Grazing of Zooplankton in the Oceanic Environment

48 pagesGrazing in the oceans, in general, refers to herbivores feeding on plant material. It is an important factor in determining primary production in the sea, and is difficult to estimate. Also, this energy transfer seems at least in part to be responsible for population changes which occur in the ocean. Since it is only in the coastal waters that other plant material besides the phytoplankton is abundant (seaweed) and that other zooplankton organisms besides the copepods are abundant (meroplankton: the planktonic larval stages of Mollusca, Echinodermata and worms), attention will be primarily focused on the relation between phytoplankton organisms and copepods. (Marshall and Orr, 1966b) Most experimental work has been done with cope pods, al though other plank tonic animals (Euphausids, Chaetognaths etc.) are abundant at certain places for part of the year. In order to understand the problems involved in studying the quantitative aspects of grazing, a general discussion of the patterns of feeding is necessary (Chapter I). The second chapter provides the theoretical background. (mathematical models) for a discussion of the methods used and measurements obtained in chapter three. The last chapter discusses grazing as it relates to the ecological problem of population control and evaluates the progress made in this area of research