Quantitative estimates of the meiofauna from the deep sea off North Carolina, USA

Abstract

In 1974 the authors collected, sorted and enumerated meiofauna from 400, 800 and 4000 m off North Carolina, USA. Samples were replicated respectively with 4 boxcores and 21 subsamples, 2 boxcores and 7 subsamples and 2 boxcores and 8 subsamples. Total meiofaunal numbers were highest in fine silt sediment at 800 m ($\bar x$=891.9 10 cm₋₂) and lowest in very fine silt at 4000 m ($\bar x$=73.5 10 cm₋₂). Fine sand at 400 m yielded a mean of 442.4 10 cm⁻². At all depths, most fauna were located in the upper 3 cm of sediment ($\bar x$ depth distribution=2.2 cm), and typically only nematodes and foraminiferans were found below 4 cm. Total community abundances significantly differed with depth; however, there were no differences among replicate boxcores at particular depths. Since most (85.7%) of the variance was associated with subsamples from a boxcore, it appears that meiofauna densities are homomeneous within large areas at particular depths, and that patchiness is a smallscale phenomenon at the level of the 10 cm² subsampler. Comparisons of sorting efficiencies of live and preserved samples indicated that to accurately enumerate formainiferans, samples must first be fixed and stained, while turbellarians and oligochaetes must be sorted live.