Ocean biogeochemical cycles

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Change in surface ocean pH in response to ocean acidification.

Biogeochemistry is the study of the processes and cycles that transfer elements (and, often, energy) around the Earth's biosphere.

Part of the focus of these JModels (the phosphorus, nitrogen, silicon and carbon models) is that they aid examination and understanding of the workings of the ocean's biogeochemical cycles. Rather than just words and pictures, they aim to provide the opportunity to learn about the operation of biogeochemical cycles through manipulating and playing around with the models. This provides an easier way of appreciating how these dynamical systems work.

The JModels can be used to understand several aspects of ocean biogeochemistry, including:

  1. Control of primary production
    Primary production refers to the numbers of new algae that grow every year in the ocean. This sunlight-fuelled primary production is the basis of nearly all food chains in the ocean and powers biogeochemical cycles. At the global scale it is controlled in turn by the availability and supply of nutrients.
  2. Control of nutrient levels
    The ocean has relatively low concentrations of all compounds that are heavily used by phytoplankton, when compared to other compounds that are delivered at a similar rate down rivers. Phosphate, nitrate and silicate are all scarce in most surface waters, to the point that they inhibit the growth of some or all of the phytoplankton living there.
  3. Effect of ocean mixing
    The models can be used to understand how oceanic nutrient cycles and primary production are affected at the global scale by changes in ocean circulation (mixing).
  4. Ocean acidification
    Due to invasion of fossil fuel CO2 into the ocean.
  5. Ocean pipes
    It has recently been proposed that vertical pipes in the ocean could be used to lift up nutrient-rich deep water which would then fuel CO2 drawdown from the atmosphere. The carbon model can be used to make a preliminary analysis of this proposal.

Further reading

  • J.L. Sarmiento and N. Gruber (2006) Ocean Biogeochemical Dynamics, Princeton University Press.
  • W.S. Broecker and T.-H. Peng (1982) Tracers in the Sea, Eldigio Press. (still worth reading)

External links