Carbon sequestration is “The process of removing carbon from the atmosphere and depositing it in a reservoir.” When carried out deliberately, this may also be referred to as carbon dioxide removal, which is a form of geoengineering. The term carbon sequestration may also be used to refer to the process of carbon capture and storage, where CO2 is removed from flue gases, such as on power stations, before being stored in underground reservoirs. The term may also refer to natural biogeochemical cycling of carbon between the atmosphere and reservoirs, such as by chemical weathering of rocks. Using seawater and calcium to remove carbon dioxide (CO2) in a natural gas power plant’s flue stream, and then pumping the resulting calcium bicarbonate in the sea, could be beneficial to the oceans’ marine life or states a new research report.
The oceans contain around 36,000 gigatons of carbon, mostly in the form of bicarbonate ion (over 90%, with most of the remainder being carbonate).
Inorganic carbon, that is carbon compounds with no carbon-carbon or carbon-hydrogenbonds, is important in its reactions within water. This carbon exchange becomes important in controlling pH in the ocean and can also vary as a source or sink for carbon. Carbon is readily exchanged between the atmosphere and ocean. In regions of oceanic upwelling, carbon is released to the atmosphere. Conversely, regions of downwelling transfer carbon (CO2) from the atmosphere to the ocean.
In addition to global warming effects, when carbon dioxide is released into the atmosphere, a significant fraction is passively taken up by the ocean in a form that makes the ocean more acidic. This acidification has been shown to be harmful to marine life, especially corals and shellfish.
If the carbon dioxide reacted with crushed limestone and seawater, and the resulting solution was released to the ocean, this would not only sequester carbon from the atmosphere, but also would add ocean alkalinity that would help buffer and offset the effects of ongoing marine acidification. Again, this speeds up the natural CO2 consumption and buffering process offered by carbonate weathering.
There are many potential techniques to control or reduce CO2 air emissions such as growing new forests, underground injection, and even a newly developed cement type that can absorb CO2 from ambient air during hardening.
Links and Sources: