文摘
Polychaete worms (Annelida), the dominant macrofaunal taxon in most fine-grained marine sediments, changed in species composition from 1983–85 to 2000–02 at nine locations on the upper continental slope of the northern Gulf of Mexico (GoM). The assemblages exhibited relative stability in abundance and diversity, but fell into six separate groups of species (>35% similarity) that were related more to time-of-sampling than depth. The upper slope experiences steep gradients in the environment but this had secondary effects on species turnover (depth-related zonation or Beta diversity). Significantly higher densities (p<0.05) in April 1984, suggest that seasonal recruitment may have occurred but the higher densities were attributed to only two species.