CURRENT RESEARCH
FRESHWATER MACROINVERTEBRATE SURVEY
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 geology, with many ephemeral and regulated streams.
Transfer of PFAS from Aquatic to Terrestrial Consumers
Many streams have historical polyfluoroalkyl substances (PFAS) contamination of sediments. PFAS accumulate in organisms and magnify in food webs, which can result in decreased immune responses and reproduction in affected organisms. Freshwater insects may accumulate PFAS from the periphyton and detritus of contaminated stream sediments. Because most freshwater insects emerge as flighted adults, they may transfer PFAS to terrestrial insectivores. This pathway of exposure may explain the higher concentration of PFAS in bats observed in certain areas compared to surrounding regions.
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.
