Littoral Sediment Bacterial Production and Abundance in Four Temperate Oligotrophic Lakes

Abstract

<p>Much of what we know regarding bacterial dynamics in lakes has been derived from pelagic based studies. Investigations into benthic bacterial production (BP) and bacterial abundance (BA) in the littoral zone are rare. Littoral sediments in oligotrophic lakes range from sand with little organic matter to highly organic mud comprised of allochthonous carbon from exogenous sources or autochthonous benthic primary production. The ratio of benthic primary production to benthic OM content (BPPr:OM) provides an integrated index of the source and amount of benthic OM. We measured benthic bacterial production and abundance in the littoral zones of four oligotrophic lakes with varying sediment types each season over the course of one year. Seasonal variation in bacterial production was high, illustrating a significant relationship between BP and temperature (t =5.274 4, p<.0001). Among lake differences in source and amount of sediment organic matter drive variation in BP and BA across lakes along a BPPr:OM gradient. Autochthonous organic matter content of littoral sediments could regulate bacterial dynamics and impact ecosystem processes such as nutrient recycling and trophic linkages to organic carbon pools.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 16, 2010</p>