Pump ambient air (which contains CO2) into a plastic tank, filled with sea water, through a gas distributor. Carbon dioxide (CO2) from the air will dissolve in the sea water. The surface of the sea water should be exposed to direct sunlight. Phytoplankton will be multiplied on the surface of the sea water by the natural process of photosynthesis, which utilizes CO2 and sunlight (as in the hot Benguela sea stream on the South African East Coast, which captures CO2 and produces phytoplankton for marine fish consumption). The plankton biomass produced by this process can then be harvested for renewable clean energy purposes and agricultural fertilizer, e.g. 1) Production of methane heating gas in a bio-digester tank to serve as combustion fuel for heating and cooking purposes in low income households with liquid fertilizer for agriculture, 2) Feed for fish in fish farms and 3) Additive for cattle feed.