Chapter 5 



Ecological Systems and Transport 



53 



TABLE 1 Estimates of Biomass of Marine Populations. All Values Have Been Converted to 

 Volume (Wet Weight) Per Cubic Meter (Parts Per Million) 



Population 

 Phytoplankton . 



Zooplankton 



cc/m' 

 10 

 25 

 41 



18.2 

 1.2 

 0.3 



0.08 — 1.0 



0.08 — 0.8 



0.006 — 0.09 



1.0 



0.042 

 0.055 

 0.124 



a. Complete utilization of maximum phosphorus concentrations; conversion P = 0.5 per cent of wet 

 weight. 



b. Ketchum and Keen, 1948, 17-21, Table 1. Conversion as in a. 



c. Riley, Stommel and Bumpus, 1949, Table VI; conversion C^IO per cent wet weight. 



d. Redfield, 1941, drained volumes, vertical tows, assumed mean depth 100 meters. 



e. Riley, et al., 1949, Table V, displacement weight. 



f. Unpublished data, W. H. O. I., surface tows at night, drained volumes. 



g. Unpublished data, S. I. O., oblique tows 200-300 meters to surface, wet plankton volumes. 



Location and character 

 .Maximum Atlantic 

 Maximum Pacific 

 Red Tide Blooms 



Long Island Sound 

 Coastal Water 

 Sargasso Sea 



. Gulf of Maine 

 Coastal Water 

 Sargasso Sea 

 N. African Upwelling 



Eastern North Pacific 

 Eastern Tropical Pacific 

 Peru Current 



Source 

 a 

 a 

 b 



c 

 c 

 c 



d 



e 



f,e 



f 



g 



g 



g 



the depth of the photosysthetic zone and the 

 production rate at various depths, are variable, 

 thus the values for production cannot be re- 

 duced without excess over-simphfication to a 

 volume basis which would permit direct com- 

 parison with Table 1. However, Riley's (1941) 

 maximum value for the standing crop of phyto- 



TABLE 2 Estimates of the Productivity of 

 Marine Phytoplankton Populations 



Location and gC/m"/ cc/m"/ 



character Source year year i 



Sargasso Sea (Atlan- 

 tic) a 18 180 



Coastal Areas (Atlan- 

 tic) a 1100 11000 



Open Ocean (Pacific) . . a 50 500 



Equatorial Divergence 



(Pacific) a 140 l400 



Coastal Areas (Pacific) . a 200 2000 



Oceanic Mean a 55 550 



Long Island Sound 



min b 95 950 



max 1000 10000 



N. Atlantic 3°-13°N. . b 278 2780 



Oceanic Mean c 340 ± 220 1200-5600 



a. Steemann Nielsen (1954). Carbon-l4 method. 

 This is given as gross production, but Ryther (1954) 

 suggests that it may be net (gross minus respiration) 

 production in nutrient poor areas. 



b. Riley (194l). Gross production, oxygen method. 



c. Riley (1944). 



1 Conversion assuming one gram of carbon = 10 cc 

 of wet plankton. 



plankton in Long Island Sound, 1.82 gC/m^, 

 showed a production of 0.187 gC/myday and 

 the annual production was twenty times as great 

 as the maximum standing crop observed at any 

 one time. Estimates of the growth of zooplank- 

 ton populations have given values ranging up 

 to 5 per cent of the standing crop per day. 



It is a truism in ecology that the total quan- 

 tity of living material which can be produced 

 decreases as the trophic level of the organisms 

 considered increases. In some ecological sys- 

 tems the biomass reflects this progression, i.e., 

 at any one time there will be a larger standing 

 crop of plants than of herbivores and the stand- 

 ing crop becomes progressively smaller as one 

 goes through the various higher steps of the 

 food web. In the oceans, however, this is not 

 necessarily true. It is common to find rather 

 high concentrations of the herbivorous zoo- 

 plankton when phytoplankton are scarce. Large 

 populations of herbivores will quickly decimate 

 the plants on which they feed. A balance may 

 be maintained as a result of the different lengths 

 of the life cycle of the various parts of the 

 food web. A population of phytoplankton can 

 double in a period of time ranging from hours 

 to days, whereas the life cycles of zooplankton 

 are more commonly measured in terms of weeks 

 or months and the life cycles of the higher 

 elements of the food web, such as fish, are 



