HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Steinman, A. D. Articles by Ogdahl, M. Search for Related Content PubMed PubMed Citation Articles by Steinman, A. D. Articles by Ogdahl, M. Agricola Articles by Steinman, A. D. Articles by Ogdahl, M. Related Collections Ecosystem Restoration Surface Water Quality

TECHNICAL REPORTS

Ecological Effects after an Alum Treatment in Spring Lake, Michigan

Annis Water Resources Inst., Grand Valley State Univ., 740 West Shoreline Drive, Muskegon, MI 49441

^* Corresponding author (steinmaa{at}gvsu.edu).

Received for publication March 21, 2007. A whole-lake alum treatment was applied to eutrophic Spring Lake during October and November 2005. Eight months later, an ecological assessment of the lake was performed and compared with data collected in 2003 and 2004. Field measurements showed reduced soluble reactive phosphorus (SRP) and total phosphorus (TP) concentrations in the water column the summer after the alum application, but chlorophyll levels and irradiance profiles were not significantly affected. Total macroinvertebrate density declined significantly in 2006 compared with 2004, with chaoborids and oligochaetes experiencing the greatest reductions. Internal phosphorus release rates, measured using sediment cores incubated in the laboratory, ranged from –0.052 to 0.877 mg TP m^–2 d^–1 under anaerobic conditions. These internal loading rates were significantly lower than those measured in 2003 at three out of four sites. Mean porewater SRP concentrations were lower in 2006 than in 2003, but this difference was statistically significant only under aerobic conditions. The NaOH-extractable SRP fraction in the sediment was also significantly lower in 2006 compared with 2003, whereas the HCl-extractable SRP sediment fraction showed the opposite pattern. Overall, these results indicate that the alum treatment effectively reduced internal P loading in Spring Lake. However, water column phosphorus concentrations remain high in this system, presumably due to high external loading levels, and may account for the high chlorophyll levels. An integrated watershed management approach that includes reducing internal and external inputs of P is necessary to address the cultural eutrophication of Spring Lake.

Abbreviations: SRP, soluble reactive phosphorus • TP, total phosphorus