Sediment macrofaunal composition, sediment grain size, and taxa functional traits of multiple deep-sea coral habitats in the Gulf of Mexico, 2009-2014

Deep-sea corals can create a highly complex, three-dimensional structure that facilitates sediment accumulation and influences adjacent sediment environments through altered hydrodynamic regimes. Infaunal communities adjacent to different coral types, including reef-building scleractinian corals and individual colonies of octocorals, are known to differ from background non-coral soft-sediment communities, often exhibiting higher macrofaunal densities and distinct community structure. However, the coral types have different morphologies, which may modify the adjacent sediment communities in discrete ways. Here we address two main questions: 1) how infaunal communities adjacent to deep-sea corals and their associated sediment geochemistry compare among coral types and 2) do infaunal communities adjacent to coral habitats exhibit typical regional and depth-related patterns expected for the Gulf of Mexico (GOM). Study areas were located in the northern GOM on the continental slope off Louisiana and Mississippi; encompassing a geographic range of 450 kilometers and an overall depth range of 263-1095 m. Infaunal communities were examined adjacent to three coral types: two scleractinian corals, Lophelia pertusa and Madrepora oculata, and octocorals. Sediment push cores were collected to assess diversity, composition, numerical abundance, and functional traits of macrofauna (>300 μm) adjacent to deep-sea coral habitats.