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The δ13C composition and genetic origin of a series straight long-chain alkyl naphthalene isomer pairs in the Upper Cretaceous lacustrine sediments of Songliao Basin, China
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.orggeochem.2024.104898
Xinxing Cao , Yan Li , Zhiguang Song
A series of straight long-chain alkyl naphthalene isomer pairs (LANs) have been detected in the Upper Cretaceous lacustrine sediments of Nenjiang Formation (K2n1+2) in the Songliao Basin, and their distribution and carbon isotopic composition were investigated. The results indicate that the composition and distribution of LANs exhibit significant variations. The relative abundance of methyl- and dimethyl-naphthalenes shows a reciprocal correlation with that of LANs, increasing and declining in tandem. The δ13C composition of LANs varies from −24.6 ‰ to –32.6 ‰, with an average of −28.5 ‰, which is notably higher than that of n-alkanes, ranging from −31.9 ‰ to −34.5 ‰. The δ13C composition of methylnaphthalenes (MNs) ranges from −26.9 ‰ to −27.1 ‰, which is generally more positive than the average δ13C composition of LANs. Analysis of the carbon isotopic composition of n-alkanes, methylnaphthalenes, and the series of LANs, along with their distribution patterns, suggests the presence of multiple formation mechanisms. Specifically, the observed declining variation pattern of δ13C values for LANs along with the increasing carbon number of the alkyl chain may indicate a novel formation pathway. This pathway likely involves a direct reaction between 13C-enriched naphthalene and 13C-depleted straight long-alkyl chains during diagenesis. The relative abundance ratio of total methyl-substituted naphthalenes (ΣMNs) to the total LANs (ΣLANs), expressed as the ΣMNs/ΣLANs ratio, exhibits a profile variation that correlates with the profile changes of the Pr/Ph ratio, TOC content, and HI index. This correlation indicates that specific environmental conditions or source inputs, such as reduced sedimentary conditions or specific algal contributions, may be conducive to the formation of LANs.
{"title":"The δ13C composition and genetic origin of a series straight long-chain alkyl naphthalene isomer pairs in the Upper Cretaceous lacustrine sediments of Songliao Basin, China","authors":"Xinxing Cao ,&nbsp;Yan Li ,&nbsp;Zhiguang Song","doi":"10.1016/j.orggeochem.2024.104898","DOIUrl":"10.1016/j.orggeochem.2024.104898","url":null,"abstract":"<div><div>A series of straight long-chain alkyl naphthalene isomer pairs (LANs) have been detected in the Upper Cretaceous lacustrine sediments of Nenjiang Formation (K<sub>2</sub>n<sup>1+2</sup>) in the Songliao Basin, and their distribution and carbon isotopic composition were investigated. The results indicate that the composition and distribution of LANs exhibit significant variations. The relative abundance of methyl- and dimethyl-naphthalenes shows a reciprocal correlation with that of LANs, increasing and declining in tandem. The δ<sup>13</sup>C composition of LANs varies from −24.6 ‰ to –32.6 ‰, with an average of −28.5 ‰, which is notably higher than that of <em>n</em>-alkanes, ranging from −31.9 ‰ to −34.5 ‰. The δ<sup>13</sup>C composition of methylnaphthalenes (MNs) ranges from −26.9 ‰ to −27.1 ‰, which is generally more positive than the average δ<sup>13</sup>C composition of LANs. Analysis of the carbon isotopic composition of <em>n</em>-alkanes, methylnaphthalenes, and the series of LANs, along with their distribution patterns, suggests the presence of multiple formation mechanisms. Specifically, the observed declining variation pattern of δ<sup>13</sup>C values for LANs along with the increasing carbon number of the alkyl chain may indicate a novel formation pathway. This pathway likely involves a direct reaction between <sup>13</sup>C-enriched naphthalene and <sup>13</sup>C-depleted straight long-alkyl chains during diagenesis. The relative abundance ratio of total methyl-substituted naphthalenes (ΣMNs) to the total LANs (ΣLANs), expressed as the ΣMNs/ΣLANs ratio, exhibits a profile variation that correlates with the profile changes of the Pr/Ph ratio, TOC content, and HI index. This correlation indicates that specific environmental conditions or source inputs, such as reduced sedimentary conditions or specific algal contributions, may be conducive to the formation of LANs.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"200 ","pages":"Article 104898"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Field and laboratory study on the distribution, fate and transport of polycyclic aromatic hydrocarbons in the loess porous medium at a refinery polluted site: Understanding the soil-groundwater interface
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.orggeochem.2024.104902
Minkai Du , Miao Li , Weijie Liu , Mingming Shi , Xiaoqian Li , Xinli Xing , Shihua Qi
Soil and groundwater pollution from industrial and agricultural activities has become a global concern. This study therefore investigates the occurrence, sources, and transport mechanisms of polycyclic aromatic hydrocarbons (PAHs) in the soil-groundwater system of a closed refinery. Field investigations and laboratory column experiments revealed widespread PAH contamination in both groundwater and soil, with higher concentrations near the groundwater level (6.45–8.75 m). PAHs in soil and groundwater were predominantly low and medium molecular weight compounds (LMW and MMW), originated from petroleum leakage and coal combustion. The region’s soil, primarily composed of loess and gravel with low total organic carbon (TOC) content (mean 0.07%), showed a positive correlation between PAH concentration and TOC/clay content, while sand content had no significant impact. Groundwater fluctuations influence PAH accumulation at the soil-groundwater interface (SGI), which may suggest potential for increased migration under varying hydraulic conditions. This vertical migration offers new insights into contaminant transport models in groundwater systems, particularly for arid regions, and could inform future remediation strategies for similar contamination scenarios.
{"title":"Field and laboratory study on the distribution, fate and transport of polycyclic aromatic hydrocarbons in the loess porous medium at a refinery polluted site: Understanding the soil-groundwater interface","authors":"Minkai Du ,&nbsp;Miao Li ,&nbsp;Weijie Liu ,&nbsp;Mingming Shi ,&nbsp;Xiaoqian Li ,&nbsp;Xinli Xing ,&nbsp;Shihua Qi","doi":"10.1016/j.orggeochem.2024.104902","DOIUrl":"10.1016/j.orggeochem.2024.104902","url":null,"abstract":"<div><div>Soil and groundwater pollution from industrial and agricultural activities has become a global concern. This study therefore investigates the occurrence, sources, and transport mechanisms of polycyclic aromatic hydrocarbons (PAHs) in the soil-groundwater system of a closed refinery. Field investigations and laboratory column experiments revealed widespread PAH contamination in both groundwater and soil, with higher concentrations near the groundwater level (6.45–8.75 m). PAHs in soil and groundwater were predominantly low and medium molecular weight compounds (LMW and MMW), originated from petroleum leakage and coal combustion. The region’s soil, primarily composed of loess and gravel with low total organic carbon (TOC) content (mean 0.07%), showed a positive correlation between PAH concentration and TOC/clay content, while sand content had no significant impact. Groundwater fluctuations influence PAH accumulation at the soil-groundwater interface (SGI), which may suggest potential for increased migration under varying hydraulic conditions. This vertical migration offers new insights into contaminant transport models in groundwater systems, particularly for arid regions, and could inform future remediation strategies for similar contamination scenarios.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"200 ","pages":"Article 104902"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Effects of digestate application, winter crop species and development on dissolved organic matter composition along the soil profile
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.orggeochem.2024.104923
Anne-Flore Didelot , Anne Jaffrezic , Thierry Morvan , Marine Liotaud , Florian Gaillard , Emilie Jardé
Applying organic waste products (OWPs) and sowing cover crops are agronomic practices to improve soil health. OWPs can be used in anaerobic digestion. Because microorganisms consume some of the labile molecules, persistent molecules accumulate in digestate. Few studies have investigated the transfer of dissolved organic matter (DOM) in soil that received digestate. Previously, effects of digestate application on dissolved organic carbon (DOC) were compared to those of the original pig slurry under wheat and a mustard catch crop for nine years at a lysimeter experimental site. DOC concentrations after digestate application were higher in the topsoil every year, due to crop development, but did not differ between treatments in the subsoil. The objectives of this study were to determine whether the observed differences in DOC concentrations caused DOM composition to differ, to identify sources (e.g., digestate, root exudation) that may have contributed to the DOM pool and to assess the DOM composition in the subsoil. The DOM composition of lysimeter samples and water extracts from the OWPs applied were analyzed by thermochemolysis coupled with gas chromatography and mass spectrometry, which identified plant- and microbial-derived biomarkers. Under mustard, the DOM pool seemed to contain mainly persistent molecules from digestate that were desorbed due to the increase in pH caused by nitrate uptake. Under wheat, the DOC pool seemed supplied by both digestate and root exudation. After applying digestate, plant-derived molecules decreased, while microbial-derived molecules increased, as depth increased, and molecules may have been sorbed from the topsoil to subsoil.
{"title":"Effects of digestate application, winter crop species and development on dissolved organic matter composition along the soil profile","authors":"Anne-Flore Didelot ,&nbsp;Anne Jaffrezic ,&nbsp;Thierry Morvan ,&nbsp;Marine Liotaud ,&nbsp;Florian Gaillard ,&nbsp;Emilie Jardé","doi":"10.1016/j.orggeochem.2024.104923","DOIUrl":"10.1016/j.orggeochem.2024.104923","url":null,"abstract":"<div><div>Applying organic waste products (OWPs) and sowing cover crops are agronomic practices to improve soil health. OWPs can be used in anaerobic digestion. Because microorganisms consume some of the labile molecules, persistent molecules accumulate in digestate. Few studies have investigated the transfer of dissolved organic matter (DOM) in soil that received digestate. Previously, effects of digestate application on dissolved organic carbon (DOC) were compared to those of the original pig slurry under wheat and a mustard catch crop for nine years at a lysimeter experimental site. DOC concentrations after digestate application were higher in the topsoil every year, due to crop development, but did not differ between treatments in the subsoil. The objectives of this study were to determine whether the observed differences in DOC concentrations caused DOM composition to differ, to identify sources (e.g., digestate, root exudation) that may have contributed to the DOM pool and to assess the DOM composition in the subsoil. The DOM composition of lysimeter samples and water extracts from the OWPs applied were analyzed by thermochemolysis coupled with gas chromatography and mass spectrometry, which identified plant- and microbial-derived biomarkers. Under mustard, the DOM pool seemed to contain mainly persistent molecules from digestate that were desorbed due to the increase in pH caused by nitrate uptake. Under wheat, the DOC pool seemed supplied by both digestate and root exudation. After applying digestate, plant-derived molecules decreased, while microbial-derived molecules increased, as depth increased, and molecules may have been sorbed from the topsoil to subsoil.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"200 ","pages":"Article 104923"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Solvent effect in Soxhlet extraction of source rocks
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.orggeochem.2024.104917
Jing Liao , Juncang Wang , Hong Lu , Guoying Sheng , Ping’an Peng , Chang Samuel Hsu
An abundant series of saturated n-C12 to n-C32 fatty acid methyl esters (FAMEs) was unexpectedly detected in the aromatic fraction of Maoming oil shale extracts. Since no pretreatments involving saponification, acidification and esterification were used, these saturated n-FAMEs were suspected either originally present in samples or formed by inadventent methylation of n-FAs during Soxhlet extraction. Several carefully designed Soxhlet extraction experiments using a mixture of n-fatty acid standards (MFASTDs) with different volume ratios of dichloromethane (DCM) and methanol (MeOH) as solvents were performed to investigate if the methyl esterification (methylation) could indeed occur in the traditional Soxhlet extraction.
The results revealed that when methanol alone was used as the extraction solvent, the esterification of fatty acids was very weak. However, with the addition of a proper amount of dichloromethane, for example, 3:2 or 4:1 vol ratio (v/v) of DCM:MeOH as extraction solvent, strong esterification reactions occurred and the esterification of MFASTDs reached almost 100 %. With 9:1 v/v of DCM:MeOH as used in conventional Soxhlet extraction, MFASTDs at lower loadings were nearly all esterified, while at higher loadings, the esterification of short-chain FAs could reach ∼ 80 % while long-chain n-FAs were completely esterified. Therefore, we conclude that n-FAs can be methylated by conventional Soxhlet extraction and DCM plays an important role in esterification.
The saturated n-C12 to n-C32 FAMEs in Maoming oil shales might be from free n-FAs derived from Botryococcus braunii (B. braunii) since they shared similar carbon number distributions as n-alkanes in the same samples, especially with a striking predominance of n-C27. Abundant clay minerals existing in the Maoming oil shales are believed responsible for the formation of free n-FAs because they can provide Brønsted acidity to accelerate hydrolysis of ester linkage to release the bound fatty acids to free forms in specific environment having suitable low water content.
{"title":"Solvent effect in Soxhlet extraction of source rocks","authors":"Jing Liao ,&nbsp;Juncang Wang ,&nbsp;Hong Lu ,&nbsp;Guoying Sheng ,&nbsp;Ping’an Peng ,&nbsp;Chang Samuel Hsu","doi":"10.1016/j.orggeochem.2024.104917","DOIUrl":"10.1016/j.orggeochem.2024.104917","url":null,"abstract":"<div><div>An abundant series of saturated <em>n</em>-C<sub>12</sub> to <em>n</em>-C<sub>32</sub> fatty acid methyl esters (FAMEs) was unexpectedly detected in the aromatic fraction of Maoming oil shale extracts. Since no pretreatments involving saponification, acidification and esterification were used, these saturated <em>n</em>-FAMEs were suspected either originally present in samples or formed by inadventent methylation of <em>n</em>-FAs during Soxhlet extraction. Several carefully designed Soxhlet extraction experiments using a mixture of <em>n</em>-fatty acid standards (MFASTDs) with different volume ratios of dichloromethane (DCM) and methanol (MeOH) as solvents were performed to investigate if the methyl esterification (methylation) could indeed occur in the traditional Soxhlet extraction.</div><div>The results revealed that when methanol alone was used as the extraction solvent, the esterification of fatty acids was very weak. However, with the addition of a proper amount of dichloromethane, for example, 3:2 or 4:1 vol ratio (<em>v/v</em>) of DCM:MeOH as extraction solvent, strong esterification reactions occurred and the esterification of MFASTDs reached almost 100 %. With 9:1 <em>v/v</em> of DCM:MeOH as used in conventional Soxhlet extraction, MFASTDs at lower loadings were nearly all esterified, while at higher loadings, the esterification of short-chain FAs could reach ∼ 80 % while long-chain <em>n</em>-FAs were completely esterified. Therefore, we conclude that <em>n</em>-FAs can be methylated by conventional Soxhlet extraction and DCM plays an important role in esterification.</div><div>The saturated <em>n</em>-C<sub>12</sub> to <em>n</em>-C<sub>32</sub> FAMEs in Maoming oil shales might be from free <em>n</em>-FAs derived from <em>Botryococcus braunii</em> (<em>B. braunii</em>) since they shared similar carbon number distributions as <em>n</em>-alkanes in the same samples, especially with a striking predominance of <em>n</em>-C<sub>27</sub>. Abundant clay minerals existing in the Maoming oil shales are believed responsible for the formation of free <em>n</em>-FAs because they can provide Brønsted acidity to accelerate hydrolysis of ester linkage to release the bound fatty acids to free forms in specific environment having suitable low water content.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"200 ","pages":"Article 104917"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Validation of the U37K′ paleotemperature proxy in the South Brazilian Bight from core-top sediments
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.orggeochem.2025.104928
Felipe Stanchak , Julie N. Richey , Amanda Gerotto , Amelia Shevenell , Marcia C. Bícego , Felipe A. Toledo , Michel M. de Mahiques , Renata H. Nagai
The paleothermometer based on the alkenone unsaturation index (U37K) is often used to reconstruct past sea surface temperatures (SST). In the SW Atlantic Ocean, however, a limited understanding of the seasonal and depth distribution of coccolithophores, which generates the U37K signal preserved in ocean sediments, hinders accurate estimates of past regional SSTs. We analyzed 45 core-top sediment samples from the continental shelf of the South Brazilian Bight (SBB, 23 °S to 28 °S) to assess regional spatial U37K-SST gradients and improve SST estimates. The U37K data were converted to SST using six published paleotemperature equations and compared to modern observational SST data from the World Ocean Atlas (2018) data set. Data indicate that the U37K signal is produced during the austral summer and autumn when regional episodic upwelling events occur over the inner-shelf and the nutricline shoals at the slope. Our analysis of core-top data shows that SST estimates derived from most calibration equations closely align with modern observed temperatures but are skewed toward warmer months associated with upwelling-derived nutrients. Our findings underscore the importance of considering regional and seasonal biases to improve the accuracy of paleotemperature reconstructions. Understanding the factors influencing the SBB U37K signal enables a more meaningful comparison between regional paleoceanographic studies, improving our understanding of past changes in the SW Atlantic Ocean and our ability to predict regional SST response to ongoing and future warming.
{"title":"Validation of the U37K′ paleotemperature proxy in the South Brazilian Bight from core-top sediments","authors":"Felipe Stanchak ,&nbsp;Julie N. Richey ,&nbsp;Amanda Gerotto ,&nbsp;Amelia Shevenell ,&nbsp;Marcia C. Bícego ,&nbsp;Felipe A. Toledo ,&nbsp;Michel M. de Mahiques ,&nbsp;Renata H. Nagai","doi":"10.1016/j.orggeochem.2025.104928","DOIUrl":"10.1016/j.orggeochem.2025.104928","url":null,"abstract":"<div><div>The paleothermometer based on the alkenone unsaturation index (<span><math><msubsup><mtext>U</mtext><mrow><mtext>37</mtext></mrow><msup><mrow><mtext>K</mtext></mrow><mo>′</mo></msup></msubsup></math></span>) is often used to reconstruct past sea surface temperatures (SST). In the SW Atlantic Ocean, however, a limited understanding of the seasonal and depth distribution of coccolithophores, which generates the <span><math><msubsup><mtext>U</mtext><mrow><mtext>37</mtext></mrow><msup><mrow><mtext>K</mtext></mrow><mo>′</mo></msup></msubsup></math></span> signal preserved in ocean sediments, hinders accurate estimates of past regional SSTs. We analyzed 45 core-top sediment samples from the continental shelf of the South Brazilian Bight (SBB, 23 °S to 28 °S) to assess regional spatial <span><math><msubsup><mtext>U</mtext><mrow><mtext>37</mtext></mrow><msup><mrow><mtext>K</mtext></mrow><mo>′</mo></msup></msubsup></math></span>-SST gradients and improve SST estimates. The <span><math><msubsup><mtext>U</mtext><mrow><mtext>37</mtext></mrow><msup><mrow><mtext>K</mtext></mrow><mo>′</mo></msup></msubsup></math></span> data were converted to SST using six published paleotemperature equations and compared to modern observational SST data from the World Ocean Atlas (2018) data set. Data indicate that the <span><math><msubsup><mtext>U</mtext><mrow><mtext>37</mtext></mrow><msup><mrow><mtext>K</mtext></mrow><mo>′</mo></msup></msubsup></math></span> signal is produced during the austral summer and autumn when regional episodic upwelling events occur over the inner-shelf and the nutricline shoals at the slope. Our analysis of core-top data shows that SST estimates derived from most calibration equations closely align with modern observed temperatures but are skewed toward warmer months associated with upwelling-derived nutrients. Our findings underscore the importance of considering regional and seasonal biases to improve the accuracy of paleotemperature reconstructions. Understanding the factors influencing the SBB <span><math><msubsup><mtext>U</mtext><mrow><mtext>37</mtext></mrow><msup><mrow><mtext>K</mtext></mrow><mo>′</mo></msup></msubsup></math></span> signal enables a more meaningful comparison between regional paleoceanographic studies, improving our understanding of past changes in the SW Atlantic Ocean and our ability to predict regional SST response to ongoing and future warming.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"200 ","pages":"Article 104928"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Lacustrine records of Paleocene-Eocene Thermal Maximum (PETM) triggered by volcanic activity
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.orggeochem.2024.104899
Yuqi Wu , Tao Hu , Fujie Jiang , Jing Guo , Feilong Wang , Zhenguo Qi , Renda Huang , Zhou Fang , Xiaowei Zheng , Di Chen
The Paleocene-Eocene thermal maximum (PETM, ∼ 56 Ma) was driven by global carbon release and temperature increases. Studies of marine strata have indicated that volcanic activity during the PETM led to significant carbon emissions. However, the impact of volcanic activity on terrestrial strata and whether this activity was regional remain unclear. Here, we conducted astrochronological analysis, polycyclic aromatic hydrocarbons (PAHs) analysis, organic petrological identification, and paleo-environmental proxies to identify lacustrine records of PETM from the Miaoxi Depression in the Bohai Bay Basin, eastern China. The analysis of natural gamma-ray (GR) series indicates that PETM occurred at 56.06 Ma and lasted approximately 0.58 Ma within the formation. Significant GR series changes, carbon isotope excursions, and red bed sedimentation were observed during the PETM. Paleo-environmental proxy changes, including decreased paleo-productivity, arid paleo-climate, increased paleo-salinity that promoted strongly reducing conditions, and decreased lake level, were correlated with the GR series and δ13CVPDB excursions. The duration of the PETM event suggests that terrigenous sediments may record climate events in great detail. The PETM corresponds to a peak in 405 kyr eccentricity, but other changes in the astronomical cycle do not align with the paleo-environment data, indicating that astronomical forcing may not be the primary driver of the PETM. Increased PAHs and volcanic proxies suggest enhanced volcanic activity during this period, indicating that the PETM event was associated with regional volcanic activity.
{"title":"Lacustrine records of Paleocene-Eocene Thermal Maximum (PETM) triggered by volcanic activity","authors":"Yuqi Wu ,&nbsp;Tao Hu ,&nbsp;Fujie Jiang ,&nbsp;Jing Guo ,&nbsp;Feilong Wang ,&nbsp;Zhenguo Qi ,&nbsp;Renda Huang ,&nbsp;Zhou Fang ,&nbsp;Xiaowei Zheng ,&nbsp;Di Chen","doi":"10.1016/j.orggeochem.2024.104899","DOIUrl":"10.1016/j.orggeochem.2024.104899","url":null,"abstract":"<div><div>The Paleocene-Eocene thermal maximum (PETM, ∼ 56 Ma) was driven by global carbon release and temperature increases. Studies of marine strata have indicated that volcanic activity during the PETM led to significant carbon emissions. However, the impact of volcanic activity on terrestrial strata and whether this activity was regional remain unclear. Here, we conducted astrochronological analysis, polycyclic aromatic hydrocarbons (PAHs) analysis, organic petrological identification, and paleo-environmental proxies to identify lacustrine records of PETM from the Miaoxi Depression in the Bohai Bay Basin, eastern China. The analysis of natural gamma-ray (GR) series indicates that PETM occurred at 56.06 Ma and lasted approximately 0.58 Ma within the formation. Significant GR series changes, carbon isotope excursions, and red bed sedimentation were observed during the PETM. Paleo-environmental proxy changes, including decreased paleo-productivity, arid paleo-climate, increased paleo-salinity that promoted strongly reducing conditions, and decreased lake level, were correlated with the GR series and δ<sup>13</sup>C<sub>VPDB</sub> excursions. The duration of the PETM event suggests that terrigenous sediments may record climate events in great detail. The PETM corresponds to a peak in 405 kyr eccentricity, but other changes in the astronomical cycle do not align with the paleo-environment data, indicating that astronomical forcing may not be the primary driver of the PETM. Increased PAHs and volcanic proxies suggest enhanced volcanic activity during this period, indicating that the PETM event was associated with regional volcanic activity.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"200 ","pages":"Article 104899"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The giant barrel sponge Xestospongia muta takes up dissolved organic matter from benthic cyanobacterial mats
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.orggeochem.2024.104922
Lauren K. Olinger , Wendy K. Strangman , Steven E. McMurray , Ralph N. Mead , Joseph R. Pawlik
With the decline of reef-building corals, other organisms are taking over Caribbean reefs, including sponges and benthic cyanobacterial mats (BCM). Sponges take up dissolved organic matter (DOM), but the sources and chemical characteristics of DOM taken up by sponges are unknown. One likely DOM source is benthic autotrophs, including BCM, which are prolific producers of DOM. We tested the hypothesis that sponges take up BCM-derived DOM using laboratory experiments in which seawater samples were collected before and after sequential incubations of BCM and small individuals of the giant barrel sponge Xestospongia muta. The concentration of DOC and relative abundance of individual features in the high resolution mass spectra using untargeted metabolomics were determined for each sample. There was a significant increase in DOC after BCM incubations, followed by a significant decrease after sponge incubations. These changes were mirrored in single feature relative abundances, with 2101 out of 3667 features significantly enriched during BCM incubations, and 54% of these (1142) depleted during sponge incubations. Among BCM-enriched and sponge-depleted features, many were halogenated, some were known BCM-derived secondary metabolites (e.g., carriebowmide, barbamide), and others matched unidentified sponge-depleted features from seawater samples collected on the reef. To our knowledge, this is the first report that sponges take up BCM exudates, including some that were detectable in reef DOM, revealing a path of molecules from source to sink through their environment. The BCM exudates taken up by sponges may be used as a food source or incorporated into sponge secondary metabolites for holobiont maintenance or chemical defenses.
{"title":"The giant barrel sponge Xestospongia muta takes up dissolved organic matter from benthic cyanobacterial mats","authors":"Lauren K. Olinger ,&nbsp;Wendy K. Strangman ,&nbsp;Steven E. McMurray ,&nbsp;Ralph N. Mead ,&nbsp;Joseph R. Pawlik","doi":"10.1016/j.orggeochem.2024.104922","DOIUrl":"10.1016/j.orggeochem.2024.104922","url":null,"abstract":"<div><div>With the decline of reef-building corals, other organisms are taking over Caribbean reefs, including sponges and benthic cyanobacterial mats (BCM). Sponges take up dissolved organic matter (DOM), but the sources and chemical characteristics of DOM taken up by sponges are unknown. One likely DOM source is benthic autotrophs, including BCM, which are prolific producers of DOM. We tested the hypothesis that sponges take up BCM-derived DOM using laboratory experiments in which seawater samples were collected before and after sequential incubations of BCM and small individuals of the giant barrel sponge <em>Xestospongia muta</em>. The concentration of DOC and relative abundance of individual features in the high resolution mass spectra using untargeted metabolomics were determined for each sample. There was a significant increase in DOC after BCM incubations, followed by a significant decrease after sponge incubations. These changes were mirrored in single feature relative abundances, with 2101 out of 3667 features significantly enriched during BCM incubations, and 54% of these (1142) depleted during sponge incubations. Among BCM-enriched and sponge-depleted features, many were halogenated, some were known BCM-derived secondary metabolites (e.g., carriebowmide, barbamide), and others matched unidentified sponge-depleted features from seawater samples collected on the reef. To our knowledge, this is the first report that sponges take up BCM exudates, including some that were detectable in reef DOM, revealing a path of molecules from source to sink through their environment. The BCM exudates taken up by sponges may be used as a food source or incorporated into sponge secondary metabolites for holobiont maintenance or chemical defenses.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"200 ","pages":"Article 104922"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Nitrogen stable isotope patterns in free and protein-bound amino acids of the anoxygenic phototroph, Rhodopseudomonas palustris
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-27 DOI: 10.1016/j.orggeochem.2025.104945
Jenan Kharbush , Raisha Rahman , Ann Pearson , Alice Zhou
Compound-specific isotope analysis of amino acids (AAs) can reveal the sources and transformations of nitrogen in ecological and environmental studies. However, there is limited information on microbial patterns of 15N distributions in AAs and the intracellular biochemical processes that determine these patterns. This leads to gaps in understanding the underlying mechanisms that determine the 15N content of key N-containing biomarkers. Here we measured δ15N values of both free and protein-bound amino acids in metabolically flexible Rhodopseudomonas palustris grown photomixotrophically under anoxic conditions. Patterns of 15N distribution in protein-bound amino acids of R. palustris resemble aerobic phototrophs, implying these microbial groups may be indistinguishable in environmental samples. Intriguingly, free amino acids consistently are ca. 5 ‰ enriched in 15N relative to protein-bound amino acids; this pattern may provide a new window to understanding intracellular fractionating processes during metabolite recycling and protein synthesis.
{"title":"Nitrogen stable isotope patterns in free and protein-bound amino acids of the anoxygenic phototroph, Rhodopseudomonas palustris","authors":"Jenan Kharbush ,&nbsp;Raisha Rahman ,&nbsp;Ann Pearson ,&nbsp;Alice Zhou","doi":"10.1016/j.orggeochem.2025.104945","DOIUrl":"10.1016/j.orggeochem.2025.104945","url":null,"abstract":"<div><div>Compound-specific isotope analysis of amino acids (AAs) can reveal the sources and transformations of nitrogen in ecological and environmental studies. However, there is limited information on microbial patterns of <sup>15</sup>N distributions in AAs and the intracellular biochemical processes that determine these patterns. This leads to gaps in understanding the underlying mechanisms that determine the <sup>15</sup>N content of key N-containing biomarkers. Here we measured δ<sup>15</sup>N values of both free and protein-bound amino acids in metabolically flexible <em>Rhodopseudomonas palustris</em> grown photomixotrophically under anoxic conditions. Patterns of <sup>15</sup>N distribution in protein-bound amino acids of <em>R. palustris</em> resemble aerobic phototrophs, implying these microbial groups may be indistinguishable in environmental samples. Intriguingly, free amino acids consistently are <em>ca.</em> 5 ‰ enriched in <sup>15</sup>N relative to protein-bound amino acids; this pattern may provide a new window to understanding intracellular fractionating processes during metabolite recycling and protein synthesis.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104945"},"PeriodicalIF":2.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The temporal distributions of seed-plant terpanes in petroleum samples: Implications as oil age-diagnostic biomarkers for crude oils
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-22 DOI: 10.1016/j.orggeochem.2025.104943
Chun Zhu , Clifford C. Walters , J. Alex Zumberge , Marlene Madincea
Gymnosperm and angiosperm are sister clades of seed-plants thriving on land since the Carboniferous and Cretaceous, respectively. Both biosynthesize specific terpenoids whose diagenetic hydrocarbon skeletons are preserved in geological samples as molecular fossils of seed-plants. Although the radiation of seed-plants has been well established, the temporal distributions of their biomarkers in geological samples remain poorly characterized. We defined angiosperm and gymnosperm ratios to quantify the relative abundances of seed-plant terpanes and examined the relationship between these ratios and geological age via well-studied, world-wide, petroleum samples deposited in various environments. Although angiosperm ratios show broad ranges in the Cretaceous – Tertiary samples, the Epoch-maxima increase from Early Cretaceous to Paleocene, and from Paleocene to Eocene-Miocene. Gymnosperm ratios remain low pre-Jurassic; however, the Period-maxima significantly increase from pre-Jurassic to Jurassic, and further increase from Jurassic to Cretaceous-Tertiary. These patterns are consistent with seed-plant evolution. We propose three age indicators: 1) O/(O + 29Ts) − an oleanane-based angiosperm ratio to distinguish age of Early Cretaceous or younger vs. Paleocene or younger vs. Eocene or younger; 2) Retene/(Retene + DBT) − a retene-based gymnosperm ratio to differentiate Jurassic or younger vs. Cretaceous or younger; and 3) under marine influence (DBT/P > 0.05), enrichment of retene [Retene/(Retene + DBT) > 0.3] and absence of oleanane [O/(O + 29Ts) < 0.04] indicative of Jurassic – Early Cretaceous. The three new age indicators improve age resolution of published age biomarkers from Era to Period level for oil age differentiation, a critical factor in de-risking petroleum systems.
{"title":"The temporal distributions of seed-plant terpanes in petroleum samples: Implications as oil age-diagnostic biomarkers for crude oils","authors":"Chun Zhu ,&nbsp;Clifford C. Walters ,&nbsp;J. Alex Zumberge ,&nbsp;Marlene Madincea","doi":"10.1016/j.orggeochem.2025.104943","DOIUrl":"10.1016/j.orggeochem.2025.104943","url":null,"abstract":"<div><div>Gymnosperm and angiosperm are sister clades of seed-plants thriving on land since the Carboniferous and Cretaceous, respectively. Both biosynthesize specific terpenoids whose diagenetic hydrocarbon skeletons are preserved in geological samples as molecular fossils of seed-plants. Although the radiation of seed-plants has been well established, the temporal distributions of their biomarkers in geological samples remain poorly characterized. We defined angiosperm and gymnosperm ratios to quantify the relative abundances of seed-plant terpanes and examined the relationship between these ratios and geological age via well-studied, world-wide, petroleum samples deposited in various environments. Although angiosperm ratios show broad ranges in the Cretaceous – Tertiary samples, the Epoch-maxima increase from Early Cretaceous to Paleocene, and from Paleocene to Eocene-Miocene. Gymnosperm ratios remain low pre-Jurassic; however, the Period-maxima significantly increase from pre-Jurassic to Jurassic, and further increase from Jurassic to Cretaceous-Tertiary. These patterns are consistent with seed-plant evolution. We propose three age indicators: 1) O/(O + 29Ts) − an oleanane-based angiosperm ratio to distinguish age of Early Cretaceous or younger vs. Paleocene or younger vs. Eocene or younger; 2) Retene/(Retene + DBT) − a retene-based gymnosperm ratio to differentiate Jurassic or younger vs. Cretaceous or younger; and 3) under marine influence (DBT/P &gt; 0.05), enrichment of retene [Retene/(Retene + DBT) &gt; 0.3] and absence of oleanane [O/(O + 29Ts) &lt; 0.04] indicative of Jurassic – Early Cretaceous. The three new age indicators improve age resolution of published age biomarkers from Era to Period level for oil age differentiation, a critical factor in de-risking petroleum systems.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104943"},"PeriodicalIF":2.6,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Geochemistry Articles – November 2024
IF 2.6 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-17 DOI: 10.1016/j.orggeochem.2025.104930
{"title":"Geochemistry Articles – November 2024","authors":"","doi":"10.1016/j.orggeochem.2025.104930","DOIUrl":"10.1016/j.orggeochem.2025.104930","url":null,"abstract":"","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"201 ","pages":"Article 104930"},"PeriodicalIF":2.6,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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Organic Geochemistry
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