HR: 14:15h
AN: NB13B-04    [Abstracts]
TI: Factors Influencing Internal Phosphorus Loading in Spring Lake, Michigan
AU: * Steinman, A
EM: steinmaa@gvsu.edu
AF: Annis Water Resources Institute, Grand Valley State University 740 W. Shoreline Drive, Muskegon, MI 49441 United States
AU: Nemeth, L
EM: nemethl@gvsu.edu
AF: Annis Water Resources Institute, Grand Valley State University 740 W. Shoreline Drive, Muskegon, MI 49441 United States
AU: Rediske, R
EM: redisker@gvsu.edu
AF: Annis Water Resources Institute, Grand Valley State University 740 W. Shoreline Drive, Muskegon, MI 49441 United States
AB: Spring Lake is a eutrophic, drowned river mouth lake that drains into the Grand River about 1 km upstream from Lake Michigan. In 2003, we determined that internal P loading accounted for approximately 65% of the total annual P load to this lake, and that an alum concentration of 24 mg/L effectively inactivated P release in experimental sediment core tubes. In 2004, we studied the influence of alum concentration, sediment resuspension, and bioturbation on P release rates from the sediments. Based on laboratory incubations, we determined that P release rates were no different at alum concentrations of 15 mg alum/L than at concentrations of 25 mg/L. Resuspension of sediments substantially increased TP concentrations, even at high alum concentrations, although total soluble phosphorus concentrations remained low in the water provided alum was present. Bioturbation did not appear to play a major factor with respect to P release in these sediments. Given the current concentration of phosphorus in the Spring Lake sediments, internal P loading can continue for another 40 years, even if all external P sources were immediately eliminated.
DE: 1845 Limnology
DE: 4845 Nutrients and nutrient cycling
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly