Center for Life in Extreme Environments, Biology Department, Portland State University, Portland, OR 97201;
Center for Life in Extreme Environments, Biology Department, Portland State University, Portland, OR 97201.
Proc Natl Acad Sci U S A. 2020 Dec 22;117(51):32627-32638. doi: 10.1073/pnas.2019021117. Epub 2020 Dec 4.
Hydrothermally active submarine volcanoes are mineral-rich biological oases contributing significantly to chemical fluxes in the deep sea, yet little is known about the microbial communities inhabiting these systems. Here we investigate the diversity of microbial life in hydrothermal deposits and their metagenomics-inferred physiology in light of the geological history and resulting hydrothermal fluid paths in the subsurface of Brothers submarine volcano north of New Zealand on the southern Kermadec arc. From metagenome-assembled genomes we identified over 90 putative bacterial and archaeal genomic families and nearly 300 previously unknown genera, many potentially endemic to this submarine volcanic environment. While magmatically influenced hydrothermal systems on the volcanic resurgent cones of Brothers volcano harbor communities of thermoacidophiles and diverse members of the superphylum "DPANN," two distinct communities are associated with the caldera wall, likely shaped by two different types of hydrothermal circulation. The communities whose phylogenetic diversity primarily aligns with that of the cone sites and magmatically influenced hydrothermal systems elsewhere are characterized predominately by anaerobic metabolisms. These populations are probably maintained by fluids with greater magmatic inputs that have interacted with different (deeper) previously altered mineral assemblages. However, proximal (a few meters distant) communities with gene-inferred aerobic, microaerophilic, and anaerobic metabolisms are likely supported by shallower seawater-dominated circulation. Furthermore, mixing of fluids from these two distinct hydrothermal circulation systems may have an underlying imprint on the high microbial phylogenomic diversity. Collectively our results highlight the importance of considering geologic evolution and history of subsurface processes in studying microbial colonization and community dynamics in volcanic environments.
热液活动的海底火山是富含矿物质的生物绿洲，对深海的化学物质通量有重要贡献，但对于栖息在这些系统中的微生物群落，我们知之甚少。在这里，我们根据地质历史和新西兰北部克马德克弧状南部兄弟海底火山地下的热液流体路径，研究了热液沉积物中的微生物多样性及其宏基因组推断的生理学。从宏基因组组装的基因组中，我们鉴定了超过 90 个假定的细菌和古菌基因组家族，以及近 300 个以前未知的属，其中许多可能是该海底火山环境的特有种。虽然受岩浆影响的热液系统在兄弟火山的火山复活锥中栖息着嗜热嗜酸菌和超门“DPANN”的多样化成员，但与火山口壁相关的两个截然不同的群落可能是由两种不同类型的热液循环形成的。群落的系统发育多样性主要与锥状部位和其他地方的岩浆影响热液系统相一致，其特征主要是厌氧代谢。这些种群可能是由与不同（更深）先前改变的矿物组合相互作用的具有更大岩浆输入的流体维持的。然而，距离较近（几米远）的群落，其基因推断出的有氧、微需氧和厌氧代谢可能是由更浅的以海水为主的循环支持的。此外，这两种不同热液循环系统的流体混合可能对微生物系统发育多样性产生潜在影响。总的来说，我们的结果强调了在研究火山环境中的微生物定殖和群落动态时，考虑地质演化和地下过程历史的重要性。
