An 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.
