Hoehler Tori M.

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Tori M.

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  • Article
    Carbon assimilation strategies in ultrabasic groundwater: clues from the integrated study of a serpentinization-influenced aquifer
    (American Society for Microbiology, 2020-03-10) Seyler, Lauren M. ; Brazelton, William J. ; McLean, Craig ; Putman, Lindsay I. ; Hyer, Alex ; Kubo, Michael D. Y. ; Hoehler, Tori M. ; Cardace, Dawn ; Schrenk, Matthew O.
    Serpentinization is a low-temperature metamorphic process by which ultramafic rock chemically reacts with water. Such reactions provide energy and materials that may be harnessed by chemosynthetic microbial communities at hydrothermal springs and in the subsurface. However, the biogeochemistry mediated by microbial populations that inhabit these environments is understudied and complicated by overlapping biotic and abiotic processes. We applied metagenomics, metatranscriptomics, and untargeted metabolomics techniques to environmental samples taken from the Coast Range Ophiolite Microbial Observatory (CROMO), a subsurface observatory consisting of 12 wells drilled into the ultramafic and serpentinite mélange of the Coast Range Ophiolite in California. Using a combination of DNA and RNA sequence data and mass spectrometry data, we found evidence for several carbon fixation and assimilation strategies, including the Calvin-Benson-Bassham cycle, the reverse tricarboxylic acid cycle, the reductive acetyl coenzyme A (acetyl-CoA) pathway, and methylotrophy, in the microbial communities inhabiting the serpentinite-hosted aquifer. Our data also suggest that the microbial inhabitants of CROMO use products of the serpentinization process, including methane and formate, as carbon sources in a hyperalkaline environment where dissolved inorganic carbon is unavailable.
  • Preprint
    Nonequilibrium clumped isotope signals in microbial methane
    ( 2015-02-09) Wang, David T. ; Gruen, Danielle S. ; Lollar, Barbara Sherwood ; Hinrichs, Kai-Uwe ; Stewart, Lucy C. ; Holden, James F. ; Hristov, Alexander N. ; Pohlman, John W. ; Morrill, Penny L. ; Konneke, Martin ; Delwiche, Kyle B. ; Reeves, Eoghan P. ; Sutcliffe, Chelsea N. ; Ritter, Daniel J. ; Seewald, Jeffrey S. ; McIntosh, Jennifer C. ; Hemond, Harold F. ; Kubo, Michael D. Y. ; Cardace, Dawn ; Hoehler, Tori M. ; Ono, Shuhei
    Methane is a key component in the global carbon cycle with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply-substituted “clumped” isotopologues, e.g., 13CH3D, has recently emerged as a proxy for determining methane-formation temperatures; however, the impact of biological processes on methane’s clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on 13CH3D abundances and results in anomalously elevated formation temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.
  • Article
    Ocean system science to inform the exploration of ocean worlds
    (Oceanography Society, 2022-05-23) German, Christopher R. ; Blackman, Donna K. ; Fisher, Andrew T. ; Girguis, Peter R. ; Hand, Kevin P. ; Hoehler, Tori M. ; Huber, Julie A. ; Marshall, John C. ; Pietro, Kathryn R. ; Seewald, Jeffrey S. ; Shock, Everett ; Sotin, Christophe ; Thurnherr, Andreas M. ; Toner, Brandy M.
    Ocean worlds provide fascinating opportunities for future ocean research. They allow us to test our understanding of processes we consider fundamental to Earth’s ocean and simultaneously provide motivation to explore our ocean further and develop new technologies to do so. In parallel, ocean worlds research offers opportunities for ocean scientists to provide meaningful contributions to novel investigations in the coming decades that will search for life beyond Earth. Key to the contributions that oceanographers can make to this field is that studies of all other ocean worlds remain extremely data limited. Here, we describe an approach based on ocean systems science in which theoretical modeling can be used, in concert with targeted laboratory experimentation and direct observations in Earth’s ocean, to predict what processes (including those essential to support life) might be occurring on other ocean worlds. In turn, such an approach would help identify new technologies that might be required for future space missions as well as appropriate analog studies that could be conducted on Earth to develop and validate such technologies. Our approach is both integrative and interdisciplinary and considers multiple domains, from processes active in the subseafloor to those associated with ocean-ice feedbacks.
  • Article
    Science goals and mission architecture of the Europa Lander mission concept
    (IOP Publishing, 2022-01-26) Hand, Kevin P. ; Phillips, Cynthia B. ; Murray, Alison E. ; Garvin, James B. ; Maize, Earl H. ; Gibbs, Roger G. ; Reeves, Glenn ; San Martin, A. Miguel ; Tan-Wang, Grace H. ; Krajewski, Joel ; Hurst, Kenneth ; Crum, Ray ; Kennedy, Brett A. ; McElrath, Timothy P. ; Gallon, John C. ; Sabahi, Dara ; Thurman, Sam W. ; Goldstein, Barry ; Estabrook, Polly ; Lee, Steven W. ; Dooley, Jennifer A. ; Brinckerhoff, William B. ; Edgett, Kenneth S. ; German, Christopher R. ; Hoehler, Tori M. ; Hörst, Sarah M. ; Lunine, Jonathan I. ; Paranicas, Christopher ; Nealson, Kenneth H. ; Smith, David E. ; Templeton, Alexis S. ; Russell, Michael J. ; Schmidt, Britney E. ; Christner, Brent C. ; Ehlmann, Bethany L. ; Hayes, Alexander ; Rhoden, Alyssa R. ; Willis, Peter ; Yingst, R. Aileen ; Craft, Kathleen L. ; Cameron, Marissa E. ; Nordheim, Tom A. ; Pitesky, Jo ; Scully, Jennifer ; Hofgartner, Jason D. ; Sell, Steve W. ; Barltrop, Kevin J. ; Izraelevitz, Jacob ; Brandon, Erik J. ; Seong, J. ; Jones, John-Paul ; Pasalic, Jasmina ; Billings, Keith J. ; Ruiz, John Paul ; Bugga, Ratnakumar V. ; Graham, Dan ; Arenas, L. A. ; Takeyama, Deidre ; Drummond, Mai ; Aghazarian, Hrand ; Andersen, Allen J. ; Andersen, Kayla B. ; Anderson, E. W. ; Babuscia, Alessandra ; Backes, Paul G. ; Bailey, Elizabeth S. ; Balentine, Daniel ; Ballard, Christopher G. ; Berisford, Daniel F. ; Bhandari, Pradeep ; Blackwood, Krys ; Bolotin, Gary S. ; Bovre, Emilee A. ; Bowkett, Joseph ; Boykins, Kobie T. ; Bramble, Michael S. ; Brice, Timothy M. ; Briggs, Paul ; Brinkman, Alexander P. ; Brooks, Shawn M. ; Buffington, Brent B. ; Burns, Brandon ; Cable, Morgan L. ; Campagnola,Stefano ; Cangahuala, Laureano A. ; Carr, Gregory A. ; Casani, John R. ; Chahat, Nacer E. ; Chamberlain-Simon, Brendan K. ; Cheng, Yun-Ting ; Chien, Steve A. ; Cook, B. T. ; Cooper, Moogega ; Dinicola, Michael ; Clement, Brian G. ; Dean, Zachary S. ; Cullimore, Emily A. ; Curtis, Aaron G. ; de la Croix, Jean-Pierre ; Di Pasquale, Peter ; Dodd, Emma M. ; Dubord, Luke A. ; Edlund, Jeffrey A. ; Ellyin, Raymond ; Emanuel, Blair ; Foster, Jeffrey T. ; Ganino, Anthony J. ; Garner, Gregory J. ; Gibson, Matt T. ; Gildner, Matt ; Glazebrook, Kenneth J. ; Greco, Martin E. ; Green, W. M. ; Hatch, Sara J. ; Hetzel, Mark M. ; Hoey, William A. ; Hofmann, Amy E. ; Ionasescu, Rodica ; Jain, Abhinandan ; Jasper, Jay D. ; Johannesen, Jennie R. ; Johnson, Glenn K. ; Jun, Insoo ; Katake, Anup B. ; Kim-Castet, So Young ; Kim, David Inkyu ; Kim, Wousik ; Klonicki, Emily F. ; Kobeissi, Brad ; Kobie, Bryan D. ; Kochocki, Joseph ; Kokorowski, Michael ; Kosberg, Jacob A. ; Kriechbaum, Kristopher ; Kulkarni, Tejas P. ; Lam, Rebekah L. ; Landau, Damon F. ; Lattimore, Myra A. ; Laubach, Sharon L. ; Lawler, Christopher R. ; Lim, Grace ; Li, Jui-Lin ; Litwin, Todd E. ; Lo, Martin W. ; Logan, Cambria A. ; Maghasoudi, Elham ; Mandrake, Lukas ; Marchetti, Yuliya ; Marteau, Eloise ; Maxwell, Kimberly A. ; McNamee, John B. ; McIntyre, Ocean ; Meacham, Michael ; Melko, Joseph P. ; Mueller, Juergen ; Muliere, David ; Mysore, Aprameya ; Nash, Jeremy ; Ono, Masahiro ; Parker, Jay M. ; Perkins, Rebecca C. ; Petropoulos, Anastassios E. ; Gaut, Aaron ; Piette Gomez, Marie Y. ; Casillas, Raul Polit ; Preudhomme, Michael ; Pyrzak, Guy ; Rapinchuk, Jacqueline ; Ratliff, John Martin ; Ray, T. L. ; Roberts, Eric T. ; Roffo, Kenneth ; Roth, Duane C. ; Russino, Joseph A. ; Schmidt, Tyler M. ; Schoppers, Marcel J. ; Senent, Juan S. ; Serricchio, Fred ; Sheldon, Douglas J. ; Shiraishi, Lori R. ; Shirvanian, James ; Siegel, Katherine J. ; Singh, Gurjeet ; Sirota, Allen R. ; Skulsky, Eli D. ; Stehly, Joseph S. ; Strange, Nathan J. ; Stevens, Sarah U. ; Sunada, Eric T. ; Tepsuporn, Scott P. ; Tosi, Luis Phillipe C. ; Trawny, Nikolas ; Uchenik, Igor ; Verma, Vandi ; Volpe, Richard A. ; Wagner, Caleb T. ; Wang, D. ; Willson, Reg G. ; Wolff, John Luke ; Wong, A. T. ; Zimmer, Aline K. ; Sukhatme, Kalyani G. ; Bago, Kevin A. ; Chen, Yang ; Deardorff, Alyssa M. ; Kuch, Roger S. ; Lim, Christopher ; Syvertson, Marguerite L. ; Arakaki, Genji A. ; Avila, Art ; DeBruin, Kevin J. ; Frick, Andreas ; Harris, Joby R. ; Heverly, Matthew C. ; Kawata, Jessie M. ; Kim‬, Sung-Kyun ; Kipp, Devin M. ; Murphy, Juliana ; Smith, Matthew W. ; Spaulding, Matthew D. ; Thakker, Rohan ; Warner, Noah Z. ; Yahnker, Chris R. ; Young, M. E. ; Magner, Tom ; Adams, Danica ; Bedini, Peter ; Mehr, Lauren ; Sheldon, Colin ; Vernon, Steven ; Bailey, Vince ; Briere, Marc ; Butler, Michael ; Davis, Amanda ; Ensor, Susan ; Gannon, Michele ; Haapala-Chalk, Amanda ; Hartka, Ted ; Holdridge, Mark ; Hong, Albert ; Hunt, J. ; Iskow, Joe ; Kahler, Faith ; Murray, Kimberly ; Napolillo, David ; Norkus, Michael ; Pfisterer, Rick ; Porter, Jamie ; Roth, David ; Schwartz, Paul ; Wolfarth, Lawrence ; Cardiff, Eric ; Davis, Anita ; Grob, Eric W. ; Adam, Jason R. ; Betts, Erin ; Norwood, Jason ; Heller, M. M. ; Voskuilen, Tyler ; Sakievich, Philip ; Gray, L. ; Hansen, D. J. ; Irick, Kevin W. ; Hewson, John C. ; Lamb, Joshua ; Stacy, S. C. ; Brotherton, Chris M. ; Tappan, Alexander S. ; Benally, Darryl ; Thigpen, Hannah ; Ortiz, Erick ; Sandoval, Dan ; Ison, Aaron M. ; Warren, M. ; Stromberg, Peter G. ; Thelen, Paul Mark ; Blasy, B. ; Nandy, Prabal ; Haddad, Alexandria W. ; Trujillo, Lynna B. ; Wiseley, T. H. ; Bell, S. A. ; Teske, Nicholas P. ; Post, C. ; Torres-Castro, Loraine ; Grosso, Chris ; Wasiolek, Maryla
    Europa is a premier target for advancing both planetary science and astrobiology, as well as for opening a new window into the burgeoning field of comparative oceanography. The potentially habitable subsurface ocean of Europa may harbor life, and the globally young and comparatively thin ice shell of Europa may contain biosignatures that are readily accessible to a surface lander. Europa's icy shell also offers the opportunity to study tectonics and geologic cycles across a range of mechanisms and compositions. Here we detail the goals and mission architecture of the Europa Lander mission concept, as developed from 2015 through 2020. The science was developed by the 2016 Europa Lander Science Definition Team (SDT), and the mission architecture was developed by the preproject engineering team, in close collaboration with the SDT. In 2017 and 2018, the mission concept passed its mission concept review and delta-mission concept review, respectively. Since that time, the preproject has been advancing the technologies, and developing the hardware and software, needed to retire risks associated with technology, science, cost, and schedule.
  • Article
    Science objectives for flagship-class mission concepts for the search for evidence of life at Enceladus
    (Mary Ann Liebert, Inc., 2022-06-08) MacKenzie, Shannon M. ; Neveu, Marc ; Davila, Alfonso F. ; Lunine, Jonathan I. ; Cable, Morgan L. ; Phillips-Lander, Charity M. ; Eigenbrode, Jennifer L. ; Waite, J. Hunter ; Craft, Kathleen L. ; Hofgartner, Jason D. ; McKay, Chris P. ; Glein, Christopher R. ; Burton, Dana ; Kounaves, Samuel P. ; Mathies, Richard A. ; Vance, Steven D. ; Malaska, Michael J. ; Gold, Robert ; German, Christopher R. ; Soderlund, Krista M. ; Willis, Peter ; Freissinet, Caroline ; McEwen, Alfred S. ; Brucato, John Robert ; de Vera, Jean-Pierre P. ; Hoehler, Tori M. ; Heldmann, Jennifer
    Cassini revealed that Saturn's Moon Enceladus hosts a subsurface ocean that meets the accepted criteria for habitability with bio-essential elements and compounds, liquid water, and energy sources available in the environment. Whether these conditions are sufficiently abundant and collocated to support life remains unknown and cannot be determined from Cassini data. However, thanks to the plume of oceanic material emanating from Enceladus’ south pole, a new mission to Enceladus could search for evidence of life without having to descend through kilometers of ice. In this article, we outline the science motivations for such a successor to Cassini, choosing the primary science goal to be determining whether Enceladus is inhabited and assuming a resource level equivalent to NASA's Flagship-class missions. We selected a set of potential biosignature measurements that are complementary and orthogonal to build a robust case for any life detection result. This result would be further informed by quantifications of the habitability of the environment through geochemical and geophysical investigations into the ocean and ice shell crust. This study demonstrates that Enceladus’ plume offers an unparalleled opportunity for in situ exploration of an Ocean World and that the planetary science and astrobiology community is well equipped to take full advantage of it in the coming decades.
  • Article
    Phosphate availability and implications for life on ocean worlds
    (Nature Research, 2023-04-25) Randolph-Flagg, Noah G. ; Ely, Tucker ; Som, Sanjoy M. ; Shock, Everett L. ; German, Christopher R. ; Hoehler, Tori M.
    Several moons in the outer solar system host liquid water oceans. A key next step in assessing the habitability of these ocean worlds is to determine whether life's elemental and energy requirements are also met. Phosphorus is required by all known life and is often limited to biological productivity in Earth's oceans. This raises the possibility that its availability may limit the abundance or productivity of Earth-like life on ocean worlds. To address this potential problem, here we calculate the equilibrium dissolved phosphate concentrations associated with the reaction of water and rocks-a key driver of ocean chemical evolution-across a broad range of compositional inputs and reaction conditions. Equilibrium dissolved phosphate concentrations range from 10-11 to 10-1 mol/kg across the full range of carbonaceous chondrite compositions and reaction conditions considered, but are generally > 10-5 mol/kg for most plausible scenarios. Relative to the phosphate requirements and uptake kinetics of microorganisms in Earth's oceans, such concentrations would be sufficient to support initially rapid cell growth and construction of global ocean cell populations larger than those observed in Earth's deep oceans.