The Biological Pump

Before I discuss the next geoengineering technique of iron fertilization, I will discuss the basic understanding of the biological pump in oceans and the relation to climate. The diagram below shows how the biological pump works. 

1. CO₂ is dissolved into surface waters.
2. Phytoplankton take up carbon through photosynthesis (CO₂ + H₂O + light ->    CH₂O + O₂)
3. Some of this organic matter can then be decomposed back to CO₂ through being consumed by other species or through respiration.
4. The rest of the organic matter will sink into the deeper water where it can either settle on ocean floor or continue the cycle by releasing the CO_2. In some places upwelling can cause nutrients to return to the surface layer.

The video below also helps to explain this process.

As mentioned in the video, the ocean holds about 50 times as much carbon as does the atmosphere, and about 20 times as much as the terrestrial biosphere. Therefore the ocean is a very important area to study and focus on. 

De La Rocha, C. L. (2007) 'The Biological Pump' Treatise on Geochemistry, 6, pp. 1-29

doi:10.1016/B0-08-043751-6/06107-7

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B782S-4CJV6M2-2T&_rdoc=4&_hierId=3021000007&_refWorkId=107&_explode=3021000007&_fmt=high&_orig=na&_docanchor=&_idxType=TC&view=c&_ct=21&_acct=C000010182&_version=1&_urlVersion=0&_userid=7237960&md5=0ce17aa7bb6fa21bd14a7f9f0d476723