Bathymetric distribution and diversity of deep water polychaetous annelids in the Sigsbee Basin, northwestern Gulf of Mexico

Changing Diversity in Changing Environment

“…Our zone 3, the farthest one from coastline and Orinoco river influence, corresponds to an oligotrophic zone, with low primary productivity due to the lower nutrient input, so the species richness is again reduced. This deep zone is dominated by species from the Pilargidae, Spionidae, Paraonidae and Cirratulidae families, similar to Pérez et al (2003) results from the Gulf of Mexico, who report the presence of these families at zones between 200-3800m depth. Therefore, in this work we stress the importance of studying large-scale biodiversity spatial and temporal patterns in marine environments subjected to heavy continental influence, in order to contribute to reduce the existent gap of information, especially in tropical regions, where riverine inputs are determinant.…”

“…The most important polychaete families in the study site were Spionidae, Pilargidae and Paraonidae, while the rest of them presented relative abundances lower than 7%. Glover et al (2001) and Pérez et al (2003) pointed out that Spionidae, Cirratulidae and Paraonidae families represent between 50-60% of the total abundance in deep water areas, in the Atlantic and Pacific, independently of the sediment organic content. The authors explained that this can relate to a very similar functional structure between these communities, dominated by detritivorous polychaetes; being also present predator habits families, mainly syllids and lumbrinerids, but in a lower proportion.…”

“…One shallow, conditioned by the river discharge, with low organic matter content in sediments (< 1%), high water turbidity and extreme salinity variations (0.25-23PSU); and a deeper, an oceanic influenced and oligotrophic zone, characterized by a steep depth gradient, low temperature and marine current influences (Martín & Bone, 2007). These environmental conditions contribute to define the polychaete community spatial distribution pattern, with low densities for the first one, and higher for the second one (Martín & Bone, 2007;Pérez et al, 2003). At the shallowest zone (< 60 m depth), there is active sedimentation, with high silt and organic content.…”

The Macrobenthic Ecology of the Straits of Magellan and the Beagle Channel

“…Decreasing species richness and increasing evenness with depth have also been reported from numerous regions, e.g. for the Gulf of Mexico (Pérez-Mendoza et al 2003). Analysis of these patterns in the polychaetes of the Pacific coast of South America suggests that a source-sink hypothesis of colonisation-extinction dynamics, where shallower "sources" maintain deeper "sinks", provides a conceptual and methodological framework that explains patterns of diversity (Moreno 2008).…”

Bathymetric zonation of deep-sea macrofauna in relation to export of surface phytoplankton production

“…Zonation studies on macrofaunal assemblages are relatively sparse (Grassle et al 1979, Rowe et al 1982, Gage et al 2000 and have mostly dealt with individual taxa (Rex 1977, Cartes & Sorbe 1997, Pérez-Mendoza et al 2003, Olabarria 2005, Aldea et al 2008. Most previous investigations were carried out along a single narrow depth transect and reported a vertical zonation across isobaths.…”