Publication Date:
2019-09-23
Description:
The oceans are by far the largest global reservoir of carbon that is available on climate relevant timescales (〈 1000 yrs). A fraction of this oceanic carbon pool, comparable in magnitude with the CO2 inventory of today’s atmosphere, is transformed via biological assimilation of inorganic carbon into dissolved or particulate organic material within the sun-lit surface ocean. Subsequently this material can be respired, returning to the ocean as CO2, or it can sink to the sediments and this forms the basis of the ‘biological pump’. The efficiency of this pump is limited by the availability of nutrients, which are essential prerequisites for the growth of phytoplankton. We now know that vast areas of the surface ocean have extremely low nutrient
concentrations limiting productivity. For instance, in the subtropical oceanic gyres, which comprise more than 40% of the Earth’s surface, the macronutrients nitrate, nitrite, ammonia and phosphate are depleted to trace levels which limit phytoplankton abundance so strongly such that the term “oceanic desert” was coined for these regions.
Type:
Article
,
NonPeerReviewed
Format:
text
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