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 The stable carbon isotope signature of methane produced by saprotrophic fungi

2020 ◽  
Author(s):  
Moritz Schroll ◽  
Frank Keppler ◽  
Markus Greule ◽  
Christian Eckhardt ◽  
Holger Zorn ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Stable Carbon Isotope ◽  
Fungal Species ◽  
Plant Litter ◽  
Stable Carbon ◽  
Saprotrophic Fungi ◽  
Δ13c Values ◽  
Pine Wood ◽  
Carbon Isotopic ◽  
Ch4 Production

Abstract. Methane (CH4) is the most abundant organic compound in the atmosphere with emissions from many biotic and abiotic sources. Recent studies have shown that CH4 production occurs under aerobic conditions in eukaryotes such as plants, animals, algae and saprotrophic fungi. Saprotrophic fungi play an important role in nutrient recycling in terrestrial ecosystems by their ability to decompose plant litter. Even though the CH4 production by saprotrophic fungi has been reported, so far, no data for stable carbon isotope values of the emitted CH4 (δ13C-CH4 values) is available. In this study we measured the δ13C values of CH4 and carbon dioxide (δ13C-CO2 values) emitted by the two saprotrophic fungi Pleurotus sapidus and Laetiporus sulphureus cultivated on three different substrates pine wood, grass and corn, reflecting both C3 and C4 plants with distinguished bulk δ13C values. Applying keeling plots, we found that the δ13C source values of CH4 emitted from fungi cover a wide range from −40 mUr to −69 mUr depending on the growth substrate and fungal species. Whilst little apparent carbon isotopic fractionation (in the range of −0.3 mUr to 4.6 mUr) was calculated for δ13C values of CO2 released from P. sapidus and L. sulphureus relative to the bulk δ13C values of the growth substrates, much larger carbon isotopic fractionations (ranging from −22 mUr to −42 mUr) were observed for the formation of CH4. Whilst the two fungal species showed similar δ13CH4 source values when grown on pine wood, δ13CH4 source values differed substantially between the two fungal species when grown on grass or corn. We found that δ13CH4 source values emitted by saprotrophic fungi are highly dependent on the fungal species and the metabolized substrate. They cover a broad range of δ13CH4 values and overlap with values reported for methanogenic archaea, thermogenic degradation of organic matter and other eukaryotes.

scholarly journals The stable carbon isotope signature of methane produced by saprotrophic fungi

2020 ◽  
Vol 17 (14) ◽  
pp. 3891-3901
Author(s):  
Moritz Schroll ◽  
Frank Keppler ◽  
Markus Greule ◽  
Christian Eckhardt ◽  
Holger Zorn ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Stable Carbon Isotope ◽  
Fungal Species ◽  
Plant Litter ◽  
Stable Carbon ◽  
Saprotrophic Fungi ◽  
Δ13c Values ◽  
Pine Wood ◽  
Carbon Isotopic ◽  
Ch4 Production

Abstract. Methane (CH4) is the most abundant organic compound in the atmosphere and is emitted from many biotic and abiotic sources. Recent studies have shown that CH4 production occurs under aerobic conditions in eukaryotes, such as plants, animals, algae, and saprotrophic fungi. Saprotrophic fungi play an important role in nutrient recycling in terrestrial ecosystems via the decomposition of plant litter. Although CH4 production by saprotrophic fungi has been reported, no data on the stable carbon isotope values of the emitted CH4 (δ13C-CH4 values) are currently available. In this study, we measured the δ13C values of CH4 and carbon dioxide (δ13C-CO2 values) emitted by two saprotrophic fungi, Pleurotus sapidus (oyster mushroom) and Laetiporus sulphureus (sulphur shelf), cultivated on three different substrates, pine wood (Pinus sylvestris), grass (mixture of Lolium perenne, Poa pratensis, and Festuca rubra), and corn (Zea mays), which reflect both C3 and C4 plants with distinguished bulk δ13C values. Applying Keeling plots, we found that the δ13C source values of CH4 emitted from fungi cover a wide range from −40 to −69 mUr depending on the growth substrate and fungal species. Whilst little apparent carbon isotopic fractionation (in the range from −0.3 to 4.6 mUr) was calculated for the δ13C values of CO2 released from P. sapidus and L. sulphureus relative to the bulk δ13C values of the growth substrates, much larger carbon isotopic fractionations (ranging from −22 to −42 mUr) were observed for the formation of CH4. Although the two fungal species showed similar δ13CH4 source values when grown on pine wood, δ13CH4 source values differed substantially between the two fungal species when they were grown on grass or corn. We found that the source values of δ13CH4 emitted by saprotrophic fungi are highly dependent on the fungal species and the metabolized substrate. The source values of δ13CH4 cover a broad range and overlap with values reported for methanogenic archaea, the thermogenic degradation of organic matter, and other eukaryotes.

scholarly journals Characterizing the origins of dissolved organic carbon in coastal seawater using stable carbon isotope and light absorption characteristics

2021 ◽  
Vol 18 (5) ◽  
pp. 1793-1801
Author(s):  
Heejun Han ◽  
Jeomshik Hwang ◽  
Guebuem Kim
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Carbon Isotope ◽  
Stable Carbon Isotope ◽  
The Yellow Sea ◽  
Bacterial Degradation ◽  
Western Coast ◽  
Stable Carbon ◽  
Δ13c Values ◽  
Lower Salinity

Abstract. In order to determine the origins of dissolved organic matter (DOM) occurring in the seawater of Sihwa Lake, we measured the stable carbon isotope ratios of dissolved organic carbon (DOC-δ13C) and the optical properties (absorbance and fluorescence) of DOM in two different seasons (March 2017 and September 2018). Sihwa Lake is enclosed by a dike along the western coast of South Korea, and the water is exchanged with the Yellow Sea twice a day through the sluice gates. The DOC concentrations were generally higher in lower-salinity waters in both periods, and excess of DOC was also observed in 2017 in high-salinity waters. Here, the excess DOC represents any DOC concentrations higher than those in the incoming open-ocean seawater. The excess DOC occurring in the lower-salinity waters originated mainly from marine sediments of tidal flats, based on the DOC-δ13C values (-20.7±1.2 ‰) and good correlations among the DOC, humic-like fluorescent DOM (FDOMH), and NH4+ concentrations. However, the origins of the excess DOC observed in 2017 appear to be from two different sources: one mainly from marine sources such as biological production based on the DOC-δ13C values (−19.1 ‰ to −20.5 ‰) and the other mainly from terrestrial sources by land–seawater interactions based on its depleted DOC-δ13C values (−21.5 ‰ to −27.8 ‰). This terrestrial DOM source observed in 2017 was likely associated with DOM on the reclaimed land, which experienced extended exposure to light and bacterial degradation as indicated by the higher spectral slope ratio (SR) of light absorbance and no concurrent increases in the FDOMH and NH4+ concentrations. Our study demonstrates that the combination of these biogeochemical tools can be a powerful tracer of DOM sources and characteristics in coastal environments.

A study of food chains in seagrass communities. III. Stable carbon isotope ratios

1985 ◽  
Vol 36 (5) ◽  
pp. 683 ◽  
Author(s):  
PD Nichols ◽  
DW Klumpp ◽  
RB Johns
Keyword(s):  
Carbon Isotope ◽  
Opposite Effect ◽  
Stable Carbon Isotope ◽  
Benthic Algae ◽  
Trophic Levels ◽  
Food Chains ◽  
Stable Carbon ◽  
Commercial Fish ◽  
Δ13c Values ◽  
Stable Carbon Isotope Ratios

Stable carbon isotope determinations have been used to obtain a general background to food chains being studied by a range of chemical and biological techniques. δ13C values indicate that animals (δ13CC - 11.4‰ to - 14.9‰), including two locally important commercial fish, Platycephalus laevigatus (rock flathead) and Hyporhamphus melanochir (southern sea garfish), from the Corner Inlet seagrass and non-seagrass communities are dependent to varying degrees upon seagrass (δ13C - 7.0‰ to - 9.3‰) and benthic algae for their carbon source. The largest changes in δ13C values in the food chains is at the point involving seagrasses and their direct herbivores. The latter have more negative δ13C values (H. melanochir - 12.1%o, isopods - 11.4%o). Little or no change in δ13C values is apparent at the higher trophic levels (carnivores - 13 .0‰ to - 14.9‰). Epiphytic material on the fresh leaves of the two seagrass species in the Inlet is depleted in 13C when compared with the seagrass leaves. An opposite effect is observed for epiphytic material on Posidonia australis detritus.

scholarly journals Degradation changes stable carbon isotope depth profiles in palsa peatlands

2014 ◽  
Vol 11 (1) ◽  
pp. 1383-1412 ◽  
Author(s):  
J. P. Krüger ◽  
J. Leifeld ◽  
C. Alewell
Keyword(s):  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Stable Carbon Isotopes ◽  
Stable Carbon Isotope ◽  
Stable Carbon ◽  
Δ13c Values ◽  
Depth Profiles ◽  
Degradation Rates ◽  
Aerobic Decomposition ◽  
Permafrost Thawing

Abstract. Palsa peatlands are a significant carbon pool in the global carbon cycle and are projected to change by global warming due to accelerated permafrost thaw. Our aim was to use stable carbon isotopes as indicators of palsa degradation. Depth profiles of stable carbon isotopes generally reflect organic matter dynamics in soils with an increase of δ13C values during aerobic decomposition and stable or decreasing δ13C values with depth during anaerobic decomposition. Stable carbon isotope depth profiles of undisturbed and degraded sites of hummocks as well as hollows at three palsa peatlands in northern Sweden were used to investigate the degradation processes. The depth patterns of stable isotopes clearly differ between intact and degraded hummocks at all sites. Erosion and cryoturbation at the degraded sites significantly changes the stable carbon isotope depth profiles. At the intact hummocks the uplifting of peat material by permafrost is indicated by a turning in the δ13C depth trend and this assessment is supported by a change in the C / N ratios. For hollows isotope patterns were less clear, but some hollows and degraded hollows in the palsa peatlands show differences in their stable carbon isotope depth profiles indicating enhanced degradation rates. We conclude that the degradation of palsa peatlands by accelerated permafrost thawing could be identified with stable carbon isotope depth profiles. At intact hummocks δ13C depth patterns display the uplifting of peat material by a change in peat decomposition processes.

scholarly journals Stable carbon isotopes as indicators for micro-geomorphic changes in palsa peats

2011 ◽  
Vol 8 (1) ◽  
pp. 527-548 ◽  
Author(s):  
C. Alewell ◽  
R. Giesler ◽  
J. Klaminder ◽  
J. Leifeld ◽  
M. Rollog
Keyword(s):  
Carbon Isotope ◽  
Climate Warming ◽  
Anaerobic Degradation ◽  
Turning Point ◽  
Stable Carbon Isotopes ◽  
Stable Carbon Isotope ◽  
Stable Carbon ◽  
Depth Profiles ◽  
The Stability ◽  
Water Saturated

Abstract. Palsa peats are unique northern ecosystems formed under an arctic climate and characterized by an unique biodiversity and ecology. The stability of the palsas are seriously threatened by climate warming which will change the permafrost dynamic and results in degradation of the mires. We used stable carbon isotope depth profiles in two palsa mires of Northern Sweden to track environmental change during the formation of the mires. Carbon isotope (δ13C) depth profile of the yet undisturbed mire Storflaket indicated very low to no degradation of the peat in the water saturated depressions (hollows) but increased rates of anaerobic degradation at the Stordalen site. The latter might be induced by degradation of the permafrost cores in the uplifted areas (hummocks) and subsequent braking and submerging of the hummock peat into the hollows due to climate warming. Carbon isotope depth profiles of hummocks indicated a turn from aerobic mineralisation to anaerobic degradation at a peat depth between 4 to 25 cm. The age of these turning point was 14C dated between 150 and 670 years and could thus not be caused by anthropogenically induced climate change. We found the uplifting of the hummocks due to permafrost heave the most likely explanation for our findings. We thus concluded that differences in carbon isotope profiles of the hollows might point to the disturbance of the mires due to climate warming or due to differences in hydrology. The characteristic profiles of the hummocks are indicators for micro-geomorphic change during permafrost up heaving.

scholarly journals Technical Note: Constraining stable carbon isotope values of microphytobenthos (C<sub>3</sub> photosynthesis) in the Arctic for application to food web studies

2013 ◽  
Vol 10 (11) ◽  
pp. 18151-18174 ◽  
Author(s):  
L. E. Oxtoby ◽  
J. T. Mathis ◽  
L. W. Juranek ◽  
M. J. Wooller
Keyword(s):  
Food Web ◽  
Carbon Isotope ◽  
Growth Rates ◽  
Stable Carbon Isotope ◽  
Carbon Sources ◽  
The Arctic ◽  
Stable Carbon ◽  
Marine Food Web ◽  
Carbon Isotopic ◽  
Marine Food

Abstract. Microphytobenthos (MPB) tends to be omitted as a possible carbon source to higher trophic level consumers in high latitude marine food web models that use stable isotopes. Here, we used previously published relationships relating the concentration of aqueous carbon dioxide ([CO2]aq), the stable carbon isotopic composition of dissolved inorganic carbon (DIC) (δ13CDIC), and algal growth rates (μ) to estimate the stable carbon isotope composition of MPB-derived total organic carbon (TOC) (δ13Cp) and fatty acid (FA) biomarkers (δ13CFA). We measured [CO2]aq and δ13CDIC values from bottom water at sampling locations in the Beaufort and Chukchi Seas (n = 18), which ranged from 17 to 72 mmol kg–1 and −0.1 to 1.4 ‰ (0.8 ± 0.4‰, mean ±1 s.d.), respectively. We combined these field measurements with a set of stable carbon isotopic fractionation factors reflecting differences in algal taxonomy and physiology to determine δ13Cp and δ13CFA values. Theδ13Cp and δ13CFA values for a mixed eukaryotic algal community were estimated to be −23.6 ± 0.4‰ and −30.6 ± 0.4‰, respectively. These values were similar to our estimates for Phaeodactylum tricornutum (δ13Cp = −23.9 ± 0.4‰, δ13CFA = −30.9 ± 0.4‰), a pennate diatom likely to be a dominant MPB taxon. Taxon-specific differences were observed between a centric diatom (Porosira glacialis, δ13Cp = −20.0 ± 1.6‰), a marine haptophyte (Emiliana huxleyi, δ13Cp = −22.7 ± 0.5‰), and a cyanobacterium (Synechococcus sp., δ13Cp = −16.2 ± 0.4‰) at μ = 0.1 d−1. δ13Cp and δ13CFA values increased by &amp;simeq; 2.5‰ for the mixed algal consortium and for P. tricornutum when growth rates were increased from 0.1 to 1.4 d−1. We compared our estimates of δ13Cp and δ13CFA values for MPB with previous measurements of δ13CTOC and δ13CFA values for other carbon sources in the Arctic, including ice-derived, terrestrial, and pelagic organic matter. We found that MPB values were significantly distinct from terrestrial and ice-derived carbon sources. However, MPB values overlapped with pelagic sources, which may result in MPB being overlooked as a significant source of carbon in the marine food web.

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