Collaborative Research: Organic Compounds in Hydrothermal Systems: A Framework for Investigating Heterotrophy at High Temperature

本研究旨在对在复杂且知之甚少的环境--浅水海洋热液系统中发现的无机和有机碳化合物进行化学测量。部分由于取样机会有限，我们对海洋热液微生物系统，特别是其有机地球化学缺乏了解。这些环境中微生物生命形式的代谢能量需求也不清楚。一系列含水低分子量有机化合物（氨基酸，碳水化合物和有机酸）的化学结构和浓度的测定将允许与异养嗜热菌代谢这些底物相关的能量边界的建模。一系列研究，包括在研究地点（西西里伊奥利亚群岛）直接进行水下呼吸器现场取样，将有助于收集热液喷口流体，包括时间变化。已知嗜热细菌是代谢机会型的，具有利用存在于其环境中的多种碳源沿着一种或多种电子受体的能力。这些生物体如何进行这样的代谢操作，以及它们如何动态地适应化学和物理环境的变化，目前还不清楚。这些研究人员将采用热力学建模方法，在已知温度下使用已知浓度的特定底物，来计算这些生物体在热液环境中使用的呼吸和发酵反应的可能生物能量产量。这反过来又将增加我们对地球化学过程的理解，这些过程可能为更深的地下生物圈中的微生物能量学提供燃料。

ABSTRACTOCE-0221417OCE-0221113This study sets out to make chemical measurements of inorganic and organic carbon compounds found in a complex and poorly understood environment, shallow water marine hydrothermal systems. Due in part to limited sampling opportunities, our understanding of marine hydrothermal microbial systems and especially of their organic geochemistry is lacking. The metabolic energy requirements of microbial lifeforms in these environments is also unclear. Determination of the chemical structures and concentrations of a series of aqueous low molecular weight organic compounds (amino acids, carbohydrates and organic acids) will allow the modeling of the energetic bounds associated with the metabolism of these substrates by heterotrophic thermophiles. A series of studies, including using direct SCUBA field sampling of the study site (Aeolian Islands, Sicily), will allow hydrothermal vent fluid collection including temporal variation. Thermophilic bacteria are known to be metabolically opportunistic, having the capability of utilizing a variety of carbon sources present in their environment along with one or more electron acceptors. How these organisms perform such metabolic manipulations and how they dynamically adapt to changes in their chemical and physical environment is not yet known. These investigators will employ a thermodynamic modeling approach, using known concentrations of specific substrates at known temperatures, to calculate the possible bioenergetic energy yields of the respiratory and fermentative reactions these organisms use in hydrothermal environments. This in turn will increase our understanding of the biogeochemical processes that may fuel the microbial energetics in the deeper subsurface biosphere.