Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Monday, February 12, 2001, Time: 2:45:00 PM

Location: Ruidoso/Pecos

Kemp, M, J, Kansas State University, Manhattan, USA, mjkemp@ksu.edu

Dodds, W, K, Kansas State University, Manhattan, USA, wkdodds@ksu.edu

COMPARISONS OF NITRIFICATION AND DENITRIFICATION IN PRISTINE AND AGRICUTURALLY INFLUENCED STREAMS

Whole stream nitrification and denitrification rates were measured in Kings Creek and Shane Creek watersheds at the Konza Prairie Biological Station, Kansas. Pristine grassland upstream and row crop-influenced downstream reaches were selected for measurements in both watersheds. Rates were determined for individual substrata and these rates were scaled up to the whole stream by the biomass of each substratum. Substrata sampled included epilithon, leaf packs and wood, filamentous algae, bryophytes, and fine benthic organic matter (FBOM). Upstream sites had significantly lower estimated whole stream nitrification and denitrification rates compared to downstream sites. Shane Creek had greater rates of nitrification than Kings Creek. This difference was driven by greater nitrification in the water column and corresponded to higher concentrations of nitrate and ammonium in Shane Creek. Rates of denitrification were greatest associated with FBOM in downstream sites, and this contributed significantly to whole stream estimates. Concentrations of nitrate in the water column were more strongly correlated with nitrification and denitrification rates than were concentrations of ammonium.

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Aquatic Sciences Meeting, Albuquerque 2001

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