Vol. 19, No. 1 Special Issue 2000
Message From The Director
It covers more than 70% of the Earth's surface and harbors more
than half of all the species living on the planet. It makes our
weather and provides us with food, jobs, transportation, and recreation.
It awes us with its tremendous power and lulls us with its music.
The ocean is indeed a world of wonder.
With a resource as vast as the ocean to explore, marine scientists
may well be the pioneers of the 21st century. Using tools ranging
from highly equipped research ships and submarines to satellites
in space, today's ocean pioneers are making steady progress in unraveling
the mysteries of the complex resource we all depend on.
Here in Delaware, where nearly our entire state lies in the Coastal
Plain, knowing more about the ocean around us is critically important.
We count on healthy bays, beaches, and wetlands. We expect plentiful
fisheries, from succulent blue crabs to keeper-size striped bass.
We want to benefit from the economy our marine resources drive,
but we also know we need to protect these resources if we want them
to sustain future generations.
At the University of Delaware Sea Grant College Program, our mission
is to promote the wise use, conservation, and management of Delaware's
marine resources. Our goals are to conduct high-quality research,
educate the nation's future marine scientists, and increase public
awareness and understanding of the ocean and coast.
During the past year, we continued to make progress in research
areas of importance and promise to Delaware and the nation, from
coastal ocean studies to environmental technology, coastal engineering,
marine biotechnology, and fisheries.
In addition to these efforts, our outreach team the Marine
Advisory Service and Marine Communications staffs shared
information with thousands of people on topics such as Pfiesteria,
boating safety, aquaculture, seafood, hurricane preparedness, open-space
conservation, nutrient management, horseshoe crabs, and many other
marine life and phenomena.
And the methods we are using to extend this information to the
public are as diverse as the topics themselves, including Web pages,
seminars, publications, radio announcements, videos, press releases,
and our award-winning Coast Day festival.
In fact, this past January, we invited Delaware students and the
public to tag along on the first deep-sea expedition of the new
millennium. As our scientists set out on an 11-day mission to hydrothermal
vent sites over a mile deep in the Sea of Cortés off Mexico,
students read daily logs, viewed video clips of each day's findings,
and met members of the crew from computers in their classrooms and
homes. Several classes also took part in a historic conference call
with our scientists as they worked aboard the submarine Alvin
on the seafloor.
So far, the interactive Web site we developed for the project has
engaged more than 60,000 people from around the world in the excitement
of discovery, opening a porthole to the ocean's greatest depths.
It's been said that "the larger the island of knowledge, the
longer the shoreline of wonder." At Delaware Sea Grant, we're
working to expand knowledge and appreciation of the ocean. It's
a resource we really can't live without.
Dr. Carolyn A. Thoroughgood
Director, Sea Grant College Program Dean,
College of Marine and Earth Studies
Coastal Ocean Studies
The "coastal ocean" constitutes less than 5% of the ocean's
total volume, yet this region nearest the shore is where human impact
is greatest. A diversity of activities is concentrated in this area,
from shipping to mining, boating, and fishing. Ironically, many
of the fisheries we rely on are harvested in the coastal ocean,
yet this area is also where our most severe pollution problems occur.
Sea Grant researchers are working to increase our ability to assess
and manage the health of coastal bays and marshes. Current efforts
focus on the sea and shores of Delaware's largest marine ecosystems
the Delaware Bay and the Inland Bays.
Building a Defensive Line to
Jack Gallagher is not a football coach, but he's working at beefing
up his defensive line. The UD botanist is trying to develop plants
capable of blocking the invasive weed Phragmites australis
in Delaware's marshes.
Phragmites, or common reed, overtakes thousands of acres
of wetlands in the United States every year, crowding out more beneficial
plants that wildlife depend on for food and habitat.
Currently, wetlands managers try to control Phragmites by
spraying the plants with an herbicide in fall and burning the dead
canes in spring for two consecutive years. Desirable plants
may then colonize the sites, but sometimes Phragmites re-invades.
Then the spray-and-burn cycle begins all over again, further delaying
the marsh's restoration as optimal wildlife habitat.
"Much of the reinvasion of marshland cleared of Phragmites
is by plants that become established on higher ground, either the
upland fringe, levees, or high spots in the marsh," Gallagher
says. "Thanks to a network of underground stems, Phragmites
can grow from these more favorable habitats down in to wet sites
where it could not initially become established."
Gallagher, colleague Denise Seliskar, and their research team at
the UD Halophyte Biotechnology Center are working to identify varieties
of marsh plants that, when planted en masse, will form a natural
barrier to Phragmites.
So far, the team has begun testing several potential "Phrag
blockers." They include plants such as black needlerush and
three-square sedge, which have rigid stems; deep, dense root systems;
and other features that would stop Phragmites from reaching
the "end zone."
In addition to Sea Grant, this project has been funded by Public
Service Electric and Gas.
Jack Gallagher, a UD botanist, examines marsh-plant tissue cultures
grown in the Halophyte Biotechnology Center at the Lewes campus.
He and his research team are working to identify and genetically
strengthen native marsh plants that can block the invasion of
Phragmites into Delaware's marshes.
Can Seafloor Life Stand More Sand?
While seldom seen, a rich variety of animals make up the benthos
the bottom-dwelling animals in Delaware Bay. Here
live worms, oysters, clams, crabs, and many other organisms.
UD oceanographer Doug Miller and his students are working to find
out how much and how often sand and mud can be dumped on the bay
floor without harming its inhabitants.
Their work should help engineers design projects for disposing
dredged sediment, or "spoil," and for replenishing eroded
shorelines with minimal impact on bottom life.
During the past year, Miller and graduate student Christine Muir
set up field studies to determine the amount of shifting sediment
that benthic animals must adapt to from nature. Four beaches now
are being monitored, including Slaughter Beach, Primehook Beach,
Broadkill Beach, and Cape Henlopen. Both Slaughter Beach and Broadkill
Beach are proposed beach nourishment sites for the U.S. Army Corps
of Engineers' Delaware River channel deepening project.
"Sediment erosion and deposition vary greatly from month to
month, with more erosion typically in the winter and deposition
in summer," says Muir. "In some areas, the beach may change
by a foot or more of sediment depth a month."
The scientists are now moving to the lab to figure out how much
and how often additional sand and mud can be deposited on the bottom
dwellers without harming them. The scientists will conduct experiments
in aquaria and water tunnels on three of the bay's common benthic
species: the sandbuilder worm, the glassy tube worm, and the mud
snail. While some people may think these animals could use a good
"mud pack" they're not very attractive Miller
notes that their small size and drab appearance do not minimize
"They are a critical food source for fisheries, from weakfish
to blue crabs," he says.
Oxygen Study Reveals an
Estuary Out of Balance
The Delaware River and Bay just isn't behaving like we think it
"Like any ecosystem, the estuary has a metabolism," says
UD oceanographer Jon Sharp. "But the chemical balance in the
river near Philadelphia is unlike that of the lower estuary near
the bay mouth. It doesn't fit the standard aquatic model."
According to that model, oxygen should increase and carbon dioxide
decrease during the day as microscopic plants use sunlight to make
organic matter through the process of photosynthesis. At night,
the oxygen in the water should decrease and carbon dioxide increase
as the organic matter is decomposed by bacteria.
"What is happening in the lower bay is consistent with our
expectations," Sharp notes."But in the urbanized river,
near Philadelphia, we're seeing a very different picture. There,
oxygen levels are highly variable. Sometimes they go down during
the day, and they are not in mirror image or proportion to carbon
dioxide, nitrogen, and phosphorus."
To find out what causes this anoma-lous behavior, Sharp and his
team are conducting intensive studies in the estuary.
At sea aboard UD's 120-foot research ship Cape Henlopen,
the scientists collect large, 300-liter water samples and study
them on deck as miniature ecosystems, or mesocosms. The samples
are incubated for 30 to 50 hours under natural light and temperature
conditions and analyzed for changes in their carbon, nitrogen, phosphorus,
silicon, and oxygen levels. Chemical tracers are added to monitor
the uptake and transfer of carbon and nitrogen by algae.
By comparing changes in the water chemistry of the lower bay, where
the system is most biologically active, with the chemistry of the
river, which receives high human inputs, Sharp hopes to sort out
the factors that control the estuary's unusual metabolism.
"Once we piece together this puzzle," he notes,"we
should be able to determine the best strategies for managing the
inputs to the river."
"What is happening in the lower bay is consistent with our
expectations. But in the urbanized river, near Philadelphia, we're
seeing a completely different picture."
When Toxic Pfiesteria Appears,
Coastal Tourism May Decline
When toxic Pfiesteria microbes invade coastal waterways,
attacking bait fish and leaving telltale sores in their flesh, tourism
and seafood sales can suffer, reports Jim Falk, UD Sea Grant Marine
Advisory Service director. He recently conducted a survey of 3,500
coastal residents from New York to the Carolinas to find out what
they think about Pfiesteria.
"According to our results, a Pfiesteria outbreak could
reduce tourism by more than 40% in an affected area," Falk
says. "Approximately 5 million visitors brought $342 million
into Delaware's Sussex County in the summer of 1998. If a Pfiesteria
outbreak were to occur here, the county could see a substantial
loss of visitors and their spending power."
Seafood sales also may plummet if an outbreak occurs. Nearly two-thirds
said they would eat less locally harvested seafood if a Pfiesteria
outbreak were reported in their waters.|
"From a human health standpoint, people are very concerned
about Pfiesteria," Falk says. "Ninety-five percent think
Pfiesteria can be harmful to them."
Pfiesteria's human health effects are not well understood.
Exposure has been linked to memory problems, headaches, and other
symptoms. Consequently, the public is advised to avoid waters where
fish can be seen floating on the surface and to notify their state
natural resource agency if Pfiesteria is suspected.
"The public views Pfiesteria as a serious threat,"
Falk notes. "The majority of our survey respondents strongly
support state government's efforts to help understand what causes
Pfiesteria outbreaks and how to prevent them." For a
copy of the final report, call UD Marine Communications at (302)
the Flow in the Inland Bays
UD oceanographer Kuo-Chuin Wong is literally "going with the
flow" in Delaware's Inland Bays. He's figuring out their circulation
The bays Rehoboth, Indian River, and Little Assawoman
suffer from high nutrient inputs from sewage, farming, and other
activities. Knowing where these pollutants are carried in the bays
and how rapidly they are flushed to sea will help coastal managers
plan water-quality improvements.
"The first task is to find out what drives the water
including gravity, wind, and tides," he says. "Then we
need to figure out how they move pollutants around. For now, we're
using the salt in the seawater as a tracer since it's non-reactive
biologically," he notes.
This summer, as a follow-up to field work last fall, Wong will
deploy current meters in Rehoboth Bay, the Lewes-Rehoboth Canal,
Massey's Ditch, and Indian River Inlet. The units measure water
velocity, temperature, and salinity. Using the data, he will continue
to build a model of the bays' flow. "In baseball, this is first
base," he says. "To truly understand the bays, you need
to know how the water is moving."
Scientists Find Islands of
Fresh Water in Salty Bay
Thanks to thermal-infrared imagery taken by low-flying air-craft
last winter, UD researchers have pinpointed locations along the
Delaware coast where warm fresh water is seeping out of the ground
and into Delaware Bay.
The scientists are working to determine if these groundwater "seeps"
may be piping pollutants such as excess nutrients from the land
into the sea.
During the past year, Bill Ullman and Doug Miller visited seeps
from Cape Henlopen to Bowers Beach to determine the origin of the
water at each site.
"We found that not all of the seeps discharge fresh water,"
says Ullman."In some instances, it's just warm marsh water.
Upland groundwaters must be percolating into the marshes lying behind
the beach. In those cases, the marshes are intercepting the nutrient
pollutants and using them before the water reaches the bay."
In some areas, however, fresh water travels directly from the ground
into the ocean, as is the case in a seepage zone not far from the
fishing pier at Cape Henlopen State Park. The scientists have begun
monitoring this site to determine what impact the seep may have
on bay-bottom life.
"So far, we've found one unusual inhabitant in this seep,
a worm that normally lives in much less salty waters than lower
Delaware Bay," Ullman says. Apparently, the organism, the red-gilled
mud worm (Marenzelleria viridis), has staked out its own"freshwater
island" in the salty bay.
Involving the Public in
Deciding the Coast's Future
Joe Farrell is working to bring people together. During the past
year, the UD Sea Grant Marine Advisory Service specialist has helped
conduct dozens of public meetings on serious issues facing the Delaware
coast, from proposed new construction to watershed restoration.
A major effort has been a series of public forums called "Saving
Our Bays," which Farrell facilitated with colleague Bill McGowan
from UD Cooperative Extension. The forums, and their companion publications,
have delivered information and helped solicit input from more than
20,000 Sussex Countians on developing a pollution control strategy
for the Inland Bays. The project was sponsored by the Center for
the Inland Bays.
"We considered a number of possible choices relating to land
use and bay use and deliberated their pros and cons," Farrell
says."Through the process, people began to see bits and pieces
of choices that will meet their needs and the environment's."
This fall, Farrell will lead a similar process for Delaware's Youth
Farrell also continues to manage the Inland Bays Citizen Monitoring
Program. Now in its tenth year of operation, the program involves
more than 30 volunteers, who collect and analyze water samples along
the bays. The program is supported by the Delaware Department of
Natural Resources and Environmental Control.
At the request of state legislators, Sea Grant Marine Advisory
Service specialist Joe Farrell recently moderated a public forum
on a proposed planned community near Little Assawoman Bay.
Monitoring a resource as large as the Delaware Bay requires the
"eyes" and "ears" that technology can provide,
from satellites in outer space to acoustic sensors positioned underwater.
Using these tools, Sea Grant researchers are working to develop
accurate, cost-effective approaches for keeping tabs on the coastal
resources we depend on and care about, from the Delaware Bay to
sea turtle populations.
How Well Do Satellites
See Microscopic Plants?
UD marine scientists have been using satellites to monitor El Niño,
predict the path of oil spills, and track the weed Phragmites
in marshes. Now they are testing how well two new sensors can detect
concentrations of microscopic plants in coastal waters.
Oceanographer Xiao-Hai Yan and his research team are using Synthetic
Aperture Radar (SAR) and the Sea-Viewing Wide-of-Field Sensor (SeaWiFS)
to determine how much plant life exists in Delaware and New Jersey
waters under different seasons, temperatures, and wind conditions.
The sensors "read" the light reflected by the tiny plants'
green pigment, or chlorophyll. The amount of chlorophyll in surface
waters is a key indicator of aquatic health.
While the satellites can easily detect chlorophyll in the open
ocean, where the water is clear, the sensors' vision clouds near
shore. The problem is the high sediment inputs from land.
Yan and his team are developing new data processing techniques
that may help the sensors sort out what is chlorophyll and what
Using Lighthouses to
Relay Data from Sea to Shore
Through the years, the lighthouses in Delaware Bay have been good
and faithful stewards, helping mariners get their bearings.
Now these sentinels may help advance the science of the sea by
relaying information on acoustics, weather, wind, tides, and currents
to oceanographers on shore.
UD marine scientist Mohsen Badiey is working with colleagues Kuo-Chuin
Wong and Alexander Cheng to equip Fourteen Foot Light, a 112-year-old
lighthouse in Delaware Bay, as a platform for gathering environmental
During the past three years, the team deployed acoustic sensors
and other oceanographic equipment in the bay. These units were connected
to computers stationed in the lighthouse.
This summer, the scientists will test the wireless communications
system that will continuously transmit the data received by the
lighthouse to the UD College of Marine Studies in Lewes. A "live"
camera system also will be installed at the lighthouse, and then
a three-month field trial will begin.
"It's an exciting project with a lot of promise," Badiey
says."If this pilot system works, our next goal would be to
connect three more lighthouses to build a long-term, low-cost monitoring
network for Delaware Bay."
In addition to Sea Grant, the project has been supported by the
U.S. Coast Guard and the U.S. Office of Naval Research.
Aboard the UD research ship Cape Henlopen, Mohsen Badiey and Art
Sundberg map the location of an acoustic sensor in Delaware Bay.
The device is tethered to Fourteen Foot Light (see
112-Year-Old Sentinel Still Lights Way for Mariners (see
pdf). Art Sundberg, UD's Assistant Director of Marine Operations,
and his wife, Debby, have a special fondness for Delaware Bay lighthouses.
According to the couple's research, Fourteen Foot Light was the
first "submarine foundation" lighthouse built in the United
States. Made of cast iron, the 80-foot lighthouse was first commissioned,
or lit, in Delaware Bay in 1888. About 21 feet of the lighthouse
is submerged. The lamp is 59 feet above the water line. One of the
sentinel's most unique attributes is a cast-iron outhouse.
While Fourteen Foot Light is closed to the public, it is well maintained
by the U.S. Coast Guard. The interior of the lighthouse was painted
in 1997, and the interior woodwork is well preserved. Since 1998,
solar energy has powered the lighthouse's beacon and horn. The Sundbergs
note that the sentinel's full name is "Fourteen Foot Bank Lighthouse."
It earned the name from being constructed on a bank, or shoal, in
Sea Turtles Count on Delaware Bay
The Delaware Bay provides critical habitat for sea turtles, according
to scientist Pamela Plotkin. Last summer and fall, she and her students
documented loggerhead and Kemp's ridley turtles during weekly aerial
surveys and estimate there are thousands in the bay.
"What we've seen confirms what I saw during a few surveys
in 1997," she says." At that time, I found the density
of sea turtles to be comparable to or greater than the U.S. southeast
coast, where sea turtles are most abundant."
Plotkin, who is on the adjunct faculty at the UD College of Marine
Studies and a senior scientist at the Center for Marine Conservation
in Washington, DC, says the turtles probably are lured to Delaware
Bay by their favorite foods blue crabs and horseshoe crabs.
Plotkin now is completing her final report, which will be shared
with federal and state agencies.
"I hope these data will be useful to them in regulating activities
that adversely impact sea turtles," she says."Worldwide,
sea turtle populations have plummeted. We all need to work together
to protect them."
The Loggerhead Turtle Common Visitor to Delaware Bay (see
pdf). This turtle visits Delaware Bay in summer and fall.
It is the most common turtle in U.S. waters, inhabiting warm, nearshore
regions of the Atlantic Ocean. Its major nesting beaches in the
United States are in South Carolina, Georgia, and Florida.
The loggerhead is named for its large head, which may measure 10
inches wide. Its reddish-brown, heart-shaped shell may reach 3 feet
long. This turtle can weigh up to 400 pounds although some tipped
the scales at 1,000 pounds years ago.
Loggerheads have powerful jaws for crushing shellfish. They eat
horseshoe crabs, blue crabs, clams, mussels, and other invertebrates.
Like all sea turtles, the loggerhead can see well underwater and
is believed to have an acute sense of smell. When active, it must
swim to the surface every few minutes to breathe. When resting,
it can stay underwater for as long as two hours without breathing.
Loggerhead turtles are listed as a threatened species. Their population
has been declining for a number of reasons, from turtles drowning
in fishing nets, to raccoons preying on their eggs. All sea turtles
are protected by law in the United States.
Growing a Shellfish Garden
in the Inland Bays
John Ewart wants to get more shellfish growing in the Inland Bays.
Adding more clams and oysters, which feed by filtering algae out
of the water, could help restore the water quality in Rehoboth,
Indian River, and Little Assawoman bays. Too many nutrients currently
plague the aquatic system.
For the past two years, the aquaculture specialist for the UD Sea
Grant Marine Advisory Service has been experimenting with various
grow-out systems for shellfish in the Inland Bays. So far, he's
had good success his oysters grew from seed to market size
in one year.
This summer, Ewart plans to set up a floating upwelling system,
or FLUPSY, to serve as a nursery for the shellfish seed. The FLUPSY
consists of a series of mesh-covered silos that house the tiny shellfish.
Piped into the silos is a constant supply of algae. When the clams
reach the size of a nickel and the oysters reach the size of a quarter,
they are less vulnerable to predation by fish and crabs and are
ready for planting.
Ewart hopes to enlist people who live along the bays to help raise
the shellfish. In Virginia, he says there are more than 1,000 "shellfish
gardeners" who grow oysters for Chesapeake Bay. He believes
Delaware could have a similar successful program in the Inland Bays.
"But our bays are more for growing clams," he says.
Delaware's sandy shores help buffer the mainland from storms and
provide habitat for spawning horseshoe crabs to nesting piping plovers.
Our beaches also attract an estimated 5 million vacationers each
Sea Grant researchers are developing computer models to advance
the science of shoreline prediction and protection. They also are
working to increase public awareness of rip currents, hurricanes,
and other coastal hazards.
Book Offers Plan for Ocean's Future
The Future of U.S. Ocean Policy: Choices for the New Century
provides a call for action on the most serious marine issues facing
the nation, from restoring America's most depleted fisheries to
protecting eroding shorelines. The critically acclaimed book was
written by UD professors Biliana Cicin-Sain and Robert Knecht.
To effectively address marine issues, the authors say we need to
consider the ocean as a whole rather than as the sum of its parts.
"Many ocean programs were established 30 years ago. One set
of regulations was created to manage offshore oil development, a
different set of laws was made to manage fisheries, and so on,"
says Knecht. "It's time now to manage the ocean as the coherent
system it is rather than by political and administrative subdivisions."
For information about the book, contact the UD Center for the Study
of Marine Policy at (302) 831-8086.
Shall We Save the Shore, or
Let Nature Take Its Course?
Maintain eroding beaches, or just let nature take its course? The
decision may be easy to make now in Delaware, but what about tomorrow?
For a state that currently spends nearly $2 million each year to
keep its beaches in place, "it's worthwhile to consider all
the options," says George Parsons.
Parsons, a UD economist, is working with coastal engineer Robert
Dalrymple to predict the costs of replenishing Delaware's ocean
beaches over the next 100 years versus retreating from the coastline.
The Department of Natural Resources and Environmental Control is
partially funding the project, with beach manager Tony Pratt serving
as an adviser.
Currently, coastal engineers Dalrymple and graduate student Courtney
Garriga are collecting beach profile data, from Lewes to Fenwick
Island, to estimate how rapidly each beach will erode in the future.
Meanwhile, Parsons and graduate student Jeff Wakefield are collecting
housing data from tax records, aerial photos, and other sources.
They're putting together an inventory of the structures that could
be threatened by beach migration in the next century and estimating
the value of the houses that could be lost to the sea. They're also
estimating how much it would cost to continue nourishing the beaches
"Too often economics gets ignored in the policy debate,"
Parsons says."We see this as a real opportunity to get economics
involved in beach policy-making."
Modeling How Waves Behave
Although coastal engineer Jim Kirby grew up on the Chesapeake Bay,
he never thought his career would have anything to do with the sea.
Fluid mechanics was "always my thing," he says, but mostly
as it applied to meteorology. He was interested in air pollution.
Then he got a job working in a hydraulics lab where his first job
was to design breakwaters in a harbor, and he became hooked on waves.
During the past year, Kirby and graduate student Arun Chawla developed
a computer model to estimate when hazardous conditions would be
expected to occur in inlets, making them unsafe for navigation.
The engineers conducted experiments in a flume in the UD Ocean
Engineering Lab to simulate high-energy waves, translated the motions
into math and physics equations, and then tested and refined their
Eventually, Kirby says, the inlet study will be integrated into
UD's popular Refraction/ Diffraction (REF/DIF) model, which can
show how waves behave near harbors, inlets, and islands. Currently,
Kirby receives more than a dozen requests for the model each month
from engineers from around the world.
Getting a Grip on Rip Currents
One of the first things Ib Svendsen's students learn in his coastal
engineering class is his guiding philosophy: "If you want to
model nature, you must copy nature. If you want to copy nature,
you must understand nature."
For the past few years, the UD coastal engineer and doctoral student
Kevin Haas have been working to sort out the complex hydrodynamics
of an infamous coastal phenomenon: rip currents.
Dangerous to swimmers, these strong currents are formed when there
is a break in an underlying sandbar or the current is diverted by
a jetty or other barrier. At these locations, water rushes out to
sea in a narrow path.
"We've found that while the rip current stretches over the
entire depth as it flows out through the opening in a sandbar, it
soon converts into essentially a surface current as it moves seaward.
Out there, the current at the bottom usually has an entirely different
direction than at the surface and often flows opposite the flow
at the surface directly toward the shore."
Svendsen and Haas are gathering data on rip current channel widths,
distances from the shore, and wave height. These measurements will
be integrated into UD's SHORECIRC computer model to improve its
ability to predict when and where these complex currents will occur
and what their effects will be.
Recently, the model was tapped for development into "a community
model of nearshore processes" by the National Oceanographic
Partnership Program in the National Oceanic and Atmospheric Administration.
Led by UD's coastal engineering team, the five-year, $5-million
project includes researchers from the Naval Postgraduate School,
Naval Research Laboratory, North Carolina State, Oregon State, Scripps
Institution of Oceanography, University of Florida, University of
Michigan, and Woods Hole Oceanographic Institution.
a Rip Current
From the air, a rip current is easy to spot. This intense current
forms when a break in an underlying sandbar funnels water out to
sea in a narrow channel. A rip current also can form along the path
established by a jetty or other coastal structure.
A rip current can sweep even the strongest swimmer out to sea.
Minimize your chance of being caught in a rip current by recognizing
A channel of
muddy-colored water flowing out to sea.
A line of foam,
seaweed, or debris floating out to sea.
A section of
A break in the
surf as the waves roll toward shore.
Rip currents can occur anytime along the shore. To protect yourself,
learn how to swim. Never underestimate the force of ocean water.
And always swim at beaches with lifeguards.
What should you do if you get caught in a rip current? The most
important advice don't panic. To escape a rip current, swim
parallel to the shore until you are out of the current, or let the
current carry you until its force diminishes. Then swim diagonally,
safely back to shore.
of Coastal Hazards
As the new coastal processes specialist for the UD Sea Grant Marine
Advisory Service, Wendy Carey wants to help Delawareans better understand
the dynamic natural forces that affect the coast and how to minimize
their impacts, from storm flooding to wind damage.
"The rapid growth of the Delaware coast has resulted in a
significant increase in the number of people and structures exposed
to storm hazards," she says. "Residents, visitors, and
property owners will benefit from knowing more about the natural
processes that shape the shoreline. An understanding of hazard mitigation
and beach management principles is essential for proper planning,
construction, and survival at the shore."
Recently, Carey helped the City of Lewes procure a $500,000 Project
Impact grant from the Federal Emergency Management Agency (FEMA)
to advance public awareness and mitigation efforts relating to hurricanes
and northeasters. She now chairs Project Impact's Public Education
and Awareness Work Group, which is developing programs on topics
ranging from disaster preparedness to the design of "storm-safe"
homes. With the help of Quality Roofing Supply Company in Lewes,
the group is working to build a portable unit that illustrates construction
techniques for protecting homes from wind and flood damage.
For information about coastal hazards and storm safety, please
contact Carey at (302) 645-4258.
How do marine organisms adapt to super-hot
underwater geysers, icy Arctic waters, and other demanding environments?
The answers may result in a host of useful products in fields ranging
from medicine to food processing.
Sea Grant researchers
are exploring two very different environments deep sea hydrothermal
vents and the Delaware Bay to learn more about the sea's
tiniest life and how they might help us.
to New Extremes
UD marine biologist Craig Cary really knows
how to "get down." In January, he led an international
team of scientists on Extreme 2000 the first deep-sea expedition
of the millennium to hydrothermal vent sites in the Sea of
Cortés off Mexico.
During the 11-day mission, the scientists
used the submarine Alvin to explore super-hot vents and their
bizarre organisms, from weird 4-foot tubeworms to ancient bacteria.
They also made a historic phone call to classrooms in three states
as part of the project's education component.
The research team used special sensors (see
article, below) to learn more about the chemistry and microbiology
at the vents. Heat-hardy bacteria were collected from vent chimneys
and even off the backs of certain vent worms.
Cary and his group now are culturing the
bacteria and analyzing its DNA. The scientists compare the unique
sections of the nucleotides, the compounds that make up DNA, to
classify the microbes. This process, called genetic fingerprinting,
is a useful tool for learning how the microbes are related to one
another, as well as for identifying their distinctive properties.
"Vent organisms have evolved the ability
to thrive under extreme pressure, temperature, and chemistry,"
Cary notes. "This ability involves special biochemical adaptations
that, if understood, could be used to improve many industrial processes,
for example those used in manufacturing pharmaceuticals. The exciting
aspect of this science," he adds, "is that every time
we explore deep-sea vents, we find something totally new."
Chemistry at Vent Sites
Researchers from the University of Delaware
and Analytical Instrument Systems, Inc., have developed an electrochemical
analyzer, a kind of under-water "snooper," that can detect
the chemicals spewing out of hot vents over a mile deep on the ocean
The analyzer, which is mounted to the submarine
Alvin, can be parked near a vent to provide readings of the
sulfur-rich compounds rocketing out of the Earth's crust. Ironically,
these toxic chemicals may serve as fingerprints, leading scientists
to the locations of deep-sea organisms that may be beneficial to
"This is the first time a system like
this has been built to operate at such great depths and pressures,"
says UD chemist George Luther.
So far, the analyzer has been tested at
a depth of 2,500 meters with pressure over 200 times what it is
on the surface. The device has withstood deep-sea temperatures from
nearly freezing to 100°C at the vents.
The system consists of two units. The first
is a foot-long wand that houses gold/amalgam electrodes, which Luther
built and coated in a super-tough plastic. The wand is attached
to one of Alvin's arms for placement near the vents.
The wand also is connected to a 3-foot-long,
8-inch-diameter tube that houses the system's electronics. This
component, built by Don Nuzzio, of Analytical Instrument Systems,
Inc., is mounted to the bottom of the sub. A 2-inch-thick anodized
aluminum housing protects the electronics from imploding under the
crushing weight of the sea.
The analyzer can detect a number of chemicals
simultaneously. Recently, the UD team found that the presence of
two compounds hydrogen sulfide (H2S) and iron
monosulfide (FeS) may be an important indicator of the oldest
microscopic vent life. These compounds react to form the mineral
pyrite ("fool's gold") and hydrogen gas. The hydrogen
provides the energy the microbes need to grow.
Based on this discovery, Luther hopes the
"snooper" eventually will aid scientists in sniffing out
ancient bacteria and yield information about other vent life.
"Learning more about the chemistry of
the vents should help us better understand the biology of the vents,
and why deep-sea organisms, such as heat-hardy Pompeii worms, live
where they live," he says. "Some of these vent dwellers
may possess enzymes useful in processing food and drugs and developing
other important applications."
Delaware River Bacteria
While they are the tiniest organisms
on Earth, microbes play many mighty roles.
In aquatic systems, these microscopic plants
and animals form the base of the food chain. They impact important
geological, biological, and chemical cycles, which among other things,
control the amount of oxygen in the water. And they detoxify certain
Some pollutants, however, harm microbes. David
Kirchman, a UD marine biologist, is examining how a major class
of pollutants polyaromatic hydrocarbons, or PAHs impact
microbes in the Delaware River near Philadelphia.
PAHs often are found in highly industrialized
estuaries. The pollutants originate from tar, wood preservatives,
oil, and other fossil fuels. The complex chemistry of the compounds
causes them to be insoluble in water. In estuaries, they can cause
tumors in fish and accumulate to lethal levels in bottom-dwelling
organisms such as oysters.
Kirchman and graduate student Dawn Ward have
been working to find out which microbes are harmed by PAHs, and
conversely, which microbes may degrade the complexchemical compounds.
The scientists are focusing on one type of microbe heterotrophic
bacteria which have an animal-like metabolism.
Since nearly all bacteria are impossible to
isolate in the lab and grow in pure culture, much of the research
relies on molecular methods, which are applied to samples from the
river. The DNA fingerprinting techniques help the scientists identify
the uncultured bacteria and compare their genetic composition.
During the past year, Kirchman and Ward were
able to isolate PAH-degrading bacteria in the samples.
"Although many bacteria can degrade PAHs
in the lab, our work is the first to show the impact of PAHs on
uncultured marine bacteria in a real environment outside of the
lab," he notes.
One of Kirchman's collaborators is the U.S.
Naval Research Laboratory, which is working to address pollution
of estuarine sites, such as the Naval shipyard at Philadelphia.
"They want to know how rapidly nature,
through bacteria, may be able to detoxify PAH pollution," he
says. "That would be a lot less expensive than cleanup efforts
costing millions of dollars and having additional environmental
Putting the Safety in Seafood
Delaware offers a bounty of fresh seafood.
But before you head out to purchase your next bushel of crabs or
pound of fillets, let's test your "Seafood Safety IQ."
Once you've purchased fresh fish at the market,
at what temperature should you keep it refrigerated? And how long
can you safely store the fish in the refrigerator before preparing
As seafood specialist for the UD Sea Grant
Marine Advisory Service, Doris Hicks works with consumers and the
seafood industry to develop educational programs about the proper
way to handle, store, and prepare finfish and shellfish.
Currently, through a grant from the U.S. Department
of Agriculture, she and Bill Daniels, a scientist at Delaware State
University, are working to develop a set of training videos on sanitation
control procedures for seafood processors. The videos will be made
available to the seafood industry on a national level.
Hicks also has been working to boost consumers'
knowledge of safe seafood handling practices. In addition to her
lectures, Web sites, and publications, she often serves as a resource
to reporters seeking information on seafood. During the past year,
she was quoted in a variety of media, ranging from the Washington
Post to the book Seafood for Dummies.
Her "Seafood Advisor" column also
regularly appears in Seafood Source, a newsletter published
by the National Fisheries Institute. It is distributed to more than
17,000 readers, including dieticians, food writers, and the seafood
"A mandatory seafood inspection program
is in place to provide the safest seafood possible," Hicks
says. "Consumers need to follow through with proper handling
techniques, from purchase to preparation, to prevent food safety
For more information about seafood safety,
contact Hicks at (302) 645-4297.
Welcome to the
World of Bacteria
Look through a microscope
and a whole new world suddenly appears. The organism shown here
is a member of a large class of bacteria called pseudomonads. It
moves about with the help of tail-like flagella.
Bacteria are microscopic plants and animals,
and they live everywhere. While we often associate them only with
disease, bacteria play many good roles. In aquatic systems such
as the Delaware River and Bay, bacteria and other microbes form
the base of the food chain. They mediate important geological, biological,
and chemical cycles. And they detoxify certain pollutants. In short,
the life in the estuary couldn't survive, nor could we live, without
Whether it's been a fine flounder dinner or a plate of mouthwatering
oysters on the half-shell, the sea's bounty has delighted us for
ages. Today, however, many commercial fish stocks are in dire need
Sea Grant researchers are working to achieve sustainable fisheries
by helping to define essential fish habitat and developing new management
tools. Projects focus on flounder, blue crabs, horseshoe crabs,
oysters, and others.
A Model Tool for Fish Managers
Lee Anderson wants to help fisheries managers better predict the
impact of various regulations on both fish stocks and the fishing
The UD economist and his students are developing computer models,
using commercial spreadsheet software, that consider different types
of fisheries facing real-world management concerns: from changes
in total quotas to limits on numbers of fishing trips.
So far, they have built models to address management issues in
the surf clam fishery and in a fishery under joint commercial/ recreational
exploitation. They are now taking a preliminary look at how marine
reserves may serve as a fish management tool.
Recently, graduate student Emiko Maruyama used one of the models
to address a request made to the International Whaling Commission.
The Japanese government asked that a commercial moratorium on minke
whales be lifted in order to increase fishery levels of the whales'
chief prey anchovies and sauries.
The UD model showed that the take of 50 minke whales from the Northwest
Pacific stock would not cause significant gains in either prey fishery.
Following the Floating Crabs
Blue crabs begin life as microscopic, insect-like larvae that float
along in the sea at the mercy of winds and currents.
UD marine biologist Charles Epifanio and oceanographer Richard
Garvine are combining their expertise to track the tiny crabs' travels
in Delaware Bay. They want to know what role natural forces play
in controlling the population of Delaware's most valuable fishery.
The scientists have found that soon after blue crab larvae are
hatched in July and August, they are carried south by the fast-flowing
Delaware Coastal Current. Summer winds can then push the larvae
back north for re-entry into the bay.
In novel research last summer, the scientists deployed drifters
in patches of crab larvae outside the mouth of Delaware Bay. The
drifters contained satellite-tracking devices, which revealed the
crab's locations over a 12-day period.
"Our study is one of very few that have tracked patches of
fish or crabs in the coastal environment," Epifanio notes.
He says the data indicate that as river discharge decreases in
late summer, wind effects on larval transport increase. Thus, the
supply of larval blue crabs may be maximum in drought years when
river flow is at a minimum.
Researchers Reel in Facts
about Flounder Habitat
UD fisheries scientist Tim Targett and Japanese ichthyologist Masuru
Tanaka have more in common than a love for sushi. They both study
Last summer, with support from UD, Sea Grant, and the Japanese
government, Targett and student Richard Wong conducted research
with Tanaka at Kyoto University's Fisheries Research Station in
"Japanese flounder are closely related to our summer flounder,"
Targett says. "They are in the same genus, have similar life
cycles, and support important fisheries."
Recently in his Delaware lab, Targett completed research to define
the optimal nursery conditions for our summer and southern flounder.
Targett says these flounder have differing habitat needs when they
are juveniles (less than 4 5 inches long). For example, young
southern flounder can tolerate fresh water, but summer flounder
need a higher salinity. Both species need temperatures greater than
20°C (68°F) to grow well.
"Knowing the conditions that help young flounder grow best
can help resource managers define and protect the nursery habitat
needed to sustain these fisheries," he says.
This summer, Targett will return to Japan to help them reel in
similar information on their flounder species.
Scientists Closing in on Artificial
Substitute for Horseshoe Crab
UD researchers are closing in on the development of an artificial
bait to serve as a substitute for the Delaware Bay's declining horseshoe
Currently, horseshoe crabs, used as bait, support a $2 million
conch fishery and a $6 million American eel fishery. In Delaware
Bay alone, watermen derive 20 50% of their total fishing
income from conch or eel harvests.
For the past four years, UD marine biologist Nancy Targett and
graduate student Kirstin Ferrari have been working to track down
the compound in horseshoe crabs that makes them so irresistible
to eels and conch.
The scientists originally thought the compound was in the tissue
of female crabs, but they now know the attractant is concentrated
in her eggs. The compound is very heat-stable and freeze-tolerant
and can be stored with refrigeration without a loss of activity,
the scientists say.
Given the attractant's molecular size and complexity, Targett says
it's unlikely that a cost-effective synthetic version of it can
be developed. However, she says another source of the chemical cue
besides horseshoe crab eggs appears to be available in hemolymph,
a component of the crab's blood.
Horseshoe crabs routinely are bled by the biomedical industry for
Limulus amoebocyte lysate (LAL), a compound used to test
drugs for bacteria. Although the chemical cue is more dilute in
hemolymph, Targett says its source is more sustainable than crab
"As a waste by-product of the LAL industry, hemolymph is available
in large quantities year-round," she notes.
She and Ferrari are working to optimize incorporation of the chemical
cue from the hemolymph into a cost-effective bait. They also have
met with a commercial bait manufacturer.
"We believe we're closing in on a long-term, sustainable solution
to the current horseshoe crab dilemma," Targett says.
Marking Oysters for Success
The oyster fishery in the Mid-Atlantic region has suffered from
overfishing, habitat degradation, and disease.
Researchers have planted hatchery-produced oyster seed in the Choptank
and Tred Avon rivers, two tributaries of the Chesapeake Bay, in
the hope that these oysters will survive and reproduce. However,
as is true in most stock enhancement efforts, it's difficult to
tell whether the introduced stock has any real effect.
UD marine biologist Patrick Gaffney is working on a tool to evaluate
oyster stock enhancement efforts. He's discovered a genetic marker
that's passed on to the offspring produced by the outplanted oysters.
Gaffney and graduate student Coren Milbury are now using molecular
techniques borrowed from the biomedical industry to analyze thousands
of young oysters collected from the bay areas that are most likely
to contain recruits from the outplanted oysters.
If successful, Gaffney says, the technique could be used in shellfish
restoration efforts in Delaware Bay as well as for other fisheries
Teaching Students and Public
about Ocean Resources
Few people know as much about sea life as Bill Hall, education
specialist for the UD Sea Grant Marine Advisory Service. Ask him
a question about any number of organisms from horseshoe crabs
to stargazers, moon jellyfish to velvet ants and rarely is
he stumped for an answer.
During the past year, Hall was asked by the Atlantic States Marine
Fisheries Commission to provide expert comment on the horseshoe
crab's decline in Delaware Bay and the crab census he helps organize
along beaches in Delaware and New Jersey.
Hall also was interviewed about the horseshoe crab by local and
national media ranging from the Delaware State News and the
Wilmington News Journal to U.S. News and World Report,
National Public Radio, and others. Last spring, in response
to a request from the U.S. Fish and Wildlife Service, he led Secretary
of the Interior Bruce Babbitt on a tour of Delaware's horseshoe
crab spawning beaches.
In addition to his work with horseshoe crabs, one of Hall's chief
objectives is to help train Delaware teachers in marine science.
Last year, in conjunction with the state Department of Education's
Smithsonian Project, he hosted workshops on insects, soil and water,
and Delaware's Inland Bays. More than 75 teachers attended and are
sharing what they've learned with students in kindergarten through
Last year, Hall also helped develop "Extreme 2000: Voyage
to the Deep," a multimedia project to engage science students
in UD deep-sea research. About 800 students learned more about the
ocean's greatest depths through a video, printed resource guide,
and interactive Web site.
Education and Outreach
Increasing public awareness, understanding, and appreciation of
the ocean and coast is a top priority at Delaware Sea Grant.
During the past year, our outreach team the Marine Communications
and Marine Advisory Service staffs developed a variety of
educational projects. Only a few are highlighted here. For additional
resources, please visit our Web site at www.ocean.udel.edu/seagrant
or contact us at (302) 831-8083.
Lectures Highlight Latest Sea
During the past year, UD Sea Grant joined with the College
of Marine Studies to host public lectures at the Hotel du Pont in
Wilmington and the Hugh R. Sharp Campus in Lewes. More than 1,000
people listened to presentations about the deep sea, horseshoe crabs,
and many other topics. The Lewes series is held from April through
September. The next Wilmington series will begin in November. For
more information, please contact UD Marine Communications at (302)
12,000 Visitors Turn Out
for Coast Day
Coast Day 1999 was one of the largest on record more
than 12,000 visitors turned out for research demonstrations, ship
tours, crab races, a seafood chowder challenge, and dozens of other
A survey was mailed to 400 visitors to assess their opinions of
the event. Respondents gave Coast Day a high ranking for its educational
value. Based on a 10-point scale, the average rating was 8.9. Forty-four
percent ranked Coast Day a perfect 10.
Ninety-nine percent of the respondents said they had a better understanding
and appreciation of marine resources after visiting Coast Day. And
88% of repeat visitors said that attending Coast Day has changed
their views of the marine environment. The number-one response was
that they are more careful to minimize their impact on the environment.
Two-thirds say they have a better understanding of marine research
and how it might affect them. Many are reading more about ocean/marine
issues, with 62% more aware of marine conservation laws and regulations.
Almost half say they support political candidates who support the
environment and environmental issues. Others are more aware of seafood
handling. And 16% said they volunteer for environmental/conservation
Students, Public Explore the
Deep Sea in Virtual Expedition
In January 2000, students and the public took a virtual trip to
the ocean's depths as they followed UD marine scientists and an
international team of colleagues on the first deep-sea expedition
of the millennium. Their mission: to explore hydrothermal vent sites
over a mile deep in the Sea of Cortés off Mexico's west coast.
The pilot project "Extreme 2000: Voyage to the Deep"
was developed by UD Sea Grant outreach staff, working with
marine biologist Craig Cary, who was the chief scientist on the
expedition. It was supported by the National Science Foundation,
Sea Grant, and Public Broadcasting Station WHYY-TV in Wilmington
The project included an interactive Web site containing photos
and video clips of the scientists' discoveries during the expedition,
a half-hour classroom video produced by WHYY-TV, and a full-color
resource guide on the deep sea.
About 800 students in 14 classrooms in Delaware, New Jersey, and
California participated in the project. One of the highlights was
a conference phone call between the classrooms and Dr. Cary as he
worked in the submarine Alvin during the historic first dive
of the millennium. The audio of the call is available on the project's
Web site: www.ocean.udel.edu/deepsea.
The Web site, which was developed by the UD Marine Communications
Office, includes information on the scientific crew, hydrothermal
vents and their bizarre creatures, and the high-tech tools that scientists
use in deep-sea exploration. The site also includes "News from
the Deep," where video clips, photos, dive logs, interviews with
the scientists, and daily journals were uploaded daily during the
11-day mission. This information was transmitted from the Sea of Cortés
to Delaware with the assistance of the Woods Hole Oceanographic Institution,
which operates the submarine Alvin.
The Extreme 2000 project also captured attention from the media,
including the New York Times, CNN Headline News, Science,
Environmental News Network, The Lancet, Pittsburgh Tribune-Review,
British Broadcasting Company, USA Today, Yahoo.com, and
While the expedition ended in January, the Web site continues to
serve as a useful resource on the deep sea. So far, the Web site
has logged more than 60,000 visitors and continues to attract new
Web travelers every day.
Dive in to www.ocean.udel.edu/deepsea
Sea Grant College Program
1, 1999 June 30, 2000
Federal & Other
Coastal Ocean Studies
| $ 61,637
In addition to this funding, Delaware investigators successfully
competed for several special grants from the National Oceanic and
Atmospheric Administration (NOAA), U.S. Department of Commerce.
Funds for these projects are managed by the University of Delaware
Sea Grant College Program and serve as an important mechanism for
the development of comprehensive and integrated research efforts:
marine biologist Patrick Gaffney received $63,000 to evaluate Chesapeake
Bay oyster stock enhancements with molecular markers. This is in
addition to his current award ($83,000) from the Sea Grant Oyster
Disease Research Program.
As part of
a regional Mid-Atlantic Sea Grant outreach project, UD Sea Grant
investigators James Falk and Tracey Bryant received $15,639 to conduct
a survey of public perceptions and attitudes about Pfiesteria
piscicida and to develop radio public service announcements about
Under the NOAA
Sea Grant Technology Program, UD investigators Biliana Cicin-Sain
and Robert Knecht are developing a policy framework for governing
marine aquaculture in U.S. federal waters. This 18-month effort
is funded at $103,608.
State University, aquaculture scientists Bernard Petrosky and William
Daniels are completing the third year of a $150,000 award to develop
aquaculture methods in the Mid-Atlantic for crawfish and bait fish.