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SFS Annual Meeting

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SUB-LETHAL ION CONCENTRATIONS ALTER SHREDDER PERFORMANCE AND LEAF LITTER PROCESSING

Salinization from agriculture and resource extraction can have lethal and sub-lethal effects on aquatic detritivores. For example, sodium chloride concentrations lethal to detritivores (5x above ambient) reduce leaf litter processing, but whether sub-lethal concentrations slow processing rates is not known. We predict sub-lethal salt concentrations may change litter-processing rates by reducing energy required by microbes and shredders for osmoregulation, and by altering litter quality for shredders. Here we predict salt-induced changes in microbial community composition and activity will decrease processing rates by reducing shredder litter palatability or nutrition. Isopods, a crustacean, were fed leaves incubated in natural streamwater (~3 mg/L NaCl), and leaves incubated in one of six NaCl or NaHCO3 treatments (16, 32, 64 mg/L). Isopods grew ~20% less in the intermediate salt concentrations compared with natural streamwater. The rate of respiration and amount that isopods ate did not differ between natural and intermediate salt concentrations. Therefore, we predict insect shredder growth will also decrease from altered nutrition when fed salt-incubated leaves. The same experiment will be performed with a common shredding stonefly. Results will show whether sub-lethal salt concentration can indirectly alter stream detrital processing.

Brooke Howard-Parker (Co-Presenter/Co-Author), University of Arkansas, bbhowardparker@gmail.com;


Natalie Clay (Co-Presenter/Co-Author), Louisiana Tech University, nclay@latech.edu;


Michelle Evans-White (Co-Presenter/Co-Author), University of Arkansas, mevanswh@uark.edu;


Sally Entrekin (Co-Presenter/Co-Author), University of Central Arkansas , sentrekin@uca.edu;


Anastasia Mogilevski (Primary Presenter/Author,Co-Presenter/Co-Author), University of Central Arkansas, amogilevski1@cub.uca.edu;