Abstract |
Laboratory and field investigations were conducted on the fate and cycling of carbon and phosphorus in selected aquatic ecosystems. Inorganic carbon, as CO2, supplied by both bacterial cultures and cylinder gases, stimulated the growth of the blue-green alga Anacystis nidulans. Diel studies of a stream which received biologically-treated sewage demonstrated that the dissolved CO2 and HCO3 continually produced in the system were essentially depleted by the autotrophic organisms during daylight hours, while the concentration of phosphorus remained unchanged. Addition of organic carbon and inorganic nitrogen and phosphorus alone and in combination to the waters studied directly stimulated the oxidative metabolism of the heterotrophic population, which resulted in increased dissolved CO2 and HCO3. This increased availability of inorganic carbon, rather than the direct metabolic removal of dissolved phosphorus by the algae, appeared to be directly responsible for the growth of the algal populations in the waters studied. (Author) |