EXECUTIVE SUMMARY 

 I. SCIENCE BASIS 



Primary production in the sea accounts for at least 30 percent of the total 

 global annual plant fixation of CO2. Marine primary production is the 

 basis for almost all life in the sea, and is an integral to major biogeo- 

 chemical cycles, such as the CO2 cycle. However, uncertainties exist in 

 the magnitude of annual marine CO2 fixation and its variability. The 

 highly productive continental shelves of the world, where 95 percent of 

 the estimated fishery yield and most of the carbon sink of atmospheric 

 CO2 occur, may actually be two or three times more productive than 

 presently estimated. Open ocean productivity estimates have recently 

 been challanged and could be underestimated by an order of magnitude. 



These uncertainties are due to a wide range of variability of biomass in 

 the shelf waters and to problems in growth rate measurement techniques 

 in the open ocean. Significant improvement in the estimates of shelf 

 productivity, and in understanding the controlling mechanisms for product- 

 ivity variations are expected when satellite measurements of ocean color 

 are combined with appropriate J_n situ observations. Such a capability 

 is clearly needed if we are to understand biological variability in 

 response to discrete and climatic changes, anthropogenic nutrient inputs 

 on fisheries, and fossil-fuel CO2 load in the atmosphere. 



The Nimbus-7 Coastal Zone Color Scanner (CZCS) has shown that the pigment 

 concentrations of the upper ocean can be measured from space with enough 

 accuracy for determining phytoplankton biomass and, in certain areas, 

 net primary productivity. Improved _i_n situ chlorophyll sensors can now 

 provide complementary calibration and interpolation data. Thus, by 

 using satellites, buoys, aircraft and ships, it is now possible to signif- 

 icantly lower the variances in estimates of phytoplankton abundance and 

 population growth rates in the ocean, and to identify biological and 

 physical factors responsible for these variances. With the appropriate 

 data sets, and from ongoing development of phytoplankton models, future 



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