Lacustrine sedimentary systems are spatially and temporally variable, but can include considerable quantities of organic-rich sediment. Seventy-five years ago, Twenhofel and McKelvey examined the sediment of Devils Lake, a small closed lacustrine system in Wisconsin. Their documentation of factors such as composition, color, and “bacteria” revealed shore-parallel zonation of sedimentary attributes. They illustrated abundant bacteria in the deeper waters, which they interpreted to be the result of anoxic conditions in the poorly circulated lake.
The sediments of Devils Lake, a eutrophic–oligotrophic lake of southern Wisconsin by W. H. Twenhofel and V. E. McKelvey