The Ocean’s Biological Pump

Half the oxygen we breathe comes from tiny phytoplankton that live in the sunlit surface layer of the ocean. They consume carbon dioxide in photosynthesis, but much of that is released again through respiration of zooplankton eating the algae and bacteria consuming the remains. Some of this carbon is released from the surface to the deep ocean in what is called the biological carbon pump. The strength and efficiency of this pump plays a key role in climate change in the earth’s history, as atmospheric carbon dioxide has gradually been taken out of the atmosphere and stored in the deep ocean through this carbon pump. Atmospheric carbon dioxide will most likely continue to increase in the future and further climate change, which will cause ocean warming and acidification and trigger major alteration in plankton composition and productivity, weakening the biological carbon pump and having a positive feedback on the carbon in the atmosphere. 

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