Carbon concentration ocean

A simplified conceptualization of oceanic DOM pools based on a two-pool model showing carbon concentrations and elemental C N P ratios of the DOM pools. In reality, the reactivity of DOM probably spans a continuum that is presented herein as two pools, labile and refractory, for the purposes of simplification. Molar elemental ratios are in the format of C N P. Source-. From Hopkinson, C. S., and J. J. Vallino (2005). Nature 433, 142-145. 

Spero HJ, Bijma J, Lea DW, Bemis BE (1997) Effect of seawater carbonate concentration on foraminiferal carbon and oxygen isotopes. Nature 390 497-500 Spivack AJ, Edmond JM (1986) Determination of boron isotope ratios by thermal ionization mass spectrometry of the dicesium metaborate cation. Anal Chem 58 31-35 Spivack AJ, Edmond JM (1987) Boron isotope exchange between seawater and the oceanic crust. Geochim Cosmochim Acta 51 1033-1043... 

Due to bioproductivity processes, carbon is transported from the surface to deep layers of the ocean, where it is re-mineralized. This process maintains the inorganic carbon concentration gradient and preservation of C02 concentration in the atmosphere at a level which is (100-200) 106 lower than it would be without bioproductivity. 

The turbulent fluxes of carbon on the thermocline-deep ocean border is considered to be proportional to the coefficient kT of the difference in carbon concentrations in the bordering layers ... 

Figure 12.2 Observations of total inorganic carbon, nitrate, total inorganic phosphorus, oxygen and H+ in the North Pacific Ocean a ef a/., in prep.). The total inorganic-carbon concentration in this figure is also shown resolved into its components, HCO3, CO and H cal axes here and in subsequent figures give depth in kilometres. Dominant species of each element are shown adjacent to each figure.

Thus, given the assumptions above, the surface-deep gradient in inorganic carbon concentration (the strength of the biological pump) is determined by (i) the C/P of the organic matter that is exported from the surface ocean, and (ii) the nutrient concentration ([POd ]) gradient between the surface and deep ocean. 

If this is an adequate description of the real low-latitude ocean, then the strength of its biological pump (the amplitude of the surface-deep gradient in inorganic carbon concentration) is controlled solely by (i) the carbon/nutrient ratio of the organic matter, and (ii) the nutrient content of the deep ocean (see Equation (5)). If the C/P ratio of export production increased or the [PO4 ] of the deep ocean increased, then biological production at the surface would drive an increase in the downward flux of carbon that is not at first matched by any change in the upward flux of carbon dioxide associated with surface-deep... 

Although ocean chemistry determines the CO2 concentration of the atmosphere in the long term and the solubility and biological pumps act to modify this long-term equilibrium, shortterm exchanges of carbon between ocean and... 

Sketch of a tall box with 10 km of air and 100 m of seawater with air and water carbon concentrations indicated. This hypothetical system is used to illustrate the effect of carbonate reactions in controlling the distribution of a perturbation of CO2 between the atmosphere and ocean at chemical equilibrium. 

The surface runoff from the World s land plays an important role in the global carbon mass exchange. The continental runoff supply of HCO is 2.4 x 10 tons/year, that is, 0.47 x 10 tons/year for carbon. Besides, the stream water contains dissolved organic matter at 6.9 mg/L, which makes up to an annual loss of 0.28 x 10 tons/year. The average carbon concentration of suspended insoluble organic matter in the stream discharge is 5 mg/L, which gives the loss of about 0.2 x 10 tons/year. Most of this mass fails to reach the open ocean and becomes deposited in the shelf and the estuarine delta of rivers. We can see that equal amounts of Cc and Co (0.5 x 10 tons for each) are annually lost from the World s land surface (Dobrovolsky, 1994). 

Fig. 7.3 Trends in inorganic carbon concentrations between 1989 and 2001. Above, atmospheric carbon dioxide concentrations as measured at the Manoa Loa observatory. Data courtesy of the Carbon Dioxide Information Analysis Center, http //cdiac.ornl.gov/ndps/ndp001.html. Below mixed layer (0-50 m Karl Lukas, 1996) DIC concentrations, normalized to a salinity of 35 per mil, at station ALOHA. Data courtesy of D.M. Karl, The Hawaii Ocean Time-series (HOT), http //hahana.soest.hawaii.edu (Karl etal., 2001b).

Martin WR, McCorkle DC (1993) dissolved organic carbon concentrations in marine porewaters determined by high-temperature oxidation. Littmology Oceanogr 38 1464-1480 McCave IN (1975) Vertical flux of particles in the ocean. Deep-sea Res 22 491-502 McCorkle DC, Emerson SR, Quay PD (1985) Stable carbon isotopes in marine porewaters. Earth Planet Sci Letters 74 13-26... 

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