Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Historic Trends in Lake Michigan Silica Concentrations.
Author Schelske, C. L. ;
CORP Author Michigan Univ., Ann Arbor. Great Lakes Research Div.;Environmental Research Lab.-Duluth, MN.;National Science Foundation, Washington, DC.
Publisher c1988
Year Published 1988
Report Number CONTRIB-485; EPA-R-806294 ;OCE-8216588; EPA/600/J-88/460;
Stock Number PB90-147679
Additional Subjects Lake Michigan ; Silicon dioxide ; Water analysis ; Trends ; Sites ; Concentration(Composition) ; Colorimetric analysis ; Diatoms ; Aquatic biology ; Sources ; Graphs(Charts) ; Sedimentation ; Geochemistry ; Reprints ; Water pollution sampling ; Eutrophication ; Aquatic ecosystems
Library Call Number Additional Info Location Last
NTIS  PB90-147679 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/15/1990
Collation 36p
Historic data on soluble silica in the offshore waters of Lake Michigan were compiled and analyzed to determine whether the data supported a decrease in silica concentration which had been hypothesized previously on the basis of other studies. Although the data base was limited and no data were obtained for offshore waters (depths >40 m) prior to 1954, the available data support the conclusion that the silica concentration decreased rapidly after 1954. The decrease in silica concentration is attributed to increased production and sedimentation of diatoms that resulted from increased anthropogenic phosphorus loading. Total phosphorus in offshore waters was probably <10 microgram P/1 during the period of rapid silica depletion. The rapid decrease in silica concentration with relatively small phosphorus enrichment demonstrates that the tight coupling of biological and geochemical processes drastically affected the biogeochemistry of silica in a large, aquatic system within a relatively short period of time.