Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Copula-Based Cosimulation for Simulating Temporal or Spatial Data in Biogeosciences","authors":"Van Huong Le,&nbsp;Rodrigo Vargas","doi":"10.1029/2025JG008802","DOIUrl":"https://doi.org/10.1029/2025JG008802","url":null,"abstract":"<p>Accurate modeling of dependencies between variables of interest is imperative for understanding biophysical processes and mechanisms relevant to biogeosciences research. This study presents copula-based cosimulation (CopCoSim) as an approach to model the temporal or spatial joint distributions of multiple variables by capturing their dependencies and correlations. We compared CopCoSim with the traditional Sequential Gaussian CoSimulation (SGCoSim) technique through two applications, representing one (i.e., time) and two dimensions (i.e., space) on a topic relevant to biogeosciences. Specifically, we present an application for soil CO₂ efflux, which is a major flux in the global carbon budget, using two case studies: (a) temporal distribution of soil CO₂ efflux and temperature and (b) spatial distribution of soil CO₂ efflux and temperature across the conterminous United States (CONUS). The methodology involves three steps: selecting a representative training data set, applying stochastic simulation methods, and evaluating model performance. The results indicate that CopCoSim provides a more accurate model with higher precision for representing variables of interest. CopCoSim better reproduces the univariate probability distribution, temporal or spatial autocorrelation, and dependency relationships between the predictor and response variables. Because CopCoSim does not rely on linear correlation structures and normality assumptions, it captures complex dependence structures and behaviors among variables. We propose that CopCoSim is useful for research in biogeosciences, where variables of interest (e.g., soil CO₂ efflux and temperature) are often interdependent and exhibit complex temporal or spatial patterns.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008802","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224451","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":"Significant Decrease in Sedimentary Organic Carbon Sequestration in the Lower Bengal Fan During the Last Sea Level Rise","authors":"Chengpeng Sun,&nbsp;Huawei Wang,&nbsp;Gang Hu,&nbsp;Tianyi Nie,&nbsp;J. Paul Liu,&nbsp;Jian Lin,&nbsp;Wenfeng Ning,&nbsp;Xinxin Li","doi":"10.1029/2025JG008948","DOIUrl":"https://doi.org/10.1029/2025JG008948","url":null,"abstract":"<p>Deep-sea fans represent the largest sediment and organic carbon (OC) accumulation zones on Earth. However, variations of sedimentary OC sequestration in deep-sea fans during the last sea level rise have not been well evaluated. Here, a gravity core (4.24 m) retrieved from the inner flank of the active channel in the Lower Bengal Fan was analyzed for mineralogy, inorganic elements, total OC (TOC) and carbon isotopes (δ¹³C, Δ¹⁴C), and lignin phenols to reconstruct sources and accumulation rates of sediment and OC over the past 15 ka. The results showed significantly higher TOC accumulation rate (TOC_AR, 443 ± 221 mg/cm²/ka), terrestrial OC proportion (53 ± 5%), and burial efficiency (37 ± 8%) during sea-level lowstand (15–10 ka) than the following sea-level highstand (10–2 ka, 7 ± 2 mg/cm²/ka, 39 ± 6%, 22 ± 4%) due to considerable decline of terrestrial sediment and OC supply when the sea level was high. This was further evidenced by decreasing lignin content (0.46 ± 0.30 vs. 0.02 ± 0.02 mg/100 mg OC) and pre-depositional age (4,607 ± 300 vs. 2,650 ± 933 years). At 2–0 ka, slight increase in these parameters was most likely due to enhanced anthropogenic interference. The re-evaluated TOC_AR and burial efficiency for global deep-sea fans during the Holocene and the last deglaciation are higher than for deep-sea plains (&gt;1,000 m) and upwelling regions, suggesting deep-sea fans are hotspots of OC sequestration. This study highlights the role of active channels of deep-sea fans in modulating OC biogeochemistry under global climate change.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224255","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":"Changes in Pyrogenic Tracers Over the Last 15,000 Years in the Congo River Catchment Through Multi-Method Analysis","authors":"Samuel D. Katz,&nbsp;Helena Osterholz,&nbsp;Riley Barton,&nbsp;Ellen R. M. Druffel,&nbsp;Xiaodong Gao,&nbsp;Caroline A. Masiello,&nbsp;Cristina Santin,&nbsp;Tassiana S. G. Serafim,&nbsp;Sasha Wagner,&nbsp;Matthias Zabel,&nbsp;Rainer Lohmann","doi":"10.1029/2025JG008772","DOIUrl":"https://doi.org/10.1029/2025JG008772","url":null,"abstract":"<p>Black carbon (BC), the most recalcitrant part of the pyrogenic carbon continuum, is formed by the incomplete combustion of biomass and fossil fuels. Methods for detecting BC include the chemical degradation of condensed aromatic compounds into benzenepolycarboxylic acids (BPCA), chemothermal oxidation of organic carbon at 375°C (CTO), ¹³C nuclear magnetic resonance combined with a molecular mixing model, thermogravimetry-differential scanning calorimetry, and the use of polycyclic aromatic hydrocarbons as tracers. However, there is limited knowledge about the comparability of these methods in marine sediments and their suitability as wildfire proxies. Here, we examined a sediment core from the Congo River outflow using a multi-methodological approach with environmental data and proxies to assess pyrogenic tracers from the Congo River basin over the last 15,000 years and determine commonalities between the methods. Despite differing analytical windows, both dry-weight and total organic carbon concentrations, and δ¹³C values for most methods showed a congruous trend. Higher BC concentrations and higher δ¹³C values were present during arid periods and lower during humid periods, reflecting changes in vegetation and terrestrial organic matter inputs. For all methods, the sedimentation flux identified significant variations in BC deposition only in the last 1,000 years BP due to anthropogenic land use changes. These findings deepen our understanding of BC in the global carbon cycle and show that BC proxies can reveal distinct transport pathways, with CTO-BC representing atmospheric deposition and BPCA-BC and NMR-BC indicating fluvial inputs to coastal margins, aiding in the reconstruction of past climates and landscapes.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008772","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224196","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":"Limited Headwater CO2 Emissions Relative to Downstream C Fluxes: Insights From a Tracer-Enabled Reactive Transport Model","authors":"William J. Larsen,&nbsp;Mark A. Torres,&nbsp;Evan J. Ramos,&nbsp;Sebastian Muñoz,&nbsp;Yi Hou,&nbsp;Tao Sun,&nbsp;Daniel E. Ibarra,&nbsp;Miriam Gammerman,&nbsp;Jonah Bernstein-Schalet,&nbsp;Kly D. Suquino,&nbsp;Preston Cosslett Kemeny","doi":"10.1029/2024JG008592","DOIUrl":"https://doi.org/10.1029/2024JG008592","url":null,"abstract":"<p>Some fraction of the total carbon (C) transported by rivers can enter the atmosphere as CO₂ via gas evasion as water transits from source to sink. Quantifying this evaded portion can be challenging due to the need to constrain chemical and physical parameters along an entire stream network using a limited number of point measurements. To address this challenge, we employed an tracer-enabled (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>δ</mi>\u0000 <mn>13</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${delta }^{13}$</annotation>\u0000 </semantics></math>C and ²²²Rn) reactive transport model to simulate CO₂ evasion along an entire stream network in the Little Deschutes River in the Eastern Cascades, Oregon, USA. We sampled the river network in distinct lanscape regimes and measured potential C sources including soil gas, groundwater springs, and wetland waters. Using these data, we first evaluated the reactive transport model using empirical gas transfer scaling relationships and measured groundwater chemistry. We then employed a Monte-Carlo optimization using riverine observations of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>pCO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{pCO}}_{2}$</annotation>\u0000 </semantics></math>, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>δ</mi>\u0000 <mn>13</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${delta }^{13}$</annotation>\u0000 </semantics></math>C and ²²²Rn, which yielded more accurate estimates of CO₂ evasion by improving estimates of spatially-averaged groundwater pCO₂ and generating a site-specific gas transfer scaling relationship. Our results demonstrate that riparian wetlands contribute to 19% of the computed CO₂ evasion flux. Lastly, we find that CO₂ evasion only accounts for 12% of the total riverine C flux, with the remaining fraction contributed by advective flux of DIC (50%) and DOC (38%) through the watershed outlet.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224254","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":"Challenges in Detecting High-Arctic Shrub Expansion From Optical Remote Sensing: Implications for Albedo and Climate Forcing","authors":"Florent Domine,&nbsp;Maria Belke-Brea,&nbsp;Arthur Bayle,&nbsp;Ghislain Picard,&nbsp;Esther Lévesque,&nbsp;Christophe Kinnard","doi":"10.1029/2024JG008593","DOIUrl":"https://doi.org/10.1029/2024JG008593","url":null,"abstract":"<p>Climate change-induced shrub expansion in the Arctic feeds back on climate by reducing surface albedo. Vegetation dynamics are typically monitored by tracking the evolution of vegetation indices, such as normalized difference vegetation index (NDVI), derived from satellite imagery in processes known as greening or browning. However, detecting changes in vegetation type requires sufficient spectral variation. Here, we measured the spectral albedos (346–2,400 nm) of assemblages of prostrate vegetation and of the only erect shrub species <i>Salix richardsonii</i> on Bylot Island in the eastern Canadian high-Arctic to assess spectral differences among common vegetation types. The broadband albedo of <i>S. richardsonii</i> (0.132 ± 0.009) was lower than that of prostrate vegetation (0.166 ± 0.008). However, NDVI values showed no significant difference (0.598 ± 0.074 vs. 0.561 ± 0.021). Satellite remote sensing using NDVI with spatial resolutions from 0.5 to 30 m using Pléiades, Sentinel-2 and Landsat-8 failed to detect differences in reflectance and NDVI between prostrate vegetation and <i>S. richardsonii</i>. These findings suggest that long-term NDVI trend analysis may be insufficient to capture the structural vegetation shift in these climate-sensitive areas. Failure to detect erect shrub expansion in the high-Arctic may therefore omit a climate change effect which produces a surface albedo decrease of 0.03 and a local summer solar forcing of 5.8 W m⁻².</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008593","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145146717","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":"Bald Cypress (Taxodium distichum) Knees Are Methane Sources Controlled by Geomorphology, Climate, and Hydrologic Extremes","authors":"Skylar K. Ross,&nbsp;Niklas Klauss,&nbsp;Marissa Miles,&nbsp;Kabi Raj Khatiwada,&nbsp;Bassil El Masri,&nbsp;Benjamin R. K. Runkle,&nbsp;Gary E. Stinchcomb,&nbsp;Jessica B. Moon","doi":"10.1029/2025JG008996","DOIUrl":"https://doi.org/10.1029/2025JG008996","url":null,"abstract":"<p>While woody root structures, such as bald cypress (<i>Taxodium distichum</i>) “knees,” can act as conduits of methane (CH₄), little has been done to explain variation from this flux pathway. We captured spatial (i.e., across knee surface, within sites, between sites) and temporal dynamics of CH₄ from knees, and built empirical models to predict the contribution of knees to net CH₄ fluxes. Knee and soil CH₄ fluxes were measured across seasons within the lower Mississippi Alluvial Valley in a main channel (semi-permanently flooded), side channel (seasonally flooded), and a reservoir edge (artificially flooded). Knees were a net source of CH₄ across all seasons, even during periods of soil CH₄ uptake. During periods of high knee CH₄ efflux, fluxes varied across the knee surface, decreasing with height from the ground. Knee CH₄ fluxes at the main and side channels decreased during a severe drought and increased ∼ ten-fold in summer and two-fold in winter following flooding events. At the reservoir edge, knee fluxes differed between the controlled draw up and draw down at the same water level, likely due to differences in temperature and oxygen availability. Knee CH₄ fluxes were positively correlated with water level (measured from subsurface wells, above ∼−70 cm in the soil profile) and subsurface temperature, but the strength of the relationships differed across geomorphic positions. Cypress knees appear to be an important contributor to wetland CH₄ efflux and accounting for the density of knees is needed to upscale their fluxes and better understand their ecosystem contribution.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145146715","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":"Microbial Resuscitation and Growth Rates in Deep Permafrost: Lipid Stable Isotope Probing Results From the Permafrost Research Tunnel in Fox, Alaska","authors":"T. A. Caro,&nbsp;J. M. McFarlin,&nbsp;A. E. Maloney,&nbsp;S. D. Jech,&nbsp;A. J. Barker,&nbsp;T. A. Douglas,&nbsp;R. A. Barbato,&nbsp;S. H. Kopf","doi":"10.1029/2025JG008759","DOIUrl":"10.1029/2025JG008759","url":null,"abstract":"<p>Permafrost is at increasing risk of thaw as cold regions in the Northern Hemisphere continue to warm. The lability of organic carbon in permafrost post-taw largely depends on the rate at which microorganisms resuscitate and proliferate after many years in freezing, dark, anaerobic conditions. Moreover, the bulk of the Earth's permafrost exists at deep subsurface horizons, far below the active layer, that have been isolated for hundreds, thousands, or millions of years. However, the resuscitation and growth rates of microorganisms in deep permafrost remain unknown. To quantify these rates, we conducted lipid stable isotope probing (lipid-SIP) on permafrost cores of late-pleistocene age from four locations within the Permafrost Research Tunnel near Fairbanks, Alaska. We compare rates of microbial growth, marker gene sequences, and greenhouse gas (CO₂, CH₄) emissions across cores held anaerobically at ambient (−4°C) and elevated temperatures (4°C, 12°C). In deep, ancient permafrost, microbial growth is exceedingly slow, often undetectable, within the first month following thaw, indicating a notable lag period, where only 0.001%–0.01% of cells turn over per day. This suggests a “slow reawakening” that could provide some buffer between anomalous warmth and C degradation if permafrost refreezes seasonally but remains anaerobic. However, within 6 months, microbial communities undergo dramatic restructuring and become distinct from both the ancient and overlying surface communities. These results have critical implications for predictions of microbial biogeochemical contributions in a warming arctic, especially as thaw proceeds into deeper and more ancient permafrost horizons.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145129283","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":"Phylogeny, Functional Types, and Environment Drive Different Leaf C:N:P Stoichiometric Patterns of Alpine Shrubs in Xizang, China","authors":"Xinru Zhang,&nbsp;Guangshuai Cui,&nbsp;Zhenjun Zuo,&nbsp;Wei Shen,&nbsp;Xinsheng Liu,&nbsp;Zhong Wang,&nbsp;Lin Zhang","doi":"10.1029/2025JG009102","DOIUrl":"10.1029/2025JG009102","url":null,"abstract":"<p>Concentrations of leaf carbon (C), nitrogen (N), phosphorus (P), and their stoichiometric ratios are essential for understanding plant nutrient uptake strategies and ecosystem functions such as primary productivity and nutrient cycling. Climate and soil factors and plant genetics all pose important impacts on the variation of leaf C:N:P stoichiometry. However, which factor determines the geographic variation of leaf C:N:P stoichiometry in alpine shrubs remains unclear. In this study, we analyzed 218 samples composed of 24 shrub species from 80 shrubland sites in Xizang to explore the geographic variations of leaf C:N:P stoichiometry in response to changes in climate, soil properties, phylogeny, and shrub functional types The stoichiometric ratios of leaf C:N:P exhibit significant geographical variation particularly along longitudinal and altitudinal gradients. However, the primary drivers of these variations differed among elements. Phylogeny accounted for the majority of the variation in leaf N content (62.02%), whereas leaf C content and the C:N ratio were primarily influenced by shrub functional types (63.96% and 57.78%, respectively). In contrast, leaf P content and the C:P ratio were predominantly regulated by environmental factors (64% and 60%, respectively). Among the environmental variables, soil pH emerged as the primary driver of leaf C:N:P stoichiometric variation, exerting a greater impact than climatic factors and soil nutrient content. This study highlights the critical roles of phylogeny, shrub functional types, and environmental factors in shaping the geographical patterns of elemental composition and stoichiometric traits, contributing to a deeper understanding of plant adaptive strategies and trait evolution under diverse environmental conditions.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145111120","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":"Linking Microbial Communities and Molecular Transformations of Dissolved Organic Matter to the Fate of Nitrogen in Karst Aquifers","authors":"Ruixuan Gai,&nbsp;Jing Bao,&nbsp;Wei Xiu,&nbsp;Fang Guo,&nbsp;Qiang Li,&nbsp;Qiang Zhang","doi":"10.1029/2025JG008961","DOIUrl":"10.1029/2025JG008961","url":null,"abstract":"<p>Understanding the biogeochemical processes governing carbon and nitrogen cycling in karst aquifers is critical. However, the specific pathways through which dissolved organic matter (DOM) influences nitrogen cycling under varying degrees of aquifer confinement remain poorly understood. This study addresses this knowledge gap by analyzing geochemical characteristics, DOM compositions, and microbial communities in three types of aquifer media, karst fissure media (KFM), karst conduit media (KCM), and karst window groundwater (KWG), at the Zengpiyan karst site in southern China, using carbon isotopes, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and amplicon sequencing. Results indicated that longer hydraulic residence time in KFM was associated with enhanced denitrification, whereas shorter residence in KCM/KWG favored nitrification. DOM was dominated by terrestrial lignin-like molecular formulas (55.92%), but residence time shaped molecular composition and biodegradation: KFM showed lower nominal oxidation state of carbon (NOSC_wa, −0.60 ± 0.37) yet a higher end-member index (I_bio, 0.37 ± 0.05), reflecting microbial preferential consumption of labile, high NOSC fractions, leaving recalcitrant lignin-like molecular formulas. Core taxa <i>Comamonas</i> and an unclassified Comamonadaceae genus were associated with lignin-like molecular formulas degradation and denitrification, while <i>Nitrospira</i> contributed to nitrification via lignin-like molecular formula-derived intermediates. Together they formed a “lignin-like molecular formulas degradation, ammonification, nitrification” cascade, with 53.82% of DOM degradation reactions involving nitrogen loss through CHON transformations. Overall, extended residence time in karst aquifers enables sequential degradation of recalcitrant lignin-like molecular formulas under low NOSC conditions via synergistic interactions between microbes, refining conceptual models of C-N coupling in hydrologically heterogeneous karst systems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145101829","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":"Modeling Attenuation of Nitrogen Loads Delivered to Coastal Bays From Ecological Restoration of Cultivated Wetlands","authors":"Adrian R. H. Wiegman,&nbsp;Casey D. Kennedy,&nbsp;Christopher Neill,&nbsp;Rachel W. Jakuba,&nbsp;Molly K. Welsh,&nbsp;David Millar,&nbsp;Anthony Buda","doi":"10.1029/2025JG008742","DOIUrl":"10.1029/2025JG008742","url":null,"abstract":"<p>Nitrogen (N) pollution is a major threat to coastal ecosystems, worsened by the loss or degradation of natural wetlands, which historically acted as N sinks. In the glacial outwash plain of Southeastern Massachusetts, N pollution primarily from human waste and turf fertilizer has caused coastal eutrophication. Social and economic factors have driven ecological restoration efforts on wetlands previously modified for cranberry farming. These restoration projects offer a chance to enhance ecosystem N attenuation, but the extent and spatial distribution of watershed N loads through these farms remain poorly understood. To address this gap, we adapted a U.S. Geological Survey (USGS) groundwater model to identify wetland contributing areas and model potential N load reduction from the retirement and restoration of 984 cranberry farms. Using modeled contributing areas and data and assumptions about attenuation rates, we estimated N load reductions for farm retirement and restoration scenarios in 24 embayments. For restoration of all farms, median N load reductions were less than 3% in nine embayments, 3%–10% in seven embayments, and 10%–30% in eight embayments. Attenuation was limited by the contributing area intercepted by cranberry farms, ranging from 1% to 75% of watershed areas. Our model serves as a screening tool to identify farms with high potential to reduce watershed N loads, but more field monitoring is needed to refine N attenuation estimates in former cranberry wetlands. This work highlights the critical linkage between wetlands, development patterns, and ecosystem health, emphasizing the need for sustainable resource management approaches.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008742","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145101654","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}