Environmental influence on the distribution of polychaete families and feeding guilds in benthic communities of the Grand Banks and Flemish Cap (NW Atlantic)

Many biodiversity patterns across the globe can be partially explained by energetics and habitat structure, including in the deep sea. Because of difficulties in logistics, studies focusing on deep-sea benthic systems often have limited sample sets that may be far apart in space. Here, we present analyses based on a well-sampled region, the northwest Atlantic, allowing us to relate patterns of polychaete community structure (using taxonomic families and feeding guilds) against well-resolved environmental gradients. We show that community structure is heterogenous in this area. We observe three major groups within polychaete communities which also show differences in feeding guilds. Several environmental gradients, including long-term variables, explained the differences between the groups. Both energetics and habitat structure variables were important, while past fishing intensity had a weak effect, although there was support for a difference in community composition for communities above and below the historical fishing limit of 1200 m. The effect of long-term environmental factors may indicate that the deep sea is not immune to climate change, and these effects must continue to be considered in future management of exploitation of this ecosystem. •Both habitat structure and energetics are important drivers of deep-sea diversity.•Deep-sea macrofaunal polychaetes are influenced by long-term temperatures.•Bottom trawling was a minor driver of deep-sea polychaete diversity.