Vertical distribution of meiofauna in sediments from contrasting sites in the Adriatic Sea: clues to the role of abiotic versus biotic control

The vertical profiles of dominant metazoan meiobenthic taxa were studied at four contrasting sites in the Adriatic Sea in relation to macrofaunal activity and oxygen penetration depth in the sediment. Vertical profiles of copepods were related to the oxygen penetration depth and showed peak densities in the upper cm or deeper in sediments with a broader oxic zone. In contrast, nematodes penetrated much deeper into the sediment and no direct relationship with oxygen penetration depth was evident. Nematode penetration depths were related to or reflected the differences in macrofaunal activity or mixing at the four sites which appears to be an important factor governing the subsurface activity of nematodes