Title

Anaerobic respiration dynamics in a eutrophic lake

Date of Completion

January 1997

Keywords

Biology, Ecology|Biology, Limnology

Degree

Ph.D.

Abstract

Environmental redox potential was investigated in both a eutrophic lake and laboratory microcosms. Redox potential decreased rapidly during the onset of anoxia but slowly afterwards. Redox potential predicted the ratio of ferrous iron in microcosms and total lake iron mass below 6 meters. The two products of anaerobic respiration, dissolved inorganic carbon (DIC), and environmental oxidants (ATEAs), were found to continue accumulating after the initiation of anoxic conditions (1 mg l$\sp{-1}$ O$\sb2).$ Total iron formed a chemocline below the anoxic boundary at the location of the 100 mV E$\rm\sb{h}$ isopleth. The stability of the chemocline suggests that a steady state condition existed between oxidized iron above, and reduced iron below, providing continued ATEAs for anaerobic respiration.^ Ambient redox potential (mV E$\rm\sb{h})$ is suggested as an intensity factor of the reducing power of anoxic water, while the sum of reduced ions is suggested as the capacity factor. ^