176 



Life 



from pieces that range from fairly well 

 known to guessed. 



In any discussion of abundance of organ- 

 isms it is necessary to distinguish clearly be- 

 tween standing crop and annual production. 

 For phytoplankton the standing crop is 

 much smaller than annual production, owing 

 to the rapidity of cell division; in contrast, 

 the large benthonic animals probably live 

 for several years, so that their standing crop 

 may be greater than their annual production. 

 The abundance of some organisms is better 

 known in terms of standing crop, whereas 

 others have been measured chiefly in terms 

 of annual production. 



Phytoplankton production in the region 

 amounts to about 500 grams/sq meter/yr 

 of dry plankton, as discussed in the section 

 on water currents at intermediate depth. 

 For the entire area of 78,000 sq km inshore 

 of the abyssal depths on Chart I, this pro- 

 ductivity corresponds to 42 million tons of 

 plankton (dry weight). Sessile plants are 

 more difficult to assess, but they are most 

 abundant along the 480 km of rocky coasts. 

 Estimates of the total tonnage of kelp have 

 been made by Crandall (1912), Cameron 

 (1915), Wohnus (1942), M. C. Sargent (per- 

 sonal communication), and probably others. 

 Sargent's estimate, the most recent one, is 

 based on an area of 265 sq km of kelp beds 

 having an average of one plant per 10 sq 

 meters, an average of 40 kg per plant, and 

 an average water content of 87 per cent. 

 According to these figures, the standing 

 crop is about 0.14 million tons dry weight. 

 Sargent and others have found the produc- 

 tion rate to be about 0.03 grams/gram-day, 

 or 10 tons/ton-yr; thus the annual pro- 

 duction of kelp must be about 1.4 million 

 tons. To this must be added the production 

 of smaller attached algae and Phyllospadix 

 which mostly live nearer shore than kelp. 

 If these total about one-fifth the production 

 of kelp, the total production of attached 

 plants must be about 1.7 million tons per 

 year, a figure beheved to be correct within 

 a factor of 20 per cent. The total produc- 

 tion for both floating and attached plants is 

 then about 44 million tons (Fig. 153). Ex- 

 pressed in agricultural terms, the produc- 



tion amounts to about 4500 pounds of 

 organic matter per acre. This is about the 

 same as the average production of wood, 

 grain, grass, and other crops on good land of 

 the United States. 



Although this annual production appears 

 to be very great, comparison with the en- 

 ergy of incident sunhght is sobering. At an 

 annual average incidence of 0.232 g-cal/sq 

 cm/min the total solar energy reaching the 

 ocean ofl' southern California is about 

 1 X 10'^ kg-cal/yr. The annual production 

 of plants, 44 X 10*^ tons, has a heat equiva- 

 lent of about 4 kg-cal/gram (Albritton, 

 1953), or a total of 1.8 x 10^^ kg-cal. The 

 plant production then represents only about 

 0.18 per cent efficiency of conversion of 

 solar energy into plant tissue, about the 

 same as the 0.3 per cent determined by 

 Riley (1941) for Long Island Sound. Al- 

 though this is much greater than the 0. 1 per 

 cent efficiency of average oceanic water, it 

 is far lower than the maximum potential 

 yield of 27 per cent based on 10 quanta of 

 red light needed for reduction of 1 mole of 

 carbon dioxide (Ryther, 1957). Losses in 

 efficiency come about because of reflection 

 of sunlight by the water surface, absorption 

 of light by water and suspended materials, 

 presence of unfavorable wavelengths in sun- 

 light, too great intensity of light near the 

 surface, deficiency of nutrients, and respira- 

 tion of the plants. 



ORGANIC BUDGET-ANNUAL PRODUCTION 



MILLIONS OF TONS-DRY WEIGHT 



SEA SURFACE 



SUNLIGHT 

 25.000 



_^ 



PHYTOPLANKTON -I- ATTACHED PLANTS 

 42 ^^ ^-^ 1.7 



ZOOPLANKTON 

 / 3.4 



FISHES 

 0.1 



MAMMALS 



0.0003 



BATHYPELAGIC ORGANISMS 

 <r0.02 



SEDIMENT SURFACE 



ORGANIC MATTER-TOP OF SEDIMENT- 

 0.4 



ORGANIC MATTER -LOST 

 0.27 



Figure 153. Approximate flow chart of organic matter 

 and annual production of the various biozones of south- 

 ern California. 



