activities— man's accelerated extraction of nitrogen from the atmosphere 

 and addition of carbon to the atmosphere. 



Large areas of the ocean, such as the central gyres, have relatively low 

 rates of production per unit surface area, but account for a major fraction 

 of total carbon fixation because of their large areal extent (Table 1-1). 

 In contrast, highly productive coastal and upwelling regions account for 

 only 10 percent of the ocean by area and probably 25 percent of the ocean 

 primary productivity; they provide more than 95 percent of the estimated 

 fishery yield, however, and most of the proposed organic carbon sink of 

 atmospheric C0 2 (Table 1-2). These various ocean provinces exhibit 

 pronounced differences in their phytoplankton species assemblages as the 

 evolutionary consequence of their physical habitat. They also have 

 significant differences in spatial and temporal variability of algal 

 biomass as a function of nutrient input grazing losses (Walsh, 1976) and 

 have very different fates of the fixed carbon (Walsh et. al., 1981). Their 

 contribution to global carbon fixation (Table 1-1) may be underestimated 

 from two- to tenfold (Smith et. al., 1981). 



There are two basic reasons for the large uncertainty in the estimates 

 of marine carbon fixation (Table 1-1); both are of equal importance. 

 First, the methodology used to estimate the rate of primary productivity 

 (the 14 c method) may be in serious error (Geiskes et. al., 1979; Eppley, 

 1980). Secondly, the highly productive shelf regions exhibit a much 

 wider range of spatial and temporal variability of biomass than the open 

 ocean, on scales which have been very poorly sampled by classical ship- 

 board programs. It is in the oligotrophy (gyre) regions, where the 

 biomass variability is not pronounced, that the methodology errors are 

 greatest. This is because the oceanic phytoplankton are thought to be 

 more sensitive to stresses related to capture and prolonged enclosure. 

 However, the long food chains and 90 percent recycling processes of the 

 offshore regime (Table 1-2) provide insignificant fish harvest (Ryther, 

 1969) and little net biotic storage of C0 2 (Eppley and Petersen, 1980). 



In the coastal regions where productivity is much higher, and the 

 results of the 14_ methodology are probably more representative of the 

 actual rate, the spatial extent and the temporal character are poorly 



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