Jennifer Keller

Abstract

The number and proportion of debilitated loggerhead sea turtles (Caretta caretta) found along the U.S. southeast coast has been increasing over the past 20 years with a substantial increase of 11% per year for the last 10 years. These debilitated turtles are extremely emaciated, lethargic, and have an unusually high barnacle cover on their soft tissue. Some even have rotting flesh and exposed bones, though they are still alive. The cause of this illness is unknown, but may be perpetuated by environmental contaminants that are known to suppress the immune system, such as polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides. A handful of previous studies have detected OC compounds in the tissues of threatened loggerhead sea turtles. Our lab recently determined that blood concentrations of these environmental contaminants significantly correlate with concentrations in the adipose tissue and with indicators of poor health, including immune parameters. In the current study, we compared the blood OC concentrations, measured by gas chromatography with electron capture detection and mass spectrometry, in apparently healthy turtles to debilitated turtles. The average blood OC concentrations in the debilitated turtles (n=7) were orders of magnitude higher than in the healthy turtles (n=107). It is unknown whether the elevated concentrations were present in the debilitated turtles prior to their illness or if the concentrations increased in their blood during lipid mobilization. The latter hypothesis is supported by the blood concentrations of a single debilitated turtle which had high concentrations when initially found, but the concentrations dropped after rehabilitation to levels typically seen in healthy turtles. Regardless of which came first, the high concentrations or the illness, the elevated concentrations observed in the debilitated turtles are cause for concern, because the toxicity threshold is unknown in sea turtles. Additional samples will be analyzed to further explore the question of "What came first?" A blood sample is now available from an apparently healthy turtle that was found dead and debilitated one year later. Blood samples taken after rehabilitation are now available from four more debilitated turtles.

Jennifer Keller

CSTL

Analytical Chemistry Division

Hollings Marine Laboratory

331 Fort Johnson Road

Charleston, SC 29412

Office 843-762-8863

Fax 843-762-8742

Jennifer.keller@noaa.gov

I am not a member of Sigma Xi.

I choose Chemistry as a category for my poster, although it fits just as easily into Biology.