COLLABORATIVE RESEARCH: Biogeochemical Exploration of Acidic and Neutral Hypersaline Environments of Australia

美国国家科学基金会生物地球科学基金已授予梅勒妮R博士。作者声明：E. Oboh-Ikuenobe（密苏里大学罗拉分校）和Kathleen C. Benison（中密歇根大学），以确定是否真的从高盐环境中捕获微生物的代表性群体。 如果这是真的，这些发现可能被推断为古代或可能是外星的微生物，并用于描述以前的微生物群落，从而解释过去的水化学和过去的气候。 微生物代表了大多数环境中存在的基本生命形式。 它们对气候参数很敏感，可以影响水化学、生物活动和矿化作用。 蒸发岩矿物对气候、水化学和水文的敏感性，是丰富的古环境资料。 此外，碳酸盐岩可以在极端的环境条件下形成，例如西澳大利亚州的极端酸性盐湖。 这些湖泊可以作为火星的很好的类似物。 传统上，对蒸发岩环境及其沉积物的研究在很大程度上忽略了微生物，因为它们通常在岩石记录中保存得很差。 然而，通过这项研究，将会找到以下问题的答案：酸性和中性盐湖环境的湖泊沃茨、地下沃茨和沉积物中存在哪些微生物？蒸发岩矿物的流体包裹体是否代表了生活在沃茨中的微生物？微生物是特定的嗜酸菌吗？微生物在水化学的演变中扮演了什么角色？ 为了回答这些问题，将前往澳大利亚进行采样，收集一整套湖水、地下水、蒸发岩和硅质沉积物样本。 实现以下目标：1.识别并比较岩盐和石膏中的生物残留物与其母沃茨和沉积物中的生物残留物。 传统的培养方法和分子生物学技术将用于比较上述环境中的微生物种群。 2.在实验室条件下培养蒸发岩晶体，研究环境对晶体形成和微生物的影响。 3.确定维多利亚和西澳大利亚州中性和中等酸性盐湖和地下水之间、西澳大利亚州一个小区域内中性和极酸性盐湖之间以及西澳大利亚州极酸性盐湖和地下水之间微生物（从原核生物到淡水甲藻和藻类）的任何差异。 将对从这些环境中分离的细菌的16 S rDNA进行测序和比较。 4.使用基础沉积学、岩相学、流体包裹体研究和孢粉学来约束沉积、环境和气候条件。 沉积结构和颗粒特征将用于追踪沉积历史。我们预计，新的微生物将被发现。这些生物体可能被用于受极端盐和酸性条件影响的污染场地的生物修复。 此外，我们的发现将对未来的火星研究以及地球以外的行星体上存在生命的可能性产生影响。 在所有被探索过的行星体中，火星与地球最为相似。 特别是，陆地酸性沉积系统在一般矿物学、地球化学和地貌学方面与火星表面相似。 此外，该项目将负责培训从本科生到博士后的学生。 还有一个重要的外联部分，包括与圣路易斯科学中心的伙伴关系，以及针对K-12教育工作者的极端环境地质学和微生物学课程。

EAR-0433040BenisonAn NSF Biogeosciences grant has been awarded to Drs. Melanie R. Mormile, Francisca E. Oboh-Ikuenobe (University of Missouri-Rolla), and Kathleen C. Benison (Central Michigan University) to determine if evaporites truly trap a representative population of microorganisms from hypersaline environments. If this is found to be true, these findings can possibly be extrapolated to microorganisms entrapped in ancient or possibly extraterrestrial evaporites and used to describe previous microbial communities and therefore, make interpretations about past water chemistries and past climates. Microorganisms represent the basic life forms existing in most environmental settings. They are sensitive to climatic parameters, and can influence water chemistry, biological activity, and mineralization. Evaporite minerals are a wealth of paleoenvironmental data due to their sensitivity to climate, water chemistry, and hydrology. In addition, evaporites can form in extreme environmental conditions, such as extremely acid saline lakes in Western Australia. These lakes might serve as good analogs to Mars. Traditionally, studies of evaporite settings and their deposits have overlooked microorganisms largely because they are generally poorly preserved in the rock record. However, through this research, answers to the following questions will be found: What microorganisms are present in the lake waters, groundwaters, and sediments of acid and neutral saline lake environments? Are the microorganisms found living in the waters represented in the fluid inclusions of the evaporite minerals? Are the microorganisms specific acidophiles? What role did the microorganisms play in the evolution of the water chemistry? To answer these questions, a sampling trip will be made to Australia to collect a comprehensive set of lake water, groundwater, evaporite, and siliciclastic sediment samples. The following objectives will be achieved: 1. Identify and compare the biological remains in halite and gypsum with those in their parent waters and sediments. Both traditional culture methods and molecular biology techniques will be used to compare the microbial populations in the environments listed above. 2. Grow evaporite crystals under laboratory conditions to study selected environmental influences on crystal formation and the microorganisms that become entrapped. 3. Identify any differences in microorganisms (ranging from prokaryotes to freshwater dinoflagellates and algae) between neutral and moderately acidic saline lakes and groundwaters in Victoria and Western Australia, between neutral and extremely acidic saline lakes within a small region of Western Australia, as well as among extremely acidic saline lakes and groundwaters in Western Australia. The 16S rDNA from the bacteria isolated from these environments will be sequenced and compared. 4. Constrain depositional, environmental, and climatic conditions using basic sedimentology, petrography, fluid inclusion studies, and palynology. Sedimentary structures and grain characteristics will be used to trace depositional history. We anticipate that novel microorganisms will be found. These organisms can possibly be used for the bioremediation of contaminated sites that are impacted by extremes in saline and acidic conditions. In addition, our findings will have implications for future Mars research and the possibility that life can occur on planetary bodies besides Earth. Of all the planetary bodies explored, Mars most closely resemble Earth. In particular, terrestrial acid sedimentary systems are similar in general mineralogy, geochemistry, and geomorphology to the Martian surface. Furthermore, this project will be responsible for the training of students ranging from undergraduate level to Post-Doctoral students. There is also a significant outreach component that includes a partnership with the St. Louis Science Center as well as a course on the geology and microbiology of extreme environments targeted towards K-12 educators.