Journal of Geophysical Research: Biogeosciences最新文献_第2页

Nitrogen Source Preferences and Ecological Implications of Phytoplankton Primary Production in the Yellow Sea, South Sea of Korea, and East/Japan Sea, 2018

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-14 DOI: 10.1029/2024JG008061

Hyo Keun Jang, Jae Joong Kang, Dabin Lee, Kwanwoo Kim, Myung Joon Kim, Sanghoon Park, Yejin Kim, Jaesoon Kim, Huitae Joo, Seok-Hyun Youn, Sang Heon Lee

{"title":"Nitrogen Source Preferences and Ecological Implications of Phytoplankton Primary Production in the Yellow Sea, South Sea of Korea, and East/Japan Sea, 2018","authors":"Hyo Keun Jang, Jae Joong Kang, Dabin Lee, Kwanwoo Kim, Myung Joon Kim, Sanghoon Park, Yejin Kim, Jaesoon Kim, Huitae Joo, Seok-Hyun Youn, Sang Heon Lee","doi":"10.1029/2024JG008061","DOIUrl":"https://doi.org/10.1029/2024JG008061","url":null,"abstract":"Understanding the partitioning of primary production into new and regenerated productions, based on nitrate or ammonium utilization, is crucial to understanding biogeochemical processes and marine ecosystems. This study addresses the scarcity of information on new and regenerated productions in the Yellow Sea (YS), South Sea (SS), and East/Japan Sea (EJS). Employing the 13C–15N tracer method, we quantified carbon and nitrogen uptake rates of phytoplankton across four seasons in 2018. Seasonal nitrate and ammonium uptake rates exhibited distinct ranges in the YS (0.2–6.1 and 0.4–22.3 mg N m−2 hr−1), SS (1.0–15.6 and 4.5–15.4 mg N m−2 hr−1), and EJS (1.5–7.3 and 4.5–15.4 mg N m−2 hr−1). Notably, nitrate uptake rates in the YS (except spring), SS, and EJS were generally lower than ammonium uptake rates, attributed to the dominance of pico-sized (<2 μm) phytoplankton with a high affinity for ammonium. Carbon uptake rates in all seas displayed significant positive correlations with nitrate uptakes rather than ammonium uptakes, suggesting that the prevailing ammonium assimilations by dominant pico-sized phytoplankton contributed to the lower primary productions in 2018. Estimated annual new productions (30, 24, and 43 g C m−2 y−1) in the YS, SS, and EJS fall within the reported ranges for other regions. However, the EJS exhibited lower productions than previous reports (146 g C m−2 y−1), potentially impacting fishery yields and export production to the deep ocean in 2018. These findings, in the context of rapid environmental changes, provide crucial baseline information for monitoring future marine ecosystems in Korean seas.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143404499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Extensive Oxygen Consumption in the Intertidal Infiltration Zone of Beach Aquifers—The Impact of Seasonal Input, Filtration Efficiency, and Morphodynamics 海滩蓄水层潮间带渗透区的大量耗氧--季节性输入、过滤效率和形态动力学的影响

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-13 DOI: 10.1029/2024JG008291

F. Auer, S. Ahmerkamp, J. Cueto, C. Winter, M. Holtappels

{"title":"Extensive Oxygen Consumption in the Intertidal Infiltration Zone of Beach Aquifers—The Impact of Seasonal Input, Filtration Efficiency, and Morphodynamics","authors":"F. Auer, S. Ahmerkamp, J. Cueto, C. Winter, M. Holtappels","doi":"10.1029/2024JG008291","DOIUrl":"https://doi.org/10.1029/2024JG008291","url":null,"abstract":"Seawater infiltration into the permeable sands of beach aquifers creates a high input of biogeochemical reactants driven by tides and waves. The upper sand layer acts as a filter, retaining particulate organic matter (POM), which is degraded by bacteria under predominantly oxic conditions. The seasonal variation of seawater POM and oxygen (O2) entering the infiltration zone, combined with the POM filtration efficiency of the highly morphodynamic upper layer, determines the organic matter turnover and subsequent redox gradients along porewater flowpaths. We investigated these effects by quantifying the seasonal O2 consumption rates directly from the incubations of sediments taken along a transect in the seawater infiltration zone at Spiekeroog Beach, Germany. We carried out a two-monthly year-long sampling campaign with high spatial resolution measurements down to 1 m depth. In summer, O2 consumption rates of up to 106 μM hr−1 were found in the first decimeters with a significant decline over depth, indicating efficient retention of reactive POM in the surface layer. Seasonal variation in organic carbon of the sand's suspendable particulates indicates rapid turnover and little storage. In winter, rates decreased significantly to below 11 μM hr−1. Integrated over the investigated oxic layer, the estimated carbon mineralization varies between 15 (winter) and 143 (summer) mmol C m−2 d−1 with a yearly average of 73 mmol C m−2 d−1. The yearly CO2 production of 35 kg per meter shoreline characterizes the beach as a high-throughout system with rapid OM remineralization in the retention layer, especially in summer, but with little OM storage.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008291","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

PDO Dynamics Shape the Fire Regime of Boreal Subarctic Landscapes in the Northwest Territories, Canada

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-13 DOI: 10.1029/2024JG008178

Nina Ryzhkova, Hugo Asselin, Adam A. Ali, Alexander Kryshen, Yves Bergeron, Daniela Robles, Sara Pineda-Zapata, Igor Drobyshev

{"title":"PDO Dynamics Shape the Fire Regime of Boreal Subarctic Landscapes in the Northwest Territories, Canada","authors":"Nina Ryzhkova, Hugo Asselin, Adam A. Ali, Alexander Kryshen, Yves Bergeron, Daniela Robles, Sara Pineda-Zapata, Igor Drobyshev","doi":"10.1029/2024JG008178","DOIUrl":"https://doi.org/10.1029/2024JG008178","url":null,"abstract":"Spatially explicit reconstructions of fire activity in northwestern boreal Canada are rare, despite their importance for modeling current and future disturbance regimes and forest dynamics. We provide a dendrochronological reconstruction of historical fire activity along Highway 3 in the Northwest Territories (NWT), Canada, within the boreal subarctic zone. We dated 129 fires that occurred between 1202 and 2015 CE, using samples from 479 fire-scarred living and dead jack pine trees (Pinus banksiana Lamb.). Three distinct periods can be distinguished in terms of historical fire cycle (FC) and fire occurrence. Initially (1340–1440 CE), fire activity was low (FC = 572 years; 1 fire/decade), before increasing notably between 1460 and 1840 (FC = 171 years; 4.45 fires/decade), and even more in recent times (1860–2015 CE; FC = 95 years; 7.63 fires/decade). Climate has been an important factor controlling changes in fire frequency and FC in the NWT since the 1300s. The 1440s and 1850s correspond with periods of increased fire activity synchronized with shifts from negative to positive Pacific Decadal Oscillation (PDO) phases. Since the mid-1800s, human activities may have contributed to the increase in fire activity, but climate remained the leading factor. During the 20th century, years with increased area burned corresponded to periods with drier-than-average conditions associated with positive PDO, suggesting fire activity in the study region is still influenced by climate. Spatial teleconnection patterns among PDO, drought, and large fire years (LFYs) in the NWT reveal persistent relationships between ocean-atmosphere circulation patterns and fire activity. PDO dynamics hold strong potential for predicting regional fire hazards across northwestern North America.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008178","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Measuring Gas Transfer Velocity in a Steep Tropical Stream: Method Evaluation and Implications for Upscaling 测量热带陡流中的气体传输速度：方法评估及对升尺度的影响

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-13 DOI: 10.1029/2024JG008420

Adam T. Rexroade, Marcus B. Wallin, Clément Duvert

{"title":"Measuring Gas Transfer Velocity in a Steep Tropical Stream: Method Evaluation and Implications for Upscaling","authors":"Adam T. Rexroade, Marcus B. Wallin, Clément Duvert","doi":"10.1029/2024JG008420","DOIUrl":"https://doi.org/10.1029/2024JG008420","url":null,"abstract":"Greenhouse gas emission estimates from streams rely, in part, on accurate measurements or estimates of the gas transfer velocity, which describes the physical efficiency for gas exchange across the water-air interface. Numerous methods for measuring or modeling gas transfer velocity exist, yet few studies compare these different methods. Additionally, current models of gas transfer velocity in streams are predominantly derived from measurements in low-gradient, temperate, or boreal streams. Here, we measured gas transfer velocity using four different methods in a high-energy, tropical headwater stream under a range of flow conditions, and compared these measurements to indirect estimates from four empirical models. Our results show that, when compared to the use of a biologically inert gas tracer (propane), floating chambers produced lower gas transfer velocity values. Using carbon dioxide (CO2) as a tracer gas was unreliable without considering other natural sources and sinks of CO2 and yielded gas transfer velocities lower than when using propane. Existing empirical models tended to underestimate gas transfer velocity, compared to the inert tracer gas. When using empirical models to upscale the emission flux along an entire stream reach, choice of model was more influential than the spatial resolution of model implementation. We also highlight the extreme spatial variability of gas transfer velocity across small spatial scales, which contrasts with its relative stability across changing hydrological conditions. The discrepancies between methods highlight the need for further research in measuring and upscaling gas transfer velocity, particularly in very turbulent steep streams.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008420","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Variability and Controls of pCO2 and Air-Water CO2 Fluxes in a Temperate River

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-12 DOI: 10.1029/2024JG008434

Fischer L. Young, Benjamin P. Colman, Alice M. Carter, Rafael Fiejó de Lima, Qipei Shangguan, Robert A. Payn, Michael D. DeGrandpre

{"title":"Variability and Controls of pCO2 and Air-Water CO2 Fluxes in a Temperate River","authors":"Fischer L. Young, Benjamin P. Colman, Alice M. Carter, Rafael Fiejó de Lima, Qipei Shangguan, Robert A. Payn, Michael D. DeGrandpre","doi":"10.1029/2024JG008434","DOIUrl":"https://doi.org/10.1029/2024JG008434","url":null,"abstract":"Measurements of riverine dissolved inorganic carbon, total alkalinity (AT), pH, and the partial pressure of carbon dioxide (pCO2) can provide insights into the biogeochemical function of rivers, including the processes that control biological production, chemical speciation, and air-water CO2 fluxes. The complexity created by these combined processes dictates that studies of inorganic carbon be made over broad spatial and temporal scales. Time-series data like these are relatively rare, however, because sampling and measurements are labor intensive and, for some variables, good measurement quality is difficult to achieve (e.g., pH). In this study, spectrophotometric pH and AT were quantified with high precision and accuracy at biweekly to monthly intervals over a four-year period (2018–2021) along 216 km of the Upper Clark Fork River (UCFR) in the northern Rocky Mountains, USA. We use these and other time-series data to provide insights into the processes that control river inorganic carbon, with a focus on pCO2 and air-water CO2 fluxes. We found that seasonal snowmelt runoff increased pCO2 and that expected increase and decrease of pCO2 due to seasonal heating and cooling were likely offset by an increase and loss of algal biomass, respectively. Overall, the UCFR was a small net source (0.08 ± 0.14 mol m−2 d−1) of CO2 to the atmosphere over the four-year study period with highly variable annual averages (0.0–0.10 mol m−2 d−1). The seasonally correlated, offsetting mechanisms highlight the challenges in predicting pCO2 and air-water CO2 fluxes in rivers.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008434","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143389223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Blue Carbon Mapping Using Temporally Optimized Satellite Remote Sensing Imagery: A Regional Study of Northeast US Salt Marshes

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-11 DOI: 10.1029/2024JG008254

Wenxiu Teng, Qian Yu, Brian Yellen, Bonnie Turek, Jonathan D. Woodruff

{"title":"Blue Carbon Mapping Using Temporally Optimized Satellite Remote Sensing Imagery: A Regional Study of Northeast US Salt Marshes","authors":"Wenxiu Teng, Qian Yu, Brian Yellen, Bonnie Turek, Jonathan D. Woodruff","doi":"10.1029/2024JG008254","DOIUrl":"https://doi.org/10.1029/2024JG008254","url":null,"abstract":"Coastal wetlands store three to five times more carbon per unit area than tropical rainforests in continually accreting peat soils, collectively referred to as “Blue Carbon.” However, variability in soil carbon density within and between sites leads to large uncertainty when estimating carbon stocks and sequestration rates. Salt marsh carbon sequestration is mainly driven by nonlinear ecogeomorphic feedback between tidal inundation, bioproductivity, and sediment supply—all of which can be observed by satellites. In this study, we used soil bulk density and soil organic content from 410 soil samples collected across 15 sites in the Northeast US to relate soil properties to remotely sensed spectral observations. We tested model fits using Landsat 5, 7, 8, and Sentinel 2 images from 1984 to 2022 to determine the optimal season and tidal conditions for relating remote sensing indices to soil properties. We explored the roles of sediment supply and tidal range in regional prediction models. The study found that (a) spatial patterns of remote sensing indices correlate well with soil properties; (b) at the marsh scale, remote sensing indices capture the spatial variability of soil properties with image acquired at high tide and vegetation phenology specific to geomorphic setting; (c) at the regional scale, tidal range improves the prediction model in barrier marshes, while sediment supply improves the prediction model in fluvial marshes. The considerable spatial variation of SOC within marshes and across regional gradients highlights the need for high resolution maps of salt marsh soil properties.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143389039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Diverse Altitudinal Patterns and Drivers of Greenhouse Gas Dynamics in Southwest China Alpine Streams and Rivers

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-11 DOI: 10.1029/2024JG008458

Ying Wang, Yuhao Li, Genxu Wang, Yang Li, Xiangyang Sun, Wenzhi Wang, Chunlin Song

{"title":"Diverse Altitudinal Patterns and Drivers of Greenhouse Gas Dynamics in Southwest China Alpine Streams and Rivers","authors":"Ying Wang, Yuhao Li, Genxu Wang, Yang Li, Xiangyang Sun, Wenzhi Wang, Chunlin Song","doi":"10.1029/2024JG008458","DOIUrl":"https://doi.org/10.1029/2024JG008458","url":null,"abstract":"Streams and rivers are globally significant sources of greenhouse gases (GHGs) to the atmosphere. However, GHG evasion from mountain streams remains poorly constrained due to scarce data. In this study, we measured concentrations and estimated fluxes of riverine carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) across three alpine catchments in Southwest China. GHG concentrations in these turbulent streams and rivers are slightly oversaturated but much lower than the global average, likely due to high gas transfer velocities that rapidly deplete GHGs. Headwater streams (first-order) exhibited higher gas evasion rates than large rivers (fourth-order), despite having lower CO2 and N2O concentrations. The partial pressure of CO2 and dissolved N2O concentrations decreased linearly with elevation, likely linked to the altitudinal patterns of forest cover and groundwater table depth. Dissolved CH4 concentrations and the three GHGs fluxes showed weak relationships with elevation. We observed significant seasonal differences in GHG fluxes, with higher evasion rates during the wet season. The seasonal and spatial heterogeneity in stream GHG concentrations and fluxes was primarily controlled by hydrology, climate, and geomorphology. Our analyses also revealed that GHG fluxes were positively correlated with stream water temperature, velocity, and channel slope. This study demonstrates that these alpine streams are underestimated net sources of GHGs, particularly CO2 and N2O, highlighting the importance of mountain headwater systems in regional and global GHG budgets. The diverse altitudinal patterns of GHG dynamics also suggest complex controls of GHG in alpine streams and rivers.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Elevated Atmospheric Sulfur Deposition Affects Predominant Forms of Sulfur in Ombrotrophic Peatlands

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-09 DOI: 10.1029/2024JG008563

Hongyan Wang, Zhi-Guo Yu, Tanja Broder, Jörg Göttlicher, Ralph Steininger, Sindy Wagner, Harald Biester, Klaus-Holger Knorr

{"title":"Elevated Atmospheric Sulfur Deposition Affects Predominant Forms of Sulfur in Ombrotrophic Peatlands","authors":"Hongyan Wang, Zhi-Guo Yu, Tanja Broder, Jörg Göttlicher, Ralph Steininger, Sindy Wagner, Harald Biester, Klaus-Holger Knorr","doi":"10.1029/2024JG008563","DOIUrl":"https://doi.org/10.1029/2024JG008563","url":null,"abstract":"Long-term transformations of sulfur from atmospheric deposition in ombrotrophic peatlands have rarely been studied, although the potential impact on carbon mineralization and particularly methane formation is acknowledged. To elucidate the long-term fate of sulfur in peat, we therefore applied sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy to investigate peatlands with either natural or anthropogenic atmospheric sulfur deposition. A peatland in central Europe (Germany, BBM) experienced high sulfur deposition during the Industrial Revolution, and an oceanic peatland (Chilean Patagonia, PBr) continuously exposed to aerosols from sea spray, were investigated. During early phases of site BBM, when sulfur deposition was constantly low, wet-chemical extractions indicated that 98% ± 0.7% of sulfur was present as organic sulfur. The S K-edge XANES fitting suggested that sulfur redox transformations mainly occurred near the water table, at which reduced sulfur forms (primarily organic sulfides, and thiols) increased from ∼40% to and stabilized at 65% ± 4% in anoxic peat. An increased contribution of reduced sulfur forms was observed in the polluted section of BBM and entire peat profile of PBr. While increases in reduced inorganic sulfur (TRIS) likely depended on available Fe, rises in the ratio of reduced organic sulfur to total organic sulfur from both sites were pronounced. This increase in reduced organic sulfur forms likely resulted from abiotic sulphurization of organic carbon after sulfate reduction. Our study highlights the long-term fate of elevated sulfur in ombrotrophic peatlands, being mainly transformed into reduced organic sulfur.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of Diagenesis on Biogenic Silica- Structural, Chemical, and Isotope Proxies

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-06 DOI: 10.1029/2024JG008160

Franziska M. Stamm, Rebecca A. Pickering, Patrick J. Frings, Daniel A. Frick, Sylvain Richoz, Daniel J. Conley

{"title":"Impact of Diagenesis on Biogenic Silica- Structural, Chemical, and Isotope Proxies","authors":"Franziska M. Stamm, Rebecca A. Pickering, Patrick J. Frings, Daniel A. Frick, Sylvain Richoz, Daniel J. Conley","doi":"10.1029/2024JG008160","DOIUrl":"https://doi.org/10.1029/2024JG008160","url":null,"abstract":"The silicon isotope composition (δ30Si) of biogenic silica is often used as an archive of past environmental conditions. For example, sponge spicule δ30Si is known to be related to seawater-dissolved Si concentrations. Such a proxy application requires that the δ30Si is not diagenetically altered—or at least that any alteration can be identified and accounted for. Yet the preservation of pristine isotope signals during (early) diagenesis is challenged by observations of structural changes to the amorphous silica (opal-A) of biogenic silica toward a more stable amorphous silica phase (opal-CT). This transformation is known to be associated with a resetting of oxygen isotope (δ18O) values but with unclear implications for the preservation of other geochemical signatures. This was investigated using modern and Cretaceous siliceous sponge spicules. Modern spicules collected from different ocean basins were uniformly transparent opal-A, whereas Cretaceous spicules exhibited two preservation states: visually similar to modern or clearly altered toward a milky, translucent composition. A comparison of δ30Si and δ18O values of spicules from both categories within single samples reveals the milky, translucent individuals are offset from the transparent individuals and thus presumably unsuitable for palaeoenvironmental applications. A suite of geochemical and structural analyses (XRD, Raman spectroscopy, and FT-IR spectroscopy) demonstrate that even visually clear Cretaceous spicules are subtly different from their modern counterparts, implying caution is required when interpreting δ30Si values or other geochemical proxies in ancient biogenic silica.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008160","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143186378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Deciphering Microbially Driven Labile and Refractory Molecular Candidates in Dissolved Organic Matter

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-02-06 DOI: 10.1029/2024JG008484

Qi Chen, Jiaxin Chen, Ruanhong Cai, Chen He, Quan Shi, Chuanlun Zhang, Nianzhi Jiao, Qiang Zheng

{"title":"Deciphering Microbially Driven Labile and Refractory Molecular Candidates in Dissolved Organic Matter","authors":"Qi Chen, Jiaxin Chen, Ruanhong Cai, Chen He, Quan Shi, Chuanlun Zhang, Nianzhi Jiao, Qiang Zheng","doi":"10.1029/2024JG008484","DOIUrl":"https://doi.org/10.1029/2024JG008484","url":null,"abstract":"Microbial activities drive the cycling of dissolved organic matter (DOM) from labile to refractory states, thus contributing to the long-term carbon sequestration in the ocean. However, due to the intricate molecular composition of DOM, identifying indicators of microbially related DOM remains a challenge. In this study, we propose molecular candidates for bio-labile (n = 537) and bio-refractory (n = 1,025) formulas, which were discerned through incubation experiments using ultrahigh-resolution mass spectrometry. Bio-labile formulas exhibited greater hydrogenation, whereas bio-refractory formulas comprised oxidized, unsaturated and aromatic molecules with higher molecular weight. Bio-candidates, in contrast to photo- or terrestrial-related counterparts, dominated molecular composition by higher relative intensity. The application of these molecular candidates facilitated the tracing of molecular distribution and transformation patterns across large-scale aquatic environmental gradients. This molecular identification framework offers insights into resolving microbially mediated molecules and advancing our understanding of biologically related DOM at the molecular level.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143186377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0