Abstract
Food production in the world is likely to become an urgent subject needing to be solved in the near future due to the steady increase of the world human population and the deterioration of farm lands for agriculture in the most productive areas. A large stock of nutrients in deep ocean water (DOW), below the euphotic zone of the world ocean, has great potential for enhancing existing marine production which could subsidize the production of animal protein on land. Three trials of ocean fertilization currently being carried out in Japan to increase fish and other marine products are summarized as follows: mixing more nutrientrich bottom water with nutrient-poor shallow water by means of an artificial seamount and prevailing current actions on the continental shelf; adding more nutrient-rich deep ocean water (DOW) to nutrient-poor surface water after it has been heated from passing it through electric power plants as a coolant; and directly discharging more nutrient-rich DOW to nutrient- poor shallow euphotic water as density current after mixing it with warm surface water.
