Controlled Eutrophication: Increasing Food Production from the Sea by Recycling Human Wastes

Natural eutrophic marine ecosystems, though highly productive, are inherently unstable, unpredictable and unlikely to produce commercially or nutritionally valuable food for man on a consistent or reliable basis. Managed ecosystems, in aquaculture, are usually managed deliberately at levels well below their maximum potential yield because of this instability. A controlled, highly eutrophic ecosystem is proposed in which maximum production is maintained by compartmentalization of the producer and consumer elements in a flowing configuration. A two-component system involving unicellular algae and oysters is used as an example. Sources of nutrients are discussed with emphasis on the use of treated sewage effluent, and the effectiveness of such a system for both aquaculture and tertiary sewage treatment is evaluated.