Fate and effect of allochthonous organic material in aquatic microbial ecosystems An analysis based on chemostat theory

Abstract

Two mathematical descriptions of a microbial ecosystem with external input of organic material were formulated. Included in these descriptions are only those parts of the ecosystem which are thought to be of key importance in the linkage between flows of organic material and mineral nutrients. The slmplest model, based upon Monod-hnetics of growth and constant cell composition, is amenable to graphical analysis. It was used to explore 2 complementary aspects: How does organic load alter the equilibirum state of the ecosystem, and how do the mechanisms of mineral cycling between bacteria, algae and protozoans influence degradation of the organic material? The other model is based on an extension of Droop's model for algal growth which allows for variations in cell composition. By simulation techniques, the effects of this refinement were explored.