Primary production global estimate

Antoine, D., Andre, J.-M., and Morel, A. (1996). Oceanic primary production, 2. Estimation at global scale from satellite (coastal zone color scanner) chlorophyll. Global Biogeochem. Cycles 10, 57-70. 

DeFries R. S., Field C. B., Fung L, Collatz G. J., and Bounoua L. (1999) Combining satellite data and biogeochemical models to estimate global effects of human-induced land cover change on carbon emissions and primary productivity. Global Biogeochem. Cycles 13, 803-815. 

Malmstrom, C. M., Thompson, M. V., Juday, G. P., Los, S.O., Randerson, J. T. and Field, C. B. (1997). Interannual variation in global-scale net primary production Testing model estimates. Global Biogeo-chem. Cycles 11, 367-392. 

In terms of organic carbon generation, the coccolithophorids are a minor player, representing only 6 to 8% of global marine primary production. But their detrital remains contribute disproportionately to the burial of carbon in marine sediments. This is due to near complete loss of POC via remineralization as the detrital hard and soft parts settle to the seafloor. As estimated from Broecker s Box model in Chapter 9, only about 1% of the POM that sinks out of the surfece water is buried in marine sediments. In comparison, about 20% of the biogenic PIC survives to become buried in the sediments. 

One comprehensive study of surface DMS concentrations was that of Andreae and Raemdonck (42). Hie concentration of DMS was determined in 628 surface seawater samples, collected at 0.05 and 3 m. From this data base they estimated that a global weighted-mean DMS concentration in surface waters is 3.2 nmol I/1, higher than the values obtained in earlier studies (21.441. They noted that the DMS concentrations varied significantly from one location to the next and suggested that this patchiness might be related to primary production and also species variations from locale to locale. The correlation between chlorophyll a and DMS concentration for 225 samples was r = 0.53, = 0.001. 

Longhurst, A., Sathyendranath, S., Platt, T., and CaverhiU, C. (1995). An estimate of global primary production in the ocean from satelhte radiometer data.J. Plank. Res. 17, 1245—1271. 

The amount of primary production carried out in the oceans each year has been estimated from ocean color satellite data and shipboard incubations to be 140 g C m for a total of 50-60 Pg C (4-5 Pmol C) hxed in the surface ocean each year (Shuskina, 1985 Martin et al, 1987 Field et al, 1998). This represents roughly half of the global annual 105 Pg C hxed each year (Field etal., 1998), despite the fact that marine phytoplankton comprise less than 1 % of the total photosynthehc biomass on Earth. Extrapolahon from Redheld ratios suggests the incorporation 0.6-0.8 Pmol N, 40-50 Tmol P into biogenic particles each year in associahon with marine primary production. From the proportion of primary production carried out by diatoms and the average Si C raho of diatoms, silica production rates may be calculated to be 200-280 Tmol Si yr (Nelson et al, 1995 Treguer et al, 1995). 

Benthic flux measurements from bottom chamber devices and porewater flux determinations have been used to estimate the rain rate of organic matter to the sediment-water interface. When compared with global primary production rates and sediment trap particle fluxes, these data indicate that about 1% of the primary production reaches deep-sea sediments and is oxidized there (Table 12.3) Qahnke, 1996). It has also been demonstrated from benthic flux experiments that about 45% of respiration in the ocean below 1000 m occurs within sediments. 

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