Spatial and temporal patterns of benthic polychaete communities on the northern Gulf of Mexico continental slope

Abstract

Community structure and abundance of benthic polychaetes along a transect on the central northern Gulf of Mexico continental slope were examined. Spatial, seasonal, short- (~1 year), and long-term (~16–17 years) temporal comparisons of assemblages were conducted with samples collected in 1983–1984 and 2000–2001. Polychaete abundance did not consistently decrease between 325 and 1500 m, but sharply decreased between 1500 and 2100 m. On the upper slope (325–1500 m) polychaete abundance approximately doubled between fall 1983 and spring 1984, but had returned to initial levels by fall 1984. On the lower slope (2500 m) seasonal variations in abundance were less pronounced. The taxonomic composition of the polychaete assemblages changed continuously along a depth gradient; however, temporal variations of the assemblages at all water depths were generally minor. This study provides a baseline for naturally occurring spatial and temporal dynamics of benthic polychaete communities on the northern Gulf of Mexico continental slope.