scholarly journals Analyses of depositional environments of the Marcellus formation in New York using biomarker and trace metal proxies

Author(s):  
Reilly M. Blocho ◽  
Richard W. Smith ◽  
Mark R. Noll

AbstractThe purpose of this study was to observe how the composition of organic matter (OM) and the extent of anoxia during deposition within the Marcellus Formation in New York varied by distance from the sediment source in eastern New York. Lipid biomarkers (n-alkanes and fatty acids) in the extractable organic component (bitumen) of the shale samples were analyzed, and proxies such as the average chain length (ACL), aquatic to terrestrial ratio (ATR) and carbon preference index (CPI) of n-alkanes were calculated. Fatty acids were relatively non-abundant due to the age of the shale bed, but n-alkane distributions revealed that the primary component of the OM was terrigenous plants. The presence of shorter n-alkane chain lengths in the samples indicated that there was also a minor component of phytoplankton and algal (marine) sourced OM. Whole rock analyses were also conducted, and cerium anomalies were calculated as a proxy for anoxia. All samples had a negative anomaly value, indicating anoxic conditions during deposition. Two samples, however, contained values close to zero and thus were determined to have suboxic conditions. Anoxia and total organic matter (TOM) did not show any spatial trends across the basin, which may be caused by varying depths within the basin during deposition. A correlation between nickel concentrations and TOM was observed and indicates that algae was the primary source of the marine OM, which supports the lipid biomarker analysis. It was determined that the kerogen type of the Marcellus Formation in New York State is type III, consistent with a methane-forming shale bed.

The Holocene ◽  
2020 ◽  
Vol 31 (1) ◽  
pp. 16-27
Author(s):  
Lilei Chen ◽  
Feng Li ◽  
Jian Liu ◽  
Xingliang He

The use of lipid biomarkers as paleoenvironmental proxies relies on an accurate assessment of their organic matter (OM) sources. In this study, we analyzed multiple lipids in core sediments recovered from the Zhejiang–Fujian coastal mud area to provide a 160-year record of OM input to the East China Sea (ECS) coastal sediments and to reconstruct paleoenvironmental conditions over this interval. The molecular composition of the samples was characterized by a mixture of natural lipids, particularly those derived from terrestrial vascular plants, marine/riverine plankton and macrophytes, and bacteria. The sources of some lipid components were ambiguous/mixed as they were potentially derived from multiple precursor organisms and because of limitations associated with modern survey techniques. There is evidence that early diagenesis caused the preferential degradation of labile aquatic lipids and that the degradation of terrestrial lipids was more severe when subjected to complex horizontal–vertical transportation processes associated with deposition, resuspension, and redeposition. These processes may have led to an enhanced terrestrial OM signal in the normal ( n)-alkane and n-alkanol records, which is at odds with, for example, those of the n-fatty acids, hopanoids, steranes, and sterols, which suggest a dominant marine OM source. Furthermore, we conclude that the occurrence of multiple sources, selective diagenesis, and test error has led to the distortion of redox and maturity indicators based on evidence from pristane-to-phytane (Pr/Ph) ratios and sterane/hopane indices in century scale. Overall, the phytol record suggests an increase in productivity after the early 20th century. Correspondingly, the diatom lipid biomarker records (based on C25 highly branched isoprenoid alkenes and C18:1ω9 fatty acids) reveal a fluctuating but overall increasing diatom productivity after the early 20th century, which coincides with a decreased proportion of the contribution from diatoms relative to that of total phytoplankton. This is believed to correspond to natural environmental changes, as well as anthropogenic impact.


2022 ◽  
Vol 308 (1) ◽  
Author(s):  
Sergio Contreras ◽  
Manlio Landahur ◽  
Karla García ◽  
Claudio Latorre ◽  
Mark Reyers ◽  
...  

AbstractIn the hyperarid Atacama Desert, water availability plays a crucial role in allowing plant survival. Along with scant rainfall, marine advective fog frequently occurs along the coastal escarpment fueling isolated mono-specific patches of Tillandsia vegetation. In this study, we investigate the lipid biomarker composition of the bromeliad Tillandsia landbeckii (CAM plant) to assess structural adaptations at the molecular level as a response to extremely arid conditions. We analyzed long-chain n-alkanes and fatty acids in living specimens (n = 59) collected from the main Tillandsia dune ecosystems across a 350 km coastal transect. We found that the leaf wax composition was dominated by n-alkanes with concentrations (total average 160.8 ± 91.4 µg/g) up to three times higher than fatty acids (66.7 ± 40.7 µg/g), likely as an adaptation to the hyperarid environment. Significant differences were found in leaf wax distribution (Average Chain Length [ACL] and Carbon Preference Index [CPI]) in the northern zone relative to the central and southern zones. We found strong negative correlations between fatty acid CPI and n-alkane ACL with precipitation and surface evaporation pointing at fine-scale adaptations to low moisture availability along the coastal transect. Moreover, our data indicate that the predominance of n-alkanes is reflecting the function of the wax in preventing water loss from the leaves. The hyperarid conditions and good preservation potential of both n-alkanes and fatty acids make them ideal tracers to study late Holocene climate change in the Atacama Desert.


2021 ◽  
Author(s):  
Layla M. San-Emeterio ◽  
Ian D. Bull ◽  
Jens Holtvoeth ◽  
Rafael López ◽  
Francisco J. González-Vila ◽  
...  

<p>Lipid biomarker analysis is an efficient tool for tracing organic matter sources in diverse environments. The quantification of biomarkers facilitates the location of soil organic carbon (SOC) from different sources in a soil profile. According to their structure, biomarkers from total lipid extracts (TLE) would exhibit different degrees of susceptibility to degradation, affecting thus their preservation in soils. Hence, it is crucial to better identify these biomarkers according to diverse stability scales. The aim of this study is to assess SOC contributions from aboveground and to develop a wider approach based on the allocation of C to quantitatively assess the sources of organic matter in low SOM content, highly weathered Mediterranean soils, following a C3-C4 rotation experiment.</p><p>Soil samples were taken from three depth intervals (0-5, 5-20, 20-40 cm) from a Mediterranean agricultural soil at “La Hampa” experimental station used for a crop rotation experiment with wheat (C3 plant) and maize (C4 plant). Lipids were extracted and quantified as described in [1].</p><p>The total lipid extracts were dominated by a homologous series of n-alkanols (saturated alcohols), short-, mid- and long-chain fatty acid methyl ester (FAME), branched FAME, unsaturated (mono- and polyunsaturated) FAME and sterols. Short-chain FAME, monounsaturated FAME were the most abundant fractions of free lipids. Mono-unsaturated alkanoic acids (Cn:1 FA) were detected in considerable amounts in all samples, namely various isomers of C16:1, C18:1, C20:1 and C22:1; these are believed to be mainly synthesised by soil bacteria. A significant increase of these compounds in rotation plots leads to an effective microbial consumption of labile organic matter in the surface soil [2]. Regarding FAME, the observed chain lengths ranged from C13 to C32, showing a unimodal distribution maximising at C16 and C18. These compounds are attributed also to microbial products, supporting our findings from the high proportion of the monounsaturated compounds found. In general, and in relation with all compounds, the abundances increased up to 20% compared with the control plots representing the initial content.</p><p>These results indicate that, only after three years of crop rotation, a considerable contribution of soil organic carbon is inherited from bacterial activity. The combination of extractable lipids has been shown to validate the use of TLE as a proxy for source and other information on vegetation change and soil processes. This work will bring a discussion on the use of these compounds for tracing the impact of crop rotation on carbon storage.</p><p>Acknowledgement: Ministerio de Ciencia Innovación y Universidades (MICIU) for INTERCARBON project (CGL2016-78937-R). L. San Emeterio also thanks MICIU for funding FPI research grants (BES-2017-07968). Mrs Desiré Monis is acknowledged for technical assistance.</p><p>[1] M. San-Emeterio, L., Bull, I. D., Holtvoeth, J., and González-Pérez, J. A.: Compound-specific isotopic analysis of fatty acids in three soil profiles to estimate organic matter turnover in agricultural soils., <em>EGU General Assembly 2020</em>, Online, 4–8 May 2020, EGU2020-18526, https://doi.org/10.5194/egusphere-egu2020-18526, 2020.</p><p>[2] Tu, T. T. N., Egasse, C., Anquetil, C., Zanetti, F., Zeller, B., Huon, S., & Derenne, S. (2017). Leaf lipid degradation in soils and surface sediments: A litterbag experiment. <em>Organic Geochemistry</em>, 104, 35-41.</p>


2015 ◽  
Vol 3 (3) ◽  
pp. SV17-SV33 ◽  
Author(s):  
Anna K. Wendt ◽  
Mike A. Arthur ◽  
Rudy Slingerland ◽  
Daniel Kohl ◽  
Reed Bracht ◽  
...  

Debate continues over paleoenvironmental conditions that prevail during deposition of organic-carbon (C)-rich marine source rocks in foreland basins and epicontinental seas. The focus of disagreement centers largely on paleowater depth and the prevalence of anoxia/euxinia. The issues of paleodepth and water column conditions are important for prediction of lateral variations in source quality within a basin because the viability of a hydrocarbon play depends on a thorough understanding of the distribution of source rock quality and depositional environments. We used inorganic geochemical data from the Middle Devonian Marcellus Shale in the Appalachian Basin to illustrate interpretive strategies that provided constraints on conditions during deposition. Source evaluation typically relies on the analysis and interpretation of organic geochemical indicators, potentially also providing evidence of the degree of thermal maturity and conditions of the preservation of the organic matter. The Marcellus Formation is thermally mature, making the evaluation of the organic-carbon fraction for geologic interpretation inadequate. Because most labile organic matter has largely been destroyed in the Marcellus Formation, analysis of inorganic elements may be used as an alternative interpretative technique. Several inorganic elements have been correlated to varying depositional settings, allowing for their use as proxies for understanding the paleodepositional environments of formations. A high-resolution geochemical data set has been constructed for the Union Springs Member along a transect of cores from proximal to distal in the Appalachian Basin in central Pennsylvania using major, minor, and trace elemental data. Our results suggested that during deposition, the sediment-water interface, and a portion of the water column, was anoxic to euxinic. As deposition continued, euxinia was periodically interrupted by dysoxia and even oxic conditions, and a greater influx of clastic material occurred. Such variations were likely related to fluctuations in water depth and progradation of deltaic complexes from the eastern margin of the Appalachian Basin.


1977 ◽  
Vol 57 (3) ◽  
pp. 223-231 ◽  
Author(s):  
S. M. GRIFFITH ◽  
M. SCHNITZER

Two samples taken from tropical volcanic surface soils and one sample from a Canadian Podzol subsurface soil were oxidized with H2O2 under conditions usually employed for the removal of organic matter from soils prior to mineralogical analyses. Between 65 and 82% of the C but only between 23 and 36% of the N in the initial organic matter in the three soils was oxidized to volatile and water-soluble products. Among the latter, small amounts of about 40 different aliphatic and aromatic compounds were identified, most of which were phenolic. Extraction with organic solvents removed n-alkanes and n-fatty acids from H2O2-resistant organic matter, but most of the latter consisted of humic substances strongly bonded to or absorbed on inorganic soil constituents. H2O2-resistant fractions accounted in the case of two soils, initially rich in organic matter, for 12.0 and 7.5% of the air-dry weights of peroxidized soils. The presence of such substantial amounts of H2O2-resistant organic matter may interfere with the dispersion and mineralogical analysis of peroxidized soils, especially those with high initial organic matter contents.


2015 ◽  
Vol 12 (15) ◽  
pp. 12975-13039 ◽  
Author(s):  
J. Holtvoeth ◽  
D. Rushworth ◽  
A. Imeri ◽  
M. Cara ◽  
H. Vogel ◽  
...  

Abstract. We present elemental, lipid biomarker and compound-specific isotope (δ13C, δ2H) data for soils and leaf litter collected in the catchment of Lake Ohrid (Albania, Macedonia), as well as macrophytes, particulate organic matter and sediments from the lake itself. Lake Ohrid provides an outstanding archive of continental environmental change of at least 1.2 M years and the purpose of our study is to ground truth organic geochemical proxies that we developed in order to study past changes in the terrestrial biome. We show that soils dominate the lipid signal of the lake sediments rather than the vegetation or aquatic biomass, while compound-specific isotopes (δ13C, δ2H) determined for n-alkanoic acids confirm a dominant terrestrial source of organic matter to the lake. There is a strong imprint of suberin monomers on the composition of total lipid extracts and chain-length distributions of n-alkanoic acids, n-alcohols, ω-hydroxy acids and α,ω-dicarboxylic acids. Our end-member survey identifies that ratios of mid-chain length suberin-derived to long-chain length cuticular-derived alkyl compounds as well as their average chain length distributions can be used as new molecular proxies of organic matter sources to the lake. We tested these for the 8.2 ka event, a pronounced and widespread Holocene climate fluctuation. In SE Europe climate became drier and cooler in response to the event, as is clearly recognizable in the carbonate and organic carbon records of Lake Ohrid sediments. Our new proxies indicate biome modification in response to hydrological changes, identifying two phases of increased soil OM supply, first from topsoils and then from mineral soils. Our study demonstrates that geochemical fingerprinting of terrestrial OM should focus on the main lipid sources, rather than the living biomass. Both can exhibit climate-controlled variability, but are generally not identical.


2021 ◽  
Author(s):  
Manuel Ruben ◽  
Florence Schubotz ◽  
Hannah Marchant ◽  
Jens Hefter ◽  
Hendik Grotheer ◽  
...  

<p>Until two decades ago, ancient carbon was regarded as non-bioavailable substrate for organisms because it was synthesised, deposited, and once before (partially) degraded thousands to millions of years ago. Such aged organic matter is stored in terrestrial permafrost deposits or sedimentary bedrock, where it is locked up and remains disconnected from the active global carbon cycle. However, with changing climatic conditions, these organic matter reservoirs are being remobilised at faster rates by receding glaciers or permafrost thaw. During transport and after redeposition in newly formed sediments, the ancient carbon can be accessed by micro-organisms, but whether or not the micro-organisms can utilize the ancient carbon is highly debated.</p><p>Using a combined approach of lipid biomarker analysis, lipidology, and radiocarbon dating of bulk organic matter as well as single compounds targeting intact polar lipid fatty acids (IPL-FAs), our research demonstrates that microbial communities utilise supposedly non-bioavailable ancient carbon for biosynthesis in Arctic marine fjord sediments. The availability of ancient carbon to the sub-surface microbes represents a carbon source that has not been accounted for in today’s climate models. These implications are of major importance concerning the increased thawing of high latitude permafrost soils, permafrost mobilization and coastal erosion due to anthropogenic climate change, catalysing associated positive feedback loops. In future research, we will use this approach to study the utilization of ancient carbon derived from North American and Siberian permafrost soils in Arctic shelf sediments to assess its importance in the global carbon budgets.</p>


2014 ◽  
Vol 11 (12) ◽  
pp. 3187-3204 ◽  
Author(s):  
C. López-Rodríguez ◽  
A. Stadnitskaia ◽  
G. J. De Lange ◽  
F. Martínez-Ruíz ◽  
M. Comas ◽  
...  

Abstract. Mud volcanoes (MVs) are the most prominent indicators of active methane/hydrocarbon venting at the seafloor on both passive and active continental margins. Their occurrence in the western Mediterranean is patent at the West Alboran Basin, where numerous MVs develop overlaying a major sedimentary depocentre containing overpressured shales. Although some of these MVs have been studied, the detailed biogeochemistry of expelled mud so far has not been examined in detail. This work provides the first results on the composition and origin of organic matter, anaerobic oxidation of methane (AOM) processes and general characteristics on MV dynamics using lipid biomarkers as the main tool. Lipid biomarker analysis was performed on MV expelled material (mud breccias) and interbedded hemipelagic sediments from Perejil, Kalinin and Schneider's Heart MVs located in the northwest margin of the Alboran Sea. The n alkane distributions and n alkane-derived indices (CPI and ACL), in combination with the epimerization degree of hopanes (22S/(22S+22R)) indicate that all studied mud breccia have a similar biomarker composition consisting of mainly thermally immature organic matter with an admixture of petroleum-derived compounds. This concordant composition indicates that common source strata must feed all three studied MVs. The past or present AOM activity was established using lipid biomarkers specific for anaerobic methanotrophic archaea (irregular isoprenoids and dialkyl glycerol diethers) and the depleted carbon isotope composition (δ13C) of crocetane/phytane. The presence of these lipid biomarkers, together with the low amounts of detected glycerol dialkyl glycerol tetraethers, is consistent with the dominance of anaerobic methanotrophs of the ANME-2 over ANME-1, at least in mud breccia from Perejil MVs. In contrast, the scarce presence or lack of these AOM-related lipid biomarkers in sediments from Kalinin and Schneider's Heart MVs, suggests that no recent active methane seepage has occurred at these sites. Moreover, the observed methane concentrations support the current activity of Perejil MV, and the very low methane seepage activity in Kalinin and Schneider's Heart MVs.


Sign in / Sign up

Export Citation Format

Share Document