Uptake of Organic Matter by Meiofauna Organisms and Interrelationships with Bacteria

Abstract

Investigations of bacteria and meiofauna in sandy beach sediments of the brackish-water Kiel Fjord and Kiel Bight (Baltic Sea, FRG) indicate inverse interrelationships: high numbers and biornass (carbon) of meiofauna are correlated with low numbers and biornass of bacteria, and vice versa. Bacterial carbon is 4 times as high as meiofauna carbon; this reflects the extreme ecological character of the wave-washed beach sediments studied. Tracer experiments using tritiated glucose reveal different participation of individual groups of meiofauna in the incorporation of labelled material. Oligochaetes (exclusively detritovores) show the highest incorporation rate of organic material, followed by turbellarians and nematodes. There is some indication that particulate organic matter originally derived from bacteria and that their extracellular products represented the major part of the organic material taken up. Laboratory experiments stress the necessity of studying melofauna activity under close-to-natural conditions.