Energy flow in the flora and meiofauna of sandy beaches

Abstract

Synopsis Investigation of a temperate and tropical beach has shown that, based on chlorophyll a analyses, an epipsammic diatom population present in the temperate beach is absent in the tropical beach. Comparison of community respiration rates for the two beach populations excluding macrofaunal respiration shows that the tropical beach rates (which were constant over the period January-March) were about 9 times the winter rates of the temperate beach and about twice the summer rates. Annual microbial production is estimated at 15 gC/m 2 for the temperate beach and 72 gC/m 2 for the tropical beach. The greatly increased rate of production in the tropical beach was considered to be a function of increased water flow into that beach. In comparison, meiofauna and macrofauna biomass are less in the tropical beach and their respective production likely to be at most no more than in the temperate beach. It is proposed from experimental studies that the failure of animal populations fully to utilise microbial production in sandy beaches is due to the relative degree of exposure stripping significant quantities of microbial growth from this system. This proposal is discussed as a means of explaining mechanisms of control of animal production in sandy beaches.