Note
Modern man is beset by two closely related, chronic problems: (1) a shortage of high-quality, animal protein food and of the fertilizers and feeds needed to produce such foods, and (2) the deterioration of his environment from the effects of his own wastes. A common manifestation of the latter is the excessive growth of algae caused by the overenrichment of natural waters with domestic wastes, a phenomenon often referred to as "eutrophication."