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Posted:
8/27/2015
Author:
mikesullivan
Description:

 University of Georgia Skidaway Institute of Oceanography scientist Clark Alexander is working on a project to predict how the Georgia coast—characterized by a complex system of barrier islands, salt marshes, estuaries, tidal creeks and rivers—may look 25, 50 and 100 years from now. As sea level rises over the next century, that picture is changing.

 Researcher LeeAnn DeLeo lowers the sensor to measure conductivity, temperature and depth from the surface to the bottom. 

Predictions of sea level rise over the next century vary from the current rate of roughly 30 centimeters—about a foot—to as much as two meters—about 6 feet. Although scientists disagree on the ultimate height of the rise, they all agree that salty water is moving inland and will continue to do so for the foreseeable future, Alexander said. Here on the Georgia coast, islands will become smaller or disappear entirely; salt marshes will be inundated by the rising waters and migrate towards the uplands; and some low-lying uplands will become salt marshes.

To predict the extent of these changes, scientists are using the predictive Sea Level Affecting Marshes Model, or SLAMM, which was originally developed for the U.S. Fish and Wildlife Service.

SLAMM predicts the effects of future sea level rise based on two key inputs: an elevation mapping of the coastal zone and salinity profiles up the rivers and waterways. Salinity and elevation are two key factors that determine the type of plants, and thus habitat, that will be present at any particular location.

“As sea level rises, the fresh water in rivers will be pushed further upstream,” Alexander said. “The brackish and salty water will also move up, and the salt marshes will expand.”

Funded by a Coastal Incentive Grant from the Georgia Department of Natural Resources Coastal Management Program, Alexander and his team have been studying the five key river systems along the coast and numerous salt marsh estuaries. Salinity along the coast is dominantly affected by river discharge into the estuaries, so the team has been conducting its surveys during both winter—high river flow—and the summer—low river flow—conditions.

“We start at the mouth of a river about an hour before high tide and then we follow that high tide up the river, mapping the surface salinity along the way,” Alexander said. “We find the maximum inshore intrusion of salinity at high tide during a spring tide. That is the location that defines the boundary between the brackish marshes and the freshwater marshes.”

In addition to tracking surface salinity, the researchers also stop periodically and measure the salinity throughout the water column to determine if what they measure at the surface is similar to what is present near the bottom. They lower a device that measures the water conductivity (which is related to salinity), temperature and depth from the surface to the bottom. Also equipped with GPS capability, the device automatically captures the location of every water column profile.

In many coastal regions, denser, saltier water tends to sink to the bottom and the lighter, fresh water remains near the surface. However, because of the energy produced by Georgia’s wide tidal range, the team found that most of the water on the Georgia coast is well mixed and doesn’t show up as layers.

The second part of the project is to fine-tune existing elevation data. Scientists have an extensive set of elevation information from airplane-mounted Light Detection And Ranging systems. LIDAR is usually very accurate, except in marshes, because it cannot see through the vegetation to the actual ground surface.

“You might be off by 30 centimeters or more, and in a low-lying, flat area like our coastal zone, that can make a big difference in predicting where the water will flood,” Alexander said.

The Skidaway Institute team is working with Georgia Southern University scientist Christine Hladik on a fix. By comparing LIDAR data with the true elevation in a particular area, Hladik observed that the LIDAR error varied according to the type of plants growing there. For example, if the area contained the dense, tall spartina, the error was large and, on average, a consistent number of centimeters. If the region was covered with a different, less-dense-growing salt marsh plant, like short spartina, the error was smaller but also consistent.

“She discovered that if you know what type of vegetation is covering a section of marshland, you can plug in the correction and come back with an accurate measure of the elevation,” Alexander said.

The research team observed the vegetation and measured the true ground level at 400 randomly selected points throughout coastal brackish and salt marshes in Georgia. That information and knowledge of plant types is being used to correct the existing marsh elevations.

The research team will complete one more set of river surveys before the project ends in September. Alexander hopes to obtain continued funding to use this newly acquired elevation and salinity data in a fresh SLAMM model run for the Georgia coast, using all the high-resolution data developed in this project.

“We should be able to look out as much as 100 years in the future and see where the different wetlands will be by then,” he said. “That way we can plan for marsh sustainability, retreat and sea level rise.”

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Posted:
8/10/2015
Author:
mikesullivan
Description:

  The University of Georgia Skidaway Institute of Oceanography has produced an informational video to educate the public about black gill, a condition affecting Georgia shrimp, and the institute’s research into the problem.

Black gill is a mysterious condition affecting shrimp from Florida to North Carolina. A number of shrimpers have blamed black gill for their reduced harvests.

Almost nothing was known of the condition until the UGA Skidaway Institute began looking into the issue in early 2014. Since then, researchers have learned much about the condition, but much is still unknown. This video provides background on the condition and the results of the investigation thus far.

The video can be accessed through the UGA Skidaway Institute Website at www.skio.uga.edu. It can also be viewed on YouTube at https://youtu.be/xJQkORTHuVE.

 The black gill research is funded by Georgia Sea Grant. The video was produced in cooperation with the UGA Marine Extension, the university’s Office of Public Service and Outreach, Georgia Sea Grant and the Georgia Department of Natural Resources.

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Posted:
6/29/2015
Author:
mikesullivan
Description:

Scientists at the University of Georgia Skidaway Institute of Oceanography joined researchers around the globe in a worldwide Ocean Sampling Day on Sunday, June 21, the summer solstice.

This was the second year Skidaway researchers have participated in the Ocean Sampling Day event. The first was conducted last year, also on the summer solstice. The event focuses on simultaneous sampling of microbes in ocean, coastal and Great Lakes waters.

This year, 191 marine research locations—from the Rothera Research Station in Antarctica to Göteborg University in Sweden—participated. The sampling program supports international missions to provide information on the diversity of microbes, their function and their potential economic benefits.

“It’s a global effort to take a snapshot of microbes across the world’s oceans at the same time, on the same day, in this case, the summer solstice,” said Skidaway Institute professor Marc Frischer.

Frischer cited the significance of the project by describing microbes as the “engines of our planet” and said half the oxygen in the atmosphere is produced by microbes in the ocean.

Skidaway Institute scientists collected samples at two locations. One team collected and processed samples from the Skidaway River estuary immediately adjacent to the Skidaway Institute campus. That also served as part of an ongoing water-quality monitoring program Skidaway Institute has supported for more than 25 years. A second group teamed up with scientists from the National Oceanic and Atmospheric Administration Gray’s Reef National Marine Sanctuary and collected samples from Gray’s Reef. The 14,000-acre marine sanctuary is located about 17 miles off the Sapelo Island coast.

“We helped Gray’s Reef by collecting and processing their samples in the way they needed to be done,” Frischer said. “You really need a laboratory for that, and we were able to provide that.”

One goal of the global project is to note the commonalities and the differences among the microbial communities around the globe. Some of those differences were seen just in the samples collected at Gray’s Reef and at the Skidaway campus, two sites only 40 miles apart.

“We generally observe a larger number of smaller organisms out in the ocean, which makes sense because they are adapting to a system with lower nutrients,” Frischer said. “We also saw a different kind of photosynthetic organisms since there is much more light available in the ocean compared to rather turbid waters in our estuary.”

Much of the fieldwork at both Skidaway Institute and Gray’s Reef was handled by undergraduate college students gaining research experience at Skidaway Institute this summer. These included students from UGA and Savannah State University’s Research Experience for Undergraduates program. 

All samples and data were sent to Bremen, Germany, for DNA extraction and sequencing to ensure maximum comparability. The resulting data will be made publicly available as soon as quality checks are finished. These cumulative samples, related in time, space and environmental parameters, will provide insights into fundamental rules describing microbial diversity and function and contribute to the blue, or oceanic, economy through the identification of novel, ocean-derived biotechnologies.

Ocean Sampling Day was jointly coordinated by Jacobs University in Bremen, Germany, and the University of Oxford in the U.K. and is part of the European Union-funded Ocean of Tomorrow research project Micro B3.

“It is really important to have a global perspective,” Frischer said. “We are glad we can participate in what they are now calling “gigascience” where we are collecting a snapshot from all over the world. It is amazing!”

Additional information on the global Ocean Sampling Day project is available at www.microb3.eu/osd.

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Posted:
6/16/2015
Author:
mikesullivan
Description:

 Scientists at the University of Georgia Skidaway Institute of Oceanography will join researchers around the globe in a worldwide Ocean Sampling Day on Sunday, June 21, the summer solstice.

Kevin McKenzie and Tina Walters pull samples during Ocean Sampling Day 2014. 

This will be the second year Skidaway researchers have participated in the Ocean Sampling Day event. The first was conducted last year, also on the summer solstice. The event focuses on simultaneous sampling of microbes in ocean, coastal and Great Lakes waters.

This year, 191 marine research locations—from subtropical waters in Hawaii to extreme environments such as the Fram Strait in the Arctic Ocean—will participate. The sampling program will support international missions to provide information on the diversity of microbes, their function and their potential economic benefits.

Skidaway Institute scientists will take samples in two locations. One team will collect and process samples from the Skidaway River estuary immediately adjacent to the Skidaway Institute campus as part of an ongoing water-quality monitoring program Skidaway Institute has supported for more than 25 years. A second group will team up with scientists from the National Oceanic and Atmospheric Administration Gray’s Reef National Marine Sanctuary and collect samples from Gray’s Reef. The 14,000-acre marine sanctuary is located about 17 miles off the Sapelo Island coast.

Much of the fieldwork at both Skidaway Institute and Gray’s Reef will be handled by undergraduate college students gaining research experience at Skidaway Institute this summer. These will include students from UGA and Savannah State University’s Research Experience for Undergraduates program. 

All samples and data will be sent to Bremen, Germany, for DNA extraction and sequencing to ensure maximum comparability. The resulting data will be made publicly available as soon as quality checks are finished. These cumulative samples, related in time, space and environmental parameters, will provide insights into fundamental rules describing microbial diversity and function and contribute to the blue, or oceanic, economy through the identification of novel, ocean-derived biotechnologies.

Ocean Sampling Day is jointly coordinated by Jacobs University in Bremen, Germany, and the University of Oxford in the U.K. and is part of the European Union-funded Ocean of Tomorrow research project Micro B3.

Additional information on the global Ocean Sampling Day project is available at www.microb3.eu/osd

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Publications
Marsico, R. M., R. J. Schneider, B. M. Voelker, T. Zhang, J. M. Diaz, C. M. Hansel, and S. Ushijima. 2015. Spatial and temporal variability of widespread dark production and decay of hydrogen peroxide in freshwater. Aquatic Sciences (pagination pending). doi: 10.1007/s00027-015-0399-2
Helms, J. R., J. Mao, H. Chen, E. M. Perdue, N. W. Green, P. G. Hatcher, K. Mopper, and A. Stubbins. 2015. Spectroscopic characterization of oceanic dissolved organic matter isolated by reverse osmosis coupled with electrodialysis. Marine Chemistry (pagination pending). doi: 10.1016/j.marchem.2015.07.007
Hunter, E. A., N. P. Nibbelink, C. R. Alexander, K. Barrett, L. F. Mengak, R. K. Guy, C. T. Moore, and R. J. Cooper. 2015. Coastal vertebrate exposure to predicted habitat changes due to sea level rise. Environmental Management (pagination pending) doi: 10.1007/s00267-015-0580-3
Rossel, P. E., A. Stubbins, P. F. Hach, and T. Dittmar. 2015. Bioavailability and molecular composition of dissolved organic matter from a diffuse hydrothermal system. Marine Chemistry (pagination pending) doi: 10.1016/j.marchem.2015.07.002
Bittar, T. B., A. Stubbins, A. A. H. Vieira, and K. Mopper. 2015. Characterization and photodegradation of dissolved organic matter (DOM) from a tropical lake and its dominant primary producer, the cyanobacteria Microcystis aeruginosa. Marine Chemistry (pagination pending) doi:10.1016/j.marchem.2015.06.016
 
 
 
 
 
 
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