Salt marshes are a vital part of the coastal ecosystem. They provide a nursery for many kinds of marine animal life. Sitting in the transition zone between the ocean and the land, salt marshes serve as a physical buffer against severe weather. They act as a chemical buffer by capturing, holding and releasing nutrients that are brought in on each tide. As a result, the marshes have a great influence on the type and amount of nutrients that enter the sounds and the ocean. That buffering capacity varies on tidal, daily and seasonal time scales, but how it functions is poorly documented.

A team of Skidaway Institute of Oceanography scientists have begun a project to get a clearer picture of how salt marshes function and interact with their surrounding environment.  

The composition of the science team reflects the interdisciplinary nature of the project. Principal investigator Jay Brandes, Aron Stubbins and Bill Savidge are chemical oceanographers, and Catherine Edwards is a physical oceanographer. Geologist Clark Alexander and physical oceanographers Jack Blanton and Dana Savidge are also contributing to the effort. The three-year project is funded by a $699, 971 grant from the National Science Foundation.

“Scientists have looked at salt marshes in the past and have gotten some good data,” Brandes said. “However, this will be the first detailed look at the combined functions of one of these marsh systems.”

The project will focus on Groves Creek, a portion of coastal salt marsh along the Wilmington River, adjacent to the Skidaway Institute campus. Groves Creek has been the site of other research projects.  Over the past three years, Blanton, Alexander, Dana Savidge and others have studied the topography and water-flow in the marsh as part of a Department of Energy-funded project.  Because of this, the physical layout of the marsh has been documented to a fine detail. 

“We already know a lot about this area, especially how the water moves in and out of the marsh on the tides,” said Brandes. “We have a very good understanding of the topography of the top of the marsh and its tidal creeks, both above and below the surface.” 

The scientists also believe the Groves Creek area is fairly representative of salt marshes along the Georgia and South Carolina coasts.

From a chemical standpoint, the research will focus on way the salt marsh uses carbon: is it a consumer or producer of carbon-based organic material and nutrients?

“Marshes take material in from the river on every high tide, and they deliver material back to the river on the falling tide -- but it isn’t the same stuff,” Savidge said. “The marsh changes the river chemistry on every tidal cycle.”

There isn’t much consensus on what controls that exchange between river and marsh. “That is one of the big questions,” said Brandes, “Trying to understand whether the marsh is a producer or consumer, and how that changes over time, the seasons, the tides and so on.”

To get a detailed history of marsh-river exchange, the scientists will place sensors in the marsh that will measure various conditions every 15 minutes. Remote sensors cannot measure everything, so the research team will also be collecting samples on a daily basis and returning them to their labs for analysis.  Understanding the big picture will come from adding up all the little incremental changes over time and relating them to the actions of sun, tide and weather on the marsh surface.

Stubbins will focus his efforts on the role of dissolved organic carbon in the marsh. Savidge will work look at how the salt marsh uses dissolved oxygen. Edwards will be modeling how water flows in and out of the system and how that movement interacts with the chemical and biological activity.

When the project is complete in three years, the Skidaway scientists expect to have a much more extensive picture of the role salt marshes play in the larger coastal ecosystem.

The 2010 Deepwater Horizon oil spill in the Gulf of Mexico is the impetus behind a research project at the Skidaway Institute of Oceanography to study the effects of spilled oil on blue crabs and grass shrimp. 

The project is looking at two forms of oil. The first, emulsified oil, is an oil-water mixture produced by wave turbulence.  The oil doesn’t change chemically, but the emulsification produces a thicker, more viscous mixture.

“Because the emulsified oil is so much thicker, it becomes a much more difficult clean-up issue, especially if it is washed ashore,” said Skidaway Institute professor Richard Lee, the chief scientist on the project.

Lee and his team are exposing blue crabs and grass shrimp to emulsified oil in sediment and then watching to see how this affects their molting, which is the way the shrimp and crabs grow. 

The second focus is on oil that has been treated with dispersants. In the case of the Deepwater Horizon spill, millions of gallons of chemical dispersants were sprayed over the surface of the Gulf to disperse the oil slick. These break the oil down into micro-droplets. Dispersed oil forms a underwater plume that can extend for many miles.

In the laboratory, the researchers are adding emulsified oil into the tanks containing the crabs and also feeding the crabs squid that has been contaminated by the emulsified oil. Dispersed oil droplets are added to tanks containing embryos of crabs and shrimp.

“What we are trying to determine here is just how the exposure to dispersed or emulsified oil affects the growth and molting crabs and shrimp,” said Lee.

The scientists selected grass shrimp and blue crabs for the study because of the important places they occupy in the marine food web. Although grass shrimp are not typically harvested as a commercial product, they are abundant in salt marshes and estuaries, and are an important food source for many fish. Blue crabs are also a food source for many fish in addition to having value as a commercial catch.

The study is funded by a $500,000 grant from the Environmental Protection Agency.

Lee is working with research associate Karrie Bulski at Skidaway Institute. The team also includes Sook Chung from the institute of Marine and Environmental Technology at the University of Maryland, and Harriet Perry and Christopher Snyder from the University of Southern Mississippi’s Gulf Coast Research Laboratory.

Sook is looking at the crab and shrimp at a molecular level. “We believe that the genes that regulate molding will be affected, and the crab and shrimp will not molt properly,” said Lee. “Hormone regulation and its relationship to contaminant exposure is something we need to learn more about, and Dr. Sook carries out that kind of research.”

The researchers will also send tissue samples, primarily from the shrimp and crab’s endocrine organs, to another researcher, Anna Walker, at Mercer University School of Medicine to look for physiological or pathological changes.

Another major part of the project will be to explain the results of the study to the public, especially the fishermen whose livelihood depends on a healthy marine ecosystem.  A significant part of the grant, $80,000, is designated for the establishment and implementation of a Community Outreach for Accurate Science Translation teams in four communities along the north central Gulf of Mexico coast.

“This is primary role for the team from the University of Southern Mississippi,” said Lee. “They will develop public presentations on the project and the results to educate them on what this all means to them.”

The project will run through 2013.

The crew of Skidaway Institute of Oceanography’s Research Vessel Savannah has been honored with the Gold Award in the Chancellor’s Customer Service Recognition Awards. The crew won the award in the team category in a competition among all 36 institutions in the University System of Georgia for year ending June 30, 2012.

The 92-foot, ocean-going R/V Savannah is used by scientists from Skidaway Institute as well as other institutions for oceanographic research in waters ranging from Cape Hatteras to the Gulf of Mexico.

The award was based on a survey of scientist-customers in which R/V Savannah crew received outstanding reviews. In the two key categories that dealt directly with the crew and their interaction with the science parties, the scientists rated the crew with an average of 4.97 on a scale of one to five.

The crew received the award in a ceremony at Clayton State University on October 4th. The team is led by Captain Raymond Sweatte, and includes First Mate Peter Casserleigh, Engineer Richard Huguley, Second Mate Chris Keene and Marine Technician John Bitchy. They are supported by Marine Superintendent Michael Richter. 

The Skidaway Institute of Oceanography is currently seeking applications for two faculty positions.

Trace Element Geochemist – This is a faculty position at the Assistant Professor level in trace element geochemistry. Applications from more senior candidates will also be considered. The successful candidate must have a Ph.D. and is expected to develop an active, extramurally funded research program. We are particularly interested in a collaborative colleague who can demonstrate experience in conducting field-based, interdisciplinary research in estuarine, coastal and/or marine environments.

For additional details, see the full job description and application guidelines at: http://www.skio.usg.edu/aboutus/jobs/1348248214.pdf

Marine Environmental Chemist – This is a faculty position at the Assistant Professor level in environmental chemistry, with interest in organic contaminant chemistry in the marine environment. Applications from more senior candidates will also be considered. The successful candidate must have a Ph.D. and is expected to develop an active, extramurally funded research program. We are particularly interested in a collaborative colleague who can demonstrate experience in conducting field-based, interdisciplinary research in estuarine, coastal and/or marine environments.

For additional details, see the full job description and application guidelines at: http://www.skio.usg.edu/aboutus/jobs/1348248079.pdf