Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Geobiology. 2020 Sep;18(5):594-605. doi: 10.1111/gbi.12396. Epub 2020 Apr 26.
Metal sulfide minerals, including mercury sulfides (HgS), are widespread in hydrothermal vent systems where sulfur-oxidizing microbes are prevalent. Questions remain as to the impact of mineral composition and structure on sulfur-oxidizing microbial populations at deep-sea hydrothermal vents, including the possible role of microbial activity in remobilizing elemental Hg from HgS. In the present study, metal sulfides varying in metal composition, structure, and surface area were incubated for 13 days on and near a diffuse-flow hydrothermal vent at 9°50'N on the East Pacific Rise. Upon retrieval, incubated minerals were examined by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and epifluorescence microscopy (EFM). DNA was extracted from mineral samples, and the 16S ribosomal RNA gene sequenced to characterize colonizing microbes. Sulfur-oxidizing genera common to newly exposed surfaces (Sulfurimonas, Sulfurovum, and Arcobacter) were present on all samples. Differences in their relative abundance between and within incubation sites point to constraining effects of the immediate environment and the minerals themselves. Greater variability in colonizing community composition on off-vent samples suggests that the bioavailability of mineral-derived sulfide (as influenced by surface area, crystal structure, and reactivity) exerted greater control on microbial colonization in the ambient environment than in the vent environment, where dissolved sulfide is more abundant. The availability of mineral-derived sulfide as an electron donor may thus be a key control on the activity and proliferation of deep-sea chemosynthetic communities, and this interpretation supports the potential for microbial dissolution of HgS at hydrothermal vents.
金属硫化物矿物，包括硫化汞（HgS），广泛存在于热液喷口系统中，这些系统中富含硫氧化微生物。目前仍存在一些问题，例如矿物成分和结构对深海热液喷口硫氧化微生物种群的影响，包括微生物活性在从 HgS 中重新迁移元素 Hg 方面的可能作用。在本研究中，在东太平洋脊 9°50'N 的弥散流热液喷口及其附近，对具有不同金属成分、结构和表面积的金属硫化物进行了 13 天的孵育。回收后，用扫描电子显微镜结合能量色散 X 射线光谱（SEM-EDS）、X 射线衍射（XRD）和荧光显微镜（EFM）对孵育矿物进行了检查。从矿物样品中提取 DNA，并对 16S 核糖体 RNA 基因进行测序，以表征定植微生物。在所有样品中都存在常见于新暴露表面的硫氧化属（Sulfurimonas、Sulfurovum 和 Arcobacter）。在孵育点之间和内部，它们的相对丰度存在差异，这表明环境的直接影响和矿物本身对它们有制约作用。离喷口样品的定植群落组成的变化更大，这表明矿物衍生硫化物的生物可利用性（受表面积、晶体结构和反应性的影响）对环境中微生物定植的控制作用大于在富含溶解态硫化物的喷口环境中的控制作用。因此，矿物衍生硫化物作为电子供体的可利用性可能是深海化能合成群落活性和增殖的关键控制因素，这种解释支持了微生物在热液喷口溶解 HgS 的潜力。
