Distribution and species diversity of deep-sea nematodes off North Carolina

In four sedimentary environments off North Carolina 209 species of free-living marine nematodes were identified. Of these, 106 were restricted to one of four habitats. Clayey-silts (800 to 2500 m) contained the most stenotopic species (49). Quartz-algal sands (50 to 100 m) contained 35, foraminiferan sands (250 to 500 m) 17, and sandy silts (500 to 800 m) only 5 stenotopic species.

A sand zone (50 to 500 m) and a clayey-silt faunistic zone (800 to 2500 m) are recognized, separated by a transition zone (500 to 800 m) characterized by little endemism. There may be zonation of the fauna within these major zones.

Species diversity decreased with increasing water depth, attributable to the decreased number of microhabitats available in the clayey-silts. Diversity is largely a function of species richness. Withinhabitat diversity in the North Carolina sediments is higher than in Long Island Sound (a shallower, temperate body of water).