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

中文翻译：

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巨型碳酸盐脊 Alpha Crucis（西南大西洋上坡）的微生物视角

深海碳酸盐丘可以容纳各种各样的异养和化学合成微生物群落，在深海底栖生态系统中提供生物多样性热点。这项研究检查了与最近描述的名为 Alpha Crucis Carbonate Ridge (ACCR)，西南大西洋的巨型碳酸盐丘相关的水柱和沉积物中的细菌和古细菌多样性和群落结构。由于先前研究中气体烟囱的声学证据，我们通过原位模拟的暗碳固定率进一步评估了化学合成初级生产。远洋微生物群落随深度变化显着，在地表水中显示出高丰度的光合群以及与中水和深水硝化相关的分类群。ACCR顶部的底栖群落与沉积深度非常相似，而ACCR底部的底栖群落则表现出明显的分层格局，深层成员主要与缺氧和化学合成生态系统有关。暗碳固定率与深海冷泉和热液喷口处于同一数量级。我们的研究首次描述了 ACCR 微生物组，并添加了新信息，以帮助制定和实施未来脆弱海洋生态系统的保护和管理战略。暗碳固定率与深海冷泉和热液喷口处于同一数量级。我们的研究首次描述了 ACCR 微生物组，并添加了新信息，以帮助制定和实施未来脆弱海洋生态系统的保护和管理战略。暗碳固定率与深海冷泉和热液喷口处于同一数量级。我们的研究首次描述了 ACCR 微生物组，并添加了新信息，以帮助制定和实施未来脆弱海洋生态系统的保护和管理战略。