© 1968 by The Society for Integrative and Comparative Biology
Zooplankton—Life in a Nutritionally Dilute Environment
Fisheries Research Board of Canada, Bedford Institute of Oceanograph Dartmouth, Nova Scotia
The classic concept of "filtering rate" often used to describe feeding by zooplankton may be outmoded. The Ivlev (1945) type of fitted curve may describe more precisely the relation between a zooplanktonic organism and its food supply. Once food is captured it is assimilated with a high degree of efficiency. There does not appear to be any relationship between the quantity of food eaten and the digestive efficiency. Examination is made of the relationship between respiratory rate and size in zooplankton. The exponential constant varies considerably from one organism to another, but may not be affected by physical parameters such as temperature. A multiple regression equation relating respiration to weight and temperature simultaneously gives a moderately good estimate of respiration for a variety of marine copepods. The relationship between uptake of oxygen and excretion of nitrogen (O:N ratio) is a useful indicator of metabolic substrate used in respiration and is related to the chemical composition of the animals. The "specific dynamic effect" (SDA) of food should be considered in studies of zooplanktonic metabolism. The literature on growth efficiency for zooplankton is reviewed and the applicability of recent growth models for fish (Paloheimo and Dickie, 1965, 1966) to zooplanktonic problems is considered.