CAREER:Geochemical Energy for Thermophilic Archaea and Bacteria

越来越多的证据表明，微生物非凡的代谢和系统发育多样性是数十亿年地质过程共同进化的结果。在可预见的未来，研究地球化学和微生物学之间的紧密耦合将成为地质研究的一个更大的焦点。研究生物地球界面的最佳和最令人兴奋的地点是浅海热液生态系统；它们无处不在，地球化学和微生物学高度多样化，甚至可以进行复杂的调查，与深海和大陆的同类相比，它们的研究不足。我的主要职业兴趣是了解地球化学对代谢多样性的限制，研究微生物在控制其化学环境中的作用。这两个过程之间的关键联系是什么？在微生物学和地球化学之间呢？是化学能源的可用性。量化嗜热古菌和细菌的地球化学能量是我未来研究的核心。我已经制定了一个研究和教育活动的综合计划，这将为长期的学术生涯奠定基础。该计划包括通过创新的课程设置和对研究生和本科生的实际指导来扩大华盛顿大学的地球生物学和地球化学。新课程旨在解决课程中几个已确定的弱点，包括地理生物学的实地/实验课，自然科学的写作强化课程，以及涵盖特殊和及时兴趣主题的多学科研讨会。这里提出的教育部分还寻求在低收入的城市地区小学提供一些额外的学习机会（通过科学俱乐部）；最终的挑战是消除学生群体之间存在的“成绩差距”。该活动将与已建立的公共推广计划、各K-5学校的教师和志愿者以及众多当地科学和自然中心进行协调。我在微生物地球化学方面的新研究方向包括：1)设计地球化学上真实的生长介质来培养迄今为止在热液生态系统中“不可培养”的嗜热菌；2)确定喷口环境中一系列氧化还原过程的原位能量产量，包括有机化合物的氧化和发酵以及含砷化合物的转化；3)进入“细胞内部”，量化分解代谢（能量产生）和合成代谢（生物合成）反应网络中常见和主要生化途径的自由能，作为温度和压力的函数。这些方法结合了实地考察（现场测量、取样）、分析化学（水溶液、气体、矿物）、实验微生物学（嗜热菌培养、基因调查）和定量建模（反应能量学、热力学性质估计）。总体目标是生成热液系统中生物地球界面的定量、预测和综合模型，并开发测试、指导和提高我们对全球生物地球化学过程理解所需的科学工具。

ABSTRACTEvidence is mounting that the extraordinary metabolic and phylogenetic diversity of microorganisms is the result of several billion years of co-evolution with geologic processes. Investigating the intimate couplings of geochemistry and microbiology will become an even greater focus of geologic research in the foreseeable future. Among the best and most exciting sites to investigate the bio-geo interface are shallow marine hydrothermal ecosystems; they are ubiquitous, geochemically and microbiologically highly diverse, readily accessible for even complex investigations, and understudied compared to their deep-sea and continental counterparts. My primary career interests are understanding the geochemical constraints on metabolic diversity and investigating the role that microorganisms play in controlling their chemical environment. A crucial link between these two processes ? and between microbiology and geochemistry in general? is the availability of chemical energy sources. Quantifying the geochemical energy for thermophilic archaea and bacteria is at the core of my future studies.I have developed an integrated plan for research and education activities that will build a foundation for a long-term academic career. The plan includes expanding geobiology and geochemistry at Washington University through innovative course offerings and hands-on mentoring of graduate and undergraduate students. New courses, which seek to address several identified weaknesses in the curriculum, include a field/lab class in geobiology, a writing intensive course in the natural sciences, and multidisciplinary seminars that cover topics of exceptional and timely interests. The educational component proposed here also seeks to provide several extra learning opportunities (through Science Clubs) in low-income, urban area elementary schools; the ultimate challenge is to eliminate the "achievement gap" that exists between groups of students. This activity will be coordinated with established public outreach programs, teachers and volunteers at various K-5 schools, and numerous local science and nature centers.My new research directions in microbial geochemistry include 1) designing geochemically realistic growth media to culture heretofore "unculturable" thermophiles in hydrothermal ecosystems; 2) determining in situ energy-yields for an array of redox processes in vent environments, including the oxidation and fermentation of organic compounds and the conversion of Arsenic-bearing compounds; and 3) going "inside the cell" to quantify the free energies of common and central biochemical pathways as a function of temperature and pressure, both catabolic (energy-producing) and anabolic (biosynthesis) reaction networks. The approaches combine fieldwork (in situ measurements, sampling), analytical chemistry (aqueous solutions, gases, minerals), experimental microbiology (thermophile culturing, gene surveys), and quantitative modeling (reaction energetics, estimation of thermodynamic properties). The overall objectives are to generate quantitative, predictive, and comprehensive models of the biogeo interface in hydrothermal systems and to develop the scientific tools needed to test, guide, and improve our understanding of global biogeochemical processes.