Oil Spill Gives New Importance to Seagrass Survey by ODU Oceanographers

A team of oceanographers from Old Dominion University has just completed a seagrass assessment on the Gulf Coast of northern Florida that could prove to be invaluable if oil from the BP Deepwater Horizon reaches that area.

ODU's Bio-Optical Research Group (BORG), led by Richard Zimmerman, chair of the Department of Ocean, Earth and Atmospheric Sciences, was commissioned to conduct the research before the oil well accident. But with the spill spreading, the seagrasses could come under extraordinary pressures, and the Florida Department of Environmental Protection would be able to use the ODU data as a baseline to help estimate damages that might occur.

That ODU's researchers were selected to do the work via a contract with the Florida Environmental Research Institute, is a credit to the specialized expertise of BORG. The expertise focuses on the use of satellite images for biological and chemical analysis of oceans and other large bodies of waters.

In order to interpret the colors of the waters seen in satellite images, scientists must do the sort of site work that BORG has been doing for more than a decade. In addition to Florida, the team's projects have been in California, the Arctic Circle and the Chesapeake Bay.

"The primary goal of this work last month in Florida was to survey the seagrass meadows, which are extensive and beautiful," said Victoria Hill, an ODU research assistant professor who is a key member of BORG. "We wanted to provide enough ground-truth data to allow us to process images from WorldView2, a commercial ocean-color satellite."

To get the ground-truth data, the researchers counted the individual shoots growing in target seagrass meadows, identified species, measured the reflective properties of the seagrass canopy and measured water column optical properties. This data will be matched with WorldView2 images captured simultaneously with the site work.

"With the image that we prepare, the Florida DEP will get a snapshot of seagrass density and total area coverage," Hill said. "With other images collected at regular intervals, we can monitor the health of the seagrass ecosystem ."

The research was conducted near Steinhatchee, in a region known as the Nature Coast. The economy there is based on tourism, fishing and scalloping close to the coast. "Seagrass health is directly related to all of these," Hill said. The grasses take in carbon dioxide and give off oxygen during photosynthesis, and they thrive in clear, unpolluted waters. Their good health indicates the good health of entire ecosystems in coastal waters.

In addition to the everyday benefits the research offers, Hill added, "Our work also means that if there is significant damage to the seagrass beds from the BP oil slick, we can quantify the loss of plants."

Other ODU researchers involved in the project were Research Associate David Ruble and graduate students Meredith McPherson, Stephanie Toro and Billur Celebi.