Carbon in the ocean
Today the oceans absorb about 25% of the atmospheric carbon dioxide produced by burning fossil fuels thereby moderating the impact of global warming. As the oceans warm, their ability to absorb atmosheric carbon dioxide will be reduced, potentially leading to accelerated global warming. The absorption of atmospheric carbon dioxide by the oceans comes at a considerable price. Increasing ocean acidification threatens the lifecycle of marine organisms with calcium carbonate shells. Research at NOC is directed at understanding the likely impact of increasing ocean acidification on marine life and the long term ability of the oceans to continue to absorb atmospheric carbon dioxide.
Biological carbon pump
The biological carbon pump is a major term in the global carbon cycle, transferring approximately 5-15 GT C yr-1 from the surface ocean to the oceans interior (Henson et al., 2011). It is of comparable magnitude to the annual increase in CO2 in the atmosphere driven by anthropogenic remobilisation of fossil fuel reserves and without it we believe that atmospheric CO2 would be order 200ppm higher (Parekh et al., 2006). Small changes in its functioning and or strength could radically affect ocean atmosphere partitioning of CO2.
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PELAGRA
Microscopic plants grow in the upper sunlit zone of the ocean, the start of a complex range of interactions and exchanges which constitute the marine food web. Although most of the action takes place within the top few tens of meters of the surface, some of the material sinks into the deeper water to feed the biological communities in the dark ocean. This process of sinking also removes carbon from the ocean surface and prevents its escape to the atmosphere where it enhances global warming. If we are to understand this process of sinking and the factors that affect it, one of the crucial factors to determine is the quantity of material settling down through the different layers of the water column. Although this may seem a simple enough question, it is in fact very hard to achieve. Traps similar to rain gauges can be placed on vertical ropes to collect material but these give very unreliable estimates of the downward flux largely because the water flows past the traps at a relatively high speed. The analogy would be to measure the accumulation of snow in gale force winds by putting a bucket on the top of a flag pole.Read more →
