Soft-sediment benthic biodiversity on the continental shelf in relation to environmental variability

Abstract

Soft-sediment macrobenthos data for the Norwegian continental shelf (61°N, 1 to 2°E) was used to examine species distributions, community structure and community differences, and how different measures of biodiversity are related to environmental variability. Water depth at 35 sites ranged from 115 to 331 m over a spatial sampling scale of ca. 45 km × 60 km, and there was considerable variation in sediment characteristics. Of a total of 508 recorded species, 39% were restricted to 1 or 2 sites, whereas only 3 species spanned the entire sampling area. Polychaetes were the most common and widespread taxonomic group; crustaceans and echinoderms were more restricted in their distributions than the other dominant groups. Whittaker's beta diversity measure ( β W , extent of change in species composition among sites) was highest for those groups with the highest proportion of restricted-range species. The number of shared species, the complementarity (biotic distinctness), and the Bray-Curtis similarity between all pairwise combinations of sites (3 beta diversity measures) were more strongly related to change in environment (notably depth, followed by median grain size and silt-clay content) than to spatial distance between sites. Likewise, a multivariate analysis (BIO-ENV) identified these factors as the major environmental variables influencing the faunal patterns, whereas univariate measures of diversity were not related to depth or median grain size. Univariate measures of diversity, beta diversity measures, and BIO-ENV analyses showed that molluscs, followed by polychaetes, were most highly related to environmental variables. In this study, alpha, beta and gamma diversity were higher than in a study of a single soft-sediment habitat type in the southern part of the Norwegian continental shelf.

Influence of environmental properties on macrobenthos in the northwest Indian shelf

“…Massad and Brunel (1979) and Robert (1979) also noticed increased richness with sand content which were independent of bathymetric position but, Bergen et al (2000) and Ellingsen (2002) observed that depth was the primary habitat factor organizing the southern California and Norwegian benthic community respectively followed by sediment grain size and not much effected by latitude. Ellingsen (2002) added that biotic factors such as availability and abundance of benthic larvae/adult might be more important than sediment characteristics in determinining benthic settlement. Dominance of polychaete species was high in deeper depths especially from family Spionidae, Cirratulidae and Capitellidae showed ability of these species in adverse conditions.…”

Testing BOPA index in sewage affected soft-bottom communities in the north-western Mediterranean

“…This necessity has led to the development of different indexes based on soft-bottom communities, which summarise ecological status and ecological quality. The relationships between macrofaunal assemblages and the effect of contaminants on them have been described extensively in the literature, (Pearson and Rosenberg, 1978;Gray and Mirza, 1979;Dauvin, 1982;Warwick et al, 1990;Simboura et al, 1995;Estacio et al, 1997;Ellingsen, 2002;Morrisey et al, 2003;Guerra-García and García-Gómez, 2004).…”

Baía de todos os santos: aspectos oceanográficos

“…Gray, 1974;Ellingsen, 2002;Blanchet et. al., 2005;Lu, 2005;Munari et al, 2005), principalmente pelas características texturais dos sedimentos, a salinidade, a profundidade, o pH e o oxigênio dissolvido.…”

“…(e.g. Gray, 1974;Snelgrove e Butman, 1994;Ellingsen, 2002). Estes fatores promovem uma grande heterogeneidade de ambientes, criando vários tipos de habitats e, consequentemente, determinando a variabilidade em diferentes escalas.…”