Everett Shock

2016-2017 GEOPIG Events and Milestones:

Dr. Charlene Estrada joined GEOPIG as a SESE Postdoctoral Fellow, Summer 2016

Dr. Kris Fecteau; PhD defense, School of Molecular Sciences, Fall 2016

Dr. Peter Canovas; PhD defense, School of Earth & Space Exploration, Fall 2016

Dr. Brian St Clair; PhD defense, Environmental Life Science Program, Spring 2017

Cuong Doan (“DC”), BS Honors thesis, School of Molecular Sciences, Spring 2017

Hydrothermal Ecosystems

GEOPIG researchers have pursued projects in Yellowstone since 1997. We typically find ourselves there at some time each summer. As of 2016 we have a newly funded project to explore the geochemical and biomolecular changes at the transition to photosynthesis in hot spring ecosystems (NASA’s Exobiology program). We are integrating geochemical sampling for major and trace elements, dissolved gases and dissolved organic compounds with sampling for DNA, lipids, pigments, and proteins in microbiomes that span the photosynthetic fringe. Integrating these diverse datasets will involve thermodynamic analyses, multidimensional statistical models, and field experiments on microbial activity. Kris Fecteau and Grayson Boyer are leading this effort, and are building on their ongoing research on pigment (Fecteau) and lipid (Boyer) distributions in hydrothermal ecosystems. Mysteries of photosynthesis in mildly acidic hotsprings feature in a recently submitted paper (Fecteau et al., 2017). Joey Romero is using molecular methods to identify and quantify the microbial communities above, at, and beyond the photosynthetic fringe in multiple Yellowstone locations. Our colleague and former GEOPIG post-doc Alysia Cox is leading the proteomics effort from her faculty position at Montana Tech.

We recently wrapped up a project on making Habitability Maps for iron oxidation and reduction. Brian St Clair designed field experiments to measure rates of microbial reactions together with rates of the corresponding abiotic reactions. He placed his rate data in the context of composition and temperature resulting in diagrams showing where each reaction can support life. Data from Yellowstone hot springs, acid mine drainage in Arizona, and cold iron-rich springs in the Swiss Alps were featured in Brian St Clair’s PhD dissertation research funded by NSF’s Geobiology and Low Temperature Geochemistry Program.

In Summer 2017, our Yellowstone expedition involved experiments on carbon uptake at photosynthetic fringe locations, sampling of systems where photosynthesis appears to be inhibited, and exploration of hydrothermal ecosystems in several areas of Yellowstone that were new to us. As expected, Yellowstone shuffles the cards and deals new and unexpected combinations of variables, which allows systems we have never encountered before. The possibilities seem nearly endless! We are beginning to probe new mysteries with geochemical and biological samples returned to the lab from our fieldwork. The intrepid Vince Debes once again deserves enormous credit for the success of our field efforts, as do all other members of our 2017 field team (Michelle Santana, Dylan Gagler, Mark Williamson, Taylor Walton, Kris Fecteau, Josh Nye, Zhaobo Zhang, Melissa Sedler, with cameo appearances by Brian St Clair, Dan Colman, Melody Lindsay, and Eric Boyd).

Serpentinization

When rocks from Earth’s mantle are exposed to the hydrosphere the resulting alteration process is called serpentinization owing to the formation of serpentine minerals like antigorite, chrysotile and lizardite. As the rocks are altered, so it the water resulting in extremely high pH and highly reduced conditions with abundant dissolved hydrogen. Although such conditions seem novel to us as native dwellers of granitic continents, water-rock reactions in ultramafic rocks like those from the upper mantle may be remarkably common on Ocean Worlds throughout our Solar System. The main serpentinizing field area we have explored is the Samail ophiolite in the Sultanate of Oman, and our work is supported by the Rock-Powered Life NASA Astrobiology Institute grant, through our involvement with an Integrated Earth System project funded by NSF, and through the Deep Energy and Deep Life communities of the Deep Carbon Observatory.  We are combining geochemical and molecular data to quantify the flow of energy and nutrients from the geosphere to the biosphere during serpentinization. Alta Howells is documenting the changes in microbiomes tied to changes in geochemistry, Peter Canovas has calculated the supplies of chemical energy (paper in press at JGR Biogeoscience), Kirt Robinson is following the flow of carbon among inorganic solutes, minerals and organic solutes, and James Leong is delving deeply into the sequences of mineral-rock reactions that can happen throughout serpentinization, and has new models of low-temperature alteration for rocks in Oman that explain the our analytical data from surface waters and hyperalkaline springs. James also explored serpentinization of oceanic crust as part of IODP expedition 360 to the Southwest Indian Ridge, and has emerged with considerable enthusiasm for the alteration of gabbros wherever that can happen.

Microbiomes in Mixing Gradients

A major theme of Alta Howells’ research, funded by a doctoral research grant from NSF, delves into how the physical process of mixing between fluids of different compositions establishes geochemical gradients that shape the resulting transitions in microbiomes. Alta has two field areas, one in Yellowstone where fluids mix from two radically different hot springs, and another in Oman where serpentinizing fluids mix with fresher surface waters. In both areas, she is also investigating the factors that control the distribution of methane oxidizers with assistance from Michelle Santana and Taylor Walton. Our thermodynamic analyses show that methane oxidation should yield abundant energy in many hot spring ecosystems and serpentinizing systems, but fieldwork shows that it is not always happening.

Mapping Metabolism throughout the Oceanic Crust

GEOPIG has a history of theoretical modeling of submarine hydrothermal systems, including high-temperature/pressure equilibria and lower temperature disequilibria that can drive abiotic organic synthesis or provide energy for geomicrobiomes. Tucker Ely has taken the effort global by using recent compilations of rock-composition data to simulate hydrothermal alteration of the entire mid-ocean ridge. The resulting global view of alteration sets the stage for assessing how chemolithotrophic metabolisms are supported differently throughout the hydrothermally active oceanic crust, and to start the process of extrapolating back in time to examine how hydrothermal systems have changed and influenced seawater compositions, alteration of the crust that ultimately gets subducted, and the distribution of life in the deep biosphere. Tucker’s work is currently supported by a graduate fellowship from C-DEBI. Peter Canovas collaborated with Tucker to evaluate chemical energy supplies in representative environments of the cold biosphere (<5°C), which represents an enormous volume of the inhabited Earth. Peter also plunged deeply into geobiochemical thermodynamics with a paper on the standard state properties of compounds involved in the citric acid cycle (Canovas & Shock, 2016)

Thermodynamics of Bioavailability

The form that metals and organic compounds take in solution can have dramatic effects on their bioavailability, or the ease with which they are harvested and consumed by microbes and other life forms. Apar Prasad is developing new methods to estimate thermodynamic properties of metal-organic complexes throughout conditions where aqueous fluids can contain life. He and Alta Howells are evaluating the consequences of metal-organic complex formation on the design of microbial growth media.

Habitability of Ocean Worlds

The selection by NASA of the Europa Clipper finds GEOPIG involved in our first space mission! Shock is a co-investigator on the MASPEX science team led by Hunter Waite from SouthWest Research Institute. As a result, we are actively engaged in envisioning how water-rock processes on Europa, Enceladus and other Ocean Worlds may be capable of supporting life, and pondering how data from the MASPEX mass spectrometer and other instruments on the Europa Clipper spacecraft will be used to test ideas about the life-supporting potential of Europa. There are thermodynamic problems to be solved, novel metabolisms to explore, and experiments on hydrothermal transformations of organic compounds to pursue. Melissa Sedler, Steven Glaser, James Leong, Peter Canovas and Tucker Ely are conducting computer calculations to explore the diversity of outcomes as fluids derived from comets react with rocks represented by meteorites.

Hydrothermal Organic Transformations

Exploration of Ocean Worlds will return exciting new data on the abundances of many volatile compounds that make up their icy surfaces or that are spewed out through plumes. A major challenge will be to explain what is happening inside Ocean Worlds from inventories of organic and other volatile compounds. We will be expected to do geology based on organic chemistry! But, it is still uncommon to be able to study volatile petrology. So, there is much to do, including developing a fundamental set of experimental observations of how organic compounds are transformed at hydrothermal conditions. Kristin Johnson and Kirt Robinson are characterizing the mechanisms of hydrothermal organic reactions with and without the presence of minerals in experiments supported by NASA’s Habitable Worlds program, and Charlene Estrada is transforming model compounds to complement her work on biosignature preservation in the fossil record.  Their work is part of the Hydrothermal Organic Geochemistry (HOG) research group that includes Kris Fecteau, as well as SMS grad students Christa Bockisch and Josh Nye, and faculty members Hilairy Hartnett, Ian Gould, Lynda Williams and Everett Shock. Related GEOPIG research funded through the Extreme Physics and Chemistry community of the Deep Carbon Observatory is focused on developing new equations of state to improve our abilities to predict thermodynamic properties of aqueous organic compounds at high temperatures and pressures.

The Other Planetary Fluid

The release of accretionary energy, together with heating by radioactive decay, warms ice-rich solar system bodies, leading to generation of fluids that are capable of rock alteration and organic transformations. Water is a familiar planetary fluid, but it is not alone. In many cases the abundance of carbon dioxide means that it can also be present as a planetary fluid. Steven Glaser is exploring how organic compound transformations in carbonic fluids may differ from aqueous alteration, with research assistance from David Gamez. This theoretical modeling project is supported by NASA’s Emerging Worlds program.

Revolutionizing Geochemical Modeling

Theoretical tools are extremely useful when testing ideas of how geochemical processes operate, and predicting their consequences, but are rarely designed so that they can interact. We are taking direct aim at this fundamental problem of computational roadblocks through the ENKI project funded by NSF. The project is led by Mark Ghiorso of OFM Research, and includes several collaborators around the country. Our portion of the project at GEOPIG is to select extant software for thermodynamic modeling with emphasis on aqueous solutions including systems containing organic molecules, and develop new approaches that rapidly enable new models. Tucker Ely is developing new computational tools that allow massive numbers of simultaneous calculations, and novel methods to visualize the results. We are working with Dimitri Sverjensky of Johns Hopkins on the design of algorithms for calibration of thermodynamic models of aqueous systems and on model interoperability of mass transfer and dynamical models.