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Geosciences LibreTexts

11.3: The Biological Pump

The biological pump is the exchange of carbon dioxide and other gas with surface water due to the respiration of biological activity within a water body, specifically the oceans of planet earth. Carbon dioxide and other gases like nitrogen are dissolved through the mixed layer of water and are utilized by photosynthetic phytoplankton. These phytoplankton fix the carbon dioxide into their tissues by means of photosynthesis, and they also produce carbon dioxide through cellular respiration. Another means of carbon fixation by plankton is the utilization of carbonate in the protective coatings of coccolithophores and foraminifora.The net carbon dioxide that is fixed into these organisms falls to the bottom of the ocean when the plankton die.