Fine Scale Assemblage Structure of Benthic Invertebrate Megafauna on the North Pacific Seamount Mokumanamana

A study of the seamount Mokumanamana in the Papahānaumokuākea Marine National Monument reveals high beta-diversity in benthic megafaunal assemblages, driven by species substitution along depth gradients and between different sides of the seamount. The research, conducted using the AUV Sentry across 200–700 m depths, identified nine distinct megafaunal assemblages dominated by sponges, corallimorpharians, cup corals, and benthic ctenophores, with abundance and diversity increasing with depth. Environmental factors such as sediment composition, oxygen levels, substrate variability, and surface currents were found to correlate with these assemblage differences, suggesting that microhabitat heterogeneity on seamounts promotes unique biodiversity patterns often overlooked in broader-scale studies. These findings underscore the importance of fine-scale sampling for conservation management and ecological understanding of seamount ecosystems.

Morgan, N. B., Goode, S., Roark, E. B., & Baco, A. R. (2019). Fine Scale Assemblage Structure of Benthic Invertebrate Megafauna on the North Pacific Seamount Mokumanamana. Frontiers in Marine Science, 6. https://doi.org/10.3389/fmars.2019.00715