Abstract:
Biological activity at deep-sea hydrothermal chimneys is driven by chemotrophic microorganisms that metabolize chemicals from the venting high-temperature fluids. Understanding taphonomy and microbial microtextures in such environments is a necessity for micropaleontological and palaeoecological research. This study examines fossilized microorganisms and related microtextures in a recent black smoker from the Roman Ruins hydrothermal vent site, Eastern Manus Basin offshore of Papua New Guinea. Whereas the center of the examined sulfide chimney is dominated by high-temperature mineralogy (chalcopyrite and dendritic sphalerite), filamentous and coccoidal biomorphs occur in an outer, warm zone of mixing between hydrothermal fluids and seawater, which is indicated by their occurrence within colloform and botryoidal pyrite of barite-pyrite coprecipitates. Both morphotypes can be interpreted as thermophilic microorganisms based on their occurrence in a high-temperature habitat. Their separate (non-commensal) occurrence hints at sensitivities to microenvironmental conditions, which is expectable for strong temperature, pH, and redox gradients at the walls of deep-sea hydrothermal chimneys. Whereas both morphotypes experienced mild thermal overprint, taphonomic differences exist: (i) spaces left by cells in filamentous fossils are predominately filled by silica, whereas inter/extracellular features (crosswalls/septae and outer sheaths) are pyritized; (ii) coccoidal fossils show both silica- and pyrite-infilled interiors, and generally better preservation of cell walls. These different manifestations presumably relate to an interplay between microenvironmental and biological factors, potentially contrasting metabolisms, and differences in cell wall chemistries of distinct bacteria and/or archaea. A further hypothesis is that the coccoidal features represent biofilm-forming organisms, whose organic matter derivates contributed to the formation of intimately associated wavy and wrinkly carbonaceous laminations that are at least locally distinguishable from the texture of the surrounding pyrite. Hence, the presented data provide evidence that microtextures of microbiota from hydrothermal systems can have a similar significance for palaeobiological research as those from sedimentary environments.
摘要:
深海热液烟囱的生物活动是由化学营养微生物驱动的,这些微生物从排出的高温流体中代谢化学物质。了解这种环境中的分类学和微生物微观结构是微古生物学和古生态学研究的必要条件。这项研究检查了最近来自罗马遗址热液喷口的黑人吸烟者的化石微生物和相关的微观结构,巴布亚新几内亚近海的东马努斯盆地。尽管所检查的硫化物烟囱的中心由高温矿物学(黄铜矿和树枝状闪锌矿)主导,丝状和球形生物形态发生在外部,热液和海水混合的暖区,这表明它们在重晶石-黄铁矿共沉淀物的胶体和肉毒黄铁矿中的存在。根据在高温栖息地中的存在,两种形态类型都可以解释为嗜热微生物。它们单独(非共生)的发生暗示了对微环境条件的敏感性,这是预期的高温,pH值,和深海热液烟囱壁上的氧化还原梯度。虽然两种形态都经历了温和的热套印,存在分类差异:(i)丝状化石中细胞留下的空间主要由二氧化硅填充,Whereasinter/externalfeatures(crosswalls/septaeandoutershiaths)arepyrized;(ii)coccoidalfossilesshowbothsilica-andydromite-invilledinteriors,和一般更好的保存细胞壁。这些不同的表现可能与微环境因素和生物因素之间的相互作用有关,潜在的对比代谢,以及不同细菌和/或古细菌的细胞壁化学差异。进一步的假设是,球形特征代表生物膜形成生物,其有机物衍生物有助于形成紧密相关的波浪状和皱纹碳质层状结构,这些层状结构至少可以与周围黄铁矿的质地区分开。因此,所提供的数据提供了证据,表明来自热液系统的微生物群的微观结构对于古生物学研究与来自沉积环境的微生物群具有相似的意义。