In the lab, Martinat will analyze the invertebrates for concentrations of heavy metals and organic compounds. If the food organisms are contaminated, then we should see a correlation of contaminants in small fish and upper level predatory-type fish. Bart and Martinat record the number and kind of invertebrates and fish and examine the stomach contents of the fish to study the diets of different species. Preliminary results after the second year of study have shown little difference in trophic and community structures between the contaminated and control sites. Even sub-lethal effects will affect community structure.
Physiological stresses can relate to changes in growth size, for example.
The next step in Bart's research project is to examine these suborganismal effects as they relate to the larger ecological community. T he next step for the fish and frog samples gathered in Devil's and Tunica swamps is a journey to the laboratory of William Hartley, assistant professor of Environmental Health Sciences in the School of Public Health and Tropical Medicine . Everything has to be done within seven or eight hours, maximum, or else the tissue degrades. In a third-floor lab in the J. Bennett Johnston Health and Environmental Research Building at the Tulane University Medical Center, graduate students and researchers work feverishly to dissect and parcel out pieces of the fish to different projects. Hartley and fish pathologist and research assistant professor Aurunthavarani Thiyagarajah receive the critical organs, such as the liver, to look for signs that could signal damage from environmental chemicals.