Faculty Seed Grant Project


Salty carbon: Testing the consequences of freshwater salinization on stream food web dynamics and ecosystem metabolism


Freshwater salinization is a global change issue with unknown consequences for food webs and ecosystem functions. Our current understanding of salinization is based on biological indicators (e.g., changes in microbial and invertebrate communities, not whole ecosystem processes (e.g., resource use, metabolism). We will leverage (1) long-term water chemistry and macroinvertebrate community data (Schoenholtz, McLaughlin) and (2) recent macroinvertebrate biomass assessments (Entrekin) to (3) integrate 1-2 with basal resource production, macroinvertebrate resource use, and ecosystem-scale metabolism in one coal mining-impacted (salinized) and one reference stream in Virginia.

Stream food webs are supported by resources from both terrestrial (leaves, soil-derived organic matter) and aquatic (in-stream photosynthesis) sources; how salinization alters consumer resource use and ecosystem-scale metabolism (photosynthesis, respiration) is unknown. As one NSF reviewer has previously commented: “this proposed research is especially exciting as it bridges ecosystem metabolism and food web research approaches, two fields that have typically been isolated but should be merged to better understand carbon cycling in streams.” The GCC seed grant will allow the team to generate preliminary data on resource pools and integrate measurements of basal resources, macroinvertebrate resource use, and whole-stream metabolism using our collective expertise in hydrology, biogeochemistry, and community and ecosystem ecology (Figure 1).

Image courtesy of Erin Hotchkiss.

Reference citations for project proposal description available upon request.