Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Elevated Spring Methane Emissions in a Sub-Arctic Peatland Fen","authors":"Marco N. Montemayor,&nbsp;Kyle A. Arndt,&nbsp;Patrick Murphy,&nbsp;Mario Tenuta,&nbsp;Susan M. Natali","doi":"10.1029/2026JG009699","DOIUrl":"https://doi.org/10.1029/2026JG009699","url":null,"abstract":"<p>The Arctic boreal region is rapidly shifting in response to global climate change, including rapid warming and permafrost thaw. Year-round monitoring of carbon fluxes in these regions is crucial to understanding seasonal and annual carbon budgets, including methane (CH₄), a potent greenhouse gas with 80 times the warming potential of carbon dioxide over a 20-year timeframe. Here we investigate the seasonal patterns and controls of CH₄ fluxes from a subarctic peatland fen in Churchill, MB, Canada using eddy covariance CH₄ flux data from 2008 to 2011 and more recent data from 2022 to 2023 in the same location. Recent data showed that surface soil temperature beneath a hollow water pool was the best predictor of CH₄ emissions with an <i>r</i>² of 0.79. There was a negative hysteretic trend in the relationship between CH₄ and soil temperature, characterized by a sustained spring methane pulse and tapering off CH₄ emissions in the fall, which is uncommon in both Arctic and wetland ecosystems. The spring pulse caused a 9.8% higher budget than would be expected based on the temperature relationship alone. The total annual CH₄ budget was 61% or 3.1 g CH₄-C m⁻² y⁻¹ higher in 2023 (8.3 ± 1.0 g CH₄-C m⁻² y⁻¹) compared to the average 2008–2011 annual estimate (5.2 ± 0.6 g CH₄-C m⁻² y⁻¹).</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG009699","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617002","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}

{"title":"Impact of Fluid Flow on Bacterial Carbon and Sulfur Cycling, Mineral Precipitation, and Transformation in Hydrothermal Sediments off the Coast of Milos","authors":"J. M. Maak,&nbsp;C. Röttgen,&nbsp;B. Winkelhues,&nbsp;E. Anagnostou,&nbsp;S. I. Bühring,&nbsp;A. Koschinsky,&nbsp;J. Liao,&nbsp;H. Strauss,&nbsp;C. Vogt,&nbsp;W. Bach,&nbsp;E. Schefuß,&nbsp;M. Elvert","doi":"10.1029/2026JG009869","DOIUrl":"https://doi.org/10.1029/2026JG009869","url":null,"abstract":"<p>Hydrothermal fluid flow not only shapes mineral deposition on the ocean floor but also creates ecological niches by altering temperature and energy availability. In these niches, microbial life thrives and has an additional, often unrecognized impact on mineral formation. In a newly discovered vent field at water depths of 100–200 m off Milos, Greece, we show how contrasting hydrothermal regimes host fundamentally different bacterial metabolism that, in turn, can impact mineralogy. Diffusive flow leads to a gradient in acidity and redox and allows sulfate-rich seawater to penetrate the sediment. Under these conditions, acetyl-CoA-based sulfate reduction is the main metabolism, resulting in fatty acid δ¹³C values down to −39‰. Sediment mineralogy is altered by kaolinization and pyrite formation, which is similarly controlled by microbial activity (δ³⁴S values of pyrite: −12‰). In contrast, vigorous venting delivers hot, acidic, carbon-rich, and sulfate-depleted fluids that likely sustain the activity of sulfide oxidizers producing fatty acids with δ¹³C values of up to −4‰. Here, the interaction of seawater with the emitting fluids leads to the precipitation of elemental sulfur, as evidenced by δ³⁴S values of +4‰. In the core lacking hydrothermal influence, little microbial activity and only quartz-rich sediments are present. Combined multivariate lipid analyses highlight Eh as the strongest environmental control, with increasing average chain length of fatty acids as an adaptation to (hydro-)thermal stress. These results illustrate how different types of fluid flow influence the activity of chemoautotrophic bacterial communities involved in the formation of characteristic sulfur minerals in hydrothermal environments.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG009869","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616138","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}

{"title":"Heat and Wildfires During the K-Pg Mass Extinction Enhanced by Fine Dust","authors":"Brandon C. Johnson,&nbsp;Alexandria V. Johnson,&nbsp;Shigeru Wakita,&nbsp;Douglas S. Robertson","doi":"10.1029/2026JG009837","DOIUrl":"https://doi.org/10.1029/2026JG009837","url":null,"abstract":"<p>The primary kill mechanisms responsible for the K-Pg mass extinction, including the end of the dinosaurs, are much debated. Here, we reexamine the hypothesis that heat and fire were the primary kill mechanisms for terrestrial organisms during the K-Pg mass extinction. We show that spherules and uncondensed vapor from the impact vapor plume are first ballistically transported globally and then decoupled spatially from one another when they encounter the atmosphere. Expanded K-Pg boundary sections provide strong evidence that this impact vapor ultimately condenses to abundant fine dust. The flux of thermal energy produced by impact spherules entering the atmosphere globally is strongly enhanced by the presence of this fine dust. This supports the idea that heat and fire were key kill mechanisms for terrestrial organisms.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG009837","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616139","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}

{"title":"The Evidence for Linearly Scaling Ocean Gas Exchange With Sea Ice Needs Strengthening","authors":"Jennifer Watts,&nbsp;Thomas G. Bell,&nbsp;Karen Anderson,&nbsp;John Prytherch,&nbsp;Brian J. Butterworth,&nbsp;Brent Else,&nbsp;Scott Miller,&nbsp;Thomas Holding,&nbsp;Jamie D. Shutler","doi":"10.1029/2025JG009346","DOIUrl":"https://doi.org/10.1029/2025JG009346","url":null,"abstract":"<p>Polar oceans are critical components of the oceanic uptake of atmospheric carbon dioxide. Estimates of this uptake across the air-sea interface require parameterizations of gas transfer velocity that account for variable sea ice concentrations. Previous studies, using eddy covariance measurements of gas exchange, have concluded that linear scaling of carbon dioxide gas transfer with sea ice concentration is appropriate. The influence of sea ice concentration data resolution and associated uncertainties in these analyses has not been fully examined. Here we re-assess published in situ air-sea gas exchange data from the Arctic and Southern Oceans using a selection of sea ice concentration data sets. In the Southern Ocean, the linear scaling assumption holds irrespective of spatial resolution. In the Arctic Ocean, deviation from the linear case occurs at ice concentrations as low as 50%. Greater deviations become apparent in both polar oceans when sea ice concentration data uncertainties are considered. In the Southern Ocean, results using satellite data sets remain consistent with linear scaling, while ship-based observations indicate greater suppression of uptake within the marginal ice zone. The Arctic response, after including uncertainties, indicates that gas exchange could be suppressed in regions with ice concentrations of 50% or higher. The contrast between the Arctic and Southern Ocean data sets potentially reflects differences in sea ice variability and environmental conditions during the observation periods, with the Arctic data capturing a transitional regime. Linear scaling may therefore serve as a first-order approximation, but intermediate to high ice concentrations, particularly in the Arctic, require further investigation.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009346","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616067","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}

{"title":"Under-Ice Phytoplankton Bloom and Associated Particulate Organic Matter Composition Dynamics in Prydz Bay, Antarctica","authors":"Archana Singh,&nbsp;Ravidas Krishna Naik,&nbsp;Pratiksha Deshmukh,&nbsp;Nandini Raj,&nbsp;Ashok Jagtap,&nbsp;Melena A. Soares,&nbsp;Manish Tiwari,&nbsp;Prema Piyusha Panda,&nbsp;Ajay Bhadran,&nbsp;Rahul Mohan,&nbsp;Jenson George","doi":"10.1029/2026JG009706","DOIUrl":"https://doi.org/10.1029/2026JG009706","url":null,"abstract":"<p>Under-ice phytoplankton blooms (UIBs) are important contributors to polar primary production; however, their organic matter dynamics remain poorly constrained, particularly in Antarctic landfast ice regions with limited field observations. We analyzed particulate organic matter (POM) composition at three different depths (surface, 50, and 140 m) along with high-resolution nutrient and chlorophyll-<i>a</i> (chl-<i>a</i>) profiling during a 38-day time-series to investigate a phytoplankton bloom under landfast ice in Prydz Bay, East Antarctica during the austral spring–summer transition. Surface (0–1 m below the ice–water interface) chl-<i>a</i> concentrations increased steadily from 0.3 to 14.4 μg L⁻¹ along with other biochemical components like particulate organic carbon, particulate nitrogen, isotopic ratios (δ¹³C and δ¹⁵N), particulate proteins (P-PRT), carbohydrates (P-CHO), and lipids (P-LIP), marking the onset and progression of an under-ice bloom (UIB) under favorable snow and ice melting, a stratified surface layer, and rapid nutrient decline. Although P-PRT dominated the surface POM throughout, the biochemical ratios (PRT/CHO, PRT/LIP, and CHO/LIP) showed a marked shift at mid-period (Day 17), indicating a relative enrichment of carbohydrates and lipids, with a concurrent shift in the monosaccharide composition. This transition suggested a combination of community shift, physiological adaptations and remineralization processes sustaining the UIB in the later-phase nutrient-depleted conditions, while Day 17 also reflected enhanced detrital inputs to the surface waters. The findings reveal strong, environment driven shifts in both the magnitude and biochemical quality of POM during the UIB, improving our understanding of biogeochemical processes and its implications for food-web dynamics and pelagic–benthic coupling in Antarctic landfast ice systems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616088","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}

{"title":"C and N Isotopic Fractionation Along Permafrost Profiles: A Theoretical Framework and Empirical Tests Across the Arctic","authors":"Lucas Deschamps,&nbsp;Jennifer Paillassa,&nbsp;Esther Lévesque,&nbsp;Vincent Maire","doi":"10.1029/2025JG009082","DOIUrl":"https://doi.org/10.1029/2025JG009082","url":null,"abstract":"<p>Anticipating the decomposition of permafrost organic matter (OM) following thaw is critical for improving projections of climate-carbon feedbacks. Stable carbon (C) and nitrogen (N) isotope profiles provide integrated records of the environmental and biogeochemical processes that shaped OM during its accumulation and may therefore improve our understanding of the factors controlling its future vulnerability to decomposition. Here, we compiled isotope data from 122 soil units across 42 Arctic sites and used Bayesian hierarchical models to test whether relationships between stable isotope signatures and soil C/N ratios varied along a gradient of soil organic carbon (SOC) content. Nitrogen isotope fractionation remained consistent across the SOC gradient, with δ¹⁵N increasing as C/N decreased. In contrast, carbon isotope fractionation differed markedly between mineral and organic soils. In mineral soils, δ¹³C increased with decreasing C/N, indicating extensive microbial processing and recycling of OM during accumulation. In organic soils, δ¹³C decreased with decomposition, consistent with the preferential preservation of relatively ¹³C-depleted plant-derived compounds under waterlogged conditions. These contrasting isotope patterns reveal distinct OM accumulation pathways in mineral and organic permafrost soils. Our results provide a revised conceptual framework linking long-term OM accumulation pathways to the properties of permafrost OM exposed by thaw, improving the interpretation of Arctic soil isotope records and their implications for permafrost carbon vulnerability.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009082","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615836","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}

{"title":"Multi-Year Continuous Lateral Fluxes of Dissolved Carbon From a Microtidal Saltmarsh","authors":"Songjie He,&nbsp;Kanchan Maiti,&nbsp;Scott V. Mize,&nbsp;Gregg Snedden,&nbsp;Gina Groseclose,&nbsp;Ryder D. Myers,&nbsp;Eric J. Ward,&nbsp;Francis S. Driscoll,&nbsp;Gage Hunter,&nbsp;Sergio Merino,&nbsp;Evan G. Camus,&nbsp;Adarelis Diz,&nbsp;Kevin D. Kroeger,&nbsp;Meagan J. Eagle,&nbsp;Qipei Shangguan,&nbsp;Camille L. Stagg","doi":"10.1029/2026JG009760","DOIUrl":"https://doi.org/10.1029/2026JG009760","url":null,"abstract":"<p>Tidal salt marshes play a critical role in coastal carbon cycling, yet quantifying lateral carbon fluxes remains challenging due to strong spatial and temporal variability. We combined multi-year continuous sensor data with discrete water-chemistry measurements to quantify dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and total alkalinity (TA) fluxes in a tidal creek draining a salt marsh in the Barataria Basin, Louisiana, USA. Multiple linear regression models trained with discrete carbon measurements and in situ sensor data were used to generate continuous DOC, DIC, and TA concentration time series from November 2021 to September 2024. Coupled with high-resolution discharge data, these estimates revealed strong tidal control on carbon exchange. Instantaneous fluxes ranged from −13,120 to 16,203 g C m⁻² yr⁻¹ for DOC, −95,290 to 93,834 g C m⁻² yr⁻¹ for DIC, and −63,703 to 62,766 g C m⁻² yr⁻¹ for TA, with mean fluxes of 56, 326, and 298 g C m⁻² yr⁻¹, respectively, indicating net export. Lateral dissolved carbon export substantially exceeded sediment carbon burial (204 g C m⁻² yr⁻¹), with mean DIC flux exceeding the burial rate by 60%. Inorganic carbon dominated lateral exports, accounting for ∼85% of total dissolved carbon flux. Although TA fluxes were lower than DIC fluxes, TA outwelling still exceeded burial by approximately 50%. Pronounced interannual and monthly variability underscores the importance of hydrological and biogeochemical controls at various scales. These results highlight how continuous multi-year observations can be used to constrain lateral carbon exchange and coastal carbon budgets.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615888","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}

{"title":"The Impact of Subglacial Drainage System Evolution and Glacier Lake Outburst on Arctic Fjord Macronutrient Dynamics","authors":"Andreas Alexander,&nbsp;Livia Piermattei,&nbsp;Philipp Assmy,&nbsp;Andrea L. Popp,&nbsp;Ken Zhao,&nbsp;Nicolas Valiente,&nbsp;Guy D. Tallentire,&nbsp;Simon Filhol,&nbsp;Thomas V. Schuler,&nbsp;Ugo Nanni,&nbsp;Jack Kohler,&nbsp;Louise S. Schmidt,&nbsp;Léo Decaux,&nbsp;George Cowie,&nbsp;Allison Bailey,&nbsp;Riko Noormets,&nbsp;Pierre-Marie Lefeuvre,&nbsp;Claire S. Earlie,&nbsp;Maarja Kruusmaa,&nbsp;Andy Hodson","doi":"10.1029/2023JG007969","DOIUrl":"https://doi.org/10.1029/2023JG007969","url":null,"abstract":"<p>Global warming is amplified in the Arctic, accelerating glacier melt and freshwater runoff. At tidewater glaciers, runoff typically enters fjords at depth and generates buoyancy-driven circulation that enhances glacier-ocean exchanges of energy and matter, influencing macronutrient delivery and marine primary production. However, most studies lack the temporal resolution to capture low-frequency, high-magnitude events, leaving their impacts poorly understood. Here, we combine glacier observations with high-frequency fjord and glacier-lake sampling to examine the 2021 glacier lake outburst flood (GLOF) from Lake Setevatnet into Kongsfjorden (Svalbard). We show how evolving subglacial conditions before and during the GLOF shaped macronutrient supply to the inner fjord through both direct runoff and entrainment of bottom waters. Early in summer, nutrient delivery was dominated by direct runoff, supplying nitrate (NO₃⁻) and silicate via an inefficient drainage system. As the melt increased, an efficient system formed, generating a subglacial plume and initiating buoyancy-driven circulation that entrained nutrient-rich deep water. Despite high NO₃⁻ lake concentrations, the flood barely affected fjord NO₃⁻ levels. Instead, it produced a seasonal maximum in nitrite (NO₂⁻). Comparisons with conservative mixing estimates and nitrogen budget analyses reveal a non-conservative nutrient signal. Although sedimentary sources cannot be excluded, the timing and spatial pattern of the NO₂⁻ anomaly suggest subglacial modification during floodwater transit. These findings indicate that Kongsfjorden functions as a summer nitrogen sink, partly shaped by subglacial transformations. Overall, nutrient delivery from tidewater glaciers depends not only on runoff volume but also on the subglacial drainage system characteristics, which evolve during high-magnitude events such as GLOFs.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007969","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148754266","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}

{"title":"VOCs Impact Soil Carbon Transformations and Sequestration","authors":"Zhaoxin Zhang,&nbsp;Juliana Gil-Loaiza,&nbsp;Antonette DiGuiseppe,&nbsp;S. Marshall Ledford,&nbsp;Markus Bill,&nbsp;Romy Chakraborty,&nbsp;Eoin L. Brodie,&nbsp;Malak M. Tfaily,&nbsp;Laura K. Meredith","doi":"10.1029/2026JG010104","DOIUrl":"https://doi.org/10.1029/2026JG010104","url":null,"abstract":"<p>Soil constitutes the largest terrestrial reservoir of organic carbon, yet small reactive volatile organic compounds (VOCs) from plants and microbes are often overlooked in carbon cycling models. We investigated the impact of five common VOCs (methanol, acetaldehyde, acetone, isoprene, and α-pinene) on soil carbon dynamics using controlled incubations and advanced metabolomic analyses. VOC-induced carbon retention ranged from 22% to 72%, with most carbon ending up as total inorganic carbon. Within the organic fraction, VOCs substantially reshaped the soil metabolome: acetaldehyde was efficiently converted to complex carbon forms with potential for long-term stabilization, methanol and acetone were largely respired by microbes, isoprene persisted under low-moisture conditions and α-pinene exhibited bidirectional carbon flow. Depending on their chemical structure and environmental conditions, VOCs were either quickly assimilated or transformed into complex long-lived metabolites. These results demonstrate that VOCs can contribute substantially to soil carbon storage and highlight the need to include these small molecules in biogeochemical models to improve predictions of carbon dynamics and climate feedback.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615835","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}

{"title":"Controls of Soil Respiration in the Global Croplands","authors":"Pramod Pokhrel,&nbsp;Varaprasad Bandaru","doi":"10.1029/2025JG009371","DOIUrl":"https://doi.org/10.1029/2025JG009371","url":null,"abstract":"<p>Unlike natural ecosystems, agricultural practices influence microclimatic conditions in croplands. This drives fluctuations in soil respiration (Rs), yet there is limited understanding of how soil environmental variables and management regulate Rs across climatic regions. We analyzed 362 records from 102 published studies that measured Rs in croplands across global climate regions and assessed the effects of soil temperature, moisture, and tillage practices on cropland Rs. Surface soil temperature primarily affected Rs, with most annual Rs well under 15 Mg C ha⁻¹ across all climatic regions. Soils of snow regions had 22%–35% higher Rs than the global average. The current global cropland annual Rs of 13.9 ± 6.4 Pg C could increase by 15%–30% by the end of 21st century, if soil temperatures rise by 2.3–4.5°C and current cropping practices continue. Soil moisture primarily limited Rs in arid and semi-arid environments but had minimal effect in warm-temperate and snow regions, where temperature limited Rs. No-tillage (NT) management reduced Rs by 21%; a 10% increase in NT adoption could offset 0.28 Pg C annual Rs from global croplands. However, high crop residue coupled with elevated soil temperatures (&gt;25°C) can offset this benefit by enhancing microbial decomposition in cooler regions. Our findings suggest that soil temperature explained more variance in cropland Rs than differences among tillage types or crop species. Snow regions exhibit higher temperature sensitivity, with Rs potentially increasing by 22%–35% under warming scenarios. The region-specific temperature-Rs relationships of cropland carbon loss provide a quantitative basis for land management policies targeting soil carbon conservation.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 7","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615887","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}