You are here:
The Effect of Catchment Urbanization on Nutrient Uptake and Biofilm Enzyme Activity in Lake Superior (USA) Tributary Streams
Citation:
LEHTO, L. L. AND B. H. HILL. The Effect of Catchment Urbanization on Nutrient Uptake and Biofilm Enzyme Activity in Lake Superior (USA) Tributary Streams. HYDROBIOLOGIA. Springer, New York, NY, 713(1):35-51, (2013).
Impact/Purpose:
This study is the first to show a statistically significant correlation between nutrient uptake in streams and biofilm EEA. The significant relationship identified between biofilm EEA and the level of urbanization within stream catchments further supports the utility of EEA assays as a useful indicator of landscape disturbances in streams. Both nutrient uptake metrics and EEA stoichiometric ratios provided complimentary data identifying the study streams as P limited.
Description:
We used landscape, habitat, and chemistry variables, along with nutrient spiraling metrics and biofilm extracellular enzyme activity (EEA), to assess the response of streams to the level of urbanization within their catchments. For this study nine streams of similar catchment area and geomorphology were chosen along the north shore of Lake Superior near Duluth, MN. Streams were selected based on varying levels of catchment urbanization. There were significant correlations between biofilm enzyme activity and the gradient of urbanization. Total glycosidase and acid phosphatase activities decreased with the percentage of the catchment covered by impervious surfaces, storm sewer length, and water Cl- concentration, and increased with the percentage of the catchment covered by forest. Total peptidase decreased with % impervious surface and water Cl- concentration, and increased with % forest. DHA decreased with % impervious surface, storm sewer length, % of the stream channel shaded by the riparian canopy, and water Cl-, and increased with % forest, % of the catchment covered by wetland, stream width and stream depth. These findings suggest a level of sensitivity to landscape disturbances measured in the EEA of stream biofilms that may not be detected with conventional measures of nutrient uptake. This study is the first to show a statistically significant correlation between nutrient uptake in streams and biofilm EEA. The significant relationship identified between biofilm EEA and the level of urbanization within stream catchments further supports the utility of EEA assays as a useful indicator of landscape disturbances in streams. Both nutrient uptake metrics and EEA stoichiometric ratios provided complimentary data identifying the study streams as P limited.
URLs/Downloads:
The Effect of Catchment Urbanization on Nutrient Uptake and Biofilm Enzyme Activity in Lake Superior (USA) Tributary Streams