Dataset: Macrofaunal morphospecies from hard substrate samples at methane seeps collected from R/V Atlantis cruise AT50-12 in the Southern California Borderland from July 16-28, 2023

Samples were collected with HOV Alvin using the manipulator. Samples were placed into individual compartments in a biobox on the Alvin basket. Before preserving, samples were kept cold and animals were handpicked to sample tissue for stable isotope analyses (see related datasets for isotopic data). The remaining sample was sieved through 0.3 mm mesh, separating the sample in two fractions (a fine fraction with the meiofauna, and a coarser one with the macrofauna), both preserved in 95% Ethanol.