Comparisons of three deep-sea wreck communities in the Gulf of Mexico

Artificial hard substrates such as shipwrecks and large debris can impact biodiversity, especially in the deep sea where hard substrate is limited. A potential complex interplay occurs where wrecks provide surfaces for recruitment of epibenthic organisms and structured habitat for mobile invertebrates and fish but may also inhibit successional processes due to the presence of oil and other toxins. Here, we examined the interplay of these dynamics using remotely operated vehicle (ROV) surveys of the wrecks of the oil rig Deepwater Horizon , the SS ‘Robert E. Lee,’ and the USS ‘Peterson.’ Megafauna were identified to the lowest possible taxonomic unit using the high-definition video captured by ROV. Comparisons of the 3 wrecks revealed communities with unique compositions, but that did not vary significantly in total abundance, density, richness, evenness, or diversity. Furthermore, while species identities varied between wreck sites, the functional roles they fulfilled based on motility, tiering, and feeding mode largely did not. We posit wreck age, depth, and the presence of oil as potentially interacting factors influencing the assembly of these artificial hard substrate communities. As industrial activities continue to introduce more artificial substrates into the deep sea, our findings suggest that these structures may not support the diverse, thriving ecosystems typically expected, which has important implications for deep-sea restoration and conservation efforts focused on enhancing biodiversity through artificial habitats.