Everett Shock | |
---|---|
Born | Everett L. Shock |
Education | University of California, Santa Cruz (BS) University of California, Berkeley (PhD) |
Awards | Fellow, American Geophysical Union (2005) [1] Fellow, Geochemical Society and European Association of Geochemisty (2009) [2] |
Scientific career | |
Fields | Geochemistry |
Institutions | Washington University in St. Louis Arizona State University |
Thesis | Standard molal properties of ionic species and inorganic acids, dissolved gases and organic molecules in hydrothermal systems (1987) |
Doctoral advisor | Harold C. Helgeson |
Doctoral students | Christopher R. Glein |
Everett L. Shock is an American geochemist and former experimental rock singer and songwriter. He is currently a professor with joint appointments in the School of Earth and Space Exploration and School of Molecular Sciences at Arizona State University. [3] Shock and his research group work within a framework of chemical thermodynamics applied to field, experimental, and theoretical geochemical investigations to understand how geochemical processes provide energy to support microbial life on Earth and potentially on other ocean worlds. [3]
Shock grew up in Garden Grove, California [4] and studied earth sciences at UC Santa Cruz, graduating in 1978. [3] In the San Francisco Bay Area, he and high school friends Erling Wold, Lynn Murdock, and Brian Woodbury formed a music theater group called Splendrix, performing in a San Francisco theater they rented. [4] After hearing the group promoting their show on UC Berkeley campus radio, musician and composer Henry Kaiser contacted them, planting the seeds for future collaboration. [4] Later, with Woodbury having left the Bay Area, Shock, Wold, and Murdock along with high school classmates Bob Adams, Mark Crawford, and Rick Crawford began recording and performing experimental/avant-garde rock music with Kaiser, calling themselves Name. [4] The group self-released an EP in 1981 and a LP in 1985 and performed at venues in the Bay Area with acts such as Negativland. [4] In 1987, Shock earned his PhD in geology at Berkeley [3] and Kaiser approached Shock about recording previously unrecorded material from the previous years before Shock left the Bay Area. The album Ghost Boys was released by SST Records in 1988 under Shock's name but with most members of Name also credited. [4] The album features Wold's use of a synclavier as well as a version of the song "Stay a Little Longer". Shock is also credited on the SST album Crazy Backwards Alphabet .
At Berkeley, Shock worked with Hal Helgeson on the estimation of thermodynamic properties for aqueous ionic species [5] and aqueous organic species [6] up to high temperatures and pressures. Shock was a professor in the Department of Earth and Planetary Sciences at Washington University in St. Louis from 1987 to 2002 before moving to Arizona State University. [3] Shock's research group maintains an extensive thermodynamic database for aqueous solutes that enables geochemical modeling of aqueous solutions at hydrothermal conditions and of water-rock reactions. [7] Continuing with a focus on the high-temperature aqueous chemistry of organic compounds, Shock leads an interdisciplinary group conducting experiments on the reactivity of organic compounds at hydrothermal conditions found in Earth's subsurface. [8] The group recently patented a process for the synthesis of isooctane, a fuel component, in high-temperature water in the presence of the Earth-abundant metals nickel and iron. [9]
Areas of focus for fieldwork include hydrothermal systems in Yellowstone National Park and serpentinizing systems of the Samail Ophiolite in Oman. [7] [3] Shock and collaborators cataloged chemical energy supplies available to thermophilic microbes in geochemically diverse hot springs in Yellowstone. [10] Shock collaborated on a project that demonstrated that substrate use in culture of a strain of Acidianus is not controlled by energy supply but rather by demand and the cost of catalyzing specific reactions. [11] [12] His research group has also examined how the geochemical composition of hot spring fluids affects microbial community composition, such as the oxidation state of microbial lipids [13] and the distribution of microbial phototrophs. [14] [15] The archaeon Thermogladius shockii was named in honor of Shock's work in Yellowstone. [16] [17] In Oman, the team determined the energy requirements for the oxidation of molecular hydrogen by methanogens may be higher in hyperalkaline fluids compared to freshwater or marine sediments, and this may contribute to competition with sulfate reducers. [18] [19] Work in Oman also led to the idea that changes in the rate of weathering of ultramafic rocks such as those found at the ophiolite may have contributed to enabling the Great Oxidation Event. [20] [21]
Submarine hydrothermal vents are another environment where chemical energy supports unique ecosystems. Shock and collaborator Jeffrey Dick used thermodynamic calculations based on the genome of Methanocaldococcus jannaschii to reveal that protein biosynthesis is an exergonic (energy-releasing) process in ultramafic submarine hydrothermal vents where the vent fluids mix with oxygenated seawater. [22] [23] [24] [25] Shock and postdoctoral researcher Vincent Milesi also developed an approach to geochemical modeling in support of ROV exploration of hydrothermal systems at Gorda Ridge off the coast of California aboard the EV Nautilus where data returned from the ROV is used to constrain models developed in advance nearly in real time, allowing for informed decision making about next steps. [26] [27] The researchers even tested how the approach can handle a built-in time delay between measurements by the ROV and receipt of the data to simulate exploration in space, in preparation for implementation of the method on the Europa Clipper mission to Jupiter. [26] Shock is a co-investigator on the MASPEX team designing the mass spectrometer that will fly on Europa Clipper to provide compositional data at Europa. [7] [28]
Magnesite is a mineral with the chemical formula MgCO
3. Iron, manganese, cobalt, and nickel may occur as admixtures, but only in small amounts.
Serpentinite is a metamorphic rock composed predominantly of one or more serpentine group minerals formed by near to complete serpentinization of mafic or ultramafic rocks. Its name originated from the similarity of the texture of the rock to that of the skin of a snake. Serpentinite has been called serpentine or serpentine rock, particularly in older geological texts and in wider cultural settings.
Serpentinization is a hydration and metamorphic transformation of ferromagnesian minerals, such as olivine and pyroxene, in mafic and ultramafic rock to produce serpentinite. Minerals formed by serpentinization include the serpentine group minerals, brucite, talc, Ni-Fe alloys, and magnetite. The mineral alteration is particularly important at the sea floor at tectonic plate boundaries.
The Lost City Hydrothermal Field, often referred to simply as Lost City, is an area of marine alkaline hydrothermal vents located on the Atlantis Massif at the intersection between the Mid-Atlantic Ridge and the Atlantis Transform Fault, in the Atlantic Ocean. It is a long-lived site of active and inactive ultramafic-hosted serpentinization, abiotically producing many simple molecules such as methane and hydrogen which are fundamental to microbial life. As such it has generated scientific interest as a prime location for investigating the origin of life on Earth and other planets similar to it.
The hydrogen cycle consists of hydrogen exchanges between biotic (living) and abiotic (non-living) sources and sinks of hydrogen-containing compounds.
The Isua Greenstone Belt is an Archean greenstone belt in southwestern Greenland, aged between 3.7 and 3.8 billion years. The belt contains variably metamorphosed mafic volcanic and sedimentary rocks, and is the largest exposure of Eoarchaean supracrustal rocks on Earth. Due to its age and low metamorphic grade relative to many Eoarchaean rocks, the Isua Greenstone Belt has become a focus for investigations on the emergence of life and the style of tectonics that operated on the early Earth.
The Guaymas Basin is the largest marginal rift basin located in the Gulf of California. It made up of the northern and southern trough and is linked to the Guaymas Fault to the north and the Carmen Fault to the south. The mid-ocean ridge system is responsible for the creation of the Guaymas Basin and giving it many features such as hydrothermal circulation and hydrocarbon seeps. Hydrothermal circulation is a significant process in the Guaymas Basin because it recycles energy and nutrients which are instrumental in sustaining the basin's rich ecosystem. Additionally, hydrocarbons and other organic matter are needed to feed a variety of organisms, many of which have adapted to tolerate the basin's high temperatures.
The class Zetaproteobacteria is the sixth and most recently described class of the Pseudomonadota. Zetaproteobacteria can also refer to the group of organisms assigned to this class. The Zetaproteobacteria were originally represented by a single described species, Mariprofundus ferrooxydans, which is an iron-oxidizing neutrophilic chemolithoautotroph originally isolated from Kamaʻehuakanaloa Seamount in 1996 (post-eruption). Molecular cloning techniques focusing on the small subunit ribosomal RNA gene have also been used to identify a more diverse majority of the Zetaproteobacteria that have as yet been unculturable.
Geochemical modeling or theoretical geochemistry is the practice of using chemical thermodynamics, chemical kinetics, or both, to analyze the chemical reactions that affect geologic systems, commonly with the aid of a computer. It is used in high-temperature geochemistry to simulate reactions occurring deep in the Earth's interior, in magma, for instance, or to model low-temperature reactions in aqueous solutions near the Earth's surface, the subject of this article.
Frederick T. Mackenzie was an American sedimentary and global biogeochemist. Mackenzie applied experimental and field data coupled to a sound theoretical framework to the solution of geological, geochemical, and oceanographic problems at various time and space scales.
Clumped isotopes are heavy isotopes that are bonded to other heavy isotopes. The relative abundance of clumped isotopes (and multiply-substituted isotopologues) in molecules such as methane, nitrous oxide, and carbonate is an area of active investigation. The carbonate clumped-isotope thermometer, or "13C–18O order/disorder carbonate thermometer", is a new approach for paleoclimate reconstruction, based on the temperature dependence of the clumping of 13C and 18O into bonds within the carbonate mineral lattice. This approach has the advantage that the 18O ratio in water is not necessary (different from the δ18O approach), but for precise paleotemperature estimation, it also needs very large and uncontaminated samples, long analytical runs, and extensive replication. Commonly used sample sources for paleoclimatological work include corals, otoliths, gastropods, tufa, bivalves, and foraminifera. Results are usually expressed as Δ47 (said as "cap 47"), which is the deviation of the ratio of isotopologues of CO2 with a molecular weight of 47 to those with a weight of 44 from the ratio expected if they were randomly distributed.
Dimitri Alexander Sverjensky is a professor in Earth and Planetary Sciences at Johns Hopkins University where his research is focused on geochemistry.
Shuhei Ono is a professor of earth, atmospheric, and planetary sciences at the Massachusetts Institute of Technology. In his research, he measures isotopes of sulfur and other elements to investigate water-rock-microbe interactions, seafloor hydrothermal systems, the deep biosphere, and global sulfur cycles.
The Rainbow hydrothermal vent field is a system of ultramafic-hosted hydrothermal vents located at 36°14'N on the Mid-Atlantic Ridge (MAR). It was discovered in 1994 from temperature readings of ten high-temperature black smokers at a depth of approximately 2.3 kilometres (1.4 mi), where fluids can exceed 365 °C (689 °F). The site is shallower and larger in area than many other vent fields along the Azores section of the MAR with an area of 1.5 square kilometres. Located 370 km (229.91 mi) southeast of Faial Island, it is a popular geochemical sampling and modeling site due to close proximity to the Azores and definitive representation of serpentinization from hydrothermal circulation and synthesis.
Carbonate-associated sulfates (CAS) are sulfate species found in association with carbonate minerals, either as inclusions, adsorbed phases, or in distorted sites within the carbonate mineral lattice. It is derived primarily from dissolved sulfate in the solution from which the carbonate precipitates. In the ocean, the source of this sulfate is a combination of riverine and atmospheric inputs, as well as the products of marine hydrothermal reactions and biomass remineralisation. CAS is a common component of most carbonate rocks, having concentrations in the parts per thousand within biogenic carbonates and parts per million within abiogenic carbonates. Through its abundance and sulfur isotope composition, it provides a valuable record of the global sulfur cycle across time and space.
In stable isotope geochemistry, the Urey–Bigeleisen–Mayer equation, also known as the Bigeleisen–Mayer equation or the Urey model, is a model describing the approximate equilibrium isotope fractionation in an isotope exchange reaction. While the equation itself can be written in numerous forms, it is generally presented as a ratio of partition functions of the isotopic molecules involved in a given reaction. The Urey–Bigeleisen–Mayer equation is widely applied in the fields of quantum chemistry and geochemistry and is often modified or paired with other quantum chemical modelling methods to improve accuracy and precision and reduce the computational cost of calculations.
Susan Humphris is a geologist known for her research on processes at mid-ocean ridges. She is an elected fellow of the American Geophysical Union.
Minoru Ozima is a geochemist and Professor Emeritus of the Department of Earth and Planetary Science, Graduate School of Science, at the University of Tokyo. He was named one of the top 100 Asian scientists for the year 2021 by Asian Scientist magazine.
Hilairy Ellen Hartnett is professor at Arizona State University known for her work on biogeochemical processes in modern and paleo-environments.
Hugh Pettingill Taylor Jr. was an American geochemist.