PLANKTON POPULATION OF CERTAIN LAKES AND STREAMS IN THE

An extensive survey of the plankton population of the streams in the Ohio River watershed was made from 1939-1942 (Brinley and Katzin, 1944). This study revealed the fact that the northern tributaries of the Ohio River support a much larger phytoplankton population in species and numbers than the southern tributaries. This difference in plankton distribution is attributed to the fact that the northern streams flow through densely populated areas, the farm lands are fertile and the surface waters are generally polluted with human and industrial wastes. The southern streams, on the other hand, pass through sparsely popu-lated regions where the soils are poor and the streams are less likely to be enriched with organic pollution. The algae population seems to be directly correlated with the amount of decomposed organic matter in the stream. Studies of the White (Brinley, 1942a) and the Cumberland Rivers (Brinley, 1942b) clearly showed that isolated sources of heavy organic pollution greatly increased the growth of algae, in numbers and species, in the stream below the entrance of the sewage. It is desirous to obtain more information on the relation of stream fertility t