Carbonate pumps

Because this pump is driven by physical processes associated with gas solubility and water circulation, it is termed the solubility or gas exchange pump. The efficiency of this carbon pump is controlled by three fectors (1) the physical movement of seawater,... 

Changes in climate and meridional overturning circulation are likely to affect plankton species distributions. As discussed in Chapter 25.5.3, such changes have the potential to alter the biological carbon pumps. The associated feedbacks are also likely to be affected due to synergistic interactions with other pollution problems including nutrient loading. 

Inorganic carbon pump The transport of carbon into the deep sea as a result of the sinking of detrital calcium carbonate formed by cococcolithophorids and foraminiferans. 

C-values in planktonic and benthic foraminifera can be used to monitor CO2 variations in the atmosphere by measuring the vertical carbon isotope gradient, which is a function of the biological carbon pump. This approach was pioneered by Shackleton et al. (1983), who showed that enhanced contrast between surface waters and deeper waters was correlated with intervals of reduced atmospheric CO2 contents. Increased organic carbon production in surface waters (possibly caused by enhanced nutrient availability) leads to the removal of carbon from surface waters, which in turn draws down CO2 from the atmospheric reservoir through re-equilibration. 

Neuer, S., Davenport, R., Freudenthal, T., Wefer, G., Llinas, O., Rueda, M. J., Rueda, D., Steinberg, D., and Karl, D. (2002a). Differences in the biological carbon pump at three subtropical ocean sites. Geophys. Res. Lett. 29, 1885, doi 10.1029/2002GL015393. 

Volk, T., and HofFert, M. I. (1985). Ocean carbon pumps analysis of relative strengths and efficiencies on ocean-atmospheric pC02 changes. In The Carbon Cycle and Atmospheric C02, Natural Variation. (Sundquist, E. T., and Broecker, W. S., eds.). Archen to Present, Geophysical Monograph Series 32. American Geophysical Union, pp. 99—120. 

Here, the preformed pool includes contributions from the saturation concentration and the degree of disequilibrium at the point of subduction. The biological fraction has contributions from both soft-tissue and carbonate pumps (Volk and Hoffert, 1985). Following Brewer (Brewer, 1978) we may, as a first approximation, interpret the soft-tissue contribution to be related to the biological fraction of nitrogen by a fixed, Redfieldian stoichiometry ... 

VolkT. and HoffertM. I. (1985) Ocean carbon pumps analysis of relative strengths and efficiencies in ocean-driven... 

The oceanic carbon pumps (solubility, soft-tissue, and carbonate) are inherently linked. The amount of CO2 dissolved in ocean surface waters is controlled not only by its equilibrium solubility, but also by the relative rates of gas exchange, ocean mixing, and soft-tissue and carbonate production. Nutrients that are necessary for soft-tissue assimilation arrive at the ocean surface with... 

There is another biological pump, called the carbonate pump, but its effect in reducing the concentration of CO2 in the atmosphere is small. Some forms of phytoplankton have CaCOa shells that, in sinking, transfer carbon from the surface to... 

The combined active biomass of all primary producers acts as a gigantic pump that concentrates inorganic carbon dispersed in both the atmosphere and hydrosphere and deposits it in the reduced organic form, (CH20) . A comparison between the average contents (%w/w) of carbon in the atmosphere (0.03), hydrosphere (0.0014) and lithosphere (0.16), as opposed to that of the biosphere (24.9), impressively illustrates the efficiency of the biological carbon pump (see Deevey, 1970). 

The carbon pump in the ocean refers to processes that create a vertical gradient in the dissolved inorganic carbon (DIC) concentration. These... 

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