The kinetics of the radioactive isotope P32 uptake by the fresh water algae, chlorella, were investigated in soil-water cultures, natural systems, and synthetic culture media. Laboratory investigations were conducted at pH values of 4, 7 and 10, at a constant temperature 20 plus or minus 2C. Tagging was done at a rate sufficient to produce an activity of 0.03 microcuries/gram. The uptake of the isotope was monitored as a function of time. The data indicated that algal systems only utilize phosphorus in the orthophosphate form. Phosphorus exchange rates with soil and information about degradation pathways are included. Two experiments, one with an oxygen rich environment and the second with a carbon dioxide rich environment, were carried out.