Community composition of mussel associates at deep-sea methane seeps in the Gulf of Mexico and the US Atlantic Margin

Efforts to understand and preserve the methane seep communities of the Gulf of Mexico and the US western Atlantic margin begin with an understanding of biodiversity and community composition. In this study, 10,143 individuals representing 63 different taxa were sampled from mussel-beds surrounding methane seeps at various depths within two different ocean basins. Diversity in mussel beds was highest at Baltimore Canyon, the shallowest site sampled in the Atlantic. Although only four species were sampled at more than one site, species composition was most alike among sites found at similar depths; the two deepest sites sampled, Florida Escarpment and Blake Ridge, showed a 9.6% similarity. However, depth is not the only predictor of similarity: Baltimore Canyon and Chincoteague are both located in the Atlantic Ocean at different depths but had a 5.3% similarity in species composition. The high diversity of individuals sampled among these sites emphasizes the importance of preserving seep communities, which provide essential nursery habitats and primary production that establish a food source for many migratory species within the deep-sea ecosystem. Not only is the diversity of seep communities unique and important to the deep sea, but seeps may be beneficial to the overall health of our Earth’s ecosystem through the support of commercial fisheries and the sequestering of methane.