News Archives 2000     current topics

Winter 2000 Topics

• A new beginning with oyster restoration
• Davis elected new board chair
• New red tide discovered
• Oyster shell research leads to fertilizer enhancer
• Scientists hope to harvest pollutants from wetlands
• Tiny crabs find new home in South Carolina
• New Sea Grant specialist hired
• S.C. Sea Grant hires administrative specialist

A new beginning with oyster restoration

Coastal managers have virtually ignored some valuable ecosystems in South Carolina for generations. For example, Sea Grant scientists had to start from scratch when they began studying how to restore the state's oyster reefs, which had been previously slighted as an important marine ecosystem and as a subject for research.

"In South Carolina, we have many healthy oyster reefs to learn from," says Loren Coen, marine ecologist at the S.C. Department of Natural Resources. "But there is not a baseline of knowledge about growth rates and diseases in South Carolina oysters, nor about how natural reefs function and develop. We need to understand these things before we can make recommendations on how to restore these habitats."

Because stocks of the eastern oyster have declined throughout its range, researchers are attempting to rebuild reef ecosystems in several regions, especially in the Chesapeake Bay. But South Carolina's reef ecology is much different from that of other oyster-producing regions, said Coen. South Carolina oysters grow high out of the water, for example, so they are exposed at low tide, whereas Chesapeake oysters are totally submerged. Perhaps local oysters have less exposure to disease, such as MSX and Dermo, as a result.

The researchers have built a total of six experimental reefs at two sites at Inlet Creek and Toler's Cove in Mt. Pleasant. Still, Coen and his colleagues are learning how South Carolina reefs should be restored. "We're trying to understand the oyster habitat here. We're starting from scratch because these areas have been studied so little. We have to build a foundation of knowledge before we can address how to restore these important habitats."

Davis elected new board chair

Dr. Leroy Davis, president of South Carolina State University, has been elected chair of the S.C. Sea Grant Consortium's Board of Directors. Davis begins his one-year term immediately.

Davis has spent much of his professional life at South Carolina State University, where he began his academic career as a biology professor. In 1990, he became Vice Provost for Academic Administration and was later promoted to Vice President for Student Services. Davis was appointed the eighth president of South Carolina State University in 1996. He has also published articles in general and technical journals. "I look forward to serving as the Consortium's board chair," said Davis. "I am excited to have the opportunity to be engaged in science, incorporating my background in molecular biology."

"I am extremely pleased that Dr. Davis has been elected chair of the Consortium Board of Directors," said Rick DeVoe, executive director of S.C. Sea Grant Consortium. "The Consortium and its programs will certainly benefit from his guidance and stature as one of the state's preeminent university leaders."

New red tide discovered

Scientists from the South Carolina Task Group on Toxic Algae are focusing research efforts on a new red tide in state estuaries. Red tides, a common event in many of the world's estuarine regions, are algal blooms that reach densities so high that the water becomes discolored. In spring 1998, the first report was documented of a red tide in Bulls Bay near McClellanville. The following spring, the same phenomenon reappeared at several sites, including North Inlet estuary (near Georgetown), Bulls Bay, and Broad Creek (Hilton Head Island).

A new species of dinoflagellate named Scrippsiella carolinium formed the red tides, according to Alan Lewitus, marine scientist at USC Belle Baruch Institute for Coastal Research. Monitoring of the North Inlet estuary indicates that Scrippsiella bloomed in April 1999 after rain that followed a prolonged dry period.

Lewitus predicts, based on the past two years' pattern, that Scrippsiella red tides will bloom this spring (April through May) after rain that follows extended dry spells.

Researchers plan to do intensive sampling then to determine Scrippsiella's distribution throughout state estuaries. They will combine aerial analyses (fly-overs) with water sampling (known as "groundtruthing") to figure out the red tide's geographic range. They will also focus on characterizing the bloom's physiological properties to learn how environmental conditions affect its growth and survival. Lewitus said that not all red tides are harmful to the environment, but they can be a warning signal of degrading ecosystems.

He stressed that there is no hard evidence that the Scrippsiella red tides are harmful, and in fact, toxicity tests on it proved negative. However, he also cautioned that further research is necessary before researchers can conclude that Scrippsiella blooms are harmless. Lewitus noted that the geographical distribution of the 1998 red tide blooms coincided with that of the 1997 oyster die-offs from McClellanville to south of Charleston. Also, in 1998, researchers found that Scrippsiella's presence caused reduced juvenile clam growth and may have affected blue crab mortality.

Even if a dinoflagellate is not toxic, it can be harmful to shellfish in other ways, such as clogging their gills. So, this spring, scientists will emphasize testing Scrippsiella's effects on shellfish, Lewitus said. They will also attempt to culture the organism using new techniques.

Oyster shell research leads to fertilizer enhancer

Some farmers are significantly improving crop yields with a biodegradable fertilizer enhancer inspired by the Eastern oyster. Sea Grant researcher A.P. "Hap" Wheeler, Clemson University biologist, has explored a variety of potential commercial uses for polyaspartic acid, modeled after oyster shell proteins. Based on Wheeler's research, scientists discovered that polyaspartic acid helps plants absorb additional nutrients from the soil. By applying this polymer to soils, farmers can gain greater yields with smaller amounts of fertilizer.

Donlar Corp., based in Bedford Park, Illinois, manufactures polyaspartic acid with the branded names AmiSorb, used on agricultural crops such as corn and wheat, and Magnet, used on vegetable crops such as tomatoes.
Wheeler doesn't knows exactly how these products help plants absorb nutrients more efficiently. "They seem to enhance movement of nutrients in soils to the plant root," says Wheeler.

Yet "the polymer does not penetrate inside the plant," says Ramon Georgis, Donlar's director of research and development. Because the fertilizer enhancer does not reach into the plant, and because it is biodegradable, the Environmental Protection Agency waived a hurdle in its normal approval process for new agricultural products.

Farmers and environmental regulators have been searching for ways to reduce fertilizer loads, because fertilizers often run off into waterways during heavy rains. Using Donlar's polymer, farmers could save money while protecting water quality. With an investment of $8-10 dollars on AmiSorb, farmers can enhance their crop yield by $20, says Georgis.

Now Wheeler is collaborating with Donlar scientists to examine how long the fertilizer enhancer lasts in the soil. This study could help show farmers what kind of application rates that crops need each year. "If the polymer stays in soil for some time, maybe you don't have to apply as much every season," says Wheeler.

In the 1980s, Wheeler and a colleague joined Larry Koskan, who later became the founder and CEO of Donlar Corp., to perfect an inexpensive process to produce polyaspartic acid, a commercial form of the oyster protein. Based on Sea Grant-funded research on oyster proteins, Donlar Corp. was founded in 1990 to produce industrial quantities of polyaspartic acid for various commercial uses. Sea Grant research was a key factor in Donlar's receipt of of a Presidential Green Chemistry Challenge Award from the Environmental Protection Agency in 1996, according to Koskan.

Scientists hope to harvest pollutants from wetlands

Many plants naturally absorb certain pollutants from soils and store or degrade these contaminants in their tissues. Now Sea Grant researcher Laszlo Marton, biologist at the University of South Carolina, is studying how one species of salt-marsh plant can be manipulated to absorb pollutants more efficiently.

Marton and USC colleagues Yungpin Chen, James T. Morris, and Mihaly Czako have identified an enzyme in the roots of the salt-marsh plant Spartina alterniflora that breaks down organic wastes from paper mills and other industries. The researchers are collecting Spartina in polluted sites, searching for plants that are first-rate cleaners. Once they have found the best pollution absorbers, the scientists will use a new cloning tool to create a genetic line of super-cleaners.

A high-tech company can use the new cloning techniques to mop up polluted sites with super-cleaning Spartina. The Sea Grant researchers hold two patents on tools used to control expression of certain genes in Spartina alterniflora. "We're toolmakers," Marton said. "We're negotiating with a company that might want to convert the tools into effective technologies."

Spartina also naturally accumulates heavy metals such as zinc, copper, tin, cadmium, and lead, but only in its root system. This plant stores heavy metals in an "internal dump site" within its root vacuoles, Marton said. But using Spartina in constructed wetlands to clean contaminated sites would require ripping out the plant's root system, an expensive, difficult, and environmentally unfriendly process.

So Marton and his colleagues are searching for a plant that could transfer the heavy metals into its upper parts. Through genetic engineering, the researchers would exaggerate this capacity, especially in the plant's leaves, which could be repeatedly harvested.

"We would introduce a gene into the plant that would induce high levels of heavy-metal accumulation in its leaves, which could be cut down, burned, and the heavy metals could be extracted and recycled."

Finally, the researchers are studying a genetic tool to improve Spartina's capacity to take up mercury from marsh sediments. Mercury is a poisonous, metallic element that forms poisonous compounds that settle in sediment and water, and bio-accumulates in the food chain, reaching humans through seafood consumption. Perhaps the best way to remove mercury pollution from sediments is to grow plants that take it up and reduce it to elementary mercury vapor, which is its least harmful form.

University of Georgia researchers have developed a tool to engineer the genetic makeup of plants, allowing the plants to absorb highly toxic forms of mercury and reduce them to a less-toxic form and eventually releasing the element as a vapor into the atmosphere. Now Marton and his colleagues are collaborating with the Georgia researchers, applying this same genetic tool to Spartina alterniflora and other wetlands plants.

Tiny crabs find new home in South Carolina

The green porcelain crab finds South Carolina waters more than just a nice place to visit. Originally hailing from tropical waters off West Africa, Brazil, and the Gulf of Mexico, the tiny crustacean has taken up residence and is thriving here, according to David Knott, marine biologist with the S.C. Department of Natural Resources (DNR). He and colleague Loren Coen, a marine ecologist also with DNR, want to know why.

The crab's population increase last summer was dramatic. Coen found 10-13 crabs per square meter at testing grounds near Charleston in April. By August, there were about 13,000 crabs in the same square meter. Just recently, Coen reported numbers of over 26,000 crabs there. "It's gone from tens to hundreds to thousands of animals per square meter," he said. "Pick up a rock or a brick, and it looks just like so many ants under there, scurrying away."

The scientists don't expect to see a reduction in numbers any time soon, for they find numerous females holding eggs. So with funding from the S.C. Sea Grant Consortium, the researchers are studying the crab. They haven't found any evidence that the animal threatens local species such as oysters or crabs. But "anytime something reaches numbers over 20,000, it can conceivably be a problem," said Coen.

The creature is not a true crab. It is a filter feeder, not a scavenger or carnivore, like the native crabs. The scientists have been able to rule out the possibility that the green porcelain crab feeds on small oysters—an initial concern since the crab is the single most prevalent creature in the oyster bed habitat. But the researchers want to know if these filter feeders make native fish's food source scarce.

The crabs have proliferated in oyster beds, but that habitat is not the Crab's favorite, Coen said. "They don't like the soft mud. They like rubble that they can take shelter under." Areas where there's rubble, like the testing grounds at Grice in Charleston and Warsaw Flats near Beaufort, are places where the species is multiplying.

At these intensive study sites, along with over 70 other coastal sites, Coen will work to learn how long the crabs live, how fast they grow, and when their numbers increase. Much of the study involves counting. And counting. Also measuring, Coen said. The scientists will use trays through April and May to collect, count, and measure. If this sounds like tedious labor, it should. The crabs can be as tiny as the head of a pin, and the largest ones are still small-about only half-an-inch in size.

"We'll stain the animals and put them back in their habitat," Coen said, "to learn how much they move." They will also discover if the crabs are eaten. Right now, scientists don't know if the species has any natural predators.

Coen intends to learn whether the crab's population increase last summer was a one-time event or whether the species will again expand dramatically. Also, he will go farther north, to Wilmington, North Carolina, looking for the crab's appearance there.

How did the creature get as far north as South Carolina to begin with? It's likely been transported through multiple sources, Knott said. Seafood stores import oysters from the Gulf of Mexico, and with the oysters, other creatures like the green porcelain crab hitchhike a ride. Ships discharging ballast water release a multitude of species into local waters. Other possible sources include shellfish and finfish farming and the aquarium trade, according to Knott and Coen.

New Sea Grant extension specialist hired

The S.C. Sea Grant Extension Program has a new community development specialist, April L. Turner, who will provide education programs on issues related to coastal growth and the conservation of natural resources.

April L. Turner is a graduate of the University of Colorado with a major in geography and received a master's degree from Clemson University in parks, recreation, and tourism management. Most recently, Turner was an environmental planner at the S.C. Dept. of Environmental Control, Office of Ocean and Coastal Resource Management.

The S.C. Sea Grant Extension Program is a cooperative coastal outreach program of the S.C. Sea Grant Consortium and the Clemson University Extension Service.or, scroll down to continue

S.C. Sea Grant hires administrative specialist

Martha Amundsen is the new administrative specialist at S.C. Sea Grant Consortium and will perform a variety of administrative assignments for the research, communications, and extension departments. She will also handle the Consortium's incoming calls and coordinate the administrative filing system.

Amundsen was previously employed as medical case manager with Careteam, Inc., a non-profit HIV/AIDS organization that serves clients in Horry, Georgetown, and Williamsburg counties.

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