PHYTOPLANKTON AND NUTRIENTS IN IOWA LAKES AND WETLANDS

  Kerry Bohl, Brian Barry, Matt Hoffert, Eugenia Tsamis, John Bumpus, Edward J. Brown and Maureen E. Clayton.

   Land use practices in the watershed affect surface waters such as lakes and wetlands due to inputs from runoff and leachate.  Nutrients added to the lake may cause algal blooms,  adversely affecting other aquatic organisms.  Phosphorus, nitrogen and chlorophyll a have been studied in Silver Lake (Delhi, IA) for the past four summers.  The same parameters were measured in the Beaver Valley Wetland system (Cedar Falls, IA) this year.  In both systems, total phosphorus and nitrate concentrations were similar (~300 mg/L and ~0.6 mg/L respectively), but chlorophyll a was much higher in the lake (~250 mg/L vs. ~100 mg/L).  This suggests that wetland buffer strips may be effective in mediating nutrient inputs and protecting surface water resources in agricultural watersheds.

This project was supported, in part, by the Roy J. Carver Charitable Trust, the Iowa Space Grant Consortium, Merck Pharmaceuticals and the American Association for the Advancement of Science.