University of Georgia Skidaway Institute of Oceanography professor Marc Frischer will discuss his on-going research into black gill in shrimp in an Evening @ Skidaway program on March 12th. The program will be in the McGowan Library at the UGA Skidaway Institute, beginning with a reception at 6:30 p.m. to be followed by the lecture program at 7:15 p.m.
A Georgia shrimp with the Black Gill characteristics clearly visible.
In recent years, Georgia shrimpers have been very concerned about black gill, a mysterious condition affecting the coastal shrimp population. While the condition does not affect the edibility of the shrimp, many shrimpers believe that black gill may be largely responsible for reduced shrimp harvests. Frischer is leading a research project involving scientists, regulators and shrimpers from three states in an effort to determine the cause, effects and possible solutions to the black gill problem.
An “Evening @ Skidaway” is sponsored by the UGA Skidaway Institute of Oceanography and the Associates of Skidaway Institute.
The free program is open to the public.
For additional information, call 912-598-2325.
A sample of marine debris collected along the Georgia coast sits on a table at the UGA Skidaway Institute of Oceanography.
University of Georgia researchers are hoping to find a consistent way to record the marine debris—particularly pieces of plastic—crowding Georgia's beaches as part of an effort to find a solution for the growing problem.
Marine debris has been washing up on Georgia beaches and uninhabited islands for years. Combatting the issue starts with figuring out how big it is, and a new two-part study from the UGA Skidaway Institute of Oceanography and Marine Extension published online in the Marine Pollution Bulletin finds that marine debris reporting can improve if it becomes standardized.
The problem right now is this: A volunteer group goes out and records the weight or volume of the marine debris collected. However, volunteers don't often record the specific square feet measured or the contents of the debris. Due to a lack of report standardization, researchers often can't compare the marine debris, especially plastic fragments, reported by different groups.
"We've seen plastic usage go up dramatically," said study co-author Dodie Sanders, a marine educator and outreach coordinator for UGA Marine Extension, a unit of the Office of Public Service and Outreach. "It's an important 21st century global issue. We need to learn more to better understand the issues of marine debris."
The study's lead author Richard F. Lee, professor emeritus with the UGA Skidaway Institute of Oceanography, agrees.
"Plastic debris is created on land and then it goes into rivers, flows into the ocean and washes up on land," he said. "We've found that plastic debris ends up not only on populated beaches, but on inaccessible islands as well. We've found plastic everywhere on the coast."
The first part of the study gathered debris from 20 sites along Georgia's coast, including Tybee, Cumberland and Ossabaw islands. The debris was reported from volunteer organizations like Clean Coast, which hold monthly beach and marsh cleanups in Georgia.
"The volunteer groups reported the weight of the debris, though we didn't know the exact amount of plastic," Lee said. "Based off the volunteer information we received, we did a follow-up study to more precisely measure the marine debris in a fixed location and period of time."
The total collected debris ranged from 180 to 1,000 kilograms. The levels of plastic debris differed at each site over the course of the study, though plastic was consistently among the mix. Found plastic included plastic bottles, wrappers, food utensils and fragments of fishing gear.
Sanders spearheaded the second part of the study, where she and students collected plastic debris from Skidaway and Wassaw islands over a period of two years.
"While Dr. Lee did data analysis, I did some of the field work," Sanders said. "We picked the two islands in the second part of the study because they were accessible sites where Marine Extension often takes students for marine education."
For the fieldwork, Sanders and students visited the islands each month. They took inventory of what kinds of plastics were on specific areas of the coast.
"On about a monthly basis, I would take students to learn about debris and tally all the items on the islands," Sanders said. "We took areas of 200 meters by 40 meters and recorded the items found. We also used GPS units to mark what areas we had done."
The students, many of them in middle and high school, came from all over Georgia to assist. As part of Marine Extension, Sanders regularly teaches visiting students about marine life. When students volunteered to clean up, she tried to emphasize the issues surrounding debris.
"The bulk of the plastic comes from land," Sanders said. "When people think of marine debris, they think of the ocean. I try to emphasize watershed concepts—what happens upstream ultimately gets downstream."
"It can take years for plastic to degrade," Lee said, adding, "80 percent of the plastic found at Wassaw turned out to be fragments. The fragments then spread and can have a number of environmental effects."
Sanders says that since plastic debris is everywhere on the coast, it has to be addressed and reported efficiently to reduce its effects.
"There are proactive and reactive approaches to the issues of marine debris, and both are important," she said. "We've been reactive so far by picking up debris. The proactive approach is our role in educating the public and researching the negative impacts of marine debris."
The study was supported by the Georgia Department of Natural Resources Coastal Incentive Grant, NOAA Southeast Atlantic Marine Debris Initiative and the NOAA Marine Debris Program.
The full article on "The amount and accumulation rate of plastic debris on marshes and beaches on the Georgia coast" is available at www.sciencedirect.com/science/article/pii/S0025326X1400820
A research team from the University of Georgia Skidaway Institute of Oceanography has completed the first high-resolution, bathymetric (bottom-depth) survey of Wassaw Sound in Chatham County.
Led by Skidaway Institute scientist Clark Alexander, the team produced a detailed picture of the bottom of Wassaw Sound, the Wilmington River and other connected waterways. The yearlong project was developed in conjunction with the Georgia Department of Natural Resources.
The survey provides detailed information about the depth and character of the sound’s bottom. This information will be useful to boaters, but boating safety was not the primary aim of the project. The primary objective was to map bottom habitats for fisheries managers. DNR conducts fish surveys in Georgia sounds, but, according to Alexander, they have limited knowledge of what the bottom is like. “One of the products we developed is an extrapolated bottom character map,” Alexander said. “This describes what the bottom grain size is like throughout the sound. Is it coarse, or shelly or muddy? This is very important in terms of what kind of habitat there is for marine life.”
A second goal was to provide detailed bathymetric data to incorporate into computer models that predict storm surge flooding caused by hurricanes and other major storms. Agencies like the United States Army Corps of Engineers, the Federal Emergency Management Agency and the National Oceanographic and Atmospheric Administration use mathematical models to predict anticipated storm inundation and flooding for specific coastal areas. A key factor in an accurate modeling exercise is the bathymetry of the coastal waters.
“You need to know how the water will pile up, how it will be diverted and how it will be affected by the bottom morphology,” Alexander said. “Since we have a gently dipping coastal plain, storm inundation can reach far inland. It is important to get it as right as we can so the models will provide us with a better estimate of where storm inundation and flooding will occur.”
Funded by an $80,000 Coastal Incentive Grant from DNR, Alexander and his research team, consisting of Mike Robinson and Claudia Venherm, used a cutting-edge interferometric side-scan sonar system to collect bathymetry data. The sonar transmitter/receiver was attached to a pole and lowered into the water from Skidaway Institute’s 28-foot Research Vessel Jack Blanton. Unlike a conventional fishfinder, which uses a single pinger to measure depth under a boat, the Edgetech 4600 sonar array uses fan-shaped sonar beams to both determine water depth and bottom reflectivity, which identifies sediment type, rocky outcroppings and bedforms, in a swath across the boat’s direction of travel.
The actual process of surveying the sound involved long hours of slowly driving the boat back and forth on long parallel tracks. On each leg, the sonar produced a long, narrow strip indicating the depth and character of the sound bottom. Using high-resolution Global Positioning System data that pinpointed the boat’s exact location, the system assembled the digital strips of data into a complete picture of the survey area.
All the other sounds on the Georgia coast were mapped in 1933, but for some reason data from that time period for Wassaw Sound was unavailable. When the team began this project, they believed they were conducting the first survey of the sound. However, just as the researchers were finishing the project, NOAA released data from a 1994 single-beam survey that had been conducted in advance of the 1996 Olympic yachting races that were held in and near Wassaw Sound.
“This worked out very well for our project, because we are able to compare the differences between the two surveys conducted 20 years apart,” Alexander said. “We see areas that have accumulated sediment by more than 2 meters, and we also see areas that have eroded more than 2 meters since 1994. Channels have shifted and bars have grown or been destroyed.”
Because of advances in technology, the current survey is significantly richer in detail than the one conducted in 1994. “We can zoom down to a square 25 centimeters (less than a foot) on a side and know the bottom depth,” Alexander said.
The survey produced a number of findings that were surprising. The intersection of Turner Creek and the Wilmington River is a deep, busy waterway. Although most of the area is deep, the survey revealed several pinnacles sticking up 20 feet off the bottom. “They are round and somewhat flat, almost like underwater mesas,” Alexander said.
The researchers determined that the deepest place mapped in the study area was a very steep-sided hole, 23 meters deep, in the Half Moon River where it is joined by a smaller tidal creek. They also found several sunken barges and other vessels.
The survey data set is available to the public on the Georgia Coastal Hazards Portal at http://gchp.skio.usg.edu/. Alexander warns that while boaters should find the survey interesting, the information is intended for habitat research and storm surge modeling, not for navigation. “Because the bottom of Wassaw Sound is always shifting and changing, as our survey showed, don’t rely on the data for safe navigation,” he cautioned.
Alexander has already received a grant for an additional survey, this time of Ossabaw Sound, the next sound south of Wassaw Sound. He expects work to begin on that survey in early 2015.
The Skidaway Institute of Oceanography is a research unit of the University of Georgia located on Skidaway Island near Savannah. The mission of the institute is to provide the state of Georgia with a nationally and internationally recognized center of excellence in marine science through research and education.
University of Georgia Skidaway Institute of Oceanography scientist Catherine Edwards is part of a research team that has received an $18.8 million grant to continue studies of natural oil seeps and track the impacts of the BP/Deepwater Horizon oil spill in the Gulf of Mexico ecosystem.
Known as ECOGIG-2 or “Ecosystem Impacts of Oil and Gas Inputs to the Gulf,” the project is a collaborative, multi-institutional effort involving biological, chemical, geological and chemical oceanographers led by the University of Georgia’s Samantha Joye. The research team has worked in the Gulf since the weeks following the 2010 Macondo well blowout.
The three-year, $18.8 million ECOGIG-2 program was funded by the Gulf of Mexico Research Initiative, or GoMRI.
“Our goal is to better understand the processes that have affected the oil spill since 2010,” Edwards said. “How the droplets were dispersed? Where the oil went? How it was taken up by small microbes and also the effects on animals further up the food chain?”
Edwards’ role in the project is to use autonomous underwater vehicles, also called “gliders,” to collect data on conditions around the spill site. Equipped with sensors to measure characteristics such as depth, water temperature, salinity and density, the gliders can cruise the submarine environment for weeks at a time, collecting data and transmitting it back to a ship or a shore station.
“We want to understand the ocean currents—how they change over time and how they change in depth,” Edwards said. “Surface measurements give us a two-dimensional picture of the ocean. Glider data in the vertical provides more valuable information for more fully understanding ocean currents and how they arise.”
The gliders will operate both in conjunction with shipboard instruments and also independently. One advantage of using the gliders is they can operate during storms and rough weather, when it may not be possible to use ships. Edwards said shipboard work doesn’t always give a full picture of ocean dynamics simply by the fact that they can only go out when the weather is reasonably clear.
When working in conjunction with research ships, the gliders can provide additional observations, significantly improving the quality of the data set. The gliders also report dissolved oxygen concentrations and optical measurements of chlorophyll and organic matter, and may also be used as a test vehicle for new instruments in development.
Edwards will use “GENIoS,” a new software package, to help navigate the gliders. GENIoS uses high-resolution forecast models of wind and ocean currents, along with information from the glider itself, to calculate the optimal path for the gliders. This will improve the quality of the scientific data collected.
GENIoS is a collaboration among Edwards, Fumin Zhang from the Georgia Institute of Technology and their two Georgia Tech Ph.D. students, Dongsik Chang and Sungjin Cho. GENIos has been tested for more than 210 glider-days on the continental shelf off Georgia and South Carolina. This experiment will be its first test in the Gulf of Mexico.
Edwards also hopes to use this project to test the gliders as platforms for new, experimental sensors developed by other members of the ECOGIG-2 team.
Others involved in ECOGIG-2 include UGA marine sciences faculty Christof Meile, Renato Castelao and Catherine Edwards as well as Annalisa Bracco and Joe Montoya of Georgia Tech.
For additional information, contact Catherine Edwards at (912) 598-2471 or firstname.lastname@example.org.
SkIO Seminar: Gelatinous zooplankton: Risks, drivers, and food web energy transfer
Kelly Robinson, Ph.D., Postdoctoral Scholar, Hatfield Marine Science Center, Oregon State University
Skidaway Institute of Oceanography, John F. McGowan Library Auditorium, Savannah, GA
Increases in the frequency, size, and extent of gelatinous zooplankton (i.e. jellyfish) blooms in a number of coastal areas worldwide have intensified concerns about their ecological and socioeconomic impacts. As humans increasingly modify and interact with coastal ecosystems, it is important to determine the drivers of change in jellyfish as well as evaluate their benefits and costs. I review how climate forces operating at varying scales and forage fish harvest have affected jellyfish populations in North American coastal waters. The role forage fish and jellyfish play as energy transfer pathways in coastal pelagic food webs is also examined.
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Frischer, M. E., C. A. Sanchez, T. L. Walters, M. E. Thompson, L. M. Frazier, and G.-A. Paffenhöfer. 2014. Reliability of qPCR for quantitative gut content estimation in the circumglobally abundant pelagic tunicate Dolioletta gegenbauri (Tunicata, Thaliacea). Food Webs 1:18-24. doi: 10.1016/j.fooweb.2014.11.001
Wolfram, S., J. C. Nejstgaard, and G. Pohnert. 2014. Accumulation of polyunsaturated aldehydes in the gonads of the copepod Acartia tonsa revealed by tailored fluorescent probes. 2014. PLOS ONE 9(11): e112522. doi: 10.1371/journal.pone.0112522
Berger, S. A., S. Diehl, H. Stibor, P. Sebastian, and A. Scherz. 2014. Separating effects of climatic drivers and biotic feedbacks on seasonal plankton dynamics: no sign of trophic mismatch. Freshwater Biology 59:2204-2220. doi: 10.1111/fwb.12424
Leal, M. C., S. A. Berger, C. Ferrier-Pagès, R. Calado, J. Brandes, M. E. Frischer, and J. C. Nejstgaard. 2014. Temporal changes in the trophic ecology of the asymbiotic gorgonian Leptogorgia virgulata. Marine Biology 161(9): 2191-2197. doi: 10.1007/s00227-014-2496-5