Metabolism of an eutrophic reservoir (Western Illinois University, USA)

Summary

1.	The effective net primary production, i. e., the biomass that remained in the water mass, was determined for an eutrophic reservoir (40.1 gm C/m2/mo).
2.	The utilization of potential carbon amounted to 82.5% (33.1 gm C/m2/mo), and the bioactivity amounted to 73.2 gm C/m2/mo.
3.	The carbon dioxide accumulation-oxygen deficit method can be profitably used to estimate net primary production in eutrophic reservoirs if 1) the outflow of water is restricted to the epilimnion, and 2) the amount of oxidation during the winter is sufficient to break down all but the more reduced carbohydrates.
4.	On the basis of the carbon released during the winter and the loss of biomass with the outflow of epilimnic water, it is suggested that reservoirs, and possibly lakes, be classified on the basis of bioactivity per year, i. e., gm /m2/year.