Kelly, J. R. US EPA Mid-Continent Ecology Division, kelly.johnr@epa.gov
Morrice, J. R. US EPA Mid-Continent Ecology Division, morrice.john@epa.gov
Cotter, A. US EPA Mid-Continent Ecology Division, cotter.anne@epa.gov
Michael, K. US EPA Mid-Continent Ecology Division, knuth.michael@epa.gov
Trebitz, A. US EPA Mid-Continent Ecology Division, trebitz.anett@epa.gov
Anderson, R. US EPA Mid-Continent Ecology Division, anderson.richard@epa.gov

 
A NEW TYPE OF "LAKE EFFECT"? SEICHE-DRIVEN NUTRIENT INPUT TO A GREAT LAKE COASTAL ECOSYSTEM
 
Like tidal influx at the ocean-estuarine discontinuity, the ecological influence of seiches upon coastal ecosystems of large lakes is understudied and the complexity warrants an array of biological, chemical, and physical approaches. A team of scientists has begun multi-disciplinary studies at a number of sites along Lake Superior, investigating ecological aspects of the bi- directional flow of organisms and material at the land-water interface. This paper reports findings for Lost Creek wetland (54 ha), which has low tributary flow (0.02 m3/sec) and communicates with the lake through a single outlet. Intensive water quality sampling has shown that concentrations of dissolved inorganic nitrogen (DIN) are highest in P-depleted lake water and lower in open waters of the wetland. In contrast, phosphorus (SRP) is highest in tributary/wetland waters. Box modeling indicates that N inputs due to nominal seiches (10-15 cm, 8 h period) exceed tributary inputs and mixing plots suggest that N is removed by the wetland ecosystem. Time series analyses of continuous records of water level and temperature provide confirming evidence on the mixing dynamics of the seiche. Synthesis of results leads to the intriguing notion that this oligotrophic (P-limited) lake may enrich its productive (but N-limited) fringing coastal wetlands.
 
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
 
Code: SS04TH0747S