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 ill the Adriatic Sea in relation to macrofaunal ac tivity and oxygen gen penetration depth in the sediment. Vertical profiles of copepods were related to, the oxygen penetration depth and showed peak d ensities in the upper cm or deeper in sediments with a broader oxic zone. I n contrast, nematodes penetrated much deeper into the sediment and no direc t relationship with oxygen penetration depth was evident. Nematode penetrat ion depths were related to or reflected the differences in macrofaunal acti vity or mixing at the four sites which appears to be an important factor go verning the subsurface activity of nematodes.