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SFS Annual Meeting

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RELATIONSHIPS BETWEEN WATERSHED LAND USE AND BACTERIAL COLONIZATION AND DECOMPOSITION OF TERRESTRIAL LITTER IN STREAMS

Terrestrial organic matter is a key carbon and energy source for headwater streams, and microbial colonization and decomposition of terrestrial litter plays a critical role in the entry of this allochthonous organic material into stream food webs. Changes in land use can impact the composition and activity of stream microbial communities, so we designed an experiment to explore the relationships between watershed land use and the microbial colonization and decomposition of terrestrial litter. We incubated model terrestrial litter substrates (cotton and silk strips, representing low and high nitrogen substrates, respectively) in 18 streams in northeast Ohio with large differences in watershed land use (e.g. percentage urban, agriculture, and forest/herbaceous). After the two month incubation the strips were analyzed for tensile strength (an indicator of decomposition) and the taxonomic composition of attached bacterial communities (via high-throughput amplicon sequencing). Decomposition of cotton strips was strongly correlated with bacterial community composition, whereas for silk strips decomposition was not correlated with bacterial community composition but was strongly correlated with watershed land use. These results suggest an interactive effect of substrate quality, land use, and microbial community composition on decomposition of terrestrial organic matter.

Andrea Fitzgibbon (Co-Presenter/Co-Author), Kent State University , afitzgib@kent.edu;


David Costello (Co-Presenter/Co-Author), Kent State University, dcostel3@kent.edu;


Scott Tiegs (Co-Presenter/Co-Author), Dept. of Biological Sciences, Oakland University, tiegs@oakland.edu;


John Kelly (Co-Presenter/Co-Author), Loyola University Chicago, Jkelly7@luc.edu;


Paul Risteca (Primary Presenter/Author), Dept. of Biology, Loyola University Chicago, pristeca@luc.edu;