Abundance and Biomass of Metazoan Meiobenthos in The Deep Sea

Abstract

Quantitative information on the abundance and biomass of deep-sea metazoan meiobenthos, gathered principally from research conducted since 1980, is summarized. Abundance and biomass in the deep Atlantic, Pacific and Indian Oceans generally range between 100 and 1000 x 103 individuals m-2 and 10 to 400 mg C m-2, respectively. Both decrease significantly with increasing water depth. Relationships between abundance and biomass of meiofauna are discussed, as are relationships between meiofaunal standing stocks and those of other benthic size groups. Available data (obtained mostly from the Atlantic deep sea) suggest that meiofaunal biomass is two orders of magnitude lower than bacterial biomass and equivalent to macroinfaunal and invertebrate megafaunal biomass. Relationships between meiofaunal standing stocks and various indices of surface-derived organic flux are generally positive, as are relationships between surface production and standing stocks. However, the functional role of metazoan meiobenthos in deep-sea food chains remains uncertain, especially the extent to which they compete with, or are food for, larger animal groups.