visually spectacu-
lar but catastrophic levels.

For some species, a decline in avail-
able nutrients provokes a switch to sexual
reproduction and a new life stage. When
they sense that their boom times are com-
ing to an end, the algae form thick-walled,
dormant cells called cysts that settle to
bottom sediments. These cysts can survive
for years, allowing a species to withstand
nutrient starvation, extreme winter tem-
peratures, or even ingestion by animals.
When favorable conditions resume, the
cysts rupture, germinate, and populate the
water column with a new generation of
photosynthetically active cells primed for
another bloom.

The cyst stage represents an effective
strategy for survival and dispersal. With
every switch into the cyst stage, a bloom
can be carried into new waters by ocean
currents, fish, or even humans (via ballast
water discharge) and then deposited as a
"seed" population that colonizes a new area.

Quiet killers

November 1987 — Over a five-week
span, 19 humpback whales die in Cape
Cod Bay, Mass., a die-off equivalent to 50
years of natural mortality. Unlike strand-
ing events, where seemingly healthy whales
swim into shallow water and beach them-
selves, these humpbacks were dying at sea
and washing ashore. Post-mortem exami-
nations showed that the whales had been
healthy immediately prior to their deaths;
no lesions or infectious pathogens were de-
tected; and many whales had fish in their
stomachs as evidence of recent feeding.
Alarmed and saddened by the mysterious
deaths, the public and the press speculated
that they were caused by pollution. Scien-
tists later discovered that the whales had
consumed mackerel with an abundance of
algal toxins stored in their flesh.

Algal blooms can have an impact even
if whales, wild fish, seabirds, and other
animals do not consume the microscopic
cells. Some algae release their toxins and
other compounds into the water, killing
creatures through direct exposure. Carniv-
orous fishes and mammals sometimes die
from the cumulative effects of consum-

A COASTAL PLAGUE — Left: A dead humpback whale washed up on the shores of Cape Cod, Mass., as a result of a harmful algal bloom in November
/ 987. Nineteen seemingly healthy whales died after consuming mackerel laced with an algal toxin. Right: Japanese fish farmers inspect their ruined
crop ofyellowtail following a devastating red tide in the 1 980s.

36 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

ing smaller fish or zooplankton
containing toxins.

Other HABs kill without
toxins. The species Chactoc-
eros has been associated with
the deaths of farmed salmon,
yet these tiny plants do not
produce a toxin at all. Instead
they have long, barbed spines
that lodge in fish gills, causing a
buildup of mucus, degeneration
of the respiratory system, and
eventual death by suffocation.

Some blooms deplete the
resources needed by marine
creatures. For instance, when
a massive bloom begins to de-
cay, the dying and decompos-
ing algae consume the available
oxygen, suffocating other plants
and animals or forcing them to
migrate. Prolonged blooms of
non-toxic algae also can reduce
light penetration to the bot-
tom, decreasing the density of
aquatic vegetation and grass
beds that serve as nurseries for
commercially important fish
and shellfish. (See "Red Tides
and Dead Zones," page 43)

Blooms of macroalgae (sea-
weeds) have also increased
along the world's coastlines,
and they often last longer than
typical phytoplankton blooms.
Once established, macroalgae
can dominate an ecosystem for
years and are particularly harmful to coral
reefs. Under the right conditions, oppor-
tunistic seaweeds outcompete, overgrow,
and replace the coral.

These chronic impacts can affect the
structure and function of entire ecosys-
tems. The mass die-off of adult fish not
only depletes the current population, it
prevents breeding-age fishes from repro-
ducing. Larvae or juvenile fish can be
stunted or killed, preventing the next gen-
eration from reaching maturity.

Such ecosystem degradation likely has
long-term consequences for the sustain-

O Neurotoxic shellfish poisoning
O Paralytic shellfish poisoning
O Ciguatera
O Brown Tide

Pfiesteria Complex
O Farmed Fish Kills
O Amnesic shellfish poisoning

Reports of harmful algal blooms in U.S. waters and around the world
have drastically increased in the past three decades. Researchers
attribute the increase partly to excessive nutrient pollution of the water
and partly to better detection of HABs by coastal monitoring programs.

ability or recovery of populations of ani-
mals further up the food chain. A popula-
tion of marine mammals might not grow
or reproduce because their main food
source has been depleted by HABs. Many
researchers now believe that such ecosys-
tem-level effects from HABs are more per-
vasive than we realize.

Watch what you eat

February to April 1 998— In Hong
Kong, where one-third ofallfinfish con-
sumed conies from fish farms, a devastat-
ing HAB wipes out half of the country's

annual aquaciilture fish stocks.
More than 1,500 tons offish are
killed by a neurotoxin-produc-
ing alga called Karenia digita-
tum. Direct losses are estimated
to be HKS250 million ($32
million U.S.). Other fish prices
plummet as consumers avoid
seafood altogether. A govern-
ment official calls it the "worst
natural disaster" ever to hit
Hong Kong.

Harmful algal blooms can
take a variety of forms, each
with a distinct and disturbing
impact on human health.
• Shellfish poisoning-
Most shellfish filter seawa-
ter for food. As they eat, they
sometimes consume toxic
\ phytoplankton and the algal
-: toxins accumulate in their
" flesh. The level of toxins can
; reach a threshold where they
:: become dangerous — sometimes

lethal— to humans and other
I animals, though not to the
± shellfish themselves. Shellfish
: poisoning syndromes can cause
I gastrointestinal and neuro-
- logical problems, from nausea,
vomiting, and incapacitating
diarrhea to dizziness, disorien-
tation, amnesia and permanent
memory loss, and paralysis.
Some syndromes are lethal.
. Ciguatera fish poisoning —
Species of the genus Gambierdiscus liv-
ing in tropical waters (particularly coral
reef communities) are known to produce
a fat-soluble toxin that causes diarrhea,
vomiting, and abdominal pain, followed
by muscular aches, dizziness, anxiety,
sweating, and tingling sensations. Cigua-
toxin-producing algae live attached to
seaweeds, and they are first consumed
by plant-eating reef fishes. Those fish
are in turn eaten by larger carnivorous,
commercially valuable finfish. The toxin,
being fat soluble, is transferred and mag-

Woods Hole Oceanographic Institution 37

MYSTERIOUS BLACK WATER — In the winter of 2002, satellites and sailors observed waters in Florida Bay turning the color of black ink. Researchers
speculated that the "black water" was a bloom of algae, though there were none of the typical signs of toxins or oxygen depletion and no
observed die-off s of marine life, fishermen noted that they found few fish within the region.

nified through the food chain, much as
occurs with pollutants such as DDT and
PCBs. That means the most dangerous
fish to eat are the largest, oldest, and most
desirable. Ciguatera is responsible tor
more human illnesses— 10,000 to 50,000
cases annually — than any other kind of
toxicity originating in fresh seafood.

• Possible Estuary-Associated Syn-
drome— This vague term reflects the poor
state of knowledge of the human health
effects of the alga Pfiesteria piscicida and
related organisms. Human exposure to
these algae in estuaries has been linked to
deficiencies in learning and memory, skin
lesions, eye irritation, and acute respira-
tory distress. In 1997, a bloom of Pfiesteria
caused massive fish die-otfs on Maryland's
eastern shore, leading consumers to avoid
all seafood from the region despite assur-
ances that no toxins had been detected in
seafood products. That single event cost at

least $50 million in lost seafood sales and
lost recreational boat charters.

Increasing awareness

January and February 2002 — Seafar-
ers and satellites notice something amiss in
the Gulf of Mexico. The seas north and west
of the Florida Keys have grown dark, with
nearly 700 square miles of water (two-thirds
the size of Rhode Island) taking on the color
of black ink. Tests show this "black water"
has normal salinity and oxygen levels, but
researchers suspect an unusual, non-toxic al-
gae bloom. There are none of the usual signs
of a HAB, but fishermen note that the black
water seems to be devoid offish.

Researchers call the recent expan-
sion of HABs an "apparent" trend because
for many locations, poor historic data
are available. It is not clear whether the
increase in HAB reports reflects height-

ened scientific awareness of coastal waters
and scrutiny ot seafood quality, or a real
increase in the number, severity, or fre-
quency ot outbreaks due to pollution and
global change.

Researchers suspect that many "new"
bloom species are simply "hidden flora"
that had existed in those waters for many
years. Such species had not been detected
or recognized as harmful until scientists
developed more sensitive toxin detection
methods and trained more observers, or
until aquaculturists placed shellfish or fish
resources in areas where toxic species had
been lurking.

That part of the expansion may be a
result of increased awareness should not
negate our concern, nor should it alter the
manner in which we mobilize resources to
attack it. The fact that harmful algal blooms
are at least partly due to human activities
makes our concerns even more urgent.

-

D:

onald M. Anderson (reviewing data with Research Associate Deana Erdner) earned a bachelors de-
gree in mechanical engineering and a doctoral degree in aquatic sciences from the Civil Engineering
; Department of the Massachusetts Institute of Technology. He accepted a postdoctoral position at WHOI
'. in 1978 and joined the staff as an Assistant Scientist in 1979. Anderson became interested in red tides and
t HABs as an MIT graduate student when a massive red tide devastated the New England coast. His work
2 investigating chemical factors regulating Alexandrium blooms led to discoveries of a cyst stage and other
| biological processes that became his research focus. Since then, his research program has expanded and
| now ranges from molecular and cellular studies of toxin genetics to large-scale studies ot the oceanography
1 and ecology of algal blooms. He is actively involved in the organization and implementation of national and
| international programs for research and training on HABs. He serves as director of the U.S. National Office
£ for Marine Biotoxins and Harmful Algal Blooms (based at WHOI). The National Oceanic and Atmospheric
Administration named him an "Environmental Hero" in 1999. He does eat shellfish and other seafood, both at home and abroad, but is careful to learn
whether the product is from approved waters. As a rule, he does not eat large, tropical reef fish. Don is an accomplished goiter, and is currently the Massa-
chusetts Senior Amateur Champion.

38 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

A Fatal Attraction for Harmful Algae

Clay sticks to algae and sinks, offering a potential solution to an expensive and deadly problem

By Mario R. Sengco, Postdoctoral Investigator

Biology Department

Woods Hole Oceanographic Institution

A Korean scientist once told me a folk
tale about an ancient emperor who
ordered servants to rid his garden ponds
ot an algal scum that killed his fish and
blemished his kingdom. One percep-
tive servant noticed that whenever rain

washed dirt, sand, and other sediments
into the ponds, the water cleared and
the fish appeared healthier. As a test, he
sprinkled various sediments into the wa-
ter, discovering that clay was particularly
effective. The algae disappeared, and the
emperor was happy.

The story otters insight into how
people in Asia may have discovered that

they could use clay to rid their waters of
"red tide" and "brown tide." Exactly how it
works is a more recent discovery.

Through laboratory and field experi-
ments, we now know that moistened clay
weighs down algal cells, causing them
to sink. On the seafloor, the fallen clay
crushes many ot these microscopic plants.
Lack ot sunlight kills the rest.

CLEANING UP WITH CLAY— Scientist Mike Henry of the Mote Marine Laboratory sprays clay slurries into Florida's Sarasota Bay while WHOI
Postdoctoral Investigator Mario Sengco and colleagues in the other boat track the dispersal of the plume with water sampling devices. The
researchers are investigating the use of natural clays as a potential tool to mitigate harmful algal blooms, or "red tides."

Woods Hole Oceanographic Institution 39

LITTLE PLANT, BIG PROBLEM— Harmful algal blooms are caused by species of tiny plants-
phytoplankton — that produce potent chemical toxins. Fueled by periodic abundances
of nutrients in the ocean, these algae multiply and proliferate until they can cover tens to
hundreds of miles of coastal ocean.

The results of this treatment can be
striking. After spraying clay in Japan's In-
land Sea during the late 1980s, researchers
noted that blooms of harmful algae quick-
ly declined, water clarity improved, and
populations ot yellowtail and opaleye fish
recovered. After South Koreans began clay
treatments in 1996, fishery losses fell from
$100 million to $1 million per year.

In the United States, clay treatment is
not yet permitted as a control strategy for
algal blooms because there are questions
about the ecological consequences of this
sort ot remediation. But as more and more
coastal communities struggle with con-
taminated fish, undermined economies,
and public health risks, interest in a solu-
tion has soared. Biologists at Woods Hole
Oceanographic Institution are part of a
team examining clay therapies that could
someday be used to mitigate and control
harmful algal blooms.

A centuries-old problem

Popularly known as "red tides" or
"brown tides" because of how they dis-
color the water, harmful algal blooms
are a natural phenomenon that has been

recorded since the book ot Exodus. They
are caused by species of tiny, plant-like
cells — phytoplankton— that produce po-
tent chemical toxins. Fueled by periodic
abundances of nutrients in the ocean,
these algae proliferate until they cover tens
to hundreds ot miles of coastal ocean.
(See "The Growing Problem of Harmful
Algae," page 34.)

These blooms occur worldwide and

have particularly affected fisheries in
Scandinavia and Asia, reef inhabitants
in the Caribbean and South Pacific, and
shelltisheries along U.S. coasts. For ex-
ample, harmful algal blooms caused by
the species Karenia brevis along the Gulf
Coast of Florida have caused extensive
fish kills and contaminated shellfish. In
humans, the toxins of this tiny plant can
trigger coughing, itchy skin, and respira-
tory problems.

Given all the trouble linked to these
toxic plants, it would seem that people
would welcome any technique to stem the
tide ot algae. But opponents of clay treat-
ment argue that clay threatens bottom -
dwelling creatures such as clams and mus-
sels, clogging their filters used tor feeding.
They also say that clay compromises water
quality and too greatly interferes with a
naturally occurring process. Proponents
counter that the cost is small compared to
the devastating impact of algal blooms on
fish and the livelihoods of fishermen.

Chemicals, skimmers, and clams

In the 1950s, Florida waters became an
early U.S. test bed for remedies to curtail
harmful algae. Crop-dusting planes head-
ed offshore, spraying copper sulfate over
vast expanses of sea. It proved an expen-
sive and temporary fix, knocking out the
algae tor just a few days while devastating

ON GUARD AGAINST ALGAE — In South Korea, fish farmers spread clay to ward off harmful
algae that could devastate the crop in their pens. The results can be striking. After South
Koreans began clay treatments, fishery losses fell from $ 100 million to $ 1 million per year.

40 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

the fish and shellfish population.

Coastal managers, scientists, and en-
gineers have tried other strategies, with
mixed success. Some have tried water fil-
ters, pumps, and surface skimmers, only to
find that they clogged or suffered mechan-
ical breakdowns. More recently, research-
ers tested algae-eating clams and mus-
sels— even parasites. There are high-tech
proposals to use ultrasonic waves or ozone
gas bubbles to cause the algae to burst.

Amidst the innovation, clay appeals as
a low-cost, pragmatic solution. It has been
the focus of my research for seven years.

A magnetic attraction

Algae stick to clay particles just as a
magnet clings to a refrigerator — through
the bonding of positive and negative
charges on their surfaces. When clay is
sprayed onto the surface of waters con-
taminated with harmful algae, the algal
cells attach to the clay, become burdened
with its heavy load, and fall to the sea-
floor. On the way down, the algae-clay
particles collide with and gather more al-
gae, forming masses of fluffy debris called
"marine snow."

I started my graduate studies by work-
ing with colleagues to identify the best clay
for making this algal snow. Not all clay is
suited, as some allow algae to pass right
through the falling particles without stick-
ing. We tested about 100 types of clay.

My colleagues and I found the most ef-
fective clays had a very fine grain and were
rich with the mineral montmorillonite. We
identified about a dozen pure clays and a
few clay-rich sediments that fit this profile.
In experiments with Karenia brevis, the
toxic algae common off Florida, we found
that our clays removed up to 90 percent ot
the algae. We had similar successes with
affected waters from Washington, Texas,
and New York.

Impacts on the seafloor

The use of clay may be effective for
clearing surface waters, but how does all
this falling debris affect the organisms on
the bottom? Clams, mussels, and other

emoving harmful algal blooms wit

Clay particl
accumulate!...
larger particles

Algae attach
to clay particles

Algae and clay
accumulate into
clumps and sink

Algal cells die from
crushing weight and lack
of sunlight

benthic creatures typically survive on the
seafloor by filtering food from overlying
water. So before we decide clay is the an-
swer to our algae problems, we need to
see how these bottom-dwellers react to
clay exposure.

In a series of experiments with col-
leagues from Canada's Institute for Marine
Biosciences and from Dalhousie Univer-
sity in Nova Scotia, we found that it we
sprayed water with small amounts of clay
and allowed it to settle, the clams neither
died nor differed in their growth com-
pared to untreated clams.

But when we added clay to areas where
currents kept clay particles suspended in
the water column for longer periods (in
our test case, more than two weeks), shell
and tissue growth in clams slowed by as

much as 90 percent. This suggested that
it was important to avoid clay application
in places where particles take a long time
to settle.

In another experiment at the Environ-
mental Protection Agency's laboratory in
Gulf Breeze, Fla., colleagues compared the
harm caused by clay and toxic algae on
grass shrimp, sheepshead minnows, and
two burrowing crustaceans. In both 4-day-
and 28-day experiments, clay alone was
not lethal. But when combined, the mix-
ture of clay and toxic algae proved deadly.

Since clay treatment may not be more
harmful to bottom-dwelling organisms
than an untreated bloom, clay could be
useful to prevent the impacts of algae near
the surface of the water, where many im-
pacts on public health and fish occur.

Woods Hole Oceanographic Institution 41

TEXAS TWO-STEP — In an experiment in Corpus Christi, Texas, WHOI scientist Mario Sengco
pumped algae-rich water into tanks and treated them with clay. Within hours, the sinking clay
removed more than 70 percent of the algae.

Taking clay to the real world

In the past tew years, we have started
testing our results in the field, taking
clays and instruments to the sites of a
brown-tide event (caused byAureococ-
cus anophagefferens) near Long Island,
N.Y., Karenia brevis red tides in Florida
and Texas, and a fish-killing Heterosigma
akashiwo outbreak in Washington's Puget
Sound. In most cases, we pumped algae-
rich waters from coastal environments
into tanks and treated them with clay;
sometimes we captured a parcel of water
in a natural enclosure where it could then
be treated and studied. Each time, we
removed more than 70 percent of algae
within hours of treatment.

Each success leads us to try experi-
ments on ever-larger scales and under
more realistic conditions.

In 2003, we released 130 kilograms
(287 pounds) of clay in a cove in Sara-
sota Bay. We tracked its movement from
the surface to the seafloor to see how
currents, tides, and other environmental
factors would influence the movement,
settling rate, and eventual distribution of

clay in the sediment.

We found that much of the clay sank
within 10 to 30 minutes of dispersal; with-
in an hour, the water column had returned
to its pre-treatment clarity. The distribu-
tion of clay within our study area appeared
to have been determined by the direction
and speed of the currents near the bottom,
which we measured using current meters
and other ocean instruments.

Based on this work, we are confident
that we should be able to track a plume
in unsheltered waters. Recently we se-
cured permits and permission to try our
techniques in the open waters of Sara-
sota Bay. We are curious to see what hap-
pens in a less controlled environment,
where the clay and algae will be stirred
by the ocean's natural ebbs, flows, cur-
rents, and turbulence.

An unexpected cleaner

People accustomed to scouring clay
from baseball uniforms, tennis whites, or
pottery scrubs are a little surprised when
I tell them I am using clay to clear toxic
algae from coastal waters. Then I remind
them how we already use clay as a clean-
ing tool. A blob ot clay rubbed on the edge
of books lifts dirt away. At spas, people
pay to have clay smeared on their faces to
remove oils. Environmental cleanup crews
use clay to absorb oil from spills.

Given the economic and environmen-
tal costs of other potential remedies for
toxic algae, we have to continue to ask:
Why not clay?

For a young Filipino boy curious about the sea, Manila's outdoor
market full of fresh seafood provided an ideal laboratory. After
=: school and on weekends, Mario Sengco visited the market to exam-
f ine the silvery bodies of fish and to prod their gills "just to see how
i they worked." After moving to New Jersey at age 14, Sengco eventu-
j §• ally took his interest in ocean life to Long Island University, where he
= studied marine biology. During his sophomore year, he attended a
g lecture on red tides by WHOI biologist Don Anderson, who in 1996
1 became Sengco's graduate advisor in the MIT/WHOI Joint Program in
^ Oceanography and Oceanographic Engineering. In 2002, he received
\ the first Panteleyev Award, presented to a graduating student who ex-
I £ emplifies a commitment to improving student lite and the educational
experience at WHOI. "I did it through song," he jokes. A tenor, Sengco coordinated several a cap-
pella groups on Cape Cod and appeared in musicals at MIT. He is now a postdoctoral investigator
in the WHOI Biology Department.

^^^^^•^^^•^•••••••^^^M

42 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

Red Tides and Dead Zones

The coastal ocean is suffering from an overload of nutrients

By Andrew R. Solow, Senior Scientist and
Director, Marine Policy Center
Woods Hole Oceanographic Institution

The most widespread, chronic envi-
ronmental problem in the coastal
ocean is caused by an excess of chemi-
cal nutrients. Over the past century, a
wide range of human activities — the
intensification of agriculture, waste dis-
posal, coastal development, and fossil
fuel use — has substantially increased the
discharge of nitrogen, phosphorus, and
other nutrients into the environment.
These nutrients are moved by streams,
rivers, groundwater, sewage outfalls, and
the atmosphere toward the sea.

Once they reach the ocean, nutrients
stimulate the growth of tiny marine plants
called phytoplankton or algae. When the
concentration of nutrients is too high, this
growth becomes excessive, leading to a
condition called eutrophication.

There is a clear connection between eu-
trophication and two significant environ-
mental problems: harmful algal blooms
(HABs) and the depletion of oxygen dis-
solved in bottom waters (hypoxia). The ef-
fects of both HABs and oxygen depletion
are felt throughout the coastal ecosystem,
with direct and indirect effects on human
health, food supplies, and recreation.

For scientists seeking to understand it,
eutrophication is a challenge because the
physical and biological processes linking
nutrients and their impacts are complex.
For policymakers seeking to manage these
impacts, the challenge is weighing the eco-
nomic benefits of the activities that gener-
ate nutrients with the environmental costs
of eutrophication.

Too much of a good thing

In the ocean, as on the land, photo-
synthesis combines energy from the Sun
with carbon dioxide and nutrients such
as nitrogen and phosphorus to produce
carbon-rich plant material. This natural

process is called primary production and
forms the base of the marine food chain.
It also provides most of the oxygen in the
atmosphere. Without primary production,
the world would be a much ditterent (and
a good deal less pleasant) place.

RIVER PLUMES ON THE GULF COAST— On Nov. 7, 2004, a satellite captured the outflow of river
sediments and dissolved nutrients into the Gulf of Mexico, as well as the abundance of algae
and phytoplankton in the water. Dark green or black patches near the shore indicate blooms of
marine plants. White spots are clouds. Each summer, a stagnant, oxygen-depleted "dead zone"
forms in the middle of the Gulf, likely caused by a surplus of nutrients from inland sources.

Woods Hole Oceanographic Institution 43

But every silver lining has a cloud. Of
the thousands of species of algae, perhaps
only a hundred are toxic. When these spe-
cies occur in high concentrations, they can
color the water and produce what are pop-
ularly referred to as "red tides" or "brown
tides." Scientists prefer to call these out-
breaks harmful algal blooms or HABs.
(See "The Growing Problem of Harmful
Algae," page 34.)

Toxic algae enter the marine food chain
when they are consumed by small marine
animals called zooplankton and by tish or
shellfish. The toxins that accumulate in
these consumers are then passed up the
food chain to marine mammals, seabirds,
and even humans, where they can cause
illness or even death.

Blooms of some non-toxic species ot
algae can also cause problems. For ex-
ample, the North Atlantic right whale is in
grave risk of extinction. This species feeds
seasonally off Cape Cod on concentrated
patches of zooplankton called copepods.
In some years, an algal species
called Phaeocystis blooms in Cape
Cod Bay. Although Phaeocystis
is not toxic, large blooms essen-
tially clog surface waters and right
whales cannot find the copepod
patches they need to eat.

Non-toxic HABs include large
blooms ot seaweed or macroalgae
that can coat beaches, interfering
with recreational activities. Other
HABs clog seagrass beds and
coral reefs, which provide nurser-
ies for commercially important
fish and support high levels of
biological diversity necessary for
a healthy environment

Harmful algal blooms occur in
every part of the world. In the U.S.
and other developed countries,
monitoring efforts and fishery
closures have reduced the inci-
dence ot human illness caused by
toxic algae. However, both moni-
toring and closures have econom-
ic costs that can be substantial.
Perhaps the most striking example

of this is the complete loss ot the wild
shellfish resource in Alaska— which once
produced 5 million pounds annually — to
persistent paralytic shellfish poisoning.

It is difficult to assess the precise way
in which human activities influence the
occurrence and severity of HABs. The
physical and biological processes involved
are not well understood, and long-term
observations are sorely lacking. To com-
plicate matters, HABs can and do occur in
relatively pristine conditions. But there is
a clear connection between nutrient lev-
els and primary production, and there is
general agreement among scientists that,
other factors being equal, the conditions
that tavor high levels of primary produc-
tion also tavor HABs.

Is it getting stuffy in here?

Phytoplankton can cause problems
even when they are dead. After they die,
phytoplankton sink to the bottom where
they decay through bacterial action. The

Overabundance of nutrients can cause certain marine plants to
grow like weeds, choking off food sources for fish and shellfish,
or literally asphyxiating the creatures from lack of oxygen.

bacteria that cause decay use oxygen dis-
solved in bottom waters. As long as the
bottom waters are well mixed with oxy-
gen-rich surface waters, the oxygen is
renewed. However, under certain condi-
tions, ocean waters become stratified so
that there is little vertical mixing, and de-
pleted oxygen is not replaced.

Stratification tends to occur in the
summer because the configuration of
warm surface waters over colder bottom
waters is stable. Stratification also tends
to be stronger near the mouths of riv-
ers where the lighter fresh water overlays
denser salt water in a stable configuration.
(See "Where the Rivers Meet the Sea,"
page 22.) Finally, stratification is strong in
enclosed and semi-enclosed parts of the
ocean— such as bays and lagoons— that
are cut off from the large-scale circulation
patterns that promote mixing.

When vertical mixing is weak or ab-
sent, oxygen -depleted bottom waters
are not refreshed, resulting in a condi-
tion called hypoxia. Hypoxic ar-
eas— popularly known as "dead
zones"— can have a dramatic ef-
fect on marine life. In some cases,
oxygen depletion occurs so quick-
ly that it cuts off escape routes and
results in fish kills.

Even when animals simply
avoid low-oxygen areas, as they
usually do, the indirect effects of
hypoxia can be substantial. Suit-
able habitat is lost, putting pres-
sure on populations. Hypoxic
zones also can interfere with the
migratory behavior of shrimp,
lobsters, and other species. More
generally, by altering the environ-
ment in which marine species
thrive, hypoxia can lead to a de-
cline in biological diversity.

A widespread problem

Hypoxia occurs throughout
the world. Two of the best-known
hypoxic areas are in the Black Sea
and the Baltic Sea. In the U.S.,
dead zones occur regularly in

44 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

Long Island Sound, the Chesapeake Bay,
and the northern Gulf of Mexico. In the
Baltic Sea, hypoxia has contributed to the
collapse of the Norwegian lobster fishery.
There is evidence that the hypoxia off the
coast of Louisiana has harmed the valuable
shrimp fishery and possibly contributed
to the replacement of bottom-dwelling
species such as snapper with less valuable
mid-water species such as menhaden.

Hypoxia can occur naturally. For ex-
ample, the bottom waters of the Black Sea
have been depleted of oxygen for thou-
sands of years. Hypoxia has also occurred
naturally in the Chesapeake and the Gult
of Mexico. But there is little doubt that,
by increasing the level of nutrients in the
ocean, human activities have increased the
frequency, extent, and severity in these
areas and throughout the coastal ocean.

Decisions we can live with

Determining the appropriate public
policy response to eutrophication is dif-
ficult. Because so many economic activities
contribute nutrients to the marine envi-
ronment, nutrient regulations potentially
touch a large part of the economy. Also,
the effects of eutrophication are compli-
cated and difficult to measure, especially in
economic terms. Comparing the costs and
benefits of alternative policies is difficult.
While eutrophication is ubiquitous, differ-
ent regions differ in both cause and effect.
For this reason, policy must be customized
to local situations: One size does not fit all.

The good news is that, because so
many human activities produce nutrients,
there are many opportunities to make
small, low-cost changes with a large cu-
mulative impact.

One promising approach to nutri-
ent reduction involves the adoption of
so-called "best management practices" in
agriculture. A major contributor to nutri-
ent pollution is the loss of fertilizer from
agricultural fields. Not only does this ul-
timately lead to eutrophication, but it is
also costly to farmers. By using improved
agricultural methods such as no-till
planting, farmers can put more fertilizer

NEXT STOP, COASTAL WATERS— Pesticides and fertilizers sprayed far from the coast still find their
way to the ocean, running off farmlands into rivers, streams, and groundwater. Minor changes
in agricultural practices could save money for farmers and reduce nutrient pollution in the sea.

in the soil and less in the ocean.

Another area for possible action is
improving the treatment and disposal of
human and animal waste. Although this is
likely to be costly, it has benefits beyond
the reduction of eutrophication.

Finally, policies could also be aimed
at curtailing the conversion— and even
promoting the restoration— of wetlands
and other natural buffers that intercept
and sequester nutrients before they reach
the ocean.

Aquaculture for remediation?

There are some novel ideas as well. A
project is currently underway at Woods
Hole Oceanographic Institution to exam-
ine the feasibility of using shellfish aqua-
culture to reduce nutrients in the coastal
ocean. The experimental shore-based
aquaculture system at the National Center
for Mariculture in Eilat, Israel, uses shell-

fish to absorb excess nutrients excreted
by fish. Researchers at WHOI are trying
to determine whether the same idea is
feasible in the ocean. As the shellfish pro-
duced by such an enterprise have econom-
ic value, this is an example of a win-win
situation. (See "Down on the Farm Raising
Fish," page 66.)

As environmental problems go, coastal
eutrophication is not particularly glamor-
ous. It is difficult to justify costly measures
to eliminate this problem, particularly
in the short term. But low-cost options
do exist and would be a step in the right
direction. Not only would this make eco-
nomic sense today, but it would set us on
a course to lighten the tread of society on
natural systems.

- This article is adapted from "Red
Tides and Dead Zones: Eutrophication in the
Marine Environment," which tint appeared
in U.S. Policy and the Global Environment.

Andrew Solow is Director of the Marine Policy Center and a Senior
Scientist at Woods Hole Oceanographic Institution. He earned a
bachelor's degree in economics from Harvard University and a doctorate
in geostatistics from Stanford University. Solow focuses on environmental
and ecological statistics, with an emphasis on modeling the population
effects of environmental variability. He is a former member of the Com-
mission on Geosciences, Environment, and Resources for the National
Academy of Sciences, and he currently serves as chair of the Environmen-
tal Protection Agency's Outfall Monitoring Science Advisory Panel for
Boston Harbor. Since 2002, he has been a member ot the Science Advisory
Panel for the U.S. Commission on Ocean Policy.

Woods Hole Oceanographic Institution 45

Mixing Oil and Water

Tracking the sources and impacts of oil pollution in the marine environment

By John W. Farrington, Senior Scientist

Vice President and Dean of Academic Programs

and Judith E. McDowell, Senior Scientist

Biology Department

Associate Dean of Academic Programs

Woods Hole Oceanographic Institution

Drop by drop — that is how most oil
enters the oceans. Catastrophic spills
make the headlines, but it is the chronic
dribble, dribble, dribble of seemingly
small inputs that supplies most of the oil
pollution in the worlds oceans.

In recent decades scientists have made
substantial progress in understanding how
oil enters the oceans, what happens to it,
and how it affects marine organisms and
ecosystems. This knowledge has led to
regulations, practices, and decisions that
have helped us reduce sources of pollu-
tion, prevent and respond to spills, clean
up contaminated environments, wisely
dredge harbors, and locate new petroleum
handling facilities.

But tracking the sources, fates, and

effects of oil in the marine environment
remains a challenge for a number of rea-
sons. For starters, oil is a complicated
mixture ot hundreds, sometimes thou-
sands, ot chemicals. Every source of oil,
and even the same general types of oil
(crude oils or fuel oils, for example) can
have distinctive compositions depending
on which oil field or well they came out of
and how they were refined.

This varying, complex mixture of
chemicals gets spilled or seeps into an

Jettisoned fuel: 0.6%

HOW DOES OIL GET INTO THE OCEAN? — About 380 million gallons of oil enter the world's oceans and coastal waterways each year from natural
and human sources. This illustration shows the approximate worldwide percentages arriving from each source; the relative inputs of oil can vary
significantly in different parts of the world. The percentages for transportation include oil lost specifically in oil/petroleum commerce (tankers,
pipelines, etc.), as well as the normal operation of all other sea-going vessels.

46 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

already complex chemical chowder of sea-
water, mud, and marine organisms in the
ocean. There, the oil is stirred by currents,
tides, and waves, altered by other physical
processes, and changed further by chemi-
cal reactions and interactions with organ-
isms in the sea.

In the midst of this dynamic situation,
scientists seek to pinpoint the impacts of
oil on myriad individual species, as well as
on entire ecosystems. Here the challenge
comes tull circle, because we now know
that the impact of oil can vary greatly, de-
pending on its distinctive chemical com-
position. But let's start at the beginning.

How does oil get into the ocean?

Scientists have known since the 1970s
that accidents account for only a small
percentage of the oil entering our waters.
In tact, accidental spills of all types —
from ships, shore facilities, pipelines,
and offshore platforms — contributed just
9.8 percent of the oil entering the marine
environment on an annual, worldwide
basis between 1990 and 1999 (but just
3 to 4 percent in U.S. waters).

That doesn't mean we should dismiss
the importance of spills. Accidents such
as the 1989 Valdez incident off Alaska or
the 2002 Prestige spill off Spain can have
devastating effects on marine life and on
people's ability to use the ocean. The im-
pact of a spill depends on the type of oil,
the amount spilled, the ocean and weather
conditions, and the dynamics of the area
or ecosystem where it takes place.

Progress in prevention — through more
stringent laws, rules, and guidelines, and
increased vigilance by industry and regu-
lators— has reduced accidental spills, at
least in developed countries. For instance,
studies of tanker spills have prompted reg-
ulations for the steady, ongoing replace-
ment of single-hulled tankers in the world
fleet with double-hulled tankers.

But spills are just one small way, albeit
dramatic, for oil to mix with our waters.
So where is the rest of it coming from?

• Seeps: Between one-third and one-
half of the oil in the ocean comes from

A 30-MILE SLICK — Satellite radar images show the extent of the 2002 Prestige oil spill along
the northwest coast of Spain. The slick (black areas) is visible because oil smooths the ocean
surface. Clean water appears bright because it scatters and reflects light back toward the
satellite. Oil can have wildly different impacts depending on the location of the spill and the
weather conditions in the hours and days afterward.

naturally occurring seeps. These are sea-
floor springs where oil and natural gas leak
and rise buoyantly from oil-laden, sub-sea-
floor sediments that have been lifted close
to Earth's surface by natural processes.

If oil is natural to the oceans and if it
is the biggest source of input, what is the
fuss about oil as a pollutant? The answer
lies in the locations and rates of oil inputs.
Oil seeps are generally old, sometimes
ancient, so the marine plants and animals
in these ecosystems have had hundreds to
thousands of years to adjust and acclimate
to exposure to petroleum chemicals. On
the other hand, the production, transpor-
tation, and consumption of oil by humans
often results in the addition of oil to en-
vironments and ecosystems that have not
experienced significant direct inputs and
have not become acclimated.

• Extraction: Accidental and normal
operation of oil drilling and production
platforms puts some oil into the sea, in-
cluding oil mixed into the briny waters
that escape from the oil reservoirs. But this
spillage and waste, and the atmospheric
releases from platform equipment, is one
of the smallest sources of oil in the sea.

• Transportation: In the 1960s and
1970s, scientists studied tar balls col-
lected along major tanker routes and the
beaches downstream. They revealed that
large amounts of oil were entering the
marine environment as a result of ballast
water (bilge) discharges and other aspects
of "normal" tanker operations. As a result
of that research, international conventions
and national laws and regulations have led
oil shippers to minimize their discharges,
particularly in harbors. Today, in spite of

Woods Hole Oceanographic Institution 47

WORSE THAN AN OIL SPILL — The everyday "normal" activities of industrialized society — driving, shipping, heating buildings, operating industrial
machinery — put far more oil and its byproducts into the oceans than all major spills combined. The impact of oil from petroleum-fueled vehicles
might even be understated, since the chronic drip of oil from mi/lions of cars and trucks is extremely hard to measure.

increasing numbers of tankers plying the
seas, the amount of oil spewed has stabi-
lized or decreased in many places.

• Consumption: The everyday use of
oil in cars, trucks, industrial and manu-
facturing plants, and other machinery of
the modern economy is the most egre-
gious and insidious source of oil pollu-
tion. The drippings and emissions from
millions of machines accumulate on land
and eventually run into our waterways.

From the 1950s through the 1970s, one
ot the most common sources was the in-
discriminate disposal of used automobile
crankcase oil down sewer systems. Since
that time, scientific findings have prompt-
ed regulations and public awareness cam-
paigns that promote the recycling and
proper disposal of used oil.

But we still have a problem. Peer un-
derneath your parked car and observe the

drip of oil. This happens day and night for
millions of automobiles, trucks, and buses,
creating a chronic, significant source of
oil to the sea. Rainstorms wash these drip-
pings into streams or storm sewers that
discharge into harbors and rivers. It is ter-
ribly hard to measure these types ot inputs.

Fossil fuel hydrocarbons from engine
exhaust also accumulate in the atmo-
sphere. Sometimes the soot is deposited
into our waters; otherwise it is washed out
of the atmosphere and into the oceans by
rain or snow.

On a smaller scale, new research has
shown that outboard engines of small
boats and pleasure craft are a significant
source of oil pollution — up to 2.2 percent
of all inputs in U.S. waters (worldwide
data are not available). Engine manufac-
turers are responding with new models
of engines that release much less oil and

gasoline, but it may take some time tor
these changes to propagate through the
boating community.

What happens to oil in the ocean?

Oil chemicals entering the ocean have
many fates. Volatile chemicals are lost by
evaporation to the atmosphere. Other
chemicals are broken up by photochemical
reactions (catalyzed by sunlight). Bacteria
can degrade certain oil components.

The combination of biological, physi-
cal, and chemical processes is usually
referred to as weathering. These weather-
ing reactions have different rates depend-
ing on the chemical structure of the oil,
habitat conditions (such as water tempera-
ture or oxygen and nutrient supply), and
mixing of the water by wind, waves, and
currents. In some spills, oil does not last
much beyond weeks to months.

48 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

But when oil pours into shallow
waters with muddy sediments — such as
marshes or lagoons — and conditions al-
low the oil to become mixed into the
mud, it will generally persist for a long
time. This is a result of the fundamental
chemistry ot oil compounds. Since they
don't dissolve in water, oil compounds
tend to adhere to particles in the water or
get incorporated into biological debris,
such as fecal matter or dead organisms.
These oiled particles and debris settle
from the water column and become part
ot the sediments on the bottom.

Once mired in the sediment, some oil
chemicals can persist for years or decades,
depending on the environment. In areas
swept by high-energy currents, the mate-
rial may be dispersed. In areas where sedi-
ments accumulate (such as ship channels
through urban harbors), the contaminated
sediments become an environmental con-
cern— both when simply lying on the bot-
tom and when channels are dredged and
the mud must be disposed.

For some types ot oil inputs and some
ecosystems, we now have enough infor-
mation to model and simulate the fate of
oil in the water. This scientific knowledge
helps policymakers make better decisions
on how to dredge harbors, control pollu-
tion sources, clean up contaminated areas,
and locate petroleum facilities.

How does oil affect marine life?

From experiments and field measure-
ments, we know that certain types and
concentrations of petroleum chemicals can
harm marine lite. Long-term effects of oil
exposure can alter the physiology and ecol-
ogy ot populations ot marine organisms,
especially those found in sensitive habitats.

Biological and physical processes can
reduce the concentration of oil chemicals
in an ecosystem, especially if the source of
pollution is cut off. As concentrations de-
cline and chemical compositions change,
plant and animal communities usually
rebound. But the recovery can range from
months to decades depending on the
chemistry, the conditions, and the organ-

isms and ecosystems affected.

One ot the significant advances in the
1970s and 1980s was the development of
guides to the sensitivity of various types
of coastal ecosystems to oil pollution.
Maps of sensitive ecosystems are now used
during responses to accidental oil spills,
improving the ability of resource manag-
ers and engineers to assess where contain-
ment booms and other prevention and
cleanup measures should be deployed.

There have been few studies, however,
on the cumulative effect of chronic inputs
ot oil to the marine environment, includ-
ing the many sources associated with oil
consumption on land. Assessing these
impacts is complicated because oil runoff
is often accompanied by other polluting
chemicals, making it difficult to tease out
which ones have which deleterious effects.
Limited experiments have taught us that
the interactive ettects among chemicals
can either increase or decrease each chem-
ical's long-term effects, depending on the
organisms and chemicals.

Much of our knowledge about the ef-
fects of oil is still limited. It has focused on
biochemical and physiological effects on a
few individual organisms and on the degra-
dation of a few particular habitats. But we
need a better understanding of the large-
scale effects of oil on entire communities
and populations, rather than individual
organisms. The complexity of how species
interact within ecosystems— such as how
damage to one species can affect the other
species that feed on it— leads to contentious

debate whenever regulators start to weigh
long-term impacts on marine life.

Fuel for further research

A high priority for the future should be
better monitoring and research so we can
better quantify how much oil is really en-
tering our waters, how much of it is com-
ing from each source, and what the effects
may be.

We also need to expand research on oil
pollution in deeper waters. Most concerns
and research have traditionally focused
on coastal waters. Yet new concerns arise
as oil production moves offshore. We can
only speculate on the impact of oil explo-
ration and production in deeper waters
until we have more detailed knowledge of
the biological organisms in these habitats
and the biogeochemical processes that
govern their lives.

Developed countries and emerging
countries consume more oil every year,
and that consumption leads to more and
more inputs of oil to the oceans. We have
learned from our colleagues in developing
countries that increased use of tossil fuels
has not been accompanied by the sort of
stringent regulations developed countries
adopted after years of harsh lessons. Fur-
ther research and education can help those
countries minimize the adverse impacts of
oil inputs on their oceanic ecosystems.
— A recent study by the U.S. National Acad-
emy of Sciences., entitled Oil in the Sea III:
Inputs, Fates and Effects, provided the
foundation for this article.

John Farrington came to WHOI in 1971 as a postdoctoral investigator
in the Chemistry Department following completion ot bachelor's and
master's degrees at Southeastern Massachusetts University and a doc-
torate at the University of Rhode Island. His research interests include
marine organic geochemistry, biogeochemistry of organic chemicals ol
environmental concern, and the interaction between science and policy.
He has served on scientific advisory panels for the National Academy
of Sciences, the National Science Foundation, the Office of Naval Re-
search, and the Commonwealth of Massachusetts.
Tudith McDowell earned her bachelor's degree in biology trom Stone-
J hill College and her master's and doctorate degrees in zoology from
the University of New Hampshire. Judy's research focuses on the ecol-
ogy of marine animals and the ettects of chemical contaminants on the
marine environment. She has served on the Committee on Oil in the
Sea for the National Research Council. She is director of the Woods
Hole Sea Grant Program.

Woods Hole Oceanographic Institution 49

Oil in Our Coastal Back Yard

Spills on WHOI's shores set the stage for advances in mitigating and remediating oil spills

By Christopher M. Reddy, Associate Scientist
Marine Chemistry and Geochemistry Department
Woods Hole Oceanographic Institution

On September 16, 1969, the barge
Florida ran aground oft Cape Cod,
rupturing its hull and spilling 189,000 gal-
lons of No. 2 fuel oil. Winds and waves
pushed the oil onto the beaches and
marshes of West Falmouth, Massachu-
setts, carrying with it dead lobsters, scup,
and cod.

In the weeks and months after the spill,
biologists Howard Sanders and George
Hampson from the nearby Woods Hole

Oceanographic Institution (WHOI) col-
lected samples ot mud and animals from
the marsh sediments, particularly from an
area known as Wild Harbor. They shared
their samples with Max Blumer and Jerry
Sass, WHOI geochemists who knew how
to analyze oil with one of the field's newest
tools, the gas chromatograph.

Together, they made a discovery that
refuted the prevailing wisdom of the day:
Oil lurked in the marsh and sub-tidal sedi-
ments long after it was no longer visible in
the water and on the beaches.

Three decades later, my research group

returned to those marshes. Equipped with
our own state-of-the-art equipment — a
two-dimensional gas chromatograph — we
analyzed new sediment samples and made
our own discovery. Some of the oil from
the Florida spill is still buried in the mud,
and its chemical composition has not
changed dramatically since the mid-1970s.
The Florida oil spill is perhaps the lon-
gest studied in history, and it has funda-
mentally changed our understanding of
what happens to oil in coastal ecosystems.
We are still building on this groundbreak-
ing research, seeking knowledge that

LEARNING FROM DISASTER — Chris Reddy, a marine chemist at Woods Hole Oceanographic Institution, examines and collects oil-covered rocks
at Nyes Neck in West Falmouth, Mass., following the April 2003 spill from the Bouchard 1 20 oil barge. Reddy and colleagues study the impact of
oil and other contaminants on coastal ecosystems, with a particular eye on how the compounds disperse and decay.

50 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

could help mitigate the environmental
impact of future oil spills and the costs of
cleaning them up.

Oil spills are awful for the environ-
ment, but they provide an excellent
opportunity to study how the ocean and
its ecosystems respond to extreme events.
(See "Mixing Oil and Water," page 46.)
Most people see a spill and focus only on
its toxic effects. But my group also sees it
as a huge injection of carbon-based food
for microbes in the coastal environment.
We ask questions like: How long does it
take the oil to decay and be consumed by
microbes? How long will oil persist at a
particular location and why? Do people
need to intervene and assist in cleanups,
or can Mother Nature remediate the eco-
system herself?

A history of spills and research

New England relies heavily on barges
for transporting fuel to its major ports
and cities. For decades, Buzzards Bay has
been a major thruway for oil barges, with
approximately 2.1 billion gallons of oil
traveling through the Cape Cod Canal
each year. With so many barges navigating
these rocky and narrow waterways, spills
due to mechanical or human errors are al-
most inevitable.

In September 1969, the inevitable
happened. When the barge Florida ran
aground, it released the largest amount of
oil spilled in Buzzards Bay history. "The
oil-soaked beaches were littered with dead
or dying fish," wrote Hampson and Sand-
ers in Oceanus at the time. "Fish, crabs,
and other invertebrates covered the shores
of the Wild Harbor River and large masses
ot marine worms, forced from their natu-
ral habitat in the sediments, lay exposed
and decaying in the tidal pools."

Applying the most advanced analyti-
cal techniques of his day, Blumer was able
to study the chemical composition of the
oil from the spill. Oil products such as
No. 2 fuel oil are made up of hundreds
ot individual chemicals that vary in their
characteristics, such as volatility, solubil-
ity, and toxicity. Blumer was able for the

Table 1: Known Oil Spills in Buzzards Bay, MA

Date

Location

Type

Volume (gallons)

Comments

1940s

Western Buzzards Bay, Westport
(at Hen and Chicks)

No. 2 fuel oil

unknown

1963

Near Nyes Neck, North Falmouth

No. 2 fuel oil

unknown

Came ashore during the winter.

9/16/1969

Fassets Point, West Falmouth

No. 2 fuel oil

189,000

Florida fuel barge. Final estimate was
4,500 barrels spilled.

10/9/1974

Cleveland Ledge (near canal
entrance)

No. 2 fuel oil

11,0001037,000
(under review)

Bouchard 65 barge grounded. Towed to
an anchorage off Wings Neck. Oil came
ashore in N. Falmouth and Bourne.

1/28/1977

Cleveland tedge

No. 2 fuel oil

81,144

Bouchard 65 barge grounded, oil on
iced-over bay, some burned. Final
estimate was 1,932 barrels spilled.

6/10/1990

Cleveland tedge

No. 6 fuel oil

7,500

Bermuda Star cruise ship went aground,
impacts to Naushon.

6/18/1990

Cleveland tedge

Diesel or heating oil

100 or 200

Bouchard 145 fuel barge

8/7/1992

Sow and Pigs Reef, Cuttyhunk

No. 6 fuel oil

50

Queen Elizabeth II cruise ship. Residual
from empty fuel tank that was ruptured.

4/27/2003

Press reports: Hen and Chicks
Reef, Westport

No. 6 fuel oil

98,000
(not final)

Bouchard 120 fuel barge

Smaller spills of gasoline and fuel oil have occurred every few years in the bay or in the Cape Cod Canal.

Woods Hole Oceanographic Institution 51

LASTING IMPACT — The Bouchard 65 spill of 1 974 devastated the marsh ofWinsor Cove in West Falmouth, Mass. Though the Spartina (marsh grass)
was not visibly coated with oil after the spill (left), enough chemical compounds settled into the underlying peat and sediments to wipe out the
vegetation for years afterward (right photo, 1977). Thirty years later, WHOI biologist George Hampson still monitors the marsh grasses, which have
not recovered to their pre- 1 974 state. New work reveals that petroleum hydrocarbons still persist in the marsh.

first time to tease out which compounds
had evaporated and decayed and which
remained in Wild Harbor. He saw some ot
the oil's constituent parts, rather than one
uniform chemical.

WHOI salt marsh ecologist John Teal
and graduate student Kathy Burns also
studied Wild Harbor through the mid-
1970s, and Teal and chemist John Far-
rington revisited the old spill in 1989. Each
time, remnants of the 1969 oil persisted.

Several other oil spills have occurred
in Buzzards Bay since the Florida spill (see
page 51 ). In October 1974, thousands of
gallons of No. 2 fuel oil from the barge
Bouchard 65 poured into the bay, with the
greatest impact in Winsor Cove, just two
miles north of Wild Harbor. Building on
their experience, WHOI researchers mea-
sured and chronicled the 1974 spill tor
comparison with the 1969 event, as both in-
volved the same type of fuel and neighbor-
ing but somewhat different shorelines. We
have found that oil at Winsor Cove from the
Bouchard 65 spill also continues to persist.

The amount of oil spilled in each case
has been rather small compared to some
high-profile spills like the Exxon Valdez.
But the convergence of these spills, all oc-
curring within 10 miles of Woods Hole,
has created a unique natural laboratory for
investigations of the short- and long-term
fates of oil in the coastal ocean.

Who does the better cleanup job?

The Oil Pollution Act of 1990 requires
that parties responsible for an oil spill must
attempt to restore the environment to its
pre-spill condition. One popular approach
is "natural attenuation," allowing or pro-
moting natural processes to clean up and
remove contaminants from affected areas.

Environmental scientists presume that,
over time, naturally occurring or artificial-
ly transplanted microbes will eat hydrocar-
bons in the petroleum soup. It is an attrac-
tive, teel-good alternative when compared
with labor-intensive and costly cleanup
schemes, and several studies have shown
that natural attenuation can sometimes be
as effective as human intervention.

In the first days and weeks after a spill,
physical processes churn the oil around in
the water, exposing it to air and sunlight,
causing some compounds to evaporate or
be broken up. Then the "bugs" take over.

Oil spills can deliver a staggering
amount of carbon — that is, food for the
ecosystem — in a short period of time. A
rough calculation from the Florida spill
indicates that 50 to 100 grams of carbon
were added to each square meter of the
impacted area in one day. By comparison,
natural photosynthesis by plants yields
about 300 grams ot carbon per square me-
ter in an entire year.

Petroleum hydrocarbons provide a rich

source of high-caloric food for a variety of
microbes. In many ways, these microbes
match or exceed humans in their chemi-
cal skills, using an incredible toolbox of
enzymes to break down complex petro-
leum compounds. But just how do these
microbes break down the oil? And why
haven't they eaten all of the oil from the
1969 spill?

Back to the future

Answering these questions requires
that we learn a lot more about the chemis-
try and composition of oil and its natural
degradation processes. We started by go-
ing back to the site ot our predecessors'
work in the salt marshes of Wild Harbor
and Winsor Cove.

We collected dozens of sediment cores,
particularly from a site in Wild Harbor
that was named M-l (marsh sample 1} by
previous WHOI scientists. Like Blumer a
generation ago, we brought a powerful sci-
entific tool to bear on the problem. With
colleagues Glenn Frysinger and Richard
Gaines of the U.S. Coast Guard Acad-
emy, we analyzed our sediment samples
using a novel technique called compre-
hensive two-dimensional gas chromatog-
raphy (GCxGC) in order to observe how
the composition of the 30-year old oil had
changed while buried in the marsh. It was
the first time anyone had used GCxGC to

52 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

Seeing the needles in the haystack

The analysis of oil compounds has come a long way in three decades, as changes in analytical equipment and in computer handling
of data have allowed researchers to better delineate the type and proportion of oil compounds present in different samples. The
data below show traditional gas chromatography and the cutting-edge view for oil-covered samples collected at Nyes Neck two
weeks and six months after the Bouchard 120 oil spill.

Traditional gas chromatographs (right)
can delineate some of the chemical
constituents in an oil sample, but cannot
resolve the details, particularly the
proportion of one compound versus
another. Note the hump that chemists
call the "unresolvable complex mixture"
(UCM), compounds with such similar
properties that they merge together
during analysis.

Unresolvable complex mixture

Unresolvable complex mixture

These chemical
compounds were lost to
microbial degradation.

These compounds were lost to
evaporation and water washing.

Modern two-dimensional gas

chromatography can resolve each

different compound in the oil. Many

of the compounds that composed the

UCM are completely separated from

each other, with each peak

representing a different

compound.

These

results

reveal

that several

compounds were

removed by evaporation

and microbial degradation

in the months after the spill, while

others linger.

Woods Hole Oceanographic Institution 53

analyze a real-world oil spill.

With traditional one-dimensional gas
chromatography (GC, as used by Blum-
er's generation of environmental chem-
ists), scientists could identify about 10
percent of the compounds in the oil, a
quantum leap tor the era. But that process
still leaves a haystack ot many compounds
(such as branched alkanes, cycloalkanes,
and aromatics) that cannot be identified.
On a data plot, it looks like a large hump
that we call the unresolvable complex
mixture (UCM). Too many of the com-
pounds have similar properties and when
analyzed with a simple chromatograph,
they merge together, making it impossible
to tell one from another.

With modern GCxGC, we can find
needles in that haystack (see page 53). We
have been able to separate and identify
many more compounds and provide a
more refined inventory ot the petroleum

hydrocarbons that persist in the marsh.
We found that the oil at the M-l site
had not weathered significantly since the
mid-1970s, and most of the compounds
typically found in oil are still present after
three decades. As we peered into the pre-
viously unresolved mass, tor instance, we
found that certain types of alkanes remain,
despite earlier research that suggested they
were completely degraded.

The oil for food program

I doubt many people would have pre-
dicted in 1969 that oil from the Florida
spill would still be present after three de-
cades. The entire marsh continues to be
mildly affected, and there are certain areas
along the shoreline where oil is particularly
concentrated. Why doesn't the oil go away?

Our findings from Wild Harbor and
Winsor Cove suggest that some marsh
sediments might be ideal for preserving

partially weathered petroleum. Evidence
indicates that oil-consuming bacteria
may have stopped eating these hydrocar-
bons more than 25 years ago. Though a
diverse community of microbes exists in
the contaminated regions of Wild Har-
bor, they are not actively consuming the
remaining oil.

We have started numerous experi-
ments to figure out this riddle, and know-
ing what types of chemicals remain can
provide essential clues. The contaminated
sediments may now lack oxygen required
by some microbes to degrade hydrocar-
bons rapidly. Perhaps the environment is
missing a key chemical species — such as
sulfate — that bacteria need to consume
and change the remaining oil compounds.

Perhaps the chemical bonds and struc-
tures of certain oil compounds locked the
microbes out, resisting their chemical at-
tacks. Or maybe the microbes prefer to eat

NOT SO SLICK — At least 98,000 gallons of fuel oil were spilled into the waters west of Cape Cod, Mass., in April 2003 after the barge Bouchard
1 20 (inset) struck an underwater ledge. The accident prompted legislators in Massachusetts to increase fines for oil spills, implement new safety
standards and navigational rules, and impose a two-cent-per-barrel fee to establish a fund for oil spill response and training.

54 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

more readily available food sources such
as plant debris.

A new spill to investigate

On April 27, 2003— just six months
after we published our findings on the
1969 oil residues in Wild Harbor— the
barge Bouchard 120 struck an underwa-
ter ledge while being tugged to a power
plant. At least 98,000 gallons of No. 6 fuel
oil poured into Buzzards Bay, and within
24 hours, helicopter surveys showed a
12-mile oil slick. Viscous, tarry petro-
leum washed up on the beaches of one of
New England's richest tourist and shell-
tishing grounds.

Like our \VHOI predecessors, Research
Associate Bob Nelson and I went to the
beaches to collect samples and observe
firsthand the war between industrialized
society and Mother Nature. We scooped
floating "pancakes" of petroleum, filled
bottles with oily blue water, and collected
tarred cobbles and sediments.

After a year of analyzing samples, we
have been able to determine the original
chemical composition of the Bouchard
120 oil and track how it has changed. Our
early results show that several groups of
compounds were lost to evaporation, wa-
ter washing, and microbial degradation
(see page 53). The degradation of oil, how-
ever, seems to have stalled after the initial
breakup in the first six months. Because
the responsible party removed nearly all of
the oil-impacted rocks at this site, we can
no longer collect samples there.

Treasures in the attic

Coastal oil spills are incredibly de-
structive, with intense short-term conse-
quences and insidious long-term ones. No
one wants to witness an oil spill, but they
happen. And when they do, we need to
take advantage of the opportunity to learn
from them.

WHOI is an extraordinary place to do
that, thanks to three decades of samples
and memories in these labs. As recently as
June 2004, Bruce Tripp, a long-time mem-
ber of the research staff and participant in

TWO GENERATIONS — For 30 years WHOI researchers have chronicled the effects of oil spills on
the west coast of Cape Cod, Mass. Above, from left: George Hampson, Linda Morse Porteous, and
Arnie Carr discuss the effects of the 1 974 Bouchard 65 spill on Winsor Cove. Below, from top: Bob
Nelson and Chris Reddy collect water samples and oil "pancakes" from Buzzards Bay in April 2003.

the earlier oil spill studies, handed me a
dusty jar he had recently found in a store-
room. It was a sample of oil collected by
WHOI scientists in 1974 from the Boucha-
rd 65 spill, which will be invaluable for our
continued work on coastal spills.

The National Science Foundation, the

Petroleum Research Fund, the Environmen-
tal Protection Agency, the Office of Naval
Research, and the WHOI Coastal Ocean In-
stitute provided funding for this research.
— WHOI Science Writer Mike Carlowicz
and Research Associate Robert Nelson
contributed to this article.

Christopher Reddy studies the fate of contaminants in the marine environment. He grew up on
Rhode Island's Narragansett Bay, and has always lived within a few miles of a coast. Chris came
to WHOI in 1997 as a postdoctoral scholar after completing undergraduate work in chemistry at
Rhode Island College and a doctorate in chemical oceanography at the University of Rhode Island.

s/oods Hole Oceanographic Institution 55

Which Way Will the Wind Blow?

Marine scientists have a key role to play in the debate over wind farms in the coastal ocean

By Porter Hoagland, Research Specialist

Marine Policy Center

Woods Hole Oceanographic Institution

Two centuries ago, citizens of the new
American republic relied on the
winds along their shores as an economic
engine. Salt farms and gristmills dotted
the coastline, their windmills tapping the
sea breezes for energy.

Two centuries later, Americans are
looking to tap coastal winds again to fuel
the modern economy, to reduce air pol-
lution, and to mitigate global warming.
Wind energy is the fastest-growing sec-

tor of the global electric power industry,
and several companies have proposed to
build large wind turbines and utility-scale
electric power-generating facilities in the
coastal waters of the United States.

Such facilities could change the way
people use the ocean, and the public is
divided over the costs and benefits. The
environmental and economic benefits of
renewable, nonpolluting sources of energy
are clear. But there may be side effects
from the placement of modern wind farms
in the ocean, including the degradation of
seascapes, impacts on birds and marine

animals, and the disruption of existing
patterns of human use of the ocean. The
laws and regulations related to the place-
ment of wind turbines in the ocean are at
best rudimentary and inchoate; at worst,
they are non-existent.

Marine scientists and engineers can
make an important contribution to this
growing public debate by clarifying our
understanding of the nature of these side
effects. They might also inform public
policies that balance the value of various
ocean resources with the rights and inter-
ests of all who wish to use them.

A NEW FARM CROP — Situated 8 to 12 miles off the west coast of Denmark, the Horns Rev wind farm is the world's largest. The 80 turbines are
spread across 7.7 square miles, with blades stretching 360 feet into the air. Completed in 2003, the project added 160 megawatts (MW) of power-
generating capacity to the country's electrical grid, and it is expected to produce nearly 2 percent of the nation's electric power. European nations
have plans to add nearly 5,000 MW of wind power production in the coming years, and nearly 50 wind farms have been proposed for US. waters.

56 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

•Tisa*0?™/^**

3S&SS$sK$*Q&&Ss

SEEING THE FUTURE IN THE PAST— An engraving from the 1840s shows the coastline of Provincetown, Mass., dotted with wind-powered salt
mills. The artist noted: "The numerous wind or salt mills, and the elevations of sand, give the place a novel appearance."

Major Freeman's legacy

lust after the American Revolution, Ma-
jor Nathaniel Freeman of Harwich, Mas-
sachusetts, suggested using wind energy
to pump seawater into large vats onshore,
where it could evaporate to form salt crys-
tals. As chronicled by historian William
Quinn, salt was crucial tor preserving fish
and furs both for American consumers and
European markets. Spurred by government
incentives and federal tariffs on imports,
1,260 "salt mills" sprouted along the coast
of Cape Cod by the 1830s.

During their heyday, coastal salt works
were so lucrative that they were referred
to as a "lazy man's gold mine." The bottom
fell out of the business in the mid- 19th
century, when it became cheaper to har-
vest salt from the more saline springs of
Virginia, Kentucky, and upstate New York.

At least 39 wind-powered gristmills
were built on Cape Cod in those early years
as well. Operated by "dry-land sailors," the
gristmills provided energy for industry and
incidentally served as important naviga-
tional landmarks. The advent of steam
power meant the end of the gristmills,
though some were relocated to the proper-

ties of affluent landowners who admired
their beauty and sound construction.

Ironically, many coastal property own-
ers now oppose building modern wind-
mills. This opposition is one measure of
how Cape Cod and other coastal areas
have shifted their economic bases from
farming and natural resource exploitation
to tourism and recreation.

Winds of change

In the past decade, worldwide electric-
ity production from wind has grown by
30 percent. Several factors have rejuve-
nated interest in wind power. Technologi-
cal advances in turbine and blade designs
over the past 20 years have reduced the
cost of producing electricity with wind by
as much as 80 percent. At the same time,
governments have responded to the grow-
ing public interest in technologies that re-
duce pollution and mitigate the impact of
global warming caused by carbon dioxide
emissions from the burning of fossil fuels.

Government policies also have encour-
aged this development. At the U.S. federal
level, a tax credit subsidizes the produc-
tion of electricity from wind power at the

rate of 1.6 cents per kilowatt hour (kWh).
Generating facilities powered by wind are
also eligible for accelerated capital depre-
ciation, making it easier to recoup some of
the expenses of building wind farms.

Many states have begun to adopt poli-
cies requiring utility companies to supply
a proportion of power from renewable
sources, including wind, hydropower, and
biomass. In addition, many states have
adopted tax breaks that parallel the federal
subsidies. Some have developed research
and development programs tor renewable
energy, financed by so-called "public ben-
efit charges" on consumer electricity bills.

With subsidies and the economies of
scale that can be achieved with large tur-
bines, wind power can now be produced
in some areas of the United States for as
little as 3 cents per kWh, making it com-
petitive with other energy sources. Land-
based, utility-scale wind turbines now
operate in 26 states. The U.S. accounts for
roughly 16 percent of the world's wind
power generating capacity. Although U.S.
capacity is now nearly 6,400 megawatts
(MW), wind power supplies less than one
percent of current U.S. energy needs.

Woods Hole Oceanographic Institution 57

TALES OF WIND AND WATER— The Judah Baker gristmill (center) and a salt mill (left) stood
near the coast of South Yarmouth, Mass., in 1866 at the height of a boom in "dry-land sailing."
The wind powered nearly 1,300 salt- and gristmills along the shores of Cape Cod in the 7 9th
century. The Baker gristmill has since been moved inland and serves as a tourist attraction.

New proposals on the horizon

Utilities in Europe have been generat-
ing power from ocean wind for more than
a decade, ever since the Vindeby facility
off Denmark became operational in 1991.
Wind farms are being developed off the
coasts of Denmark, Great Britain, Sweden,
and the Netherlands, creating 246 MW
of power generating capacity — including
160 MW at the Horns Rev wind farm that
came online in 2003 along Denmark's west
coast. An additional 5,000 MW of capacity
is planned for northern Europe.

In recent years, proposals have been
floated — some serious and some ridicu-
lous— for as many as 50 wind farms in
the U.S. coastal ocean and Great Lakes.
The ocean attracts wind energy compa-
nies because winds tend to be stronger
and more consistent over open areas,
such as large bodies of water. Also, the
"land" tor placing turbines is cheap be-
cause the ocean is a public resource and
not privately owned.

There is little precedence for mod-

ern wind farming in the United States, so
there are no provisions for renting areas
of the ocean to wind farmers, as there are
for oil and natural gas producers. The lack
of a precedent leads to contradictions. For
instance, is it sensible for the government
to subsidize wind power on one hand
while charging a "land rent" on the other?
There are also serious questions about
which agencies, federal and local, have
the authority to make decisions about
this resource. The existing federal per-
mitting process for regulating offshore
wind farms is loosely based on the Rivers
and Harbors Act of 1899, which gives ju-
risdiction to the U.S. Army Corps of En-
gineers over any "obstructions to naviga-
tion." While navigational issues for ships
are important, the issues surrounding
wind farming go well beyond navigation.
Neither the old law nor the more recently
developed public review process appears
adequate for making decisions about the
use of the ocean for activities such as
wind tarming.

Running aground on the shoals

These vagaries and gaps have spawned
an impassioned debate and a public policy
quandary. Since 2002, the center of that
debate has been Nantucket Shoals, off the
southeast coast of Cape Cod.

Successful small-scale wind power
projects on Cuttyhunk, Nantucket, and
other islands in the 1970s and 1980s in-
spired interest in placing large wind tur-
bines and a utility-scale power facility in
the coastal waters of New England. The
current proposal includes 130 wind tur-
bines—each 400 feet tall— to be located
0.3 to 0.5 miles apart within a 25-square
mile area of Nantucket Sound.

Public opposition to wind farms in
nearshore waters is based mainly on wor-
ries that they will spoil seascapes and
have detrimental effects on birds, marine
animals, and their habitats. Other groups
have expressed concerns about the poten-
tial impact on sailors and important com-
mercial fisheries.

Cape Cod and the islands of Nantucket
and Martha's Vineyard are national tour-
ist havens. Many summer homes have
outstanding views of the nearby sounds,
where the sailing is superb, the stripers
and blues run thick, and fishing for lob-
ster, scallops, and squid has been a popu-
lar livelihood for ages. If the wind farm
is built on Nantucket Shoals, these views,
and quite possibly the established pattern
of ocean activities, could be altered per-
manently. Consequently, many Cape Cod-
ders and Islanders who otherwise support
the idea of renewable energy — just not on
Nantucket Shoals — have become oppo-
nents to the wind farmers.

Need for coastal ocean research

Why not put wind farms tar out in the
ocean, beyond the sight of land, where
winds are even stronger? After all, it wind
farms are developed in more remote sites,
the potential for public opposition should
dwindle significantly and the wind re-
source would grow. (In fact, civil engineer-
ing professor William Heronemus of the
University of Massachusetts suggested in

58 Ocean us Magazine- Vol. 43, No. 1 • 2004 • ocean usmag.whoi.ed

ilH^^IH^H^HIIHH^^^^^^^^^^^^^H^^H

1972 that it was feasible to construct an
array of floating "wind stations" as far off-
shore as Georges Bank.)

As with most environmental problems,
this potential solution entails tradeoffs.
Wind energy developers would prefer to
place wind turbines in shallow, protected
waters that are close to existing electrical
transmission lines. These criteria limit the
number ot good locations tor ocean wind
farms. Business models suggest that deep-
water sites are less profitable, but the true
costs and benefits of building wind farms
in deep water are not yet understood.

Given the uncertainties surrounding
wind energy as a new use of the ocean,
a number of research questions have
emerged. What are the effects ot the ocean
environment on wind turbines placed in
the ocean? What are the effects of wind
turbines on the ecosystem? And what are
the features ot a public policy that could
make the tradeoffs easier to understand,
leading to more rational and balanced de-
cisions about human uses?

Marine scientists and policy experts are
in a good position to help clarify and re-
solve these issues, and research is needed
in several key areas:

U.S. Electric Energy Generation by Source (2003)

Recent advances in the design of wind
turbines, as well as government incentives,
have made the cost of wind power
production comparable to other forms of
energy. But calculating their true power-
generating impact is tricky. Wind farms often
cite total capacity, but average production is
typically 70 percent lower because winds do
not always blow at optimal strength.

Type

Generation
(billion kWh/yr)

Generation
(% of Total)

Cost
(C/kWh)

Coal

1,928

51

<1-6

Nuclear

781

21

<1-15

Natural gas

648

17

2-6

Hydropower

296

8

1-6

Biomass

34

1

7-10

Oil

31

1

1-3

Wind

17

<1

3-6

Geothermal

14

<1

2-8

Solar

1

<1

25-30

TOTAL

3,750

100

• Ocean physics — What is the nature of
wind and wave patterns and current flows
(particularly during extreme storm events)
around each proposed wind farm site?
How does the seafloor change over time,
as a consequence of both flowing currents
and seismic events? What is the likelihood
of ice formation and movement through a
wind farm area?

• Environmental impact— How would
wind turbines affect songbirds that mi-
grate through these regions or seabirds
that frequent them as productive habitat?
How do these structures affect marine
ecological processes or important com-
mercial fisheries? What is the impact ot
turbine noise on protected species, includ-
ing whales, dolphins, and seals?

• Marine policy — How do we design a
system of access that balances the needs
of ocean wind developers against the legal
interests of people and businesses already
benefiting from these areas? What can we
learn from the existing models of planning
for use of the ocean and public lands?

All of these research efforts must be
undertaken with an awareness of the eco-
nomics of ocean wind power because the
answers to these questions will affect the
engineering design of ottshore structures.

Prospects

Some environmentalists believe that
the production of energy from both
ocean- and land-based wind farms has the

potential to satisfy the global demand not
only for electricity, but also for all forms
of energy. Realizing such a vision would
require many thousands of large wind
turbines, as well as the development of
technologies to store the energy (such as
the production of hydrogen as a fuel). It
would also require a process for locating
wind turbines in the coastal ocean that
balances the benefits with the costs.

When faced with a new activity that
might change the way we use the ocean
environment, the public is often ambiva-
lentToday we are faced with a split be-
tween those who favor renewable energy
through offshore wind farms and those
who decry the potential degradation ot the
seascape. As new information is discov-
ered and learning occurs, societal prefer-
ences about the mix ot appropriate uses ot
the coastal ocean undoubtedly will shift.
At the same time, science may uncover
new options and opportunities, perhaps
revealing the true potential for wind farms
in the coastal ocean.

Porter Hoagland is a
research specialist in
the Marine Policy Center
5 of Woods Hole Oceano-
'j graphic Institution. He
g holds a bachelor's degree
3 in biology from Hobart
College, a master's in public administration
from Harvard University, and master's and
doctorate degrees in marine policy from the
University of Delaware.

Woods Hole Oceanographic Institution 59

For the Navy, the Coast Isn't Clear

Oceanographers mobilize to help the Navy operate effectively in complex, shallow waters

By Rear ADM (Ret.) Richard F. Pittenger
Vice President for Marine Operations (Ret.)
Woods Hole Oceanographic Institution

Every so often, circumstances can con-
spire to make a battleship turn on a
dime. Fifteen years ago, two geopolitical
events prompted the U.S. Navy to abruptly
change long-standing research priorities
and steer rapidly in a new direction.

When the Berlin Wall collapsed in
1989, so did the Navy's Cold War necessity
to counter the Soviet Union's huge sub-

marine force throughout the world's deep
oceans. A year later, the first Persian Gulf
War shifted the Navy's interests to land-
ing troops and operating ships in shallow,
often mined, coastal waters. The research
focus changed from "blue water" to what
the Navy dubbed "littoral" warfare.

Oceanography for national defense

One of the strengths of the U.S. Navy
has been its ability to exploit the ocean
environment in the same wav land-based

soldiers use the landscape to their advan-
tage. The key is understanding the ocean's
physical and geological properties, a basic
research endeavor promoted and funded
by the Navy for six decades.

Columbus O'Donnell Iselin, second di-
rector of the Woods Hole Oceanographic
Institution, was quick to realize the po-
tential symbiosis between oceanographers
and the Navy. In August 1940, he wrote a
letter to Frank B. Jewett, a member of the
newly created National Defense Research

A LIFE-SAVING LECTURE — During World War II, WHOI scientist Dean Bumpus teaches a class of Navy submariners how to use bathythermographs
to avoid detection by enemy sonar. The instruments, developed at WHOI, measure ocean salinity and temperature, which affect the propagation
of sound under water.

60 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

Committee, whose charge was to marshal
the nation's scientific resources for an in-
evitable global war.

"The Woods Hole Oceanographic In-
stitution... has been engaged in oceano-
graphic research since 1931," Iselin wrote.
"This memorandum sets forth some
suggestions as to how the personnel and
equipment of this laboratory can be bet-
ter utilized for the national defense, for it
seems likely that the training and experi-
ence of oceanographers will enable them
to attack successfully various problems
having a naval consequence."

Thus began WHOI's long and con-
tinuing tradition of research for the
Navy. During World War II, Institution
scientists investigated many aspects of
underwater explosives. They found ways
to prevent fouling of ships' hulls by bar-
nacles, seaweed, and other marine life
that caused turbulence and increased
fuel consumption— research that lowered
the Navy's fuel bill by 10 percent. They
showed how salinity and temperature
changes in the ocean affected the propa-
gation of sound under water. They built
instruments (bathythermographs) to
measure these changes and trained sailors
to use them to avoid detection from so-
nar, which "saved many of our ships," the
Navy reported.

Such wartime research successes led
in 1946 to the creation of the U.S. Office
of Naval Research (ONR), which funds
instrument and technology development
and wide-ranging basic research on ocean
properties and processes, particularly in
ocean acoustics.

Listening for submarines

As in World War II, oceanographic re-
search proved valuable to the Navy during
the Cold War. Research begun at WHOI
by Maurice Ewing and J. Lamar Worzel
culminated in the discovery of the SOund
Fixing And Range (SOFAR) channel, a
layer of water in the ocean that acts like a
pipeline for efficiently transmitting low-
frequency sound over vast distances.

The discovery enabled the creation of

the Navy's highly successful SOund SUr-
veillance System (SOSUS), which could
detect submarines by their faint acoustic
signals. SOSUS, and more advanced sys-
tems derived from it, allowed U.S. forces
to track and, if circumstances warranted,
engage Soviet submarines.

Countering the Soviet submarine
threat was a daunting task, prompting a
Navy research investment of about $14
billion per year, but it was a primary Cold
War mission. Being able to accurately keep
track of Soviet submarines whenever they
operated created a powerful deterrent to a
shooting war.

A new theater of operations

The end of the Cold War brought a
shift in priorities and a major reduction in
Navy research funding. But new conflicts
emerged, as well as renewed attention to
old ones in the Middle East, Yugoslavia,
Korea, and Taiwan. These served to refo-
cus the Navy's attention on learning how
to operate safely and effectively in coastal
waters, which are extraordinarily challeng-
ing for naval warfare.

The properties of the waters from the
continental shelf to the coast are funda-
mentally different from the cold, deep
ocean. The simple, stable, and predict-
able structure of water masses in the deep
ocean (such as the SOFAR channel) does
not exist in the shallows.

Coastal waters contain water masses

with widely different temperatures and
salinity levels, and the properties ot these
water masses are constantly attected by a
wide variety of coastal factors and process-
es—including tides, wind-driven currents,
inflows from rivers, changing air tempera-
tures, and mixing between water masses.
As the water masses shift, so does the
structure of the ocean's water column and
the transmission of sound through it.

The result is a highly complex and dy-
namic—and highly unpredictable— struc-
ture inimical to the Navy's cold, deepwater
acoustic tools and techniques. Shipping
noise, fishing activities, and shallow, rever-
berating seatloor topography add further
acoustical complications.

These acoustic difficulties in coastal
waters make it hard to detect mines. Dur-
ing the first Persian Gulf War, Iraqis used
World War I-era mines deployed from
small boats to staunch the movement of
U.S. amphibious forces.

Another uniquely coastal danger is bio-
luminescence. Nutrient-rich coastal waters
are full of marine life that glows when
excited by movement and can reveal the
presence of ships, subs, or Navy SEALs.

As they have since the days before Pearl
Harbor, WHOI scientists have mobilized
to conduct basic oceanographic research
funded by the Navy in this new theater ot
operations. The four articles that follow
highlight some of their work related to lit-
toral warfare.

Dick Pittenger was born in Nebraska during the worst of the Dust
Bowl/Depression era of the mid-1950s. His family moved west, even-
I tually settling in Tacoma, Wash. Pittenger was attracted to the sea and

actively participated in the Sea Scouts and Sea Cadets. He joined the U.S.
1 i Naval Reserves during the Korean War and earned an appointment to the
J Naval Academy through the Reserves. Graduating in 1958, Dick was com-
| missioned an ensign and went on to serve for 52 years, rising to the rank
| of rear admiral. He earned a master's degree in physics (underwater acous-
| tics) at the Naval Postgraduate School. His duties included mostly destroy-
• c ers, and he specialized in anti-submarine warfare (ASW). He commanded
a minesweeper in Vietnam, a fast frigate that was a member of the then-revolutionary "ASW Squad-
ron," and a destroyer squadron. His last duties in the Navy were as director of ASW for the Chief
of Naval Operations, and as the Oceanographer of the Navy. Upon retirement, Pittenger came to
WHOI where he led the Institutions Marine Operations Division. His era at WHOI saw the addi-
tion of Atlantis to the WHOI fleet, the retirement of Atlantis II, the mid-life conversions of Knorr
and Oceanus, the construction of the coastal research vessel Tioga, the revitalization of deep sub-
mergence, including bringing the tethered vehicles Argo/Medea/Jason/DSL-120 into the National
Deep Submergence Facility and, in 2004, the award of a grant to build a replacement for Alvin.

Woods Hole Oceanographic Institution 61

Where Are Mines Hiding on the Seafloor?

New research reveals how waves, currents, and swirling sands can bury mines

200

Eternally and incessantly, waves and
currents stir up sand from the sea-
floor near the coast. Sediments get sus-
pended in the ocean, carried onshore
and oft", and deposited elsewhere. In the
process, objects on the
seafloor — natural and un-
natural—can get buried
and uncovered.

It is a seemingly
esoteric process, but the
Navy has a vested interest
because its enemies use
mines to defend coast-
lines. Those mines often
become buried by sand,
making them all the more
dangerous. Buried mines
are difficult to detect, yet
they still can be triggered
by ships passing overhead.
To assess the threats from
mines and ways to avoid
them — from mine hunting
and sweeping to avoiding
areas entirely — the Navy would like to pre-
dict what may be buried under the harbors
and beaches where it wants to maneuver.

That requires an understanding of how
mines get buried in different environ-
ments. In the past, divers tried to observe
the processes firsthand. But diving once
or twice a day, they could rarely observe a
burial in progress. They merely observed
the before-and-after conditions. And div-
ers cannot work in storms and strong tidal
currents— precisely the forces that cause
most burials.

Observing the entire process

For more than a decade, WHOI sci-
entist Peter Traykovski has doggedly ex-
plored the complex factors that move sand
to continually reshape the seabed and our
shorelines. That work has drawn attention

from the Navy. Traykovski, with the as-
sistance of WHOI scientist Jim Irish, has
developed instrument systems that mea-
sure waves and currents and that capture
images of sands shifting on the seafloor

Seafloor node

•500

-400

300

-200

100

MINE EYES HAVE SEEN— WHOI scientist Peter Traykovski helped reveal how
mines are buried by sand on the seafloor, using a rotary sidescan sonar that
continuously monitored the process. This sonar image shows a partially buried
mine and the seafloor node that supplies power to the sonar.

and suspended in the ocean.

From 2001 to 2004, Traykovski and
colleagues at WHOI and the Naval Re-
search Laboratory conducted a series
of experiments, funded by the Office of
Naval Research, to make continuous,
long-term observations that no human
divers could ever make. Using the WHOI
Marthas Vineyard Coastal Observatory,
they plugged instruments — including
acoustic Doppler velocimeters, pressure
sensors, and rotary sidescan sonars— into
seafloor nodes, powered via cables from
the observatory's shore-based facility. (See
"The New Wave of Coastal Ocean Observ-
ing," page 16.)

In the fall, they deployed mines on the
coastal seafloor, armed not with explo-
sives but with instruments that recorded
how the mines pitched, rolled, or sank.

Divers who returned in April found a
smooth seafloor desert and no hint of
the buried mines. But Traykovski's rotary
sidescan sonar— sampling every half-hour
for nearly eight months and producing
thousands of images —
provided an unprecedent-
ed view of the processes

that buried the mines.
Mine

Different sands,
different effects

It turned out that
mines behaved differently
depending on the type of
sand they sat on. In fine
sand, mines jutting up-
ward created turbulence
that accelerated the flow
around them. A simi-
lar process occurs when
waves rush past your foot
on the beach. The sand
disappears around your
foot, your foot sinks, and
then sand washes back to fill in the hole
and bury your foot. Likewise, fine sand
quickly covers mines, and once buried,
they stay buried.

In coarse sand, however, waves and cur-
rents create big sand ripples on the seafloor.
The currents rotate the mines to align with
the ripples. At that point, the mines become
integrated into the rippled seascape, and
currents bury them no deeper than the
height of the surrounding ripples.

Armed with such information, the Navy
can better predict and detect the presence
of buried mines in different locales and
circumstances. Beyond this crucial military
relevance, Traykovski's research also offers
coastal managers greater understanding ot
the forces and phenomena that shape our
beaches, harbors, and coastal zones.

— Lonny Lippsett

62 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edi

New Instrument Sheds Light on Bioluminescence

A WHOI engineer invents a device to measure a critical but elusive ocean phenomenon

On a 1995 research cruise in the Ara-
bian Sea, WHOI Research Engineer
Paul Fucile asked an innocent question,
just to satisfy his curiosity. He had been
watching a three-person Naval Research
Laboratory (NRL) team use a deck-
mounted winch and a steel wire to maneu-
ver a half-ton, golf-cart-sized, $500,000
piece of equipment called the High Intake
Defined EXcitation (HIDEX) photometer.
It was monsoon season, the weather was
rough, and the crew struggled to lower
HIDEX safely over the side.

"What do you measure with that?"
Fucile asked, not thinking that his query
would launch him into a completely new
line of research.

The answer was "light" — light created
by living things.

Marine organisms ranging from bacteria
to fish make their own chemically induced
light — called bioluminescence — to hunt,
frighten predators, attract mates, communi-
cate, or camouflage themselves. Movement
in the water excites marine life to glow. It
also stimulates the Navy's interest.

Bioluminescence has betrayed the
positions of submarines and sealed their
doom. Sailors have detected the luminous
wakes of torpedoes. Returning pilots have
followed luminescent trails over many
miles to find their aircraft carriers, as have
their enemies. Navy SEALs are mindful of
certain beaches where bioluminescence
would give them away.

Building a better light-trap

Bioluminescence is ubiquitous in the
oceans, and especially prevalent in coastal
regions where nutrients are abundant and
life thrives. Yet scientists have little basic
understanding of how bioluminescence is
influenced by water temperatures, depths,
seasons, geographic locations, even differ-
ent times of day. They have been limited

by a scarcity of observations and instru-
ments to make them.

After watching his colleagues' difficul-
ties with HIDEX, Fucile spent his night
watch that evening drawing a sketch tor a
light-sensing instrument that was smaller,
sturdier, less complicated, and less expen-
sive. From the ship, he e-mailed a list of
materials to WHOI Experimental Machin-

WHOI engineer Paul Fucile invented
an inexpensive, easy-to-deploy bathy-
photometer. It measures light levels from
bioluminescent marine life, which can reveal
the positions of Navy ships, subs, and SEALs.

ist Mark St. Pierre, asking him to get them
ready so that Fucile could start construc-
tion as soon as he returned.

Eight weeks later, back in the Arabian
Sea with the same NRL team, Fucile tested
a prototype of his bathy-photometer, an

instrument to measure bioluminescence in
the ocean. The NRL team was impressed
with the initial results. It worked well
enough to earn Fucile a Cecil H. and Ida
M. Green Technology Innovation Award,
given to WHOI engineers to launch new
ideas in instrumentation or technology. A
year later, he was awarded an Office of Na-
val Research grant.

Portable, tough, and inexpensive

Fucile's patented 10-pound, 28-inch-
long instrument is so inexpensive, it's
expendable. His Expendable Bathy-Pho-
tometers (XBPMs) can be easily trans-
ported and pitched over the side of a ship
by one person even in the worst weather
conditions. As they descend, the XBPMs
spool out a thread-like wire that trans-
mits digital data to a computer on deck.
Fucile also developed and patented this
telemetry system.

The sophisticated HIDEX is capable of
making a wide range of subtle measure-
ments, including distinguishing individual
types of bioluminescent plankton. But for
the first-order task of measuring biolu-
minescence levels, the XBPM is about 90
percent as accurate as HIDEX — without
HIDEX's fragile and expensive glass-tube
technology. Thus, Fucile envisions that
XBPMs could be launched from subma-
rines, deployed by SEALs, dropped from
airplanes, and used on fleets of gliders.

Beyond military research, XBPMs are
already being used in an environmental
study of Bioluminescent Bay in Vieques,
Puerto Rico. The bay, named for its rich
marine life, is now deteriorating because
of a surge of coastal construction. In the
future, Fucile hopes that musters of
XBPMs will be used routinely by scien-
tists to make inroads into our now-sparse
knowledge of bioluminescence.

— Lonny Lippsett

Woods Hole Oceanographic Institution 63

The Cacophony on the Coast

The Navy's deep-ocean acoustic detection methods don't apply in complex shallow waters

In the monotonous hush and uniform
neatness of a library, it is quite possible
to hear the soft echoes of a pin dropping
many aisles away. But try it in the clut-
tered confines of a teenager's room, where
a changing medley of music, cell phone
rings, and television voices bounces off
a jumble ot strewn clothes, halt-opened
drawers, and scattered possessions.

Unlike light, sound travels ef-
ficiently through water, and the
Navy uses sound to monitor what's
going on in the ocean. To under-
stand the sound messages trans-
mitted through the seas, you need
to understand the medium through
which they are transmitted.

Like a library, the deep ocean
is a structured environment with
a few basic, reliable rules about
sound. To monitor Soviet subma-
rines during the Cold War, the
Navy exploited the SOFAR chan-
nel, a persistent deep-ocean water
layer whose properties efficiently
transmit low-frequency sound
waves over vast distances.

But when the Navy shifted its
focus to battle zones near the coast,
it found that shallower, coastal waters are
as noisy and chaotic as a teenager's room.
In recent years, several WHOI research-
ers have participated in pioneering cruises
aimed at examining the complicated behav-
ior of sound waves in shallow- water regions.

A complex environment

In 1996-97, many WHOI researchers
(including Glen Gawarkiewicz, Ken Brink,
Frank Bahr, Robert Beardsley, Michael
Caruso, and lames Lynch) joined naval re-
searchers to conduct the Shelfbreak PRIM-
ER experiment, funded by the Office of Na-
val Research (ONR). They deployed arrays
of instruments over a 40-square-kilometer

(25-square-mile) area 96 kilometers (60
miles) south of Marthas Vineyard, where
the relatively shallow continental shelf
begins to slope steeply into the Atlantic-
abyss. Some instruments transmitted sound
waves, while others listened for them. Still
other instruments measured the character-
istics of the watery pathways through which
the sound waves propagated.

HANG ON — Amid large waves crashing onto the fantail, WHOI
Research Specialist Frank Bahr (left) and the bosun of the R/V
Endeavor hold on to WHOI's SeaSoar surveying instrument —
and each other — during a 1 997 Navy-sponsored research cruise.

Unlike the deep ocean, the structure of
water masses near the coast is neither sim-
ple nor stable. Within the narrow confines
of the continental shelf, fresh water from
rivers and cold water from coast-hugging
currents confront warmer, saltier, deeper
water masses near the continental slope.
These water masses remain distinct-
flowing, changing, and rearranging them-
selves, not unlike cold and warm fronts in
our atmosphere.

These coastal water masses drive
strong currents along the shelf edge, which
rearrange water temperatures over the
outer shelf as they meander. Temperature
gradients between warm- and cold-wa-

ter masses can also be altered by spin-
ning, independent water masses within
the oceans— called eddies or warm-core
rings— that often form at the edge of the
continental shelf. Warm or cold air can
also change coastal water temperatures
over seasons or days. All these phenom-
ena can change water properties and shift
coastal oceanic fronts, which, in turn,

scatter or distort sound waves in

unpredictable ways.

Waves within the ocean

The irregular shape of the
coastal seafloor adds another vari-
able. Funded by ONR, WHOI
and Navy researchers participated
in the 2001 Asian International
Acoustics Experiment in the East
and South China Seas. As part of
i the experiment, WHOI research-
== ers Keith von der Heydt and John
% Kemp designed and deployed an
I autonomous hydrophone array
that recorded the longest, highest-
quality shallow-water acoustics
data set ever collected.

Analyzing the data, WHOI sci-
entists John Colosi and Tim Duda
found that as tides move over steep sea-
floor canyons and ridges in shallow waters,
they generate internal waves. These huge
ripples in the interior of the ocean, formed
along the boundaries of different water
masses, add yet another factor that compli-
cates shallow-water sound propagation.

"The coastal ocean is a much more en-
ergetic environment than the deep ocean,
and small day-to-day changes produce
large complications," said WHOI physi-
cal oceanographer Glen Gawarkiewicz.
Oceanographers have just begun to learn
how to extract distinct and useful signals
from the coastal noise.

— Lonny

64 Oceanus Magazine • Vol. 43, No. 1 •2004-oceanusmag.whoi.edu

Robo-Sailors

Navy-sponsored research spawns a new generation of underwater vehicles

They look like torpedoes, but their
mission isn't destruction.

In the mid-1990s, the Navy began
funding research for small, robotic vehi-
cles to perform unmanned reconnaissance
in coastal waters. At WHOI, that helped
spark the development of REMUS (Re-
mote Environmental Monitoring UnitS),
designed and built by Chris von Alt, Ben
Allen, and colleagues in the Oceanograph-
ic Systems Laboratory.

Launched on pre-programmed under-
water flight patterns and equipped with a
changeable array of sensors, REMUS can
map the seafloor or collect data on tem-
perature, salinity, currents, phytoplankton
abundance, and other seawater properties.
The 5-foot-long, 80-pound vehicle can be
launched and recovered by two people from
a small boat, without a crane or special
handling equipment. Easily programmed,
REMUS can work alone for more than 20
hours before its batteries need recharging.
It can travel at speeds up to 2.5 meters per
second and to depths of 100 meters.

REMUS has proved a remarkable sci-
entific tool, expanding researchers' ability
to explore previously inaccessible regions.
The Navy also gained a valuable tool: Sail-
ors used several REMUS vehicles to detect
mines in the Persian Gulf harbor of Umm
Qasr in 2002. Navy officials said that each
REMUS could do the work of 12 to 16 hu-
man divers, and the vehicles were "unde-
terred by cold temperatures, murky water,
sharks, or hunger."

The Office of Naval Research also has
funded Dave Fratantoni and colleagues at
WHOI to develop another small, easy-to-
deploy surveying technology — the glider.
Gliders employ an internal displacement
piston or an oil bladder to change their
buoyancy. They now sink up to 200 meters
(656 feet) in the ocean and then rise again
to the surface, but vehicles under develop-

ment will be able to dive ten times deeper. on the job for several months.

Gliders fly in a saw-tooth pattern,
measuring ocean properties and surfacing
periodically to transmit data via satellite
to scientists on ship or shore. They are
slower than REMUS, but they can remain

Valuable to the Navy, these new-gen-
eration undersea robots are also having
productive non-military careers in the ser-
vice of scientists exploring a wide range of
ocean phenomena.

U S NAVAL SHIP

BRUCE C. HEEZEN

GLIDER READY FOR TAKEIOFF—WHOI Research Associate John Lund worked with naval
personnel aboard USNS Bruce C. Heezen to deploy one of seven WHOI gliders used in an
experiment in the western tropical Pacific Ocean.

UNDERWATER RECONNAISSANCE— WHOI Senior Engineering Assistant Greg Packard puts
a REMUS 600 autonomous underwater vehicle through a series ofpre-launch checks on the
WHOI dock before it is tested in the waters near Woods Hole. Crane operator Doug Handy
stands by. The REMUS 600 can carry a variety of sensors for underwater surveying and mapping
and, not incidentally, can be deployed through submarine torpedo tubes.

Woods Hole Oceanographic Institution 65

Down on the Farm. . .Raising Fish

Aquaculture offers more sustainable seafood sources, but raises its own set of problems

By Hauke L. Kite-Powell, Research Specialist

Marine Policy Center

Woods Hole Oceanographic Institution

Imagine for a moment that the beef
and poultry in your refrigerator came
not from ranches and farms, but from
the woods and prairies. Imagine that ev-
ery pig, chicken, turkey, and steer was
"tree range," hunted from wild herds and
brought to market. What would that mean
to you as a consumer?

In the simplest terms, it would mean
that your local supermarket would have
higher prices and a less dependable and
less plentiful supply of meat. The idea of
abandoning our modern practice of rais-
ing livestock and harvesting all of our

meat from the wild is absurd.

And yet that is exactly how we ob-
tained most of our seafood until quite
recently.

Aquaculture, or fish farming, is chang-
ing how we think about one of our main
sources of protein. With many fish stocks
shrinking due to overfishing or environ-
mental degradation, aquaculture holds the
promise of more reliable and more sus-
tainable seafood production. The econom-
ic and social benefits could be significant
for both consumers and producers.

But every benefit has a cost, and the
costs of poorly executed aquaculture
range from ecological damage to rampant
disease in the cultured fish stocks. The

financial costs of raising healthy fish also
remain problematic in parts of the world.
Current research is testing some solutions
to these problems.

A new wave in the seafood industry

In 1950, about 20 million tons offish
were harvested globally, with nearly all
of that catch coming from wild stocks in
oceans, bays, lakes, and rivers. In the five
decades since then, the world's popula-
tion has tripled. Today, seafood produc-
tion stands at 130 million tons per year,
with one quarter of that total coming from
aquaculture. About 20 million tons are
tanned in freshwater facilities, 15 million
tons in salt water.

MUSSEL BUILDING — To study the feasibility of commercial shellfish farming offshore of New England, researchers from Woods Hole
Oceanographic Institution created this demonstration system that grows blue mussels in the open ocean. The "longline mooring" uses
submerged ropes and buoys to allow juvenile mussels to develop in nutrient-rich, naturally flushed waters.

66

Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

Aquaculture first began to contrib-
ute significantly to world production in
the 1970s, when it became clear that wild
capture seafood harvests could no longer
keep pace with the demand for fish. Many
popular fish stocks had been overexploited
even before that era, but the fishing indus-
try compensated by repeatedly switching
to previously "underutilized" species. By
the 1980s, even diversifying the wild har-
vest could not increase the yield enough to
feed the world's booming population and
growing appetite.

Humans directly consume 75 percent
of all seafood produced, with the remain-
der being processed into fish meal and
oil for use in feeds for land animals and
larmed fish. Thanks to the development of
aquaculture — output has increased more
than fourfold since 1985 — the per capita
supply of fish has remained roughly con-
stant since 1970.

Seafood accounts for about 15 percent
of the protein in the average human diet,
about 16 kilograms per person per year.
Residents of the United States, however,
consume 7 or 8 kilograms per person,
about half the global average. When they
do eat seafood, few U.S. consumers realize
that more than half of what they eat comes
from fish farms.

Developing countries outpace U.S.

By global standards, U.S. aquaculture
production is relatively modest, with a
value of less than $1 billion per year of
the worldwide total of $50 billion. Cat-
fish, salmon, and oyster farms dominate
the U.S. efforts. Aquaculture develop-
ment is constrained by economics, espe-
cially competition from low-wage foreign
producers and a lack ot available and
affordable coastal real estate. As a result,
the U.S. imports more than half of the
seafood it consumes.

At the other extreme, China accounts
for more than half of world aquaculture
production, primarily through its large
production of freshwater carp, the world's
most plentiful aquaculture crop. (There
are grounds for suspecting that the Chi-

I 60

I Aquaculture Capture fisheries

.lll'llll

1950 1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 1994 1998 2000

WORLD CAPTURE FISHERIES AND AQUACULTURE PRODUCTION— Since 1950, both wild fish
catch and farmed fish have increased significantly as the world population has tripled.

nese production statistics maybe inflated.)
Other significant crops include shrimp (ti-
ger prawns) grown in coastal ponds, and
seaweeds, oysters, mussels, and salmon
grown in ocean cages.

Global aquaculture has focused on
species that command a relatively high
price. The freedom to select target species

Live fish are moved from shore-based
aquaculture tanks and pens onto a boat for
transportation to an open-ocean netpen.

is greater for the fish farmer than for the
wild capture fisher, and farmers have been
selling their products for about $1.50 per
kilogram, nearly twice the average price of
wild capture seafood. That is good news
for the developing world, where aquacul-
ture can feed populations both directly
and through income from exports.

Fish in a barrel

The most common technique for farm-
ing fish is pond culture, where fish are
reared in shallow, earthen, open-air ponds
that look like flooded agricultural fields.
This method is mostly used to grow carp
and other freshwater fish in Asia, shrimp
in Latin America and Asia, and catfish in
the southern United States. The simplest
ponds are "self-contained" ecosystems in
which fish feed on naturally occurring
water plants. The density offish stocked in
these ponds is generally low — about 1 ki-
logram per cubic meter of water — but can
be increased with investment in feed and
in aeration systems that maintain oxygen
levels in the water.

A higher stocking density can be
achieved in ocean cage cultures ( 10 to 20
kilograms per cubic meter), where cages
or "netpens" are anchored to the seafloor
in open waters. This approach is often
used for raising carnivorous marine spe-
cies such as salmon. Natural currents
remove waste products and maintain

Woods Hole Oceanographic Institution 67

A NEW TYPE OF HARVEST— Left: Rigid cages are used to contain surf clams in a shellfish aquaculture demonstration experiment supported by
Woods Hole Sea Grant. Adolescent clam "seedlings" are held in submerged cages until they grow to commercially viable size and weight. Right:
Will Ostrom (blue hard hat), a senior engineering assistant in the WHOI Department of Physical Oceanography, and Joe Alvernes, a crewmember
of the fishing vessel Nobska, scrape mussels from a rope that had been submerged for 19 months.

oxygen levels by continually replacing the
water in the cages.

The highest densities are achieved in
onshore tank farms, where up to 100 ki-
lograms of fish are raised per cubic meter.
These industrial style aquaculture meth-
ods use pipes, filters, and flushing systems
to remove wastes and restore oxygen lev-
els. Onshore systems rely on regular water
exchanges — replacing tank water with
fresh water from an external supply — or
they circulate the tank water through
systems of filters and other water quality
systems.

Not as easy as it looks

Fish farmers and aquaculture research-
ers face a number of challenges as they at-
tempt to expand aquaculture production.
These include:

• Reproduction: To produce ever-larger
quantities of fish in a sustainable way (that
is, without further depleting wild stocks)
and to obtain fish with optimal character-
istics for farming, it is necessary to "breed"
juvenile fish from specially selected captive
stocks. But getting fish to reproduce consis-
tently in captivity remains a challenge for
many valuable species, such as tuna.

• Feed: There is no one-size-fits-all
approach to feeding fish, and the opti-
mal food for healthy growth is often spe-
cies-specific. Farmers need feeds with
ingredients that are economically vi-
able, ecologically sensible, and healthy
(free of contaminants) to the animals and
consumers. For example, the farming of
carnivorous fish such as salmon has been
criticized for using excessive quantities of
other fish in the production of feed. It the
feed fish are plentiful and of little interest
for human consumption, and if their fish-
ery is managed properly, there shouldn't
be a problem. But it not properly man-
aged, these practices can contribute to
overfishing of wild stocks.

• Disease management: As with cattle
ranches, farming fish can lead to disease
because parasites, viruses, and bacteria
have a better chance of propagating in a
densely packed population. Controlling
disease presents its own problems. The ex-
cessive use of antibiotics and other agents
can have negative effects on the environ-
ment and human consumers (for instance,
repeated exposure to antibiotics can lead
to immunity to such drugs).

• Genetics: Efforts to develop taster-

growing fish through genetic manipula-
tion are controversial, in part because
escapees may affect wild stocks by com-
peting or interbreeding.

• Waste disposal: Natural waste pro-
duced by the farmed animals, as well as
excess feed, can result in an overabun-
dance of nutrients in the areas around
fish ponds or ocean farming areas. If this
nutrient loading exceeds certain limits,

it can encourage the excessive growth of
algae and contribute to algal blooms. This
ecological imbalance can culminate in
eutrophication, the depletion of oxygen in
the water to a point where it suffocates or
drives away marine species.

• System design and economics: Engi-
neers must design containment ponds and
cages that can address these environmen-
tal issues while withstanding the forces of
nature, doing all of it at a reasonable cost.

Many of these challenges come into
play in two aquaculture ventures in very
different settings where researchers from
Woods Hole Oceanographic Institution
(WHOI) have undertaken demonstra-
tion projects: the coast of New England
and the island of Zanzibar off the coast of
East Africa.

68 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

HHMMIHl^^^^^HM^^^^RI^^^^^^^^^^^^l

Yankee thrift and ingenuity

New England has a long association
with fishing and seafood, not to men-
tion one of the world's wealthiest popula-
tions. Seafood consumption in the region
is below the global average, yet 25 percent
higher than the U.S. average. Aquaculture
production has been limited to mostly
oysters and other shellfish, but the collapse
of several traditional fish stocks, grow-
ing economic and regulatory pressure on
fishermen, and an increasing reliance on
imports has boosted interest.

There are several obstacles to aquacul-
ture in New England. The first is the ready
availability of low-cost seafood imports,
which make it tough for local producers
in this high-cost-of-living area to com-
pete. The second is a shortage of afford-
able coastal real estate, both onshore and
in nearshore waters, which makes coastal
ponds and nearshore cage farming imprac-
tical. As a result, the future for this region
appears to lie in high-density, onshore tank
farming or in offshore, open-ocean opera-
tions focusing on high-end niche markets.

Before commercial aquaculture can
begin in the open ocean, government
agencies are going to have to develop
a straightforward system for granting
"tenure" to a piece of watery real estate.
Depending on the location, several fed-
eral or state agencies may be involved in
granting a permit for the installation of an
offshore growout system. Even far from
shore, conflicts can arise if a farm site is
in or near established commercial fishing
grounds, shipping lanes, or the habitat of
protected species. In the long run, the na-
tion may move toward a marine zoning
system, much like that used onshore, to
assign priority uses — fishing, shipping,
recreation, or aquaculture — to parcels of
ocean real estate.

Growing finfish or shellfish in open
ocean waters also requires a significant
engineering investment. Cages and other
"growout" systems need to be able to sur-
vive the storms, choppy waves, and cur-
rents of the North Atlantic. Within the
past decade, cage systems have been devel-

oped that can survive hurricane condi-
tions (tor instance, by submerging tempo-
rarily below the wave energy zone). Still,
the economics of supplying and maintain-
ing growout systems far from shore are
only now being tested.

\VHOI has undertaken one of these
demonstration projects in the open wa-
ters of Rhode Island Sound, with support
from the National Oceanic and Atmo-
spheric Administration, the Sea Grant
College Program, and the Massachusetts
Department of Fisheries and Agriculture.
Researchers and engineers are working
to prove the technical and economic fea-
sibility ot growing blue mussels on ropes
("longlines") hanging from submerged
buoys in deep water.

Early results from the New England
demonstration projects are encourag-
ing. During our first two-year experi-
ment, hundreds of pounds of mussels
were harvested from a single longline.
Market-size mussels grew on the ropes
in half the time they would take to grow

in the colder waters north of Cape Cod.
The equipment showed very little wear or
damage, even though a hurricane passed
through the area. Long-term success will
depend on developing local markets that
are willing to pay a premium for a reliable
and consistent supply of fresh seafood,
and on engineering to keep costs down.

Necessity and invention

On the island of Zanzibar, in the Indian
Ocean off Tanzania, seafood is not a luxu-
ry but a means of survival. It is the domi-
nant source of protein for the island's one
million residents, who consume three to
four times as much seafood as the average
New Englander. As in the North Atlantic,
many wild capture fish stocks are under
intense pressure or depleted, and the catch
today is half of what it was 20 years ago.
But unlike New Englanders, the people of
Zanzibar cannot afford to import fish. The
per capita income is about $300 per year.

Aquaculture is critical for the food sup-
ply and for economic development of this

FARMING IN OPEN WATER — Researchers and commerical fishermen check on an open-ocean
cage for finfish aquaculture in a demonstration project by the University of New Hampshire.
The submersible cage is raised for feedings, cleaning, and maintenance, then lowered to allow
the fish to develop in water that is naturally flushed by ocean currents.

Woods Hole Oceanographic Institution 69

UNDER AFRICAN SKIES — Aquaculture holds the promise of feeding the impoverished populations of some developing countries, while also
providing a key crop for export. Left: Coastal fish ponds on the island ofPemba, Zanzibar. Right: Local fish farmers and researchers from the
Zanzibar Institute of Marine Science use nets to haul in fish grown in the coastal ponds.

island. Zanzibar developed a successful
seaweed farming industry in the 1980s,
and that crop is now second only to tour-
ism in the island's export trades. Seaweed
is a source of carrageenan, a key ingredi-
ent in the cosmetics, manufactured foods,
and pharmaceuticals industries.

This success has spurred interest in
other kinds ot aquaculture, such as pond
farming of tintish and the addition of
shellfish to the seaweed plots in coastal
lagoons. Limited infrastructure— unreli-
able utilities and scarce materials — and
the lack of a reliable source of juvenile fish
have slowed these efforts. So, too, have
concerns about environmental degrada-
tion from nutrient loading, which could
threaten the island's vital tourism business.

With the technical assistance of re-
searchers from Israel's National Center for
Mariculture and from WHOI, and support
from the German-Israel Fund tor Research
and International Development, the Lear
Foundation and the McKnight Founda-
tion, scientists in Zanzibar are developing
a research and training infrastructure to
meet these challenges. They have focused
on pond culture using low-technology so-

lutions, such as tidal flow instead of pumps
for water exchange. They are working with
"biofilters," using shellfish and seaweeds to
remove excess nutrients from pond water
before returning it to the sea. Cage culture
experiments in protected nearshore waters
are also being planned, and work is starting
on a simple hatchery to provide juvenile
fish tor stocking. Researchers are also de-
veloping techniques to add shellfish farm-
ing to established seaweed plots.

Initial results from pond culture experi-
ments are promising, and scientists on Zan-
zibar have begun to instruct would-be fish
farmers in how to replicate the experimen-
tal farms. The hope is that farmed fish will
soon increase the supply ot seafood protein
available to the residents ot the island.

Beating hooks into plowshares

Aquaculture holds great promise,
especially in developing countries and
historically non-productive coastal areas
with few natural wild fish stocks. Nega-
tive environmental effects from poor
planning, design, and operating proce-
dures have in some cases been problem-
atic, but can be avoided through sensible
regulation and monitoring. In the U.S.,
automation and other technologies will
have to be harnessed to compensate for
higher labor costs.

But from a global protein perspective,
aquaculture is necessary. The question
is not whether to farm fish, but how and
where.

H;

[auke Kite-Powell studied naval architecture, marine engineering,
policy, management, and economics at MIT, earning his bachelor's
degree, two master's degrees, and a doctorate. His research interests in-
clude the economics and management of marine industries and resources,
including maritime transportation, fisheries and aquaculture, and ocean
observing systems. He first came to WHOI as a summer student fellow in
1985 and has conducted research full-time at the Institution since 1988. In
I ^ addition to his research skills, he was officially admired by science butts
in 1997 when he was chosen as Mr. March for the "Studmuffins of Science" calendar developed by
National Public Radio producer Karen Hopkin.

70 Oceanus Magazine • Vol. 43, No. 1 • 2004 • oceanusmag.whoi.edu

MB1. WHOI LIBRARY

UH IflBY

The Ocean Institutes

In 2000, Woods Hole Oceanographic
Institution established four Ocean
Institutes to accelerate advances in
knowledge about the oceans and to
convey discoveries expeditiously into
the public realm. The Ocean Institutes'

goals are to catalyze innovative thinking
that can open up new scientific vistas,
to spur collaboration among scientists
in different disciplines, and to stimu-
late a rich and productive educational
environment that will engage future

leaders of oceanography. Concurrently,
each Institute's mission is to shorten the
time between acquiring knowledge and
making it accessible to decision-makers
who can use this information to benefit
society and steward the Earth.

The Deep Ocean Exploration Institute investigates Earths dy-
namic processes — beneath the oceans where more than 80 percent
of all earthquake and volcanic activity occurs and where the clues to
understanding the inner workings of our planet lie. The seafloor is
our window into the dynamic, fundamental processes that generate
natural disasters, produce oil and mineral resources, create and destroy
oceans, rend continents, build mountains and islands, and foster life.

The Deep Ocean Exploration Institute:

• explores how our dynamic planet evolves and changes

• examines the basic forces that create earthquakes and volcanoes
. develops technology related to seafloor observatories and

deep-submergence vehicles

• investigates unusual chemosynthetic communities of life on and
below the seafloor

• explores potential new energy and mineral resources in the oceans

The Ocean Life Institute explores the oceans extraordinary di-
versity of life— from microbes or whales— to identify ways to sustain
healthy marine environments and to learn about the origin and evolu-
tion of life on Earth. The more we look into the oceans, the more we
find remarkable life forms thriving in environments ranging from
Antarctic sea ice to the volcanic crust below the seafloor.

The Ocean Life Institute:

• explores biodiversity in the oceans

. finds ways to monitor and sustain the health of marine ecosystems

• studies marine life's physiological and ecological adaptations

• investigates the evolution of life in Earths oceans

• develops new techniques and instruments to explore ocean life

The Ocean and Climate Change Institute seeks to understand the
role of the ocean in regulating Earths climate and to improve our abil-
ity to forecast future climate change. The ocean stores vast quantities
of heat, water, and carbon dioxide and works with the atmosphere in
regulating global and regional climates — on time scales ranging from
days (storms and hurricanes), seasons (monsoons), years (El Ninos),
to centuries and longer.

The Ocean and Climate Change Institute:

« identifies the climatic effects of ocean circulation patterns

• develops an ocean-monitoring network to forecast climate changes

• examines geological records to better understand ocean behavior

• studies ocean dynamics that may trigger large, abrupt climate shifts

• evaluates the oceans response to the buildup of greenhouse gases

The Coastal Ocean Institute examines one of the most vital—
and vulnerable— regions on Earth: the coast. Our planets exploding
population has put stress on the fragile coastal ocean and has exposed
more people to coastal hazards such as storms, beach erosion, and
pollution. Understanding the complex, delicately balanced processes
at work in coastal areas is the key to ensuring that they remain pro-
ductive and attractive.

The Coastal Ocean Institute:

• reveals basic processes underlying the coastal ocean's fertility

• provides sound science to guide coastal management policies

• examines uses of coastal resources, such as wind, oil, and fisheries

. identifies strategies to mitigate coastal hazards and natural disasters
. promotes awareness of the coastal zone's importance to society

Woods Hole Oceanographic Institution 71

, -lit)

I'1!.

-----^