Diversity and composition of the copepod communities associated with megafauna around a cold seep in the Gulf of Mexico with remarks on species biogeography

In order to characterize the copepod communities associated with tubeworm and mussel aggregations around a hydrocarbon seep in the Green Canyon of the Gulf of Mexico, diversity, abundance, and community composition were analyzed. Also analyzed were species biogeography and the potential connectivity to other chemosynthesis-based habitats. Copepod abundance and biomass were very low among tubeworms and mussels, with 0.22 to 6.08 individuals per 10 cm(2) sampled area and 9.02 to 42.43 mu g wet weight 10 cm(2) sampled area, respectively; but, abundance was significantly higher among the mussels. Fifty-five copepod species were identified, of which most were newly discovered and primarily belonging to the Harpacticoida order. Four copepod species were previously recorded from other food-rich and hard-substrata environments, such as hydrothermal vents or wood falls. Another four species showed close morphological proximity to species described from cold seeps, hydrothermal vents, and wood falls. Copepod diversity and community composition showed no significant differences between the foundation species. However, differences in the relative abundance and dominance of single species indicate a rather homogeneous community in mussel beds and a more heterogeneous community among tubeworms, indicating that foundation species may shape the abundance and community composition of associated copepods at cold seeps.