MICROORGANISMS, BUT NOT SHREDDERS, RESPOND TO TEMPERATURE ACCORDING TO THE METABOLIC THEORY OF ECOLOGY
Breakdown of terrestrial organic matter in streams and rivers is an essential part of the global carbon cycle. This process is driven by both microbial decomposers and macroinvertebrate detritivores, whose relative activity affects the ultimate fate of carbon in streams. These dynamics are especially important in the context of projected stream temperature increases, which may shift the relative contributions of microbes and detritivores to litter breakdown. Specifically, the rate of detritivore-mediated litter breakdown in streams may be lower than expected based on the Metabolic Theory of Ecology (MTE) due to these organisms' sensitivity to increased temperature. Building on preliminary data that suggest that the relationship between litter breakdown and temperature is steeper than expected based on MTE, we conducted a series of litter incubations in streams across a temperature gradient at the Coweeta Hydrologic Laboratory (NC, USA). We compared litter breakdown rates between coarse and fine mesh litterbags to quantify the relative contributions of detritivores and microbes to organic matter processing across temperatures. This work expands our understanding of how organismal responses to temperature shifts may scale up to affect ecosystem-level carbon cycling in streams.
Carolyn Cummins (Primary Presenter/Author), The University of Georgia, firstname.lastname@example.org;
Amy Rosemond (Co-Presenter/Co-Author), University of Georgia, email@example.com;
Phillip Bumpers (Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia, firstname.lastname@example.org;
Jonathan Benstead (Co-Presenter/Co-Author), University of Alabama, email@example.com;
Vlad Gulis (Co-Presenter/Co-Author), Coastal Carolina University, firstname.lastname@example.org;