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Columns::March 3, 2003
Federal budget supports several university projects
‘Next generation’ debuts: MyUGA lets users customize their Web sites
Word of mouth: State’s poets, novelists, writers gather here for Literary Festival
Points of views
Major fellowships, scholarships are offered to 72 prospective students
Ramsey Student Center is named a Red Cross emergency shelter
Two university employees named outstanding advisers for 2003
International law prof works to help regulate global climate change
Administrative Changes
Kudos
Model behavior
Building the new learning environment
Campus News
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| An aerial survey shot--taken this past December--of the Jericho River along Interstate 95 shows large patches of marshland that have begun to die. (Photo by Matt Ogburn) |
Marsh reality
Researchers look for cause of plague spreading in coastal area
By Phil Williams
phil@franklin.uga.edu
In the spring of 2002, large patches of marshland along the Georgia coast began to die. Brown areas, in which vegetation had vanished, appeared irregularly. Alarmed landowners from a number of areas in coastal Georgia have called to report dying
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James Hollibaugh
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marshlands. UGA scientists have been working closely with the Coastal Resources Division of the Georgia Department of Natural Resources to study the problem.
“If you drive down I-95 along the Georgia coast, you really notice it, especially north of the road where it crosses the Jericho River,” says James T. Hollibaugh, head of the department of marine sciences at UGA. “Unfortunately, it seems to be spreading, because we have also seen what appear to be new patches along the Duplin River in McIntosh County.”
In some areas the die-off is so complete that the marsh has been reduced to bare mud that is beginning to slough off into creeks and tidal estuaries, causing damage that may be slow to heal.
A common marsh plant called Spartina is the biological glue that holds the fragile salt marshes along the Atlantic coast together, and a widespread die-off would have major consequences for coastal resources. Georgia, in fact, is not the first state where marsh die-off has been reported. Louisiana, Texas, South Carolina and even New York have reported problems with marsh health, although it is not clear whether all of these incidences have the same cause.
At first, UGA researchers divided the possible causes into three main categories: drought-related; biotic stress, such as from pathogens; and other problems, including chemical spills and sediment “starvation.” Even an over-abundance of snails--presumed to be caused by the decline in the populations of blue crabs that normally keep snail populations in check--was considered.
“I don’t think the problem is drought, because the patterns of the die-off are wrong for it,” says Hollibaugh. “And an inventory showed that there was not an excessive number of grazing snails that might be killing the plants in the marsh. The pattern seems to indicate a disease, so we’ve been looking for evidence of a pathogen, though it’s not yet clear if that is the cause.”
One problem with the idea that the die-off is being caused by a pathogen is that most are specific to a given host. Researchers are not quite sure what to make of the fact that both Spartina (smooth cordgrass) and Juncus (needlerush) are dying. Spartina and Juncus are only distantly related, but it may be that this pathogen affects them both. The few broad-leaf plants that are found in affected marshes seem to be immune to whatever is killing Spartina.
These studies into the problem have been substantially aided by data from the well-established Georgia Coastal Ecosystems Long Term Ecological Research Project, which studies the role of river flow in the ecological linkages between upland areas and the coastal zone in central Georgia. This project, which is based at UGA’s Marine Institute, has given scientists a head start by providing background data on marsh health and marsh function and on the microbes normally associated with Spartina.
Other scientists are also working on the problem. The Coastal Resources Division of DNR is using aerial surveys to track marsh die-offs and has employed Geographic Information System analysis of satellite images for the same purpose.
In November 2002, the Georgia Coastal Research Council, a newly formed think tank for coastal science in Georgia, held a meeting in Brunswick to discuss the problem. Representatives from UGA, Savannah State University, Skidaway Institute of Oceanography, the Georgia Sea Grant College Program, Sapelo Island National Estuarine Research Reserve, the Georgia Environmental Protection Division, Gray’s Reef National Marine Sanctuary and the Coastal Conservation Association attended the meeting.
“Originally, we considered a number of possible causes for the marsh die-off, but we were able to rule some out early,” says Merryl Alber, a UGA marine scientist who coordinated the meeting with research scientist Janice Flory, also of UGA. Mary Ann Moran of UGA’s department of marine science is also involved in the search for a possible pathogen.
One outcome of the meeting was the establishment of a standard procedure that can be used by students and “marsh watch” groups to see how--and if--the die-off is spreading.
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