Global Biogeochemical Cycles最新文献

{"title":"Improved Isotope-Based Source Apportionment of Iron Reveals Strong Anthropogenic Input in the North Pacific Ocean","authors":"Tianle Zhang,&nbsp;Mei Zheng,&nbsp;Wenkai Guan,&nbsp;Junyi Liu,&nbsp;Bingxing Zhu,&nbsp;Yaxin Xiang,&nbsp;Qi Zhou,&nbsp;Yuncong Ge,&nbsp;Ruifeng Zhang,&nbsp;Haoran Zhang,&nbsp;Yuntao Wang,&nbsp;Yan Zhang,&nbsp;Qi Ying,&nbsp;Chongguo Tian,&nbsp;Fei Chai,&nbsp;Tong Zhu","doi":"10.1029/2026GB009132","DOIUrl":"https://doi.org/10.1029/2026GB009132","url":null,"abstract":"<p>The iron cycle is a fundamental component of the Earth system. Growing evidence indicates that anthropogenic emissions can significantly perturb the iron cycle, beyond the influence of natural dust. The iron isotope technique has emerged as a powerful tool for quantifying anthropogenic iron in the marine environment. However, anthropogenic contributions derived from such an apportionment approach are highly sensitive to the selection of isotopic end-members, which are mainly determined by source tests and inconsistent across literature. Analysis of aerosol samples collected during a spring 2022 cruise in the Chinese marginal seas showed that anthropogenic iron contributions traced by isotope analysis ranged from 0.12 ± 0.12 to 0.43 ± 0.24, depending on the end-members derived from literature. To address uncertainty, an observation-based approach was developed to constrain isotopic end-members directly from ambient measurements. Shipborne high-time-resolution measurements of multiple elements were conducted, and a Positive Matrix Factorization (PMF) receptor model was used to quantitatively distinguish dust and anthropogenic contributions to iron. By combining the constraints from PMF results with filter-based iron isotope measurements, isotopic end-members of +0.44‰ for dust iron and −1.43‰ for anthropogenic iron were newly determined in ambient aerosol. Applying these updated end-members to iron sources based on previously published iron isotope data sets from the North Pacific indicates that anthropogenic contributions were ubiquitously underestimated, with maximum underestimation likely exceeding 30%. The application of observation-based end-members, as opposed to the conventional source-test-based end-members, allows for more accurate quantification of anthropogenic iron inputs by better capturing isotopic fractionation during atmospheric transport, thereby advancing isotope biogeochemistry.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 9","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148994021","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":"Drivers of Dissolved Thorium Isotope Distributions Along the Adélie Land Margin, East Antarctica: The Roles of Reversible Scavenging, Conservative Transport, and Lithogenic Supply","authors":"Thomas J. Williams,&nbsp;Andrea M. L. Davies,&nbsp;Pauline Latour,&nbsp;George H. Rowland,&nbsp;Zanna Chase,&nbsp;Taryn Noble,&nbsp;Ashley T. Townsend,&nbsp;Matthew Corkill,&nbsp;Andrew R. Bowie","doi":"10.1029/2025GB008882","DOIUrl":"https://doi.org/10.1029/2025GB008882","url":null,"abstract":"<p>In this study, we present a mix of full-depth profiles and near-bottom observations of dissolved ²³⁰Th and ²³²Th from the Adélie Land margin in East Antarctica, a key site of Antarctic Bottom Water (AABW) formation. We show that the distribution of dissolved Th isotopes in this region is governed by a combination of reversible scavenging, conservative transport and strong lithogenic inputs, especially on the continental shelf. A model incorporating both reversible scavenging and the upwelling of Circumpolar Deep Water successfully reproduces observed ²³⁰Th_xs distributions in the upper and mid-water column. However, deviations at depth point to additional processes, such as enhanced scavenging near the seafloor, and inputs of ²³²Th from benthic and/or suspended sediment dissolution. Exceptionally high inputs of ²³²Th to bottom waters on the Adélie shelf, likely sourced from glaciogenic sediments near the Mertz Glacier, are observed. This lithogenic inputs impart a distinct elevated ²³²Th/²³⁰Th_xs signature to shelf waters, which appears to be largely removed via scavenging before entering the abyssal ocean within the AABW. In contrast, the upper 200 m of the water column shows offshore transport of shelf-derived ²³²Th within Winter Water (WW). Based on the strong correlation between ²³²Th/²³⁰Th_xs and dissolved manganese (dMn) in Shelf Water samples, we estimate ∼75% of the dMn observed in WW is sourced from the dissolution of shelf sediment. As WW is progressively mixed into overlying surface waters, this source likely acts as a “slow release” pathway of dMn to the euphotic zone, potentially supporting biological productivity.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 9","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB008882","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943353","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":"Natural Isotope Constraints on River Nitrate Sources in Polluted Regions","authors":"Xue-Yan Liu,&nbsp;Wei Song,&nbsp;Hao-Ran Guo,&nbsp;Yin-Dong Tong,&nbsp;Cong-Qiang Liu","doi":"10.1029/2026GB009230","DOIUrl":"https://doi.org/10.1029/2026GB009230","url":null,"abstract":"<p>River nitrogen (N) pollution drives eutrophication and dead zones in more than two-thirds of global estuaries and bays. Nitrate (NO₃⁻) is a highly mobile form of reactive N. Elevated NO₃⁻ concentrations in rivers deteriorate water quality and threaten aquatic biota and human health through toxic and carcinogenic effects. Mitigating river NO₃⁻ in polluted regions is pivotal to achieving Sustainable Development Goal 6 (SDG 6. Clean Water and Sanitation). However, the contributions of major sources to river NO₃⁻ loads remain poorly resolved, hindering ongoing mitigation efforts. Prevailing source apportionment models attribute river NO₃⁻ primarily to atmospheric deposition and agricultural non-point sources. Here we establish a multi-isotope mass-balance framework that integrates natural N and oxygen isotopes (<i>δ</i>¹⁵N, <i>δ</i>¹⁸O, Δ¹⁷O) with concentration, flux, and isotope effect pertaining to river NO₃⁻ sources, pools, and fates. Application of this framework to polluted rivers in Europe, Asia, and North America reveals that atmospheric deposition contributes only 5 ± 3%, non-point sources account for 30 ± 9% (lower than previously reported &gt;60%), wastewater remains a dominant contributor at 37 ± 8%, and previously neglected in-stream nitrification contributes 28 ± 7%, effectively offsetting the fraction formerly overattributed to non-point sources. This finding demonstrates the importance of strengthening wastewater treatment and controlling in-river secondary NO₃⁻ production to reduce river NO₃⁻ pollution, and significantly advances our knowledge of river NO₃⁻ sources, which is essential for optimizing mitigation strategies to achieve SDG 6.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 9","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942801","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":"Temporal Amplification of Microbial Necromass Contribution to Soil Organic Carbon Under Nutrient Addition","authors":"Peng Zhang,&nbsp;Yue Li,&nbsp;Chenyang Zhang,&nbsp;Nan Sun,&nbsp;Andong Cai,&nbsp;Minggang Xu","doi":"10.1029/2026GB009455","DOIUrl":"https://doi.org/10.1029/2026GB009455","url":null,"abstract":"<p>Nutrient inputs can simultaneously regulate microbial necromass formation and soil organic carbon (SOC) accrual, but whether the contribution of microbial necromass to SOC changes over time under nutrient addition, and whether this temporal dependence differs among residue components remains unclear. We synthesized 303 paired observations of microbial necromass and SOC from 50 global studies to quantify the coupling between SOC responses and the responses of total necromass carbon (TNC), fungal necromass carbon (FNC), and bacterial necromass carbon (BNC), and to test how these relationships changed with experimental duration. Across nutrient input types, combined mineral and organic inputs produced the strongest responses, nitrogen, phosphorus, and potassium fertilization combined with manure increasing TNC, FNC, BNC, and SOC by 42.91%, 40.86%, 51.34%, and 44.01%, respectively. Microbial necromass responses were the strongest predictors of SOC responses, yet necromass increased more rapidly than SOC, indicating that enhanced residue production did not translate proportionally into persistent SOC accrual. The contribution of BNC to SOC was comparatively time independent and was mainly regulated by nutrient type. The contribution of FNC showed a convergent trend over time and was significantly influenced by ecosystem type. In contrast, the experimental duration significantly amplified the contribution of TNC to SOC. These findings indicate that long-term SOC sequestration is an emergent system property arising from the time-dependent coordination of distinct stabilization pathways. Accounting for this temporal dependence can refine microbial carbon pump theory and provide a globally relevant basis for improving long-term soil carbon sink projections and nutrient-management strategies under global change.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 9","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942419","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":"Lateral Accounting of Transport in Terrestrial Ecosystems (LATTE): A High-Resolution Global Land-Atmosphere CO2 Flux Data Set From 1961 to 2022 for Atmospheric Inversions and Carbon Budgeting Studies","authors":"Philippe Ciais,&nbsp;Frédéric Chevallier,&nbsp;Yilong Wang,&nbsp;Ronny Lauerwald","doi":"10.1029/2026GB009142","DOIUrl":"https://doi.org/10.1029/2026GB009142","url":null,"abstract":"<p>Lateral transport of terrestrial carbon—via harvested biomass, bioenergy supply chains, and riverine export—redistributes atmospheric CO₂ uptake and subsequent CO₂ emissions across space and time, complicating regional carbon budgeting and atmospheric inversion estimates. We present Lateral Accounting of Transport in Terrestrial Ecosystems (LATTE), a high-resolution (5 arc-min) global gridded data set of annual land-atmosphere CO₂ fluxes attributable to lateral carbon transfers for 1961–2022. LATTE quantifies paired CO₂ sinks at production locations and compensatory CO₂ sources at receptor locations, for four major lateral transport mechanisms: (a) crop harvest, trade, and consumption; (b) industrial roundwood harvest, trade, and storage in harvested wood product pools with country-specific decay and delayed emissions, (c) biofuel production, and use, including crop biofuels and fuelwood; and (d) the inland water carbon transport loop, including soil-to-river leaching, river and lake CO₂ evasion, aquatic burial, and export to the ocean. National production and trade statistics and biofuel energy balances are converted to carbon units and downscaled using satellite net primary productivity, forest carbon removal maps, population density, livestock distributions, and gridded biofuel combustion proxies. Inland water fluxes are based on published climatology with basin-scale mass balancing across major river basins. Example maps illustrate distinct spatial patterns of sinks and sources associated with crop products, wood products, biofuels, and inland waters, with global totals consistent with previous assessments. LATTE enables improved representation of lateral carbon transport in atmospheric inversions and supports spatially explicit regional and national carbon budget analyses.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 9","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942374","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":"Uncovering the Underestimated Greenhouse Gas Emissions of Hydropower Reservoirs: A Global Synthesis","authors":"Xin Liu,&nbsp;Wei Wen Wong,&nbsp;Seng Chee Poh,&nbsp;Hang Wen,&nbsp;Wan-Fa Wang,&nbsp;Tian-Li Guo,&nbsp;Fu-Jun Yue,&nbsp;Perran L. M. Cook,&nbsp;Si-Liang Li","doi":"10.1029/2026GB009359","DOIUrl":"https://doi.org/10.1029/2026GB009359","url":null,"abstract":"<p>Hydropower reservoirs, long considered as a clean energy solution, are increasingly recognized as major greenhouse gas (GHG) emissions hotspots. However, over 97% of these hydropower reservoirs remain unmonitored, creating major uncertainties in global GHG budgets. Here, machine learning models were employed to predict GHG fluxes from hydropower reservoirs lacking reported direct GHG measurements using 67 widely accessible environmental predictors covering climate, land use, soil properties, geology, and topography. The predicted GHG fluxes revealed marked spatiotemporal heterogeneity, characterized by distinct monthly variability and emission hotspots predominantly concentrated in tropical and arid zones, particularly across Africa. Moreover, scaling the predictions to 5,293 unmonitored hydropower reservoirs yielded total emissions of 304 ± 37 Tg CO₂eq year⁻¹, enabling a more geographically representative assessment of global reservoir GHG emissions. Methane notably dominates emissions (55.3%), followed by carbon dioxide (41.3%) and nitrous oxide (3.4%), with the latter often overlooked but gaining relevance during increasing eutrophication. In addition, our gas-specific models identified temperature-related variables as the primary drivers of GHG dynamics, emphasizing the central role of thermal regimes, especially in African reservoirs. Our findings call for a re-evaluation of the climate costs of hydropower and suggest that future warming may further amplify reservoir-based GHG emissions. The predictive capacity of our models provides a scalable tool for refining global GHG inventories and guiding low-carbon hydropower development under a changing climate.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 9","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GB009359","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942099","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":"High-Resolution Spatiotemporal Analysis of Nitrogen Balance and Use Efficiency in Chinese Annually Planted Cropland (1980–2020)","authors":"Xingxing Duan,&nbsp;Kaikui Cai,&nbsp;Jincheng Li,&nbsp;Man Zhang,&nbsp;Qingsong Jiang,&nbsp;Guozhu Mao,&nbsp;Yue Qin,&nbsp;Zhen Wu,&nbsp;Yong Liu","doi":"10.1029/2026GB009165","DOIUrl":"https://doi.org/10.1029/2026GB009165","url":null,"abstract":"<p>Nitrogen (N) plays a critical role in sustaining global food production and maintaining ecosystem stability. However, the rapid increase in fertilizer use over recent decades has led to excessive N input that surpasses the N uptake capacity of annually planted cropland, thereby imposing substantial environmental pressures. Optimizing annually planted cropland N utilization has thus become an urgent global challenge. In this study, we quantified the spatiotemporal dynamics of N fluxes in Chinese annually planted cropland at a 5-arc-minute resolution from 1980 to 2020 and investigated the factors influencing nitrogen use efficiency (NUE). The results showed that total N input to Chinese annually planted cropland increased markedly during this period, with chemical fertilizer being the dominant source. Concurrently, N output also rose substantially, mainly driven by crop harvests, although its growth rate lagged behind that of N input, resulting in a persistent N accumulation. Spatially, both N input and output were concentrated in intensively cultivated agricultural regions such as North China and the Huang-Huai-Hai Plain, whereas lower values were observed in Northwest and Southwest China. The XGBoost model identified soil thickness, soil organic carbon, and temperature as key determinants of NUE, although their relative importance varied across regions. By employing high-resolution data, this study provides a refined depiction of regional variations in cropland N fluxes and efficiency, overcoming the limitations of previous analyses conducted at administrative scales. The findings offer a robust scientific foundation for improving cropland N management practices and NUE in China, with implications for sustainable agricultural management.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 9","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148860106","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":"Substrate-Specific Potential N2O Production and Hybrid Isotopic Signatures in the Epipelagic Eastern Indian Ocean","authors":"Ting Gu,&nbsp;Zhuo Chen,&nbsp;Jun Sun","doi":"10.1029/2026GB009149","DOIUrl":"https://doi.org/10.1029/2026GB009149","url":null,"abstract":"<p>Nitrous oxide (N₂O) production in epipelagic oligotrophic oceans remains poorly constrained because multiple microbial pathways can co-occur under predominantly oxic conditions and may respond differently to oxygen and substrate availability. Here, we combined multi-substrate ¹⁵N tracer incubations (¹⁵NH₄⁺, ¹⁵N-urea, ¹⁵NO₂⁻, and ¹⁵NO₃⁻), isotopocule-based partitioning of labeled N₂O, and microbial community and genome analyses to investigate pathway-specific potential N₂O production in the epipelagic eastern Indian Ocean. Substrate-specific potential N₂O production exhibited distinct vertical distributions and oxygen responses. Ammonium-, urea-, and nitrite-driven N₂O production generally increased from well-oxygenated waters (&gt;100 μmol L⁻¹ O₂) toward oxycline waters (&lt;100 μmol L⁻¹ O₂), whereas nitrate-driven production showed a non-monotonic response with a maximum at intermediate low-O₂ concentrations of ∼20–50 μmol L⁻¹. Isotopic labeling further revealed widespread hybrid N₂O production, indicating that labeled substrates were coupled with nitrogen intermediates during N₂O production in epipelagic waters. Microbial community patterns and regional genomic potential were consistent with ammonia-oxidizing archaea as candidate contributors to hybrid N₂O production in oxic waters, denitrification-associated taxa near the oxycline, and <i>nosZ</i>-bearing lineages as candidate groups with potential for N₂O reduction. Depth-integrated potential N₂O production was positively related to primary productivity, suggesting that carbon fixation, particle export, and nitrogen remineralization may jointly enhance epipelagic N₂O production. Together, these results provide process-level constraints on oxygen-dependent pathway partitioning of epipelagic N₂O production and highlight a potential carbon-nitrogen linkage whose climatic effect depends on sea-air exchange, water-column transport, and biological N₂O consumption.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 9","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148860062","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":"Beyond the Martin Curve: A Mechanistic Yet Simple Model for Dynamic Ocean Particulate Organic Carbon Fluxes","authors":"Hengdi Liang,&nbsp;Emily J. Zakem,&nbsp;Jonathan M. Lauderdale,&nbsp;Raffaele Ferrari","doi":"10.1029/2026GB009184","DOIUrl":"https://doi.org/10.1029/2026GB009184","url":null,"abstract":"<p>Biological processes contribute to ocean carbon storage, playing a critical role in the global carbon cycle by maintaining lower atmospheric <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> levels. A major pathway is the gravitational sinking of particulate organic carbon (POC), yet how POC fluxes change in a warming ocean remains uncertain due, in part, to high spatiotemporal variability in observations. Observed POC fluxes, when averaged, typically exhibit a power-law decrease with depth (the “Martin curve”), yet prognostic models require structural complexity or poorly constrained, empirically tuned parameters to reproduce this behavior. Here, we propose considering the Martin curve as an asymptotic equilibrium benchmark that process-based models should converge to in their long-term, time-averaged behavior. We introduce a simple model for oceanic POC fluxes applicable to the entire water column, grounded in the theory that organic matter remineralization rate scales inversely with its age. We derive an analytical formula linking temporal and vertical variability and evaluate the scheme in an idealized 2D Atlantic Meridional Overturning Circulation model with oscillating surface productivity, which generates time-lagged vertical POC fluxes and dynamic water-column responses while converging to the power-law attenuation in the long term. The results demonstrate that much of the POC flux spatiotemporal variability, including its lack of synchronization with surface productivity and between different depths, can result solely from local surface variability, without invoking complex microbial shifts or lateral advection by ocean currents. This POC flux model enables simulations of ocean carbon cycling across diverse timescales and facilitates model-data comparisons, enhancing our mechanistic understanding of ocean carbon dynamics.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 8","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GB009184","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848725","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":"Influence of Deep-Sea Carbonate Sediments on the Long-Term Durability of Carbon Storage From Ocean Alkalinity Enhancement","authors":"Sina Acksen,&nbsp;Wolfgang Koeve,&nbsp;Markus Pahlow,&nbsp;Christopher J. Somes,&nbsp;Andreas Oschlies","doi":"10.1029/2026GB009203","DOIUrl":"https://doi.org/10.1029/2026GB009203","url":null,"abstract":"&lt;p&gt;Ocean Alkalinity Enhancement (OAE) is a marine carbon dioxide removal (CDR) strategy with a theoretical sequestration potential of several Gt &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{C}mathrm{O}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;y&lt;/mi&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{y}mathrm{r}}^{-1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. The long-term durability of OAE-induced carbon storage depends on the persistence of the added alkalinity in the ocean, which is influenced by sedimentary processes and biogeochemical and physical feedbacks. Using the University of Victoria v2.10 Earth System Model of intermediate complexity, we investigated the millennial-scale durability of OAE-induced extra alkalinity and associated additional carbon storage and, specifically, the role of deep-sea calcium carbonate sediments in limiting the durability. We conducted 10,000-year simulations for four emissions scenarios, each combined with a global alkalinity addition experiment (0.135 Pmol &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mtext&gt;yr&lt;/mtext&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{yr}}^{-1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; for 50 years) with and without interactive carbonate sediments. Neither the added alkalinity nor the associated oceanic carbon storage remained fully stable on millennial timescales compared to a baseline simulation. By year 10,000, 35%–59% of the initial alkalinity increase through OAE is lost due to &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CaCO&lt;/mtext&gt;\u0000 &lt;mn&gt;3&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CaCO}}_{3}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; dynamics in deep-sea sediments, resulting in a reduction of the OAE-induced carbon storage by 14%–27% compared to simulations without &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 ","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 8","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GB009203","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148783639","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}