Collaborative Research: Geobiology of high pH springs in the Philippines ? probing the deep biosphere

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Part A. Technical description Microbial communities inhabiting the Earth?s subsurface occupy a scientifically uncharted realm. The habitable subsurface may penetrate the Earth?s crust to depths of 5?10 km, depending on geothermal gradients. It has been estimated recently that the deep subsurface habitat could accommodate more biomass and biodiversity than on Earth?s surface. Yet, we know little about carbon cycling, nitrogen cycling, or any other biogeochemical cycling that takes place in this subsurface biosphere or how these may impact surface processes. This project will investigate these processes in high pH fluids found in ophiolite regions of the Philippines, where active sepentinization brings H2 and CH4 in contact with formation fluids, energizing the subsurface biosphere.This proposed research will deliver baseline biogeochemical data for a suite of high pH serpentinizing springs in two Philippines ophiolite localities (Zambales and Palawan). In a focused two-year research plan, we will elucidate biogeochemical cycling in high pH, deeply sourced fluids in our Philippines field locations, and tie the role of microorganisms directly to biogeochemical processes. Our three parallel research strands involve whether (1) deeply sourced, ophiolite-derived fluids afford habitable niches for chemolithotrophic microbial communities that can be predicted by the geochemistry of the system, (2) nucleic acid based analyses and culturing approaches reflect functional genetic competence that confirms the predicted metabolic strategies, and (3) chemoheterotrophic metabolisms and/or methanotrophs dominate over alternative chemoautotrophic metabolisms in these subsurface fluids, due to low CO2 and bicarbonate in the Philippine high pH fluids. This project also comprises intentional mentorship of graduate and undergraduate students in field, laboratory, and analytical methods, and the development of a blended specimen- and web-based learning module tying together field findings with science education initiatives at the collegiate and high school levels, particularly with the Earth Science Literacy Initiative goals in mind (http://www.earthscienceliteracy.org.Scientific and societal broader impacts include support for life on the Early Earth and other planetary bodies, as it has been proposed that serpentinization (the aqueous alteration of ultramafic rocks, yielding diatomic hydrogen, and possibly complex organic molecules) can provide critical energy, and carbon to primitive ecosystems. These processes likely continue to support life in ?extreme? subsurface settings on the modern Earth. Ophiolite regions are also of great interest to researchers investigating the possibilities of long term carbon storage in serpentinites, as geological repositories of CO2. Because secondary mineralogy resembles concrete, ophiolites are also gaining attention as potential radioactive waste depositories. With these diverse impacts in mind, a better concept of biogeochemical cycling in ophiolite-hosted fluids is necessary to understand potential impacts for these applications.Part B. Non-technical explanation of the project?s broader significance and importanceMicrobial communities inhabiting the Earth?s subsurface occupy a scientifically uncharted realm, and may penetrate the Earth?s crust to depths of 5 to 10 km--until it is too hot to survive. It has been estimated recently that the deep subsurface habitat could accommodate more biomass and biodiversity than on Earth?s surface, and the impact of this vast reservoir of biomass on biogeochemical cycling on Earth is a gaping hole in our current knowledge of Earth systems. This project will investigate how life transforms water and rock in high pH springs at two localities in the Philippines, at Zambales and Palawan, and allow us to learn more about critical chemical and biological connections in ways that may serve both science (particularly in defining the unknown edge of the biosphere in these exciting settings?including how microbes survive in low oxygen, low nutrient settings) and society (with strong links to ongoing experiments in carbon sequestration, toxic waste storage, bioremediation of mining wastes, and micro-scale medical applications). Dr. Meyer-Dombard?s research focus has been the geobiology of terrestrial and shallow submarine hydrothermal systems, and Dr. Cardace has studied the geobiology of tectonic margins, with field localities in the seabed and coastal settings. Together in this collaborative research project, they intend to learn how Earth is evolving in concert with life in ways that impact reservoirs of carbon and other elements. They bring a commitment to mentorship and training in research to the table also, and the funds granted here will allow more students to gain skills including quantitative reasoning, analytical research, and science writing, and materials and findings will be rapidly shared with in service teachers and their students through school visits and interactive, data-rich on-line modules.