Global Biogeochemical Cycles最新文献

{"title":"A Top-Down View of Global and Regional Carbon Budgets From an Ensemble of Atmospheric Inversions","authors":"A. M. van der Woude,&nbsp;I. T. Luijkx,&nbsp;R. J. de Kok,&nbsp;W. Peters,&nbsp;F. Chevallier,&nbsp;C. Rödenbeck,&nbsp;P. Ciais,&nbsp;N. Chandra,&nbsp;K. Wang,&nbsp;R. Janardanan,&nbsp;H. van Asperen,&nbsp;A. Bastos,&nbsp;A. van den Berg,&nbsp;A. A. Bloom,&nbsp;S. Botía,&nbsp;K. Bowman,&nbsp;J. G. Canadell,&nbsp;R. A. F. de Souza,&nbsp;C. Q. Dias-Junior,&nbsp;L. Feng,&nbsp;P. Friedlingstein,&nbsp;L. V. Gatti,&nbsp;E. Gloor,&nbsp;K. Ishijima,&nbsp;F. Jiang,&nbsp;Z. Jin,&nbsp;W. Ju,&nbsp;X. Lan,&nbsp;J. Liu,&nbsp;Z. Liu,&nbsp;T. Machida,&nbsp;S. Maksyutov,&nbsp;A. C. Manning,&nbsp;A. Martinez,&nbsp;G. A. Martins,&nbsp;K. McKain,&nbsp;J. B. Miller,&nbsp;L. Nayagam,&nbsp;Y. Niwa,&nbsp;P. I. Palmer,&nbsp;P. K. Patra,&nbsp;P. A. Pickers,&nbsp;B. Poulter,&nbsp;B. B. Stephens,&nbsp;C. Sweeney,&nbsp;S. Wofsy,&nbsp;Z. Wu,&nbsp;D. Yang,&nbsp;J. Yun,&nbsp;N. Zeng","doi":"10.1029/2025GB008779","DOIUrl":"https://doi.org/10.1029/2025GB008779","url":null,"abstract":"<p>Atmospheric inversions provide surface CO₂ flux estimates based on in situ observed atmospheric CO₂ mole fractions or satellite-based column average CO₂ (XCO₂). Here, we provide a detailed assessment of 14 atmospheric CO₂ inversions included in the Global Carbon Budget (GCB2024). We develop tools to further assess and use these inversions in global and regional carbon cycle studies including the GCB and the REgional Carbon Cycle Assessment and Processes (RECCAP2) initiative. We show that the global atmospheric CO₂ growth rate and its interannual variability are reproduced well by all inversions. In contrast to bottom-up models, inversions provide carbon flux estimates directly constrained by observations. Our ensemble mean estimates of the global sinks for the period 2015–2023 are −1.41<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 </mrow>\u0000 <annotation> $pm $</annotation>\u0000 </semantics></math>0.55 PgC yr⁻¹ for the net land sink (including land-use change emissions) and −2.97<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 </mrow>\u0000 <annotation> $pm $</annotation>\u0000 </semantics></math>0.55 PgC yr⁻¹ for the global net ocean sink (uncertainties reported as <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 <mn>1</mn>\u0000 <mi>σ</mi>\u0000 </mrow>\u0000 <annotation> $pm 1sigma $</annotation>\u0000 </semantics></math> across inversions; estimates include fossil fuel and river flux adjustments). On regional scales, we find significant spread in flux estimates between inversions across regions, and we present criteria and metrics to derive flux-observation relation constraints or subselect ensembles of inversions based on independent observations. Furthermore, we use the atmospheric inversions to assess the atmospheric growth rate of CO₂. We show that the factor used to convert annual observation-based growth rates to net fluxes is variable over time as a result of atmospheric mixing. Finally, we propose guidelines on how to use the inverse results in global and regional carbon budget studies by the wider carbon cycle community.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB008779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"East-West Variability in Nitrogen Sources Sustaining Pelagic Food Webs in the Subtropical North Pacific Ocean Revealed by Stable Isotopic Analyses","authors":"Sachiko Horii,&nbsp;Hiroaki Saito,&nbsp;Keitaro Fukushima,&nbsp;Yuji Onishi,&nbsp;Keisuke Koba,&nbsp;Ken Furuya,&nbsp;Kazutaka Takahashi","doi":"10.1029/2025GB009062","DOIUrl":"https://doi.org/10.1029/2025GB009062","url":null,"abstract":"<p>Biological N₂ fixation sustains pelagic ecosystems in subtropical oligotrophic waters. However, its impact on food webs as a nitrogen source remains poorly understood. Here, we quantified the contribution of diazotroph-derived nitrogen to grazing food chains in the subtropical North Pacific in summer, where N₂ fixation activity varies markedly along a zonal gradient in the supply of the essential micronutrient, iron. To resolve this spatial variability, we conducted an ecosystem-scale analysis based on δ¹⁵N budgets along a longitudinal transect from 120°W to 137°E at 23°N and near the California Current in August-September 2017. The contribution of N₂ fixation to export (new) production varied from approximately 20% in the western part of the subtropical gyre (137–150°E) to approximately 50%–60% in the eastern and marginal areas of the gyre (140–170°W), whereas it decreased to almost 0% at the subarctic-subtropical boundary. The δ¹³C-δ¹⁵N biplots revealed consistent trophic enrichment from suspended particulate organic matter to mesozooplankton and micronektonic fish throughout the sampling areas. Despite the east-west difference in the diazotrophic nitrogen contribution across the subtropical gyre, δ¹⁵N values of biotic components were at similar magnitudes. This apparent discrepancy can be attributed to lower nitrate δ¹⁵N in the western gyre (∼4‰) than in the eastern (5–6‰), which depresses the δ¹⁵N signatures across food-web components to levels comparable to those in the eastern gyre, where diazotroph-derived nitrogen inputs are substantial. This nitrate δ¹⁵N pattern suggests that regenerated-nitrified nitrogen coupled with lateral transport plays an important role in sustaining biological production in the subtropical western North Pacific.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB009062","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148282478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Situ and Space-Based CO2 Observations Reveal Moisture-Induced Seasonal Compensation of the Western U.S. Carbon Cycle","authors":"Bharat Rastogi,&nbsp;John B. Miller,&nbsp;Aleya Kaushik,&nbsp;Sourish Basu,&nbsp;Lori Bruhwiler,&nbsp;Kathryn McKain,&nbsp;Arlyn E. Andrews,&nbsp;Caroline B. Alden","doi":"10.1029/2026GB009121","DOIUrl":"https://doi.org/10.1029/2026GB009121","url":null,"abstract":"<p>Earth's arid and semi-arid regions have been hypothesized to contribute significantly to interannual variability of the global terrestrial carbon sink. Arid and semi-arid regions such as the Western U.S. also show high vulnerability to climate extremes in the form of droughts, heatwaves, and large forest fires, compelling a need to quantify their climate-carbon responses. We quantify the net ecosystem exchange of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> (NEE) using a high-resolution regional inverse model with constraints from both in situ and space-based <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> observations during 2015–2016. Posterior fluxes are evaluated against withheld aircraft observations across the North American observation network. Observationally constrained fluxes suggest moisture-driven seasonal compensation in NEE across the 2 years, evidenced by a decrease in NEE of 244–262 [Tg C] during the early carbon uptake period and an increase in NEE of 281–389 [Tg C] later during the carbon uptake period, relative to 2016. Atmospheric constraints on NEE, combined with remote sensing and machine learning-based upscaled gross primary productivity (GPP) products, allow for benchmarking of net and gross <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> fluxes as estimated by a suite of terrestrial biosphere models. These benchmarks allow us to link changes in NEE and GPP constrained by atmospheric and space-based observations to changes in stomatal conductance and water use efficiency. High-precision in situ observations, such as those from the Global Greenhouse Gas Reference Network, are key constraints for bias-free carbon flux estimates.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GB009121","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148282190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erosional and Hydrological Controls on the Age and Thermochemical Stability of Particulate Organic Carbon in an Arctic River","authors":"Marisa Repasch,&nbsp;Suzanne P. Anderson,&nbsp;Robert S. Anderson,&nbsp;Josie Arcuri,&nbsp;Valier Galy,&nbsp;Joshua C. Koch,&nbsp;Irina Overeem","doi":"10.1029/2026GB009202","DOIUrl":"https://doi.org/10.1029/2026GB009202","url":null,"abstract":"<p>Understanding the mechanisms that drive the mobilization and fate of organic carbon (OC) in Arctic landscapes is important for modeling the feedbacks among permafrost thaw, carbon cycling, and climate change. While significant progress has been made toward measuring in situ OC decomposition in permafrost soils and bulk particulate organic carbon (POC) export from Arctic rivers, few studies have distinguished the source and lability of POC across Arctic landscapes, limiting our ability to predict whether mobilized POC will be oxidized to CO₂ and CH₄ or buried in downstream depositional environments. This study uses ramped pyrolysis/oxidation radiocarbon (RPO-¹⁴C) analyses to investigate spatial and temporal variations in the thermochemical stability and radiocarbon content of fluvial POC during downstream transport from mountains to the coast in the Canning River (North Slope, Alaska). Fluvial POC in the headwaters is predominantly comprised of high activation energy, thermally recalcitrant petrogenic OC (OC_petro) derived from shale bedrock. Moving into the foothills and low-relief coastal plains, river bank erosion primarily drives mobilization of labile, low activation energy, soil-derived OC (OC_soil). Fluvial POC in mountainous upstream reaches consisted of ∼70% OC_petro and just ∼30% OC_soil, while POC in the downstream coastal plain reaches comprised ∼85% OC_soil and ∼15% OC_petro. The high relative lability of POC exported to the coast indicates high susceptibility to oxidation and microbial decomposition, which could enhance CO₂ release as the Arctic hydrologic cycle intensifies. However, the persistence of refractory OC_petro in the suspended load indicates the potential for long-term burial of rock organic carbon in marine sediments.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GB009202","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting the Ocean's Metabolic Balance: Correcting Biases in Bottle Incubations Reveals a More Autotrophic and Dynamic Ocean","authors":"Yao Liu,&nbsp;Yibin Huang,&nbsp;Mingwang Xiang,&nbsp;Junjie Zhou,&nbsp;Bingzhang Chen,&nbsp;Nicolas Cassar,&nbsp;Weilei Wang,&nbsp;Bangqin Huang","doi":"10.1029/2026GB009114","DOIUrl":"https://doi.org/10.1029/2026GB009114","url":null,"abstract":"<p>The ocean's metabolic state—reflecting the balance between organic carbon production and consumption—is fundamental to understanding carbon sequestration potential. Yet, whether the ocean is net autotrophic or heterotrophic remains actively debated. Classic light-dark bottle incubations often suggest net heterotrophy, whereas geochemical tracer-based assessments indicate widespread autotrophy. Here, we show that bottle incubations systematically overestimate heterotrophy by artificially exacerbating bacterial activity, especially in oligotrophic waters. Applying a correction to global incubation data reduces the fraction of areas exhibiting net heterotrophy from 66% to 12% and shifts the euphotic zone carbon budget from a deficit of −9 ± 2.4 Pg C yr⁻¹ to a surplus of +12 ± 3.5 Pg C yr⁻¹. Moreover, our revisited estimate reveals that oligotrophic gyres are seasonally dynamic, oscillating between net autotrophy and heterotrophy, yet remain net autotrophic on an annual scale. These results help partly reconcile the long-standing methodological discrepancy in ocean metabolic balance and highlight the need to reassess biologically mediated carbon flux estimates in other aquatic systems broadly reliant on incubation-based measurements.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dissolved Organic Matter (DOM) Dynamics at the Sediment-Water Interface in the North Sea: Implications for Global Benthic DOM Fluxes","authors":"Bingbing Wei,&nbsp;Hannelore Waska,&nbsp;Zhe Zhou,&nbsp;Ding He,&nbsp;Hendrik Grotheer,&nbsp;Manuel Ruben,&nbsp;Gesine Mollenhauer,&nbsp;Marcus Elvert,&nbsp;Moritz Holtappels","doi":"10.1029/2025GB008980","DOIUrl":"https://doi.org/10.1029/2025GB008980","url":null,"abstract":"<p>Sediment–water exchange of dissolved organic matter (DOM) represents a critical yet poorly constrained component of the marine carbon cycle. Here, we combine quantitative, molecular, and carbon isotope (δ¹³C and F¹⁴C) analyses to investigate the production, composition, and export of porewater DOM in the German Bight, North Sea, and evaluate its broader implications using a global data set. In the German Bight, transport-regulated diagenetic pathways govern porewater DOM signatures. Diffusion-limited fine-grained sediments act as “selective reservoirs”, accumulating younger, terrestrially derived, and compositionally less refractory DOM via preferential remineralization of labile marine carbon. Conversely, permeable sands function as “biocatalytic filters” where advection-driven oxygen infiltration fosters rapid mineralization of fresh intermediates, leaving a transformed, refractory residual pool. Globally, sediment organic carbon (OC) exerts a first-order control on porewater dissolved organic carbon (DOC) concentration and F¹⁴C signatures, while its δ¹³C is influenced by external inputs such as methane-derived carbon at seeps. Benthic fluxes export younger, reactive compounds that facilitate the molecular renewal of bottom-water DOM. By utilizing negative-pressure techniques to minimize sampling artifacts, we obtain diffusive DOC flux estimates (0.48 and 0.12 mol C m⁻² yr⁻¹ for shelf and slope/deep-sea sediments, respectively) that avoid the systematic overestimation inherent in post-freeze-thaw centrifugation. Collectively, these findings emphasize that porewater DOM is a dynamic intermediary, regulated by sediment transport regimes, that actively shapes the quantity, composition, and long-term cycling of the marine DOM reservoir.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB008980","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent Changes in Global Ocean N2O Fluxes and Their Relationship to Ocean Climate Variability","authors":"Kai Ma,&nbsp;Manfredi Manizza,&nbsp;Yonglin Liu,&nbsp;Dimitris Menemenlis,&nbsp;Hanqin Tian,&nbsp;Kate Zhang,&nbsp;Qinghua Yang,&nbsp;Chuanyu Liu,&nbsp;Yang Feng","doi":"10.1029/2025GB008942","DOIUrl":"https://doi.org/10.1029/2025GB008942","url":null,"abstract":"<p>While the ocean is a critical regulator of atmospheric nitrous oxide (N₂O) levels, its specific contribution remains poorly constrained. Here, we implemented an N₂O module into the Estimating Circulation and Climate of the Ocean-Darwin (ECCO-Darwin) to investigate global sea-air N₂O fluxes, trends and interannual variabilities. From 1992 to 2017, the model yielded a global the oceanic N₂O efflux of 2.43 ± 0.43 Tg N yr⁻¹, with a declining trend of −0.021 ± 0.0031 Tg N yr⁻², attributed mainly to a reduction in N₂O production induced by strengthened upper-ocean stratification. The Eastern Tropical Pacific (ETP), Indian Ocean (IO) and Southern Ocean (SO) emerge as the primary three hotspots for N₂O outgassing, where interannual variability is modulated by regional climate modes. In the ETP and IO, N₂O fluxes strongly correlate with the El Niño Southern Oscillation index, with correlation coefficients of <i>r</i> = −0.93 and 0.53, respectively. During El Niño, reduced wind speeds and the deepening of the thermocline lead to decreased N₂O outgassing in the ETP. El Niño events also tend to result in a positive Indian Ocean Dipole, which causes the thermocline in the Eastern Tropical IO to shoal, resulting in increased N₂O outgassing. In the SO, the interannual variability of N₂O fluxes is positively correlates with the Southern Annular Mode (SAM) index (<i>r</i> = 0.76). When the SAM is positive, westerly winds shift poleward, strengthening Ekman pumping and resulting in more subsurface N₂O-laden water being upwelled and outgassed. Our study provides a mechanistic understanding of the critical role of ocean-atmosphere dynamics and climate variability in modulating oceanic N₂O emissions.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Herbivorous Vertebrates Decrease CO2 Sequestration Across Global Terrestrial Ecosystems","authors":"Yanping Wu,&nbsp;Wenjing Yang,&nbsp;Zhengjun Jian,&nbsp;Jiafei Ye,&nbsp;Bo Yao,&nbsp;Qiwu Hu,&nbsp;Jinying Xu","doi":"10.1029/2025GB008878","DOIUrl":"https://doi.org/10.1029/2025GB008878","url":null,"abstract":"<p>Herbivorous vertebrates are potent drivers of terrestrial carbon fluxes, yet the mechanistic pathways underlying this regulation remain unresolved. Here, we synthesized data from 138 studies to systematically untangle the complex mechanisms by which herbivorous vertebrates regulate carbon cycling via distinct body sizes and behavioral disturbance patterns (grazing, excretion, trampling, and burrowing). Synthesizing these data reveals that herbivorous vertebrates induce a global “flux contraction,” driving a 23.6% reduction in the absolute magnitude of Net Ecosystem Exchange (|NEE|) by concurrently lowering Gross Primary Production (GPP, 15.4%) and Ecosystem Respiration (RE, 9.3%). This asymmetric inhibition, where production declined more sharply than respiration, suggests that herbivorous vertebrates primarily constrain the overall magnitude of terrestrial carbon sequestration. Specifically, large mammals diminished |NEE| by 21.7%, acting as strong suppressors of net exchange, while small mammals reduced RE by 17.1%. Notably, birds exerted the strongest constraints, reducing |NEE|, GPP, and RE by 37.5%, 38.7%, and 28.6%, respectively. Among disturbance modes, grazing was the dominant driver, reducing |NEE| and GPP by 24.0% and 12.9%. In contrast, trampling and excretion stimulated soil respiration (RS) via physical priming and nutrient pulses, thereby modulating the net grazing-induced suppression, whereas burrowing had minimal net impact on CO₂ fluxes due to offsetting effects. These influences were most pronounced in wetlands, where herbivorous vertebrates compromised the net CO₂ sink (a 30.9% reduction in |NEE|) while simultaneously amplifying methane (CH₄) emissions by 73.5%. This study establishes herbivorous vertebrates as critical ecosystem engineers, highlighting the urgent need to integrate biotic effects into biogeochemical models to refine natural climate solutions.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional Patterns and Regulatory Mechanisms of Aquatic Carbon Transfer in China","authors":"Yongmei Hou,&nbsp;Si-Liang Li,&nbsp;Hang Wen,&nbsp;Sen Xu,&nbsp;Yuxin Li,&nbsp;Shuai Chen,&nbsp;Fu-Jun Yue,&nbsp;Xiaolong Liu,&nbsp;Lishan Ran","doi":"10.1029/2025GB009017","DOIUrl":"https://doi.org/10.1029/2025GB009017","url":null,"abstract":"<p>Inland waters constitute vital components in the global carbon (C) cycle. Nevertheless, the regional patterns of aquatic carbon transfer across China remain poorly quantified, and their impacts on the terrestrial carbon budget remain unclear. Here, we quantified the three primary aquatic carbon output fluxes and evaluated their implications for China's terrestrial carbon budget. We showed that the total aquatic carbon output flux was 165 ± 20 Tg C yr⁻¹, counteracting 29% of China's terrestrial net ecosystem productivity (NEP). Carbon dioxide (CO₂) emissions from river networks (86 ± 19 Tg C yr⁻¹) dominated the aquatic carbon transfer, accounting for 52% ± 13% of China's aquatic carbon output flux. Carbon burial in reservoirs (20.2 ± 3.4 Tg C yr⁻¹) represented a significant anthropogenic redistribution of terrestrial carbon equivalent to 46% ± 8% of the downstream carbon export (43.6 ± 1.8 Tg C yr⁻¹) across China. Furthermore, the positive correlations between aquatic carbon yield and precipitation and terrestrial NEP indicated a direct climatic control on aquatic carbon dynamics, whereas human activities have amplified these effects. Considerable spatial variations were observed in the net landscape carbon balance (NLCB) across China. Specifically, the NLCB in low-productivity regions was sensitive to aquatic carbon transfer, whereas terrestrial ecosystem productivity exerted the dominant control in high-productivity ecosystems. Our findings elucidate the spatial patterns and regulatory mechanisms governing aquatic carbon transfer across China, establishing a robust framework to refine regional carbon balance assessments and inform targeted climate management strategies.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB009017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trace Metal Biogeochemistry in the Nordic Seas: Arctic and Atlantic Water Inflows Determine (Micro)Nutrient Availability","authors":"Yaqing Ruan,&nbsp;Stephan Krisch,&nbsp;Thomas J. Browning,&nbsp;C. Mark Moore,&nbsp;Mario Esposito,&nbsp;Tim Steffens,&nbsp;Eric P. Achterberg","doi":"10.1029/2025GB008954","DOIUrl":"https://doi.org/10.1029/2025GB008954","url":null,"abstract":"<p>We present a data set of macronutrient and dissolved and total dissolvable trace metal concentrations collected in June 2012 across the Nordic Seas. Surface water and depth profiles of manganese, iron, cobalt, nickel, copper, zinc, phosphate, silicic acid, and NOx (nitrate + nitrite) reveal how warm saline Atlantic waters and cold fresh Arctic waters shape regional (micro)nutrient availability and phytoplankton growth conditions. At the surface, Arctic waters, depleted in NOx (3.44 ± 3.30 μM) but enriched in Si(OH)₄ (2.15 ± 1.42 μM) and dissolved trace metals (e.g., up to 1.03 nM dFe during peak to post-bloom), reach the western Nordic Seas via the Transpolar Drift and East Greenland Current. Conversely, the North Atlantic Current transports waters enriched in NOx (up to 10.7 μM) to the surface high-latitude North Atlantic (HLNA) and eastern Nordic Seas. These contrasting inputs create distinct nutrient-deficiency regimes: The western Nordic Seas were N deficient, whereas the HLNA and eastern Nordic Seas showed Fe deficiency following the spring bloom. Benthic flux and internal cycling processes, including remineralization and scavenging, further shape (micro)nutrient distributions in the deep waters, in addition to their pre-formed supply in water mass formation regions. The (micro)nutrient fluxes across the Greenland-Scotland Ridge, combined with reported estimates from the Fram Strait and Barents Sea Opening, highlight the Nordic Seas as a transitional region in mediating (micro)nutrient exchange between the Arctic Ocean and HLNA. Future changes in Arctic export may alter elemental stoichiometry in the Nordic Seas, with implications for primary production and biogeochemical cycling.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 6","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB008954","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}