title: Feasible metabolisms in high pH springs of the Philippines.
abstract: A field campaign targeting high pH, H2-, and CH4-emitting serpentinite-associated springs in the Zambales and Palawan Ophiolites of the Philippines was conducted in 2012-2013, and enabled description of several springs sourced in altered pillow basalts, gabbros, and peridotites. We combine field observations of pH, temperature, conductivity, dissolved oxygen, and oxidation-reduction potential with analyses of major ions, dissolved inorganic carbon, dissolved organic carbon, and dissolved gas phases in order to model the activities of selected phases important to microbial metabolism, and to rank feasible metabolic reactions based on energy yield. We document changing geochemical inventories in these springs between sampling years, and examine how the environment supports or prevents the function of certain microbial metabolisms. In all, this geochemistry-based assessment of feasible metabolisms indicates methane cycling, hydrogen oxidation, some iron and sulfur metabolisms, and ammonia oxidation are feasible reactions in this continental site of serpentinization.
authors.affiliation: Microbe Mineral Interactions Laboratory, Department of Geosciences, University of Rhode Island Kingston, RI, USA.
authors.forename: Dawn
authors.initials: D
authors.lastname: Cardace
authors.affiliation: Ecosystem Dynamics in Geochemical Environments Lab, Department of Earth and Environmental Science, University of Illinois at Chicago Chicago, IL, USA.
authors.forename: D'Arcy R
authors.initials: DR
authors.lastname: Meyer-Dombard
authors.affiliation: Ecosystem Dynamics in Geochemical Environments Lab, Department of Earth and Environmental Science, University of Illinois at Chicago Chicago, IL, USA.
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Woycheese
authors.affiliation: National Institute of Geological Sciences, College of Science, University of the Philippines Diliman, Quezon City, Philippines.
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Arcilla
keywords: Philippines Islands; geochemical modeling; high pH springs; microbial metabolisms; serpentinization; ultramafic