376 



[chap. 17 



few, but those which are reported leave little doubt that the benthic community 

 plays an important, if not dominant, role in the organic production of the 

 coastal region. 



The California coast maintains some of the densest stands of vegetation 

 known. Crops of the large kelps may amount to several kilograms per square 

 meter. Compare this with the estimated maximum potential standing crop of 

 25 g carbon/m 2 of phytoplankton (page 353). Measurements of the rate of 

 production of these kelps give staggering values, as high as 33 g carbon/m 2 /day 

 (Blinks, 1955). In two months, a crop of 4400 g/m 2 of Laminaria was produced, 

 a figure comparable to over 1000 g carbon/m 2 /month, ten times the annual 

 production of phytoplankton in temperate waters. 



Cold, rich water upwells along the California coast, as we have discussed. 

 What of benthic production in less fertile regions? According to Odum and 



20 



30 



40 50 



Fig. 14. Primary production in a sewage oxidation pond (A) and in the Sargasso Sea off 

 Bermuda (B). (After Ryther, 1960.) 



Odum (1955) some 12 g carbon/m 2 are produced daily by the algal members of 

 a coral reef in the tropical Pacific. Comparable values were obtained for a 

 community of marine turtle grass (Thalassia) in Florida (Odum, 1957). These 

 values, unlike those reported elsewhere in this chapter, represent gross produc- 

 tion (photosynthesis uncorrected for the respiratory requirements of the plants 

 themselves). In most natural environments, net plant production is equivalent 

 to 50-75% of gross production (Ryther, 1959). Thus, even the coral reef could 

 be expected to produce a net 2000 g of plant carbon/m 2 /year, a synthesis which 

 incidentiy is consumed as quickly as it is produced by the animal members of 

 the coral reef community. These figures, then, give some idea of the relatively 



