CURRENT RESEARCH
ARNOLD AIR FORCE BASE FRESHWATER MACROINVERTEBRATE SURVEY
As a follow-up for a study done 19 years ago on Arnold Air Force Base in Tullahoma, TN, I am assessing community composition and population density of freshwater macroinvertebrates. This diverse group of streams from the Elk and Duck drainages are influenced by military activities and karst geology, with many ephemeral and regulated streams.
Transfer of Polychlorinated Biphenyls from Aquatic to Terrestrial Consumers
Many streams on Arnold Air Force Base have historical polychlorinated biphenyl (PCB) contamination of sediments. PCBs accumulate in organisms and magnify in food webs, which can result in decreased immune responses and reproduction in affected organisms. Freshwater insects may accumulate PCBs from the periphyton and detritus of contaminated sediments of impacted streams on Arnold Air Force Base. Because most freshwater insects emerge as flighted adults they may transfer PCBs to terrestrial insectivores. This pathway of exposure may explain the higher concentration of PCBs in bats observed from the Air Force Base compared to surrounding areas.
Impacts of Didymosphenia on Larval Midges (Chironomids)
In collaboration with Matt Green from Clemson University, I have been examining chironomid larvae from Didymosphenia impacted streams from Eastern Tennessee dam tailwaters. Didymosphenia is a mat-forming nuisance diatom which reduces the biotic diversity and distribution of many freshwater invertebrates. However, chironomids of the family Orthocladiinae are documented have increased abundance in Didymosphenia impacted streams. This community composition shift may be aided by their consumption of Didymosphenia. However, the size of Didymosphenia could potentially impact larval feeding structures, including the mentum. Preliminary results suggest that only some chironomid genera have increased abundance in impacted streams and that mentum wearing was most prevalent in chironomid taxa which feed on Didymosphenia frustules.
