scholarly journals Effects of Temperatures and High Pressures on the Growth and Survivability of Methanogens and Stable Carbon Isotope Fractionation: Implications for Deep Subsurface Life on Mars

2018 ◽  
Author(s):  
Navita Sinha ◽  
Sudip Nepal ◽  
Timothy Kral ◽  
Pradeep Kumar
Keyword(s):  
Methane Concentration ◽  
High Pressures ◽  
Stable Carbon Isotope ◽  
Isotopic Fractionation ◽  
Methanogenic Archaea ◽  
Stable Carbon ◽  
Isotopic Data ◽  
Deep Subsurface ◽  
Carbon Isotopic ◽  
Temperature And Pressure

AbstractIn order to examine the potential survivability of life in the Martian deep subsurface, we have investigated the effects of temperature (45°C, 55°C, and 65°C) and pressure (1 atm, 400 atm, 800 atm, and 1200 atm) on the growth, carbon isotopic data, and morphology of chemolithoautotrophic anaerobic methanogenic archaea,Methanothermobacter wolfeii. The growth and survivability of this methanogen were determined by measuring the methane concentration in headspace gas samples after the cells were returned to their conventional growth conditions. Interestingly, this methanogen survived at all the temperatures and pressures tested.M. wolfeiidemonstrated the highest methane concentration following exposure to pressure of 800 atm and a temperature of 65°C. We found that the stable carbon isotopic fractionation of methane, δ13C(CH4), was slightly more enriched in12C at 1 atm and 55°C than the carbon isotopic data obtained in other temperature and pressure conditions. A comparison of the images of the cells before and after the exposure to different temperatures and pressures did not show any obvious alteration in the morphology ofM. wolfeii. The research reported here suggests that at least one methanogen,M. wolfeii, may be able to survive under hypothetical Martian subsurface conditions with respect to temperature and pressure.

scholarly journals Effects of temperatures and high pressures on the growth and survivability of methanogens and stable carbon isotope fractionation: implications for deep subsurface life on Mars

2018 ◽  
pp. 1-7
Author(s):  
Navita Sinha ◽  
Sudip Nepal ◽  
Timothy Kral ◽  
Pradeep Kumar
Keyword(s):  
Methane Concentration ◽  
High Pressures ◽  
Stable Carbon Isotope ◽  
Isotopic Fractionation ◽  
Methanogenic Archaea ◽  
Stable Carbon ◽  
Isotopic Data ◽  
Deep Subsurface ◽  
Carbon Isotopic ◽  
Temperature And Pressure

AbstractIn order to examine the potential survivability of life in the Martian deep subsurface, we have investigated the effects of temperature (45°C, 55°C and 65°C) and pressure (1, 400, 800 and 1200 atm) on the growth, carbon isotopic data and morphology of chemolithoautotrophic anaerobic methanogenic archaea,Methanothermobacter wolfeii. The growth and survivability of this methanogen were determined by measuring the methane concentration in headspace gas samples after the cells were returned to their conventional growth conditions. Interestingly, this methanogen survived at all the temperatures and pressures tested.M. wolfeiidemonstrated the highest methane concentration following exposure to pressure of 800 atm and a temperature of 65°C. We found that the stable carbon isotopic fractionation of methane, δ13C(CH4), was slightly more enriched in12C at 1 atm and 55°C than the carbon isotopic data obtained in other temperature and pressure conditions. A comparison of the images of the cells before and after the exposure to different temperatures and pressures did not show any obvious alteration in the morphology ofM. wolfeii. The research reported here suggests that at least one methanogen,M. wolfeii, may be able to survive under hypothetical Martian subsurface conditions with respect to temperature and pressure.

scholarly journals A high resolution record of atmospheric carbon dioxide and its stable carbon isotopic composition from the penultimate glacial maximum to the glacial inception

2013 ◽  
Vol 9 (2) ◽  
pp. 2015-2057 ◽  
Author(s):  
R. Schneider ◽  
J. Schmitt ◽  
P. Köhler ◽  
F. Joos ◽  
H. Fischer
Keyword(s):  
Carbon Cycle ◽  
Isotopic Composition ◽  
Atmospheric Carbon Dioxide ◽  
Stable Carbon Isotope ◽  
Carbon Isotopic Composition ◽  
Ice Cores ◽  
Glacial Maximum ◽  
Stable Carbon ◽  
Isotopic Data ◽  
Carbon Isotopic

Abstract. The reconstruction of the stable carbon isotope evolution in atmospheric CO2 (δ13Catm), as archived in Antarctic ice cores, bears the potential to disentangle the contributions of the different carbon cycle fluxes causing past CO2 variations. Here we present a highly resolved record of δ13Catm before, during and after the Marine Isotope Stage 5.5 (155 000 to 105 000 yr BP). The record was derived with a well established sublimation method using ice from the EPICA Dome C (EDC) and the Talos Dome ice cores in East Antarctica. We find an 0.4‰ offset between the mean δ13Catm level in the Penultimate (~140 000 yr BP) and Last Glacial Maximum (~22 000 yr BP), which can be explained by either (i) changes in the isotopic composition or (ii) intensity of the carbon input fluxes to the combined ocean/atmosphere carbon reservoir or (iii) by long-term peat buildup. Our isotopic data suggest that the carbon cycle evolution along Termination II and the subsequent interglacial was controlled by essentially the same processes as during the last 24 000 yr, but with different phasing and magnitudes. Furthermore, a 5000 yr lag in the CO2 decline relative to EDC temperatures is confirmed during the glacial inception at the end of MIS 5.5 (120 000 yr BP). Based on our isotopic data this lag can be explained by terrestrial carbon release and carbonate compensation.

scholarly journals Stable Carbon Isotopic Composition in Annual Rings of a Pine Tree (Pinus Densiflora) from Yeongwol, Korea: Possible Application to Climate Study

Radiocarbon ◽  
2017 ◽  
Vol 59 (2) ◽  
pp. 373-381
Author(s):  
Chi-Hwan Kim ◽  
Jang Hoon Lee ◽  
Jin Kang ◽  
Sujin Song ◽  
Myung-ho Yun ◽  
...  
Keyword(s):  
Tree Rings ◽  
Pinus Densiflora ◽  
Stable Carbon Isotope ◽  
Carbon Isotopic Composition ◽  
Precipitation Data ◽  
Stable Carbon ◽  
Climate Data ◽  
Carbon Isotopic ◽  
Pine Tree ◽  
Paleoclimate Proxy

AbstractStable carbon isotope ratios were measured on the alpha-cellulose in tree rings of a pine tree (Pinus densiflora) from Yeongwol, Korea. We developed an annual-resolution δ13C series (1835–1905) by correcting the measured data for changes in δ13C of air to minimize non-climatic influences. To investigate the climatic signal in the δ13C series, we performed correlation analysis between δ13C and the Cheugugi climate data. The Cheugugi precipitation data were first recorded by King Sejong (1397–1450) of the Joseon Dynasty. However, the longest set of precipitation data available is the one collected in Seoul (1776–1907). Although many studies support the reliability of the Cheugugi data, no previous studies have investigated the potential of the δ13C signal in tree rings as paleoclimate proxy using the Cheugugi data. Recent precipitation trends in Yeongwol are quite similar to that of Seoul, and we found significant correlations between the Cheugugi data and the δ13C series. We suggest further studies to replicate these results and confirm whether comparing δ13C variations in tree rings and Cheugugi data is a useful method of investigating the potential of the δ13C signal as a paleoclimate proxy in or near the Korean peninsula.

The use of stable carbon isotope trends as a correlation tool: an example from the Surat Basin, Australia

2016 ◽  
Vol 56 (1) ◽  
pp. 355 ◽  
Author(s):  
Astrid Hentschel ◽  
Joan S. Esterle ◽  
Sue Golding
Keyword(s):  
Carbon Isotope ◽  
Turning Point ◽  
Stable Carbon Isotope ◽  
Stable Carbon ◽  
Δ13c Values ◽  
Carbon Isotopic ◽  
Gas Source ◽  
Rapid Reversal ◽  
Allogenic Processes ◽  
Coal Measures

The Surat Basin’s Middle Jurassic Walloon Subgroup is a productive coal seam gas source in Queensland, Australia. The Walloon Subgroup can be subdivided into the Upper and Lower Juandah coal measures, the Tangalooma Sandstone, the Taroom Coal Measures, and the Eurombah/Durabilla Formation, from top to bottom. Correlation across the basin is challenging due to high lateral variability and lack of extensive stratigraphic markers. The Walloon Subgroup is also, in places, incised by the overlying Springbok Sandstone, sometimes interpreted as far down as the Tangalooma Sandstone. New age dates suggest that the Walloon Coal Measures are Oxfordian in age and mark a period of high rates of Corg production and burial, and an intermittent decrease of atmospheric pCO2. The un- or dis-conformable base of the Springbok Sandstone coincides with a turning point of this supposedly global phenomenon. This study uses organic stable carbon isotope trends as a correlation tool within the Surat Basin’s Walloon Subgroup and its overlying Springbok Sandstone. Analysis of a stratigraphic suite of coal samples from several wells across the Surat Basin shows a gradual enrichment in 13C up section from the Taroom to the Lower Juandah Coal Measures, with the most positive δ13C values within the Upper Juandah Coal Measures. Thereafter there is a rapid reversal to more negative δ13C values for coal samples of the Springbok Sandstone. The upward enrichment occurs well before the shift in maceral composition to increased inertinite content in the coals, suggesting more global allogenic processes are controlling the carbon isotopic trend. The consistency of these trends lends a more confident correlation for sub-units within the Walloon Subgroup, and assists in determining the level of incision disconformity of the Springbok Sandstone.

scholarly journals Stable Carbon Isotope Fractionation by Methylotrophic Methanogenic Archaea

2012 ◽  
Vol 78 (21) ◽  
pp. 7596-7602 ◽  
Author(s):  
Jörn Penger ◽  
Ralf Conrad ◽  
Martin Blaser
Keyword(s):  
Carbon Isotope ◽  
Isotope Fractionation ◽  
Stable Carbon Isotope ◽  
Methanogenic Archaea ◽  
Methanosarcina Barkeri ◽  
Stable Carbon ◽  
Methyl Fluoride ◽  
Content Type ◽  
Carbon Isotope Fractionation ◽  
Stable Carbon Isotope Fractionation

ABSTRACTIn natural environments methane is usually produced by aceticlastic and hydrogenotrophic methanogenic archaea. However, some methanogens can use C1compounds such as methanol as the substrate. To determine the contributions of individual substrates to methane production, the stable-isotope values of the substrates and the released methane are often used. Additional information can be obtained by using selective inhibitors (e.g., methyl fluoride, a selective inhibitor of acetoclastic methanogenesis). We studied stable carbon isotope fractionation during the conversion of methanol to methane inMethanosarcina acetivorans,Methanosarcina barkeri, andMethanolobus zinderiand generally found large fractionation factors (−83‰ to −72‰). We further tested whether methyl fluoride impairs methylotrophic methanogenesis. Our experiments showed that even though a slight inhibition occurred, the carbon isotope fractionation was not affected. Therefore, the production of isotopically light methane observed in the presence of methyl fluoride may be due to the strong fractionation by methylotrophic methanogens and not only by hydrogenotrophic methanogens as previously assumed.

scholarly journals Stable isotopes provide revised global limits of aerobic methane emissions from plants

2007 ◽  
Vol 7 (1) ◽  
pp. 237-241 ◽  
Author(s):  
D. F. Ferretti ◽  
J. B. Miller ◽  
J. W. C. White ◽  
K. R. Lassey ◽  
D. C. Lowe ◽  
...  
Keyword(s):  
Methane Concentration ◽  
Ice Core ◽  
Stable Carbon Isotope ◽  
Atmospheric Methane ◽  
Stable Carbon ◽  
Terrestrial Plants ◽  
Unknown Mechanism ◽  
Stable Carbon Isotope Ratios ◽  
Annual Total ◽  
Plant Emissions

Abstract. Recently Keppler et al. (2006) discovered a surprising new source of methane – terrestrial plants under aerobic conditions, with an estimated global production of 62–236 Tg yr−1 by an unknown mechanism. This is ~10–40% of the annual total of methane entering the modern atmosphere and ~30–100% of annual methane entering the pre-industrial (0 to 1700 AD) atmosphere. Here we test this reported global production of methane from plants against ice core records of atmospheric methane concentration (CH4) and stable carbon isotope ratios (δ13CH4) over the last 2000 years. Our top-down approach determines that global plant emissions must be much lower than proposed by Keppler et al. (2006) during the last 2000 years and are likely to lie in the range 0–46 Tg yr−1 and 0–176 Tg yr−1 during the pre-industrial and modern eras, respectively.

Stable carbon isotope analysis of faecal and blood samples of sheep in relation to the diet

2003 ◽  
Vol 2003 ◽  
pp. 159-159
Author(s):  
A. Balcaen ◽  
E. Claeys ◽  
V. Fievez ◽  
P. Boeckx ◽  
O. van Cleemput ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotope ◽  
Carbon Fixation ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Isotope Analysis ◽  
Calvin Cycle ◽  
Isotopic Fractionation ◽  
Woody Species ◽  
Stable Carbon

Stable isotopes have been extraordinarily helpful in understanding animal migration, diet, food webs and nutrient flow (Hilderbrand et al., 1996), based on the property that C3 and C4 plants possess distinctly different 13C/12C ratios (δ13C value) due to isotopic fractionation during photosynthetic carbon fixation (Smith & Epstein, 1971). Most woody species and temperate graminoids assimilate carbon via the Calvin cycle (C3), which discriminates stronger against the heavier isotope (13C) than Hatch-Slack (C4) species (tropical and subtropical graminoids and some shrubs). C3 and C4 plant species have mean δ13C values of -27 ‰ and -13 ‰ respectively (O’Leary, 1981). DeNiro & Epstein (1978) were one of the first to show that the isotopic composition of the whole animal body is similar to that of its diet. Other authors have also found relationships between the isotopic composition of animal tissues and the diet (González-Martin et al., 1999; Jones et al., 1979). The aim of this study was to investigate stable carbon isotope composition in sheep fed diets consisting of either C3 or C3+C4 plants.

scholarly journals Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input

2021 ◽  
Vol 9 ◽  
Author(s):  
Jonathan Schenk ◽  
Henrique O. Sawakuchi ◽  
Anna K. Sieczko ◽  
Gustav Pajala ◽  
David Rudberg ◽  
...  
Keyword(s):  
Carbon Isotopic Composition ◽  
Isotopic Fractionation ◽  
Boreal Lakes ◽  
Stable Carbon ◽  
Deep Lake ◽  
Subarctic Lakes ◽  
Carbon Isotopic ◽  
Deep Waters ◽  
Littoral Sediments ◽  
Different Characteristics

Methane (CH4) is an important component of the carbon (C) cycling in lakes. CH4 production enables carbon in sediments to be either reintroduced to the food web via CH4 oxidation or emitted as a greenhouse gas making lakes one of the largest natural sources of atmospheric CH4. Large stable carbon isotopic fractionation during CH4 oxidation makes changes in 13C:12C ratio (δ13C) a powerful and widely used tool to determine the extent to which lake CH4 is oxidized, rather than emitted. This relies on correct δ13C values of original CH4 sources, the variability of which has rarely been investigated systematically in lakes. In this study, we measured δ13C in CH4 bubbles in littoral sediments and in CH4 dissolved in the anoxic hypolimnion of six boreal lakes with different characteristics. The results indicate that δ13C of CH4 sources is consistently higher (less 13C depletion) in littoral sediments than in deep waters across boreal and subarctic lakes. Variability in organic matter substrates across depths is a potential explanation. In one of the studied lakes available data from nearby soils showed correspondence between δ13C-CH4 in groundwater and deep lake water, and input from the catchment of CH4via groundwater exceeded atmospheric CH4 emissions tenfold over a period of 1 month. It indicates that lateral hydrological transport of CH4 can explain the observed δ13C-CH4 patterns and be important for lake CH4 cycling. Our results have important consequences for modelling and process assessments relative to lake CH4 using δ13C, including for CH4 oxidation, which is a key regulator of lake CH4 emissions.

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