ANTHROPOGENIC AND BATHYMETRIC DETERMINANTS OF MARINE BENTHIC ASSOCIATIONS IN COASTAL NORTH CAROLINA

Marine benthic associations from present-day habitats can provide multidisciplinary quantitative insights into community ecology, paleontology, and conservation biology. This approach is particularly fruitful when data on live communities and death assemblages are collected in concert. Here, we employ systematic quantitative sampling of live and dead marine benthos in coastal North Carolina to evaluate macro-faunal associations along an onshore-offshore gradient in a region variably affected by anthropogenic activities.

This preliminary report is based on 75 bulk live samples collected using dredges and grabs at multiple sites, including bays, estuaries, harbors, and the open shelf. A total of over 3000 live specimens representing 130 species have been collected so far. The detrended correspondence analysis of the resulting abundance data indicates that bathymetry is the primary controlling factor, with faunal assemblages changing predictably in terms of their taxonomic composition with depth. This is consistent with paleontological studies that show that water depth tends to control multivariate ordinations of fossil benthic assemblages. In contrast, anthropogenic factors appear to play secondary role in influencing the multivariate ordination of samples.

The concurrent examination of anthropogenic and bathymetric factors suggests that benthic marine associations of coastal North Carolina are primarily controlled by bathymetry (as would be expected in many pristine settings). In contrast, anthropogenic effects, while discernible, play only a secondary role in determining taxonomic composition of local communities.