Extraordinary 13C enrichment of diether lipids at the Lost City Hydrothermal Field indicates a carbon-limited ecosystem

Bradley, Alexander S.; Hayes, John M.; Summons, Roger E.

doi:10.1016/j.gca.2008.10.005

Cited by 108 publications

(114 citation statements)

References 100 publications

(172 reference statements)

Supporting

Mentioning

109

Contrasting

Unclassified

Order By: Relevance

“…Multiple carbon and hydrogen isotopic data suggest the methane that is abundant in the fluids emanating from the Lost City hydrothermal field, a site of contemporary serpentinization on Earth, has an abiogenic origin. However, it is known that methanogenic Archaea are also active in this system (Bradley et al, 2009). Accordingly, carbon isotopes are of limited value in discriminating between biological and abiogenic sources where multiple processes can contribute to a pool of methane and reservoir affects provide added complications (Bradley and Summons, 2010).…”

Section: Insert Figure 1 Hereaboutsmentioning

confidence: 99%

“…For example, carbonates deposited as a consequence of microbial metabolisms sometimes hold an excellent record of those processes as is the case with methane seep limestones (e.g. Birgel et al, 2008) or hydrothermal systems like Lost City (Bradley et al, 2009). Silica-rich water derived from hydrothermal systems is another well-established medium that promotes faithful preservation (e.g.…”

Section: Preservation Potentialmentioning

confidence: 99%

“…Although ultramafic rock is rare on the ocean floor today, occurring mainly at ultraslow-spreading ridges, it could have been more prevalent in the geological past (Sleep et al, 2004;Sleep and Bird 2007). Molecular and isotopic data indicate that Lost City fluids sustain a flourishing microbial community of methanogens and sulfate-reducing bacteria (SRB) (Bradley et al, 2009;Brazelton et al, 2006). Although the SRB would be sulfate-limited if disconnected from a sulfate supply that is ultimately coupled to oxygenic photosynthesis or abiotic oxidation reactions occurring at the surface or subsurface, there appear to be no such constraints on the activity of methanogens that require only hydrogen and CO 2 .…”

Section: Potential Biological Sources Of Organic Carbon On Marsmentioning

confidence: 99%

“…Thus, the recent detection of serpentine deposits in Noachian terrains on the surface of Mars (Ehlmann et al, 2010) identifies the probable past occurrence of hydrogen-producing water-rock reactions and, therefore, an established set of processes that would both support chemosynthetic life and preserve a molecular and/or isotopic record of its prior existence (e.g. Kelly et al, 2005;Bradley et al, 2009) At life's origin, the dominant energy source was unlikely to have been sunlight. Energy flowing from chemical and thermal disequilibria and particularly from the interaction of hot rocks with water is more likely.…”

Section: Potential Biological Sources Of Organic Carbon On Marsmentioning

confidence: 99%

See 3 more Smart Citations

Preservation of Martian Organic and Environmental Records: Final Report of the Mars Biosignature Working Group

Summons

Amend²,

Bish³

et al. 2011

Astrobiology

Self Cite

265

207

View full text Add to dashboard Cite

International audienceThe Mars Science Laboratory (MSL) has an instrument package capable of making measurements of past and present environmental conditions. The data generated may tell us if Mars is, or ever was, able to support life. However, the knowledge of Mars' past history and the geological processes most likely to preserve a record of that history remain sparse and, in some instances, ambiguous. Physical, chemical, and geological processes relevant to biosignature preservation on Earth, especially under conditions early in its history when microbial life predominated, are also imperfectly known. Here, we present the report of a working group chartered by the Co-Chairs of NASA's MSL Project Science Group, John P. Grotzinger and Michael A. Meyer, to review and evaluate potential for biosignature formation and preservation on Mars. Orbital images confirm that layered rocks achieved kilometer-scale thicknesses in some regions of ancient Mars. Clearly, interplays of sedimentation and erosional processes govern present-day exposures, and our understanding of these processes is incomplete. MSL can document and evaluate patterns of stratigraphic development as well as the sources of layered materials and their subsequent diagenesis. It can also document other potential biosignature repositories such as hydrothermal environments. These capabilities offer an unprecedented opportunity to decipher key aspects of the environmental evolution of Mars' early surface and aspects of the diagenetic processes that have operated since that time. Considering the MSL instrument payload package, we identified the following classes of biosignatures as within the MSL detection window: organism morphologies (cells, body fossils, casts), biofabrics (including microbial mats), diagnostic organic molecules, isotopic signatures, evidence of biomineralization and bioalteration, spatial patterns in chemistry, and biogenic gases. Of these, biogenic organic molecules and biogenic atmospheric gases are considered the most definitive and most readily detectable by MSL

show abstract

Section: Insert Figure 1 Hereaboutsmentioning

confidence: 99%

Section: Preservation Potentialmentioning

confidence: 99%

Section: Potential Biological Sources Of Organic Carbon On Marsmentioning

confidence: 99%

Section: Potential Biological Sources Of Organic Carbon On Marsmentioning

confidence: 99%

See 2 more Smart Citations

Preservation of Martian Organic and Environmental Records: Final Report of the Mars Biosignature Working Group

Summons

Amend²,

Bish³

et al. 2011

Astrobiology

Self Cite

265

207

View full text Add to dashboard Cite

show abstract

“…For example, CH 4 concentrations in vent fluids at the Lost City hydrothermal site are elevated relative to the predicted log-linear increase in n-alkane abundance with decreasing carbon number for polymerization of hydrocarbons (ANDERSON, 1984;. In addition to possible biogenic sources (BRADLEY et al, 2009), abiotic mechanisms may be responsible for these elevated abundances. It has largely been assumed that uncatalyzed aqueous reduction of CO 2 to CH 4 by H 2 is kinetically prohibited (HORITA and BERNDT, 1999;LUTHER, 2004) and with the exception of recent work by SEEWALD et al (2006), there have been few studies of hydrothermal CO 2 reduction in the absence of heterogeneous catalysts.…”

Section: Introductionmentioning

confidence: 96%

Laboratory and field-based investigations of subsurface geochemical processes in seafloor hydrothermal systems

Reeves¹

2010

View full text Add to dashboard Cite

This thesis presents the results of four discrete investigations into processes governing the organic and inorganic chemical composition of seafloor hydrothermal fluids in a variety of geologic settings. Though Chapters 2 through 5 of this thesis are disparate in focus, each represents a novel investigation aimed at furthering our understanding of subsurface geochemical processes affecting hydrothermal fluid compositions. Chapters 2 and 3 concern the abiotic (nonbiological) formation of organic compounds in high temperature vent fluids, a process which has direct implications for the emergence of life in early Earth settings and sustainment of present day microbial populations in hydrothermal environments. Chapter 2 represents an experimental investigation of methane (CH 4 ) formation under hydrothermal conditions. The overall reduction of carbon dioxide (CO 2 ) to CH 4 , previously assumed to be kinetically inhibited in the absence of mineral catalysts, is shown to proceed on timescales pertinent to crustal residence times of hydrothermal fluids. In Chapter 3, the abundance of methanethiol (CH 3 SH), considered to be a crucial precursor for the emergence of primitive chemoautotrophic life, is characterized in vent fluids from ultramafic-, basalt-and sediment-hosted hydrothermal systems. Previous assumptions that CH 3 SH forms by reduction of CO 2 are not supported by the observed distribution in natural systems. Chapter 4 investigates factors regulating the hydrogen isotope composition of hydrocarbons under hydrothermal conditions. Isotopic exchange between low molecular weight n-alkanes and water is shown to be facilitated by metastable equilibrium reactions between alkanes and their corresponding alkenes, which are feasible in natural systems. In Chapter 5, the controls on vent fluid composition in a backarc hydrothermal system are investigated. A comprehensive survey of the inorganic geochemistry of fluids from sites of hydrothermal activity in the eastern Manus Basin indicates that fluids there are influenced by input of acidic magmatic solutions at depth, and subsequently modified by variable extents of seawater entrainment and mixing-related secondary acidity production. CHAPTER 1 IntroductionSeafloor hydrothermal systems associated with the generation of oceanic crust represent a dramatic expression of heat and mass transfer from the interior of the Earth. In addition to profound effects on ocean chemistry, convective circulation of seawater through volcanically active oceanic crust leads to the formation of metal sulfide deposits. In addition, seafloor hot springs are often invoked as ideal settings from which early microbial life could have emerged.Since the initial discovery of low temperature venting at the Galápagos Spreading Center in 1977 (CORLISS et al., 1979), our understanding of the composition and diversity of hydrothermal solutions has expanded greatly. During convection through oceanic crust of basaltic composition, O 2 -replete seawater reacts with crustal rock, typically producin...

show abstract

Brucite chimney formation and carbonate alteration at theShinkaiSeepField, a serpentinite‐hosted vent system in thesouthernMariana forearc

Okumura

Ohara

Stern

et al. 2016

Geochem. Geophys. Geosyst.

View full text Add to dashboard Cite

Brucite-carbonate chimneys were discovered from the deepest known ($5700 m depth) serpentinite-hosted ecosystem-the Shinkai Seep Field (SSF) in the southern Mariana forearc. Textural observations and geochemical analysis reveal three types (I-III) of chimneys formed by the precipitation and dissolution of constitutive minerals. Type I chimneys are bright white to light yellow, have a spiky crystalline and wrinkled surface with microbial mat and contain more brucite; these formed as a result of rapid precipitation under high fluid discharge conditions. Type II chimneys exhibit white to dull brown coloration, tuberous textures like vascular bundles, and are covered with grayish microbial mats and dense colonies of Phyllochaetopterus. This type of chimney is characterized by inner brucite-rich and outer carbonate rich zones and is thought to have precipitated from lower fluid discharge conditions than type I chimneys. Type III chimneys are ivory colored, have surface depressions and lack living microbial mats or animals. This type of chimney mainly consists of carbonate, and is in a dissolution stage. Stable carbon isotope compositions of carbonates in the two types (I and II) of active chimneys are extremely 13 C-enriched (up to 124.1&), which may reflect biological 12 C consumption under extremely low dissolved inorganic carbon concentrations in alkaline fluids. Type III chimneys have 13 C compositions indicating re-equilibration with seawater.Our findings demonstrate for the first time that carbonate chimneys can form below the carbonate compensation depth and provide new insights about linked geologic, hydrologic, and biological processes of the global deep-sea serpentinite-hosted vent systems.

show abstract

Extraordinary 13C enrichment of diether lipids at the Lost City Hydrothermal Field indicates a carbon-limited ecosystem

Cited by 108 publications

References 100 publications

Preservation of Martian Organic and Environmental Records: Final Report of the Mars Biosignature Working Group

Preservation of Martian Organic and Environmental Records: Final Report of the Mars Biosignature Working Group

Laboratory and field-based investigations of subsurface geochemical processes in seafloor hydrothermal systems

Brucite chimney formation and carbonate alteration at theShinkaiSeepField, a serpentinite‐hosted vent system in thesouthernMariana forearc

Contact Info

Product

Resources

About