. Elements of ecology. Ecology. Consumers All However, food dependencies are difficult to determine, and several divergent views have been held as to the critical relations. Since observations at sea indicated that diatoms were often abundant when copepods were scarce and vice versa, some investigators argued that no direct food dependency occurred. The quandary of this apparent contradiction represents the danger of generalizing from isolated ob- servations or from statistical tabulations of the occurrence of animals and plants without due regard to the dynamic aspect of their growth and life
. Elements of ecology. Ecology. Consumers All However, food dependencies are difficult to determine, and several divergent views have been held as to the critical relations. Since observations at sea indicated that diatoms were often abundant when copepods were scarce and vice versa, some investigators argued that no direct food dependency occurred. The quandary of this apparent contradiction represents the danger of generalizing from isolated ob- servations or from statistical tabulations of the occurrence of animals and plants without due regard to the dynamic aspect of their growth and life cycles. If diatoms are scarce at a given point where copepods are abundant, does it mean that the copepods have just finished consuming the population, or does it mean that copepods are primarily dependent upon some other source of food? U. Light Nutrient supply. Clarke, 1943 Fig. Simplified representation of main ecological cycle in the sea. As data on this problem were gathered, two theories emerged. One was the theory of animal exclusion proposed by Hardy (1936) that high concentrations of phytoplankton are harmful to zooplankton and, therefore, that water masses containing large numbers of diatoms are actively avoided by copepods. Exclusion was originally believed to have taken place chiefly in the vertical direction and thus to curtail the upward phase of the diurnal migration of the zooplankton. Hori-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Clarke, George L. (George Leonard), 1905-. New York, Wiley
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Keywords: ., bookcentury1900, bookpublishernewyorkwiley, booksubjectecology
