Vol. 18, No. 1 Special Issue 1999
Message From The Director
Delaware's marine resources benefit millions of people in some
way, on some level.
Our sandy beaches attracted more than 5 million tourists last year.
Not only do these beaches provide vacationers with respite and contribute
to Delaware's economic health, but they are also essential to the
welfare of the horseshoe crab. And the horseshoe crab's health is
critical to our own.
This crab's eggs provide food for thousands of shorebirds migrating
northward each spring to Arctic nesting grounds. The horseshoe crab
also yields a component that's used to test every intravenous medication
for bacteria. So if you or someone you love has ever been hospitalized,
it's likely that the horseshoe crab played a role in your recovery.
Each year, more than 70 million tons of cargo are transported up
the Dela-ware Bay and River to the nation's fifth largest port complex
for distribution to consumers throughout the region. The estuary
also supplies a myriad of other vital needs, from nursery grounds
for major fisheries such as blue crabs and sea trout, to drinking
Delaware's Inland Bays Rehoboth, Indian River, and Little
Assawoman bays shelter striped bass, diamondback terrapins,
black ducks, and many other sea life. The bays are a favorite with
anglers and birdwatchers and also rank as the state's top boating
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 marine research,
educate the nation's future marine scientists, and advance public
understanding of the ocean and coast.
During the past year, with the aid of our Sea Grant Advisory Council
and external scientific panels, we underwent an intensive strategic
planning process and determined the following research priorities
that our program should address in the next five years:
Coastal Ocean Studies. Improve the scientific basis for assessing
and managing the response of estuaries, coastal waters, and watersheds
to human impacts.
Environmental Technology. Develop cost-effective technologies
for monitoring the health of coastal ecosystems.
Marine Biotechnology. Explore, develop, and use the unique,
adaptive capabilities of marine organisms.
Fisheries. Achieve sustainable fisheries and aquaculture.
In the following pages, you'll learn more about the research projects
we've funded under each of these priorities, as well as our efforts
in public education on behalf of the coast.
Our Marine Advisory Service and Marine Communications staff play
a key role in building the bridges between our labs and the public.
Whether developing a report, designing a Web page, or coordinating
our award-winning Coast Day festival, our outreach staff are dedicated
to providing you with accurate, useful information.
As new and continuing challenges face the Delaware coast, our program's
role will be to continue to provide the objective, research-based
information critical to sound environmental decision-making. It's
our commitment to you, and to the environment.
Recently, we expanded our Web site to share a variety of educational
resources with you, from research summaries and press releases to
pub- lications, audio clips of our popular "SeaTalk"
radio series, and information on seafood, aqua- culture, tourism,
and other topics.
I encourage you to visit us at www.ocean.udel.edu/seagrant
or contact us at (302) 831-8083 to learn more about the educational
resources we offer. We look forward to hearing from you!
Dr. Carolyn A. Thoroughgood
Director, Sea Grant College Program Dean,
College of Marine and Earth Studies
Coastal Ocean Studies
The goal of this Delaware Sea Grant research priority is to improve
the scientific basis for assessing and managing the response of
estuaries, coastal waters, and watersheds to human impacts. Thus,
this research requires establishing linkages among land-use practices,
shipping activities, ecosystem production, and water quality.
Our Coastal Ocean Studies currently focus on the Delaware River
and Bay, and Delaware's Inland Bays. They range from assessing dissolved
oxygen concentrations in the Delaware River and Bay, to determining
how the tides affect nutrient inputs in the Inland Bays.
Oxygen Study Important to the
Delaware and Other Urbanized Estuaries
In the 1940s, the Delaware River and Bay was so polluted from sewage
and industrial effluents, there was no oxygen in the water in the
upper estuary. At times, a 20-mile section of the estuary, from
Philadelphia south, was devoid of oxygen and reeked the hydrogen-sulfide
odor of rotten eggs.
In the last 25 years, however, the estuary has made a dramatic
comeback thanks to reductions in municipal and industrial inputs.
"The Delaware Estuary has shown improvements in water quality
unequaled by almost any other estuary in the world," says Jonathan
Sharp, an oceanographer at the University of Delaware.
Today, the estuary's oxygen concentrations exceed the minimum level
set by regulatory agencies, even in the warmest summer conditions.
But the minimum is low, prompting agencies to consider revising
their guidelines to keep the estuary on the path to improvement.
Dissolved oxygen levels in the estuary can vary significantly due
to a host of factors, some of which are not well understood. In
a three-year Sea Grant project that started in February, Sharp and
his research group have begun field experiments at specific locations
in the estuary. They're analyzing water chemistry and comparing
differences to determine what role carbon, nitrogen, and phosphorus
play in the system's oxygen dynamics.
The group's results should help resource managers as they evaluate
water-quality guidelines, and aid major municipalities, such as
the city of Philadelphia, with wasteload allocations. The project's
results also should be translatable to other urbanized estuaries.
"A number of estuaries are in similar condition as the Delaware,
such as the Hudson, Potomac, and others," Sharp notes. "There are
many inputs reaching these systems through human activities. We're
working to sort out their effects."
Are Groundwater Seeps Piping
Excess Nutrients into the Sea?
Historically, the chief concern associated with the hydrological
connection between groundwater the water that flows beneath
the Earth's surface and the ocean has been saltwater intrusion
into coastal drinking-water supplies.
However, several studies now suggest that groundwater discharges,
or "seeps," may play a significant role in transporting
contaminants, particularly excess nutrients, from the land to the
Oceanographers Bill Ullman and Doug Miller from the University
of Delaware College of Marine Studies are using infrared images
taken by aircraft and ground surveys to map where these freshwater
seeps enter Delaware Bay. Their study area is the Delaware coast
from Cape Henlopen to the St. Jones River.
Once the seeps have been identified, the scientists will use several
chemical techniques to determine the differences in distributions
of nitrogen the predominant nutrient contaminant in Delaware
groundwater in the seep zones compared to adjacent, non-seep
They also will analyze bottom-dwelling organisms to assess differences
in their abundance between the two areas. Ullman notes that some
freshwater worm species often occupy the seeps, which are like islands
of fresh water in the salty bay.
"Our ultimate goal is to determine the effect of groundwater seeps
on the bay's biological productivity and how their nutrient inputs
can be controlled," says Ullman.
"If the bulk of the groundwater enters the bay in a few areas,
like water from a pipe, treatment technologies could be applied
to these seeps to help reduce the amount of nutrient input," he
How Do Sediments
Impact Bottom Life?
Dredging and beach nourishment projects are a necessity along
the coast. However, these projects can have a down side: disruption
of the unique community of marine organisms that occupy the benthos,
or sea bottom, including worms, oysters, and other creatures.
"While seldom seen, these organisms play an important role
in the ecosystem," says University of Delaware oceanographer
Doug Miller. "They provide food for fish, crabs, and birds.
Some of these animals also serve as 'conveyor belt' species, turning
over the bottom sediment and mixing it in the process."
During the next two years, Miller will be working to determine
what rates and frequencies of sediment deposition are detrimental
to the bay's major benthic species. He then will examine how the
results can be incorporated into the design of dredge spoil disposal
and beach nourishment projects to minimize harmful impacts on benthic
Sludge-Busting Plant Takes
Root at Local Facilities
In the annals of marsh research, it's a tale reminiscent of The
Strange Case of Dr. Jekyll and Mr. Hyde.
The common reed, Phragmites australis, overtakes hundreds
of acres of wetlands in the United States each year, crowding out
more desirable plants that wildlife depend on for food and habitat.
Once transplanted in sewage treatment facilities, however, Phragmites
is proving to be a real benefit. The extensive root system that
makes the plant a nemesis of the marsh helps Phragmites rapidly
dry and break down treated waste, reducing sludge removal costs
and landfill fees.
So far, the Phragmites installed through Sea Grant research
at the Bridgeville Wastewater Treatment Plant has saved the town
$2,000 per year for the past three years.
Recently, at the University of Delaware's Halophyte Biotechnology
Center, botanist Jack Gallagher and his team used tissue-culture
techniques to develop a sterile variety of Phragmites to
allay concerns that the wild plant, used in open-air sludge beds,
could revert to its old habit and seed and degrade marshes.
These techniques entail "planting" seeds on a growth
medium of hormones, sugar, and minerals, where the seed produces
a tumor-like callus. When the hormones are changed, the callus
forms many embryonic plants, often with different genetic traits.
The scientists have regenerated 1,000 Phragmites plants
from tissue culturesand are now evaluating them in lab and field
tests in search of plants with superior traits for sludge drying
and decomposition, such as compact shoots, large leaves, and strong,
If the scientists succeed, the idea of using Phragmites
for sludge busting may take root in other towns.
Studies Address Dredging
Two University of Delaware marine scientists recently received
Sea Grant funds to conduct preliminary studies relating to the environmental
impact of deepening the Delaware Bay shipping channel from its present
depth of 40 feet to 45 feet.
Both are "white paper" studies, based solely on surveys of existing
literature on two topics: sediment geochemistry and bottom-dwelling
Oceanographer Tom Church and postdoctoral fellow Najid Hussain
have reviewed over 40 scientific reports on heavy metals, radionuclides,
pesticides, and other hazardous materials that could be released
and remobilized from river-bottom sediments.
Oceanographer Doug Miller has surveyed more than 60 published reports
on the effects of disposing dredged material, or "spoil," on the
worms, oysters, and other organisms that comprise the bay's benthic
Both studies voice several concerns about the potential environmental
impacts of the proposed dredging project.
Technical reports on the two studies are now in production. For
information, contact the University of Delaware Marine Communications
Office at (302) 831-8083, or MarineCom@udel.edu.
Water-Use Plan to Aid Bays
From bird-watching to boating, Delaware's Inland Bays, in Sussex
County, support a diversity of activities. With the county's population
projected to increase by 35%, to more than 180,000 people by the
year 2020, demands on the bays are destined to grow.
During the past year, Jim Falk, director of the University of Delaware
Sea Grant Marine Advisory Service, has been working with resource
managers and local residents to develop a water-use plan for the
bays. The plan's goal is to outline acceptable uses of the bays
to ensure that user conflicts and environmental impacts are minimized.
"Our plan focuses on the multitude of activities occurring
on the bays and the adjacent shoreline," Falk says. "We
recommend strategies and actions to help decrease the negative effects
these activities have on the environment. Additional enforcement
is one action we considered. More often, additional education is
needed to make users better aware of the things they can do to protect
the health of the Inland Bays."
The Center for the Inland Bays has appointed an implementation
team to carry out the plan's action items. For information about
the plan, call Falk
at (302) 645-4235.
Brown Tide Found in
Little Assawoman Bay
Last summer, oceanographer David Hutchins went searching for brown-tide
organisms in the Inland Bays and found them.
Brown tide (Aureococcus anophagefferens) is a microscopic
plant that can "bloom," or reproduce, so rapidly that
surface waters take on its color. While harmless to human health,
brown-tide blooms have devastated shellfish beds by forming a thick
mat of vegetation impenetrable by sunlight. Brown-tide blooms in
New York, New Jersey, and other states have cost the fisheries and
tourism industries millions in losses.
Hutchins' research, funded by Delaware Sea Grant and the Center
for the Inland Bays, was conducted in conjunction with regular water
sampling performed by the Department of Natural Resources and Environmental
Surface water was collected from 13 sites. Eleven samples, from
Indian River and Rehoboth bays, were negative. But both samples
from Little Assawoman Bay indicated the organism's presence.
"Although Delaware has not had a brown-tide bloom, the organism
definitely is here," Hutchins says. "We're now working to give
managers some idea of the potential for a harmful bloom and the
conditions under which it would be likely to occur."
How Do Tides Affect the Flow
Nutrients in the Inland Bays?
Delaware's Inland Bays Rehoboth, Indian River, and Little
Assawoman Bays have been deemed a "National Estuary"
by the Environmental Protection Agency, advancing efforts to remedy
the bays' most serious problems, including excess nutrients from
land runoff and sewage discharge.
One question that scientists and resource managers cannot yet answer
is how long these nutrients stay in the bays before they are flushed
out to the Atlantic Ocean.
In a new Sea Grant project, oceanographer Kuo-Chuin Wong of the
University of Delaware College of Marine Studies is taking the first
step in addressing this question. He's working to determine what
role the bays' physical processes the twice-daily tides
play in transporting dissolved material in and out of the
system. Wong is using a simple dissolved material as his tracer:
During the next year, Wong and his team will deploy current meters
at Indian River Inlet, the bays' chief outlet to the Atlantic Ocean;
Massey's Ditch, where Indian River Bay meets Rehoboth Bay; and the
Lewes-Rehoboth Canal, which links Rehoboth Bay to the ocean.
These meters will provide measurements of water velocity, temperature,
and salinity. Their data can then be used to determine the system's
rate, which affects the flow of all dissolved material, including
Coastal managers need to be able to easily observe resources as
large as the Delaware Bay and track key health indicators, from
pollutants in the water, to the productivity of wetlands that provide
nursery areas for fish.
The goal of this Delaware Sea Grant research priority is to develop
cost-effective technologies for monitoring coastal ecosystems using
satellites, acoustic sensors, and other tools.
Taking the Coast's
Pulse from Space
From their vantage point in space, satellites are the "eyes"
that help us with tasks from weather forecasting to military surveillance.
During the past three years, in a special research initiative called
the Coastal Ecosystem Health Project, a team of University of Delaware
scientists and an advisory group of resource managers from throughout
the state have been working together to improve the use of satellites
and related technologies in monitoring the health of the coast.
Resource managers must grapple with a host of water-quality issues
and impacts, sorting out the factors that increase and ameliorate
water pollution problems.
For example, an increase in impervious surface from development
in a watershed helps accelerate the rate of stormwater runoff, while
an increase in vegetation zones around streams and wetlands may
buffer excess nutrient
inputs to coastal waters.
Assessing these factors is difficult, but improvements in the processing
of satellite images may soon make the task much easier.
Recently, Sea Grant scientists completed a detailed land use/land
cover classification of a 1993 Landsat Thematic Mapper satellite
image of Delaware (see figure in pdf).
This classification breaks out major land-cover sectors, from developed
areas to mudflats. To aid Delaware resource managers, the image
is being segregated into the 39 sub-basins used for water-quality
reporting in the state.
As additional satellite images undergo classification, managers
may be able to assess watershed changes, right at their fingertips.
Research Offers Students
Ocean of Opportunity
A key mission of the University of Delaware Sea Grant College Program
is to educate graduate students in marine studies, providing them
with the hands-on experience critical to the development of keen
analytical and problem-solving skills.
For example, a dozen students participated in Sea Grant's Coastal
Ecosystem Health Project (article, above), advancing research in
areas ranging from satellite oceanography to marine policy.
Additionally, several policy students on the project participated
in internships and fellowships with the Delaware Nature Society
and the Department of Natural Resources and Environmental Control,
examining riverfront development, exotic species, and other issues.
Tracking Turtles in Delaware
Sea turtles visit the Delaware Bay each summer to feed on blue
crabs, horseshoe crabs, and other favorite foods.
Two years ago, University of Delaware scientist Pam Plotkin conducted
three aerial surveys of Delaware Bay and found the density of sea
turtles to be comparable to or greater than numbers reported for
the southeastern U.S. coast, where sea turtles are most abundant.
This summer, Plotkin will be conducting more extensive aerial surveys
to gather more complete data on turtle densities and the bay's importance
as turtle habitat.
"Many sea turtle species have declined dramatically,"
she says. "If our data confirm that the Delaware Bay provides
habitat critical to sea turtles, we hope to begin building regional
cooperation to protect them and help their populations recover."
Lighting the Way
to New Technologies
Lighthouses have guided mariners for centuries. Now these beacons
may light the way to new technologies for monitoring the health
of coastal waters.
With permission from the U.S. Coast Guard, a team of scientists
from the University of Delaware, including Mohsen Badiey, Kuo-Chuin
Wong, and Alexander Cheng, recently began exploring the use of Fourteen
Foot Light, in Delaware Bay, as a platform for gathering environmental
In recent underwater communications fieldwork supported by the
U.S. Office of Naval Research, the scientists demonstrated the feasibility
of attaching cable from computers stationed in the lighthouse to
acoustic sensors positioned in the bay.
This summer, the team will return to the lighthouse to deploy sensors
for a three-month test period when acoustics, weather, tide, and
current data on the bay will be continuously transmitted from sea
"The beauty of this approach is that it makes use of existing
infrastructure lighthouses which makes it extremely
economical," Badiey says. "It could save thousands of
dollars currently spent for more expensive shipboard monitoring."
Badiey notes that since the scientists control the sensors by remote
control in their labs, they have the capability of monitoring the
environment at will, even during big storms, an impossibility with
"The biggest benefit of using the lighthouses," he adds,
"is that we will be able to provide the long-term, real-time
measurements needed to formulate sound strategies for protecting
Tributary Teams Work
Organizing the Inland Bays' Tributary Action Teams has been a real
During the past year, Joe Farrell, Sea Grant Marine Advisory Service
specialist, worked with Bill McGowan, from University of Delaware
Cooperative Extension, and Ed Lewandoski, education coordinator
for the Center for the Inland Bays, to build the teams for Rehoboth,
Indian River, and Little Assawoman bays.
"The Inland Bays Tributary Action Teams are charged with building
agreement among stakeholder groups in the estuary, from property
owners to industry operators, on a plan of action for reducing habitat
loss and nutrient enrichment in the bays," says Farrell.
"Our goals are to improve the bays' water quality using sound
science as a basis for decisions and to use creativity in solving
nutrient and habitat problems," he notes.
Currently, the Tributary Action Teams are working to develop a
nutrient pollution control strategy that conforms to the Total Maximum
Daily Load limits for nitrogen and phosphorus set by the state.
The teams meet once a month. For information, contact Farrell at
Delaware's beaches and dunes play important roles in protecting
coastal communities from storms, in supporting marine life from
piping plovers to horseshoe crabs, and in fueling a healthy tourism
The goals of this Sea Grant research priority are to develop predictive
models of shoreline change and assess and improve strategies for
countering coastal erosion.
Coastal Engineers Make
Waves for Science
For most of us, the sight and sound of ocean waves rolling in to
shore evoke a feeling of great peacefulness.
For coastal engineers, the scene inspires a nagging desire to better
understand the physics of waves and currents, so that we can figure
out better ways to protect the beaches we love.
"Even a beach that appears to be stable is constantly changing,
with periods of erosion balanced over time by periods of sand deposition,"
says Robert Dalrymple, director of the University of Delaware's
Center for Applied Coastal Research.
Dalrymple and his colleagues, Jim Kirby, Nobuhisa Kobayashi, and
Ib Svendsen, are developing and refining a series of computer models
to advance the science of coastal protection. The models are aimed
at improving our capability of predicting future shoreline changes
during short-term events
such as northeasters, and in the long term, during decades of sea-level
Dalrymple is modeling how the descending eddies in breaking waves
act as small tornadoes to lift sediment, while Nobuhisa Kobayashi
is working to predict the impact of wave run-up on beaches.
Jim Kirby is studying how waves at tidal inlets are affected by
changes in depth and by the presence of currents. The model he develops
should be useful in the design and analysis of navigable inlets.
Ib Svendsen is testing a model called SHORECIRC, which was developed
in previous Sea Grant research, to further study the hydrodynamics
of rip currents, including those induced by coastal structures such
as submerged breakwaters.
At "Modelers Week" in Egmond, the Netherlands, this past
November, Kevin Haas, one of Svendsen's graduate students, took
part in a workshop where he and colleagues from England, France,
the Netherlands, and Spain were challenged to simulate the hydrodynamics
at a site on the Dutch coast.
Each participant was provided with data from the same field experiment
and then used his model to simulate it. At the end of the five-day
event, the University of Delaware's SHORECIRC model came out on
top, giving the best agreement with respect to the data.
"We were proud of the way our model performed," Haas
says. "But we're working to make it even better."
Engineer Wins International
Robert Dalrymple, director of the University of Delaware's Center
for Applied Coastal Research, has received the 1999 International
Coastal Engineering Award from the American Society of Civil Engineers.
The award was made to Dalrymple in recognition of his "outstanding
and continuing achievements and contributions to the advancement
of coastal engineering through research, teaching, and professional
Dalrymple, his colleagues, and students conduct research funded
by Sea Grant and other agencies aimed at improving coastal shoreline
prediction and protection.
He has produced over 175 research publications, from books to technical
reports; and advised 30 students, many of whom have gone on to leadership
positions in universities and coastal institutions. He also has
developed educational resources on the Internet for the coastal
engineering profession and the public at www.coastal.udel.edu.
Giving the Ocean a Voice
The ocean took center stage last June when the Clinton administration
hosted the National Ocean Conference in Monterey, California. The
historic event, to set the direction of national ocean policy in
the 21st century, featured key speeches by President Clinton, Vice
President Gore, and First Lady Hillary Rodham Clinton. In attendance
were a number of Cabinet officers, members of Congress, and 500
leaders in government, business, and the academic community.
Among them were University of Delaware marine policy professors
Biliana Cicin-Sain and Robert Knecht. The policy scientists recently
completed a Sea Grant report on U.S. coastal tourism and recreation
for the National Oceanic and Atmospheric Administration. The report
highlighted the status of coastal tourism, its economic benefits,
and growing challenges related to beach restoration and other sustainable
Currently, with Sea Grant support, the scientists are producing
Ocean & Coastal Policy Network News, a newsletter designed
to provide a forum for the exchange of news and viewpoints on U.S.
national ocean policy. For information, contact the University of
Delaware Center for the Study of Marine Policy at (302) 831-8086.
Should We Save the Beach
or Say Goodbye?
As the shoreline is swallowed up by storms and sea-level rise,
coastal states often respond by renourishing beaches with sand to
keep them in place.
"Most analysts argue that nourishment costs under such a policy
will increase over time, which raises the issue of whether retreating
from the coastline
may be a more sensible policy," says George Parsons, an environmental
economist at the University of Delaware.
Parsons is working on a Sea Grant project with coastal engineer
Robert Dalrymple (see article above) to estimate the long-term economic
costs of beach retreat versus nourishment for the Delaware coastline.
"Delaware has a policy of beach nourishment but has given
consideration to retreat as a possible long-run strategy,"
"Nourishment and retreat both involve economic costs. The
issue is which policy is the least costly for a given coastal community."
Although the scientists' focus is the Delaware coast, Parsons says
their method will be transferable to other regions.
Counting Horseshoe Crabs
and Their Benefits
The horseshoe crab's eggs sustain hundreds of thousands of migrating
shorebirds that stop along Delaware Bay each spring. While few may
know it, the crab also has saved countless human lives.
"The horseshoe crab's blood contains a unique clotting agent
that the pharmaceutical industry uses to test intravenous drugs
for bacteria," says Bill Hall, marine education specialist
for the Sea Grant Marine Advisory Service. "No IV drug reaches
your pharmacy and no prosthesis reaches your hospital without its
horseshoe crab test. So if you or someone you love has ever been
hospitalized, you owe a lot to the horseshoe crab."
Hall helps organize a regional census of the Delaware Bay's spawning
horseshoe crab population. The census is conducted on selected bay
beaches by volunteers from Delaware and New Jersey. This year, the
census is being expanded to additional beaches along both sides
of the bay with support from the Atlantic States Marine Fisheries
"Delaware Bay is the world's population center for horseshoe
crabs, but recently, we've noted a significant downturn in the animal's
population," Hall says.
"Scientists believe the decline is due to overfishing of the crab
for eel and conch bait and to the loss of the sandy beaches it needs
"The census is designed to help resource managers and scientists
gain a better understanding of the horseshoe crab's status and what
we can do to guard our 'golden goose,"' he notes.
This Delaware Sea Grant research priority focuses on exploring
the unique capabilities of marine organisms to adapt to demanding
environments. This knowledge, applied to human settings, can result
in a host of useful products in fields ranging from medicine to
Our current projects share a common goal of understanding the role
and function of marine bacteria in two very different ecosystems
the deep sea and the Delaware Bay.
Exploring New Depths in
Search of Useful Marine Microbes
From lipstick-like tubeworms to giant clams, a bizarre community
of organisms inhabits hydrothermal vent sites over a mile deep on
the Pacific Ocean floor.
Hydrothermal vents occur at fractures in the ocean floor where the
Earth's crustal plates move apart. Here, super-heated seawater spews,
carrying with it a mix of toxic minerals and gases.
These unique conditions support the only complex ecosystem known
to live on energy from chemicals rather than energy from the sun.
No natural light ever reaches these sites. And the pressure on them,
created by the weight of the vast ocean above, is tremendous, at
3,500 pounds per square inch.
In a new Sea Grant project at the University of Delaware, molecular
biologist Craig Cary, and chemist George Luther, are combining their
expertise to explore the diversity, ecology, and evolutionary history
of the tiniest life that thrives at vent sites: bacteria.
"Deep-sea hydrothermal vent bacteria are of great interest
to industry because they produce enzymes that are able to withstand
both high temperature and pressure," Cary says.
Last year, he and colleagues documented that the vent-dwelling
Pompeii worm is the most heat-tolerant creature on Earth, able to
withstand temperatures up to 176°F. The worm is covered by a
fleece of bacteria that may harbor enzymes useful in food processing,
drug manufacturing, and other high- temperature applications.
Cary's molecular techniques now will be aided by a unique microelectrode
sensor that George Luther developed in previous Sea Grant research
The sensor will enable the scientists to detect small variations
in concentrations of oxygen, manganese, iodine, iron, and hydrogen
sulfide, all of which are thought to determine the distribution
of bacteria living in hydrothermal vent communities.
As the scientists track down the ecology and evolution of deep-sea
bacteria, they will screen the organisms for enzymes with potential
applications in biotechnology.
Sensor Goes the Distance
The microelectrode sensor (closeup, see
pdf) that George Luther has developed with Sea Grant support
is helping to advance marine chemistry research because the device
can quickly and simultaneously measure dissolved oxygen, hydrogen
sulfide, manganese, and iron. Previous sensors could measure only
Last year, Luther tested the sensor's sea legs at a depth of 40
feet on the bottom of Raritan Bay off the east coast of New Jersey,
and the device performed well. The experiment, conducted with colleagues
at Rutgers Institute of Marine and Coastal Sciences, is reported
in the February issue of Sea Technology.
The sensor was mounted, with a submersible electrochemical analyzer
and companion microprofiling instruments, on a Remotely Operated
Vehicle, or ROV. All of the devices were controlled by the scientists
from a research vessel anchored above the study site.
Luther now is working with colleague Craig Cary to put the microelectrode
to work at much greater depths. On a research cruise this past May,
the scientists reported the microelectrode's first measurements
at hydrothermal vent sites. The sensor was deployed on the sub Alvin
over a mile deep on the Pacific Ocean floor.
How Do Pollutants Affect Bacteria
in the Delaware River and Bay?
For many of us, the word "bacteria" carries a negative
connotation. But not all of these one-celled organisms are carriers
In fact, many of the bacteria that live in the Delaware River and
Bay actually play critical roles in maintaining the estuary's health.
"These organisms form the base of the food chain, they mediate
a number of important biogeochemical cycles, and they detoxify certain
kinds of pollutants," says marine biologist David Kirchman.
In his laboratory at the University of Delaware's College of Marine
Studies in Lewes, Kirchman is using DNA fingerprinting techniques
to examine the impact of one major class of organic pollutants polyaromatic hydrocarbons, or PAHs on bacteria in the Delaware
River and Bay.
Originating from oil, tar, wood preservatives, and the incomplete
combustion of fossil fuels, PAHs can occur in high concentrations
in estuaries heavily impacted by industrial activity.
These compounds persist in the environment because of their complex
chemical structure. The many aromatic rings in their chemical makeup
cause them to be insoluble in water and difficult to degrade.
PAHs have been linked to a host of serious effects. Studies have
shown that these compounds can bioaccumulate and cause tumors in
"PAHs also are especially harmful to bottom-dwelling organisms
like oysters and worms because these compounds adsorb onto particles,
which then concentrate in the sediments," Kirchman says.
This summer, Kirchman and his research team will collect water
and sediment samples from the Delaware River and Bay and then use
molecular methods to find out which bacteria degrade PAHs and which
bacteria are inhibited by the compounds. This work relies on DNA
fingerprinting techniques because nearly all marine bacteria cannot
Throughout the project, Kirchman will collaborate with colleagues
at the Naval Research Lab who are working to solve problems caused
by organic pollution of estuarine sites, such as the Naval shipyard
on the Delaware River at Philadelphia.
"Like others, the Navy would like to know which contaminated
sites need active remediation and which can be left untouched, for
remediation by naturally occurring processes," Kirchman says.
"The processing of pollutants by bacteria may be Nature's way
of solving the problem."
New Brochure Informs
Consumers about Seafood Safety
Seafood safety what does it mean?
"Think of a safety net designed to protect you, the consumer,
from food-borne illness" says Doris Hicks, seafood specialist
for the University of Delaware Sea Grant Marine Advisory Service.
"Every facet of the seafood industry, from harvester to consumer,
plays a role in holding up their edge of the safety net."
While a mandatory seafood inspection program is in place to give
consumers the safest seafood possible, Hicks says consumers need
to follow through with proper handling techniques, from purchase
During the past year, she spearheaded development of "Seafood
Safety: What Consumers Need to Know." This brochure
provides guidelines for the proper handling, storage, preparation,
and serving of seafood to prevent food-borne illness.
Supported by the National Seafood HACCP Alliance, the brochure
was written by Hicks and colleague Don Kramer, Marine Advisory Service
director at the University of Alaska Sea Grant College Program.
Delaware Sea Grant's Marine Communications Office designed, edited,
and oversaw the printing of the brochure.
So far, nearly 35,000 copies of the brochure have been printed
and distributed to the Alaska Seafood Marketing Institute, the National
Seafood HACCP Alliance, and the Sea Grant programs at California,
Connecticut, Maryland, Michigan, Minnesota, Mississippi-Alabama,
New Jersey, New York, North Carolina, South Carolina, Texas, Virginia,
and Woods Hole.
Hicks is providing copies of the brochure to seafood retail outlets
throughout Delaware. For more information, contact her at (302)
Many commercial fish stocks in U.S. waters are over-exploited and
in dire need of rebuilding. The goal of this Delaware Sea Grant
research priority is to achieve sustainable fisheries and aquaculture
Current projects range from monitoring the effects of chronic reduced
oxygen levels on economically vital coastal fisheries, to defining
the best methods for culturing crayfish in the region.
Oxygen Study to Net Answers
to Fish Habitat Questions
In the rows of aquaria in Tim Targett's lab at the University of
Delaware, experiments are under way to determine the effects of
reduced oxygen levels on four economically important Atlantic fishes:
weakfish, summer flounder, winter flounder, and striped bass.
Oxygen levels fluctuate on a daily and seasonal basis in estuaries
as a result of natural biogeochemical cycles. But chronic low-oxygen
conditions, known as hypoxia, often occur in waterways afflicted
by excess nutrients.
The objective of Targett's Sea Grant research is to assess the
impact of hypoxia on young fish that utilize estuaries as nursery
grounds. These "juveniles" are less than a year old and
average only about 2 to 3 inches long.
"Besides determining the effects of a range of reduced oxygen
levels on the fish, we'll also be examining them to see if they
adopt certain behaviors to avoid low-oxygen areas," Targett
Targett says that by examining the growth and behavioral responses
to hypoxia of a variety of species with different "life styles"
from active swimmers to more sedentary flatfish scientists
may be able to predict the susceptibility of different species to
"Resource managers are working to define 'essential fish habitat'
habitat that's critical to fish survival," Targett says.
"Our research should reveal the environmental conditions needed
for healthy nursery areas."
Mapping Blue Crabs
Using Space-Age Tools
When blue crab larvae are spawned at the mouth of the Delaware
Bay each summer, they are carried southward by a fast-moving conveyor
belt called the Delaware Coastal Current. Most of the tiny crabs
are shuttled south to other estuaries, but some return to repopulate
the Delaware Bay. But how?
University of Delaware marine biologist Chuck Epifanio and oceanographer
Richard Garvine are refining a computer model that maps the travels
of the larval crabs. The model shows that once carried out to sea,
some of the crabs return to the bay with the help of summertime
The model also highlights an area along the northern mouth of Delaware
Bay, where patches of blue crab larvae are found. Using satellite-tracked
drifters and larval crab collectors, the scientists now are working
to determine what role this larval reserve plays in maintaining
the bay's most valuable fishery.
A Model System for Managing
Fisheries managers wish they had a crystal ball to help them determine
the effectiveness of regulations before they are enacted.
Lee Anderson is working on it. The University of Delaware economist
is developing computer models that can predict the effects of any
proposed management regulation on fish stocks and the economic conditions
Anderson is building the models using a commercial spreadsheet
package. They will be structured to consider various types of fisheries
facing real-world management concerns, from changes in total quotas,
to limits on numbers of fishing trips.
Artificial Bait to Relieve
Pressure On Horseshoe Crabs
Commercial fishermen have known for years that female horseshoe
crabs, when used for bait, are practically irresistible to eels
A common practice has been to collect the female crabs when they
come ashore to spawn and then quarter them for bait for eel and
Concern about recent declines in the Delaware Bay's horseshoe crab
population has spurred research at Delaware Sea Grant to find a
way to relieve fishing pressure on the crab, by providing fishermen
with an effective substitute for the living creature.
The horseshoe crab provides a host of ecological and human benefits.
Its eggs fuel shorebirds that stop along Delaware Bay on their spring
migrations. Its blood, removed without harming the animal, contains
a compound that is used to test prosthetics and intravenous drugs
Recently, at the University of Delaware College of Marine Studies,
marine biologist Nancy Targett and her research team identified
the natural chemical attractant in female horseshoe crabs that makes
them such a desirable bait for eels and conch.
The active compound has been isolated, characterized with respect
to molecular size and stability, and tested on eels. The scientists
now are working to incorporate the compound into a variety of artificial
"Next year, we hope to have baits ready for field testing
in collaboration with local fishermen," Targett says. "If
we come up with a bait that works, it'll be a win-win situation
for everyone, and especially for horseshoe crabs."
Crayfish Research to Benefit
Mid-Atlantic Fish Farmers
The eastern white river crayfish, a large species native to the
Mid-Atlantic region, might rival the popularity of its crayfish
cousins in Louisiana someday.
In Sea Grant research at Delaware State University, scientists
and Bill Daniels are working to pinpoint the optimum conditions
for growing the native shellfish so that local farmers can produce
it in a single growing season.
"Crayfish has long been a favorite in Cajun cuisine"
Petrosky says. "It's growing in popularity with consumers in
our region and throughout the United States."
Currently, the scientists are conducting experiments to determine
the effects of differing temperature and light conditions on crayfish
growth and reproduction. The scientists' goal is to define the conditions
needed to accelerate the crayfish's egg development during the winter
to provide a "jump start" on production and expand the
growing season. The scientists also are assessing the feasibility
of providing juvenile crayfish alternative feed, such as brewery
waste, to potentially reduce production costs.
In related research, the scientists are honing in on the best techniques
for growing mummichogs as commercial bait. One study of the fish
has been completed; another is scheduled for the upcoming season
in Delaware State's aquaculture ponds.
Web Site Aids Aquaculturists
Do any of Delaware's colleges offer courses in aquaculture? How
do you grow striped bass? Where can I learn more about ornamental
fish for my backyard pond?
Tap into the Web site of the Delaware Aquaculture Resource Center,
at darc.cms.udel.edu, and
you'll find the answers. The site is a gateway to a vast network
of resources relating to marine and freshwater culture.
The site provides "hot links" to sources for aquaculture
education and training; on-line publications; and local, regional,
and national sources for information and assistance. It's updated
continually by John Ewart, aquaculture specialist for the University
of Delaware Sea Grant Marine Advisory Service.
"There's an unbelievable amount of useful information available
to fish farmers on the Internet" Ewart says. "Our Web
site is designed to help Delawareans and other Mid-Atlantic residents
find answers to their questions about aquaculture."
Ewart operates the site from the Delaware Aquaculture Resource
Center, which is based in Cannon Laboratory at the University's
If you don't have access to the Internet, Ewart welcomes visitors
to drop by the resource center for a tour of the Web site. The center
is open, Monday through Friday, from 8 a.m. to 4:30 p.m. For information,
call Ewart at (302) 645-4060.
Education and Outreach
Educating Delawareans about the ocean and coast will always be
a top priority at Delaware Sea Grant. We're committed to boosting
Delaware's "Ocean IQ."
During the past year, our outreach team the Marine Communications
Office and Marine
Advisory Service developed a variety of educational projects,
some of which are highlighted here. For more information, visit
us at www.ocean.udel.edu/seagrant
or contact us at (302) 831-8083.
Coast Day Draws Sea of Visitors
Since its debut in 1977, the University of Delaware's Coast Day
festival has attracted thousands of visitors to the Lewes campus
to learn more about the ocean. Delaware Sea Grant's outreach staff
coordinate Coast Day. Despite a steady drizzle at last year's festival,
an estimated 8,000 visitors turned out to take part in activities
ranging from the Great Crab Race, to the Seafood Chowder Challenge.
One highlight was a visit by the artist Wyland, who has painted
life-size marine murals "Whaling Walls"
on buildings across the United States. Wyland kicked off the Delaware
leg of his national Ocean Mural Challenge at Coast Day, inspiring
youngsters to join together to paint the 24-foot-long mural (see
pdf). The mural is now on display in Cannon Laboratory at the
Awards for Excellence
The Marine Communications Office, the public information unit of
Delaware Sea Grant and the College of Marine Studies, won a total
of 12 awards in local, regional, and national communications competitions
during the past year. The winning projects ranged from the staff's
Coast Day poster, to the "SeaTalk" radio series.
The awards were made by the Delaware Press Association, International
Association of Business Communicators, National Federation of Press
Women, and Society for Technical Communication.
The staff includes David Barczak, art director; Tracey Bryant, marine
outreach coordinator; Pam Donnelly, production manager; and Claire
McCabe, marine outreach specialist.
Free Tours Showcase Marine
Thanks to a dedicated corps of volunteers called docents, hundreds
of people each year are learning more about the research conducted
at the University of Delaware College of Marine Studies and Delaware
Sea Grant. The docents lead free, guided tours of the college's
Lewes campus for visitors age 12 and up. For information, call the
Sea Grant Marine Advisory Service at (302) 645-4346.
Ballard Intrigues Thousands
Tale of Deep-Sea Adventure
Last October, Delaware Sea Grant co-sponsored a special
lecture by renowned ocean explorer Robert Ballard at the University
of Delaware's Bob Carpenter Center in Newark. Known to millions
for his discovery of the wreck of the Titanic and other historic
vessels, Ballard told a riveting tale of deep-sea research and exploration.
The talk drew nearly 3,000 visitors with many lining up for the
book signing held after the talk.
Brochure Highlights Boater
for Protecting Inland Bays
It's coming soon Boating in Delaware's Inland Bays: Tips
for Protecting the Environment. Developed with funding from
the Center for the Inland Bays, the full-color brochure provides
simple tips that boaters can adopt to lessen shore erosion, prevent
fuel spills, and protect bay life. For information, contact Marine
Communications at (302) 831-8083.
Web Site Offers
Ocean of Information
Research briefs, seafood information, publications, press
releases . . . these are just a few of the resources now available
at Delaware Sea Grant's Web site www.ocean.udel.edu/seagrant.
Special features include a publications catalog with an electronic
ordering form, and audio clips of the "SeaTalk" radio
series, which is broadcast on 40 AM and FM stations in the Mid-Atlantic
Dive into "Scientists in the News" on the site's News
& Events page, and you'll find out about University of Delaware
ocean scientists who recently made national headlines.
Sea Grant College Program
1, 1998 June 30, 1999
Federal & Other
Coastal Ocean Studies
In addition to this funding, University of Delaware Sea Grant 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 Delaware Sea Grant
and serve as an important mechanism for the development of comprehensive
and integrated research efforts:
For a project
slated to begin in February 2000, University of Delaware 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 of $83,000 from Sea Grant's Oyster
Disease Research Program.
was awarded $31,251 from the National Marine Fisheries Service to
study the genetic structure of spring- and summer-spawned bluefish.
scientists Bernard Petrosky and William Daniels, at Delaware State
University, began the third year of a three-year award, totaling
$150,000, to develop aquaculture methods appropriate to the Mid-Atlantic
region for crayfish and bait fish.
Service specialist Doris Hicks was awarded $16,500 as part of a
nationwide program for improving retail seafood quality and safety.
of Delaware marine biologist Ana Dittel received $23,306 from the
Marsh Ecology Research Program to continue investigations of the
production of juvenile blue crabs in coastal wetland areas.
David Hutchins and Craig Cary, at the University of Delaware, were
awarded $121,000 from NOAA and $10,000 from the Center for the Inland
Bays to investigate life-stage-specific molecular tools to predict
received $25,000 from the Center for the Inland Bays and $10,000
from DelawareSea Grant to research the possible development of brown
tide, a harmful algal bloom (HAB), in the Inland Bays.