SPATIOTEMPORAL VARIATION IN MICROBIAL ACTIVITY IN INTERMITTENT STREAMS IN THE SOUTHEASTERN UNITED STATES

Microbial processes in streams fluctuate with changes in nutrient availability, organic matter, temperature, hydrology, and land use. To investigate drivers of microbial processes in intermittent streams, we studied the ability of streambed microbial communities to metabolize organic material in streams in three different geological regions in Alabama. Leaf litter and sediment were collected from Pendergrass, Burks Creek, and Shambley Creek over six seasons (March 2022 to January 2024). We measured the activity of microbial enzymes involved in organic carbon degradation (β-glucosidase, phenol oxidase, peroxidase) and organic phosphorus (phosphatase) and nitrogen (N-acetylglucosaminidase) mineralization. Microbial enzyme activity was significantly greater in leaf litter than sediment across all streams and seasons, with rates ranging from 4.6-24.2 μmol/h/g and 0.04-1.1 μmol/h/g, respectively. Stream, season, and sample type influenced phenol oxidase and peroxidase activity, with phenol oxidase activity greatest in Burks Creek’s leaf litter and peroxidase activity greatest in Shambley Creek sediment. Activities of β-glucosidase and N-acetylglucosaminidase peaked in summer and were lowest in spring, with Burks Creek showing the lowest activity. Water availability and season affected enzyme activity in Shambley and Burks Creek sediment. Enzyme activity in sediment varied more between streams than that of leaf litter, irrespective of season. This highlights the complexity of microbial functioning and the factors driving these processes in intermittent streams.

Presentation Preference: Poster

Primary Presenter: Andrielle Larissa Kemajou Tchamba, University of Mississippi (akemajou@go.olemiss.edu)

Authors:

Andrielle Larissa Kemajou Tchamba, University of Mississippi  (akemajou@go.olemiss.edu)

Charles T. Bond, University of Southern Mississippi  (Charles.Bond@usm.edu)

Kevin A. Kuehn, University of Southern Mississippi  (kevin.kuehn@usm.edu)

Lydia H. Zeglin, Kansas State University  (lzeglin@ksu.edu)

Amy J. Burgin, University of Kansas  (burginam@ku.edu)

Yaqi You, SUNY College of Environmental and Earth Sciences  (yyou@esf.edu)

Ken Aho, Idaho State University  (ahoken@isu.edu)

Colin R. Jackson, University of Mississippi  (cjackson@olemiss.edu)