Trophic conditions and meiofaunal assemblages in the Bari Canyon and the adjacent open slope (Adriatic Sea)

Abstract

Due to their topographic features, submarine canyons are generally sites of intense shelf-slope exchanges of water and material, fuelling the deep basins with large quantities of sediment exiting from the continental shelf. In order to provide new insights about the role of submarine canyons in controlling the relationships between food availability and benthic biodiversity patterns along the continental slope, we investigated the quantity and the biochemical composition of sediment organic matter and the abundance of meiofaunal assemblages in the sediments along two different branches of a canyon and in an adjacent open slope located in the Bari margin (Adriatic Sea). Our results highlight that even twin branches within the same canyon may exhibit very large differences in the quantity, depth-related patterns and biochemical composition of sediment organic matter as well as of meiofaunal abundance. We also report here that the trophic relationships in the canyon sediments are tightly connected with the hydrodynamic conditions and that the steeper and the more flushed the canyon the more hostile environment for the benthos.

Keywords:

• submarine canyon
• Adriatic Sea
• organic matter
• meiofauna

Acknowledgements

This study was conducted in the framework of the project HERMES (Hot-spot Ecosystem Research on the Margins of European Seas; Contract No. GOCE-CT-2005-511234-1). We are grateful to F. Trincardi (CNR, Italy) for the help in addressing our knowledge of the local geological setting and his courtesy in providing us with high definition maps of the Bari canyon. Thanks are due to the crew of the R/V Urania and to D. Zeppilli and M. Mea for sampling.