Microbial perspective on the giant carbonate ridge Alpha Crucis (Southwestern Atlantic upper slope)

Abstract Deep-sea carbonate mounds can harbor a wide variety of heterotrophic and chemosynthetic microbial communities, providing biodiversity hotspots among the deep-sea benthic ecosystems. This study examined bacterial archaeal diversity community structure in water column sediments associated to recently described giant mound named Alpha Crucis Carbonate Ridge (ACCR), Southwestern Atlantic. Due acoustic evidence gas chimneys from previous study, we further evaluated primary production through situ-simulated dark carbon fixation rates. Pelagic communities varied significantly with depth, showing high abundance photosynthetic groups surface waters taxa related nitrification intermediate deep waters. The top ACCR were very similar along sediment while those base showed clear stratification pattern, members strata mainly anoxic Dark rates same order magnitude as cold seeps hydrothermal vents. Our provides first description microbiome adds new information help formulate implement future conservation management strategies for vulnerable marine