-Designed and implemented research program, with goal of modeling how reaction between seawater and ocean crust contributed to chemical evolution of seawater and global climate throughout geologic history. This chemical exchange has implications for origin and evolution of life on Earth, and habitability in subsurface oceans on icy moons elsewhere in our solar system. -Lead multi-university effort (Princeton, Berkeley, Minnesota, Cambridge) to analyze calcium isotopic composition in global array of oceanic hydrothermal fluids. Designed and carried out experiments to determine kinetics of hydrogen isotope (D/H) fractionation between water, methane, and hydrogen gas, with implications ranging from geothermometry to origin of water in solar system. -Derived versatile rate law based on water density and used this to 1) determine subsurface flow rate of geothermal fluids and 2) identify when micro-organisms are catalyzing isotope exchange in natural hot springs.

Carried out fundamental and applied research into aspects of geothermal energy, nuclear waste management, and viability of geological (subsurface) sequestration of anthropogenic CO2 emissions to mitigate effects of climate change.-Served as field engineer and analyst during test injection of CO2 into pilot-scale subsurface reservoir (Otway, Victoria, Australia): Test involved injecting CO2 with inert tracer gases to understand efficiency of CO2 trapping mechanisms. -Determined thermodynamic partition coefficients for tracer gases between supercritical CO2 and water, necessary for conducting multi-phase (CO2+water) models. Engineered and successfully tested new high-temperature/pressure experimental system interfaced with analytical instrumentation. -Conducted lab experiments on chemical reactivity of reservoir rocks in CO2-saturated (acidic) fluids from pilot carbon sequestration sites. Conducted thermodynamic and kinetic models to interpret results, considering long-term risks. -Engineered and successfully tested novel high-temperature/pressure potentiometric titration apparatus, capable of gathering data on mineral surface charge density using new solid-state pH electrode. Coordinated inter-laboratory calibration effort to test electrode response against theoretical values.-Used new apparatus to determine stability and dissociation constants of amino acid lysine at elevated temperatures, relevant to evolution of life in hydrothermal settings.-Conducted experiments on effect of dissolved salts and pH on rates of micro-crack growth in stressed glass, monitored at nanometer scale using hydrothermal atomic force microscope. Results showed water pH had significant effect on crack propagation rates.-Collaborated with geophysicists in interpreting time-series changes in physical properties of reservoir rock by using micro-earthquake recordings taken during injection of water into high-temperature regions of The Geysers geothermal system (CA).

Research on chemistry and origin of deep-sea hydrothermal fluids. Volcanic activity along oceanic (tectonic) plate boundaries results in seafloor hot springs that create large metal deposits and provide chemical energy for primitive micro-organisms. Such settings are considered likely to have fostered origin/evolution of life on Earth.Had organizational role in 5 interdisciplinary oceanographic expeditions (2005 - 2016): Characterized chemistry of seafloor hot springs using both manned (DSV Alvin) and robotic (ROV Jason) submersible technologies. -Lead scientist aboard Alvin (submarine) dives 4840, 4843, 4392, starboard scientist aboard Alvin dive 4142.Designed and performed laboratory experiments to simulate physical and chemical conditions likely affecting chemistry of natural spring fluids in order to interpret field data. Engineered and successfully tested two novel high-temperature/pressure flow systems.-Conceived and experimentally calibrated new geochemical temperature/pressure proxies that use hydrothermal fluid chemistry to indicate sub-seafloor depth where fluids originate and associated temperature. Used proxies to 1) elucidate changes in physical/heat structure beneath a magmatically active ridge using time series fluid chemistry, and 2) calculate likely effects of sea level change (due to glaciation) on hydrothermal flux of biologically important metals from mid-ocean ridges.-Derived vapor-liquid partition coefficients for alkaline earth and transition metals in two-phase electrolyte solutions, to account for effect of boiling on metal transport in hydrothermal systems. Revealed fundamental connection between coefficients and ionic radii of metals.-Derived rates of hydrocarbon synthesis from precursor H2 and CO2. Results placed constraints on conditions/mechanisms of abiotic hydrocarbon formation in natural hydrothermal settings, important for understanding potential pathways of biological evolution.