Global Biogeochemical Cycles最新文献

{"title":"Widespread Black Carbon Deposition of Varied Origin Exported From Glaciers","authors":"Amy D. Holt,&nbsp;Riley Barton,&nbsp;Sasha Wagner,&nbsp;Amy M. McKenna,&nbsp;Jason Fellman,&nbsp;Eran Hood,&nbsp;Tom I. Battin,&nbsp;Hannes Peter,&nbsp;Vanishing Glaciers Field Team,&nbsp;Robert G. M. Spencer","doi":"10.1029/2024GB008359","DOIUrl":"https://doi.org/10.1029/2024GB008359","url":null,"abstract":"<p>Atmospheric deposition delivers carbon to glacier surfaces, including from fossil fuel and biomass combustion. Nonetheless, spatial variation in the sources of organic and black carbon deposited on glaciers is poorly understood, along with their role in driving glacier outflow dissolved organic matter (DOM) composition and fate. Here, we used bulk and compound-specific carbon isotopic analyses to constrain the sources of dissolved organic carbon (DOC) and dissolved black carbon (DBC) in 10 glacier outflows across four regions. To understand the relationships between glacier DOM composition and sources of DOC and DBC, isotopic data were used in conjunction with ultrahigh resolution molecular-level analyses. Globally, a substantial yet variable component of DOC was sourced from anthropogenic aerosols (12%–91%; median 50%), influencing regional DOM composition (aliphatics 26.9%–58.4% relative abundance; RA). Relatively older radiocarbon ages (i.e., larger fossil-derived component) of glacier DOC were correlated with more ¹³C depleted DOC and DBC signatures, where DOM had higher aromaticity, elevated RA of condensed aromatics, and a lower RA of aliphatic compounds. This study highlights that anthropogenic deposition is pervasive, but its extent varies spatially with ramifications for DOM composition, and thus reactivity and fate.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143801545","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":"Multi-Elemental Tracers in the Amerasian Basin Reveal Interlinked Biogeochemical and Physical Processes in the Arctic Ocean Upper Halocline","authors":"L. M. Whitmore,&nbsp;L. Jensen,&nbsp;J. Granger,&nbsp;Y. Xiang,&nbsp;L. Kipp,&nbsp;A. Pasqualini,&nbsp;R. Newton,&nbsp;A. M. Agather,&nbsp;R. F. Anderson,&nbsp;E. E. Black,&nbsp;K. L. Bowman,&nbsp;A. Bourbonnais,&nbsp;M. A. Brzezinski,&nbsp;R. M. Bundy,&nbsp;M. A. Charette,&nbsp;R. L. Edwards,&nbsp;J. N. Fitzsimmons,&nbsp;D. A. Hansell,&nbsp;P. J. Lam,&nbsp;P. Morton,&nbsp;M. A. Saito,&nbsp;P. Schlosser,&nbsp;A. M. Shiller,&nbsp;W. M. Smethie,&nbsp;B. S. Twining,&nbsp;R. J. Woosley,&nbsp;R. Zhang","doi":"10.1029/2024GB008342","DOIUrl":"https://doi.org/10.1029/2024GB008342","url":null,"abstract":"<p>The physical and biogeochemical properties of the western Arctic Ocean are rapidly changing, resulting in cascading shifts to the local ecosystems. The nutrient-rich Pacific water inflow to the Arctic through the Bering Strait is modified on the Chukchi and East Siberian shelves by brine rejection during sea ice formation, resulting in a strong halocline (called the Upper Halocline Layer (UHL)) that separates the cold and relatively fresh surface layer from the warmer and more saline (and nutrient-poor) Atlantic-derived water below. Biogeochemical signals entrained into the UHL result from Pacific Waters modified by sediment and river influence on the shelf. In this synthesis, we bring together data from the 2015 Arctic U.S. GEOTRACES program to implement a multi-tracer (dissolved and particulate trace elements, radioactive and stable isotopes, macronutrients, and dissolved gas/atmospheric tracers) approach to assess the relative influence of shelf sediments, rivers, and Pacific seawater contribution to the Amerasian Arctic halocline. For each element, we characterized their behavior as mixing dominated (e.g., dCu, dGa), shelf-influenced (e.g., dFe, dZn), or a combination of both (e.g., dBa, dNi). Leveraging this framework, we assessed sources and sinks contributing to elemental distributions: shelf sediments (e.g., dFe, dZn, dCd, dHg), riverine sources, (e.g., dCu, dBa, dissolved organic carbon), and scavenging by particles originating on the shelf (e.g., dFe, dMn, dV, etc.). Additionally, synthesized results from isotopic and atmospheric tracers yielded tracer age estimates for the Upper Halocline ranging between 1 and 2 decades on a spatial gradient consistent with cyclonic circulation.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008342","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793519","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":"Pacific-Arctic Ocean Acidification: Decadal Trends and Drivers","authors":"Thomas Caero,&nbsp;Hongjie Wang,&nbsp;Annika Jersild","doi":"10.1029/2024GB008249","DOIUrl":"https://doi.org/10.1029/2024GB008249","url":null,"abstract":"&lt;p&gt;This study presents the first regional-scale analysis to quantify decadal trends and drivers of surface ocean acidification (OA) across the highly sensitive Pacific-Arctic Region (PAR) using a consistent trend methodology. From 1993 to 2021, the Southern PAR acidified at rates comparable to the global average, with &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;pH&lt;/mtext&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{pH}}_{mathrm{T}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; declining by 0.018 units &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;dec&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; ${text{dec}}^{-1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and aragonite saturation state &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Ω&lt;/mi&gt;\u0000 &lt;mtext&gt;Ar&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({{Omega }}_{text{Ar}}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; decreasing by 0.063 units &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;dec&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; ${text{dec}}^{-1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, primarily driven by anthropogenic &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;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; uptake. In contrast, the Bering Strait exhibited slower acidification, with &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;pH&lt;/mtext&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{pH}}_{mathrm{T}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; declining by 0.011 units &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;dec&lt;/mtext&gt;\u0000 &lt;mro","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008249","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793520","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":"The North American Greenhouse Gas Budget: Emissions, Removals, and Integration for CO2, CH4, and N2O (2010–2019): Results From the Second REgional Carbon Cycle Assessment and Processes Study (RECCAP2)","authors":"Benjamin Poulter,&nbsp;Guillermo Murray-Tortarolo,&nbsp;Daniel J. Hayes,&nbsp;Philippe Ciais,&nbsp;Robbie M. Andrew,&nbsp;Ana Bastos,&nbsp;Brendan Byrne,&nbsp;David Butman,&nbsp;Josep G. Canadell,&nbsp;Abhishek Chatterjee,&nbsp;Grant Domke,&nbsp;Andrew Feldman,&nbsp;Kelsey Foster,&nbsp;Neha Hunka,&nbsp;Robert B. Jackson,&nbsp;Werner A. Kurz,&nbsp;Ayia Lindquist,&nbsp;Maodian Liu,&nbsp;Ingrid Luijkx,&nbsp;Arnaud Mialon,&nbsp;Anna M. Michalak,&nbsp;John Miller,&nbsp;Wolfgang A. Obermeier,&nbsp;Naiqin Pan,&nbsp;James T. Randerson,&nbsp;Peter A. Raymond,&nbsp;Pierre Regnier,&nbsp;Laure Resplandy,&nbsp;Gerard Rocher-Ros,&nbsp;Nemesio Rodriquez-Fernandez,&nbsp;Judith Rosentreter,&nbsp;Julio César Salazar-Neira,&nbsp;Suzanne E. Tank,&nbsp;Hanqin Tian,&nbsp;Rodrigo Vargas,&nbsp;Yohanna Villalobos,&nbsp;Jonathan A. Wang,&nbsp;Xinyuan Wei,&nbsp;Kimberly P. Wickland,&nbsp;Christopher Williams,&nbsp;Lisamarie Windham-Myers,&nbsp;Christopher Woodall,&nbsp;Qing Ying,&nbsp;Zhen Zhang","doi":"10.1029/2024GB008310","DOIUrl":"https://doi.org/10.1029/2024GB008310","url":null,"abstract":"<p>Accurate accounting of greenhouse-gas (GHG) emissions and removals is central to tracking progress toward climate mitigation and for monitoring potential climate-change feedbacks. GHG budgeting and reporting can follow either the Intergovernmental Panel on Climate Change methodologies for National Greenhouse Gas Inventory (NGHGI) reporting or use atmospheric-based “top-down” (TD) inversions or process-based “bottom-up” (BU) approaches. To help understand and reconcile these approaches, the Second REgional Carbon Cycle Assessment and Processes study (RECCAP2) was established to quantify GHG emissions and removals for carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O), for ten-land and five-ocean regions for 2010–2019. Here, we present the results for the North American land region (Canada, the United States, Mexico, Central America and the Caribbean). For 2010–2019, the NGHGI reported total net-GHG emissions of 7,270 TgCO₂-eq yr⁻¹ compared to TD estimates of 6,132 ± 1,846 TgCO₂-eq yr⁻¹ and BU estimates of 9,060 ± 898 TgCO₂-eq yr⁻¹. Reconciling differences between the NGHGI, TD and BU approaches depended on (a) accounting for lateral fluxes of CO₂ along the land-ocean-aquatic continuum (LOAC) and trade, (b) correcting land-use CO₂ emissions for the loss-of-additional-sink capacity (LASC), (c) avoiding double counting of inland water CH₄ emissions, and (d) adjusting area estimates to match the NGHGI definition of the managed-land proxy. Uncertainties remain from inland-water CO₂ evasion, the conversion of nitrogen fertilizers to N₂O, and from less-frequent NGHGI reporting from non-Annex-1 countries. The RECCAP2 framework plays a key role in reconciling independent GHG-reporting methodologies to support policy commitments while providing insights into biogeochemical processes and responses to climate change.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008310","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778151","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":"Climate and Vegetation-Driven Increase of Soil Heterotrophic and Autotrophic Respiration in China's Subtropical Forests Over 2000–2020","authors":"Yibo Yan,&nbsp;Wohlfahrt Georg,&nbsp;Ni Huang,&nbsp;Mengmeng Cao,&nbsp;Xiujun Wang","doi":"10.1029/2024GB008363","DOIUrl":"https://doi.org/10.1029/2024GB008363","url":null,"abstract":"<p>Soil respiration significantly counteracts the carbon sequestration of forest ecosystems, but large uncertainties remain in quantifying its components including heterotrophic (HR) and autotrophic respiration (AR). We used previously collected field data from subtropical forests of southern China, and developed independent models for HR and AR. The HR model incorporated the regulation of substrate quantity and quality and co-limitations of soil temperature and moisture on microbe activity. The AR model considered fine root biomass and productivity as substrates and temperature effects on root activity. Using high-quality forcing data and new models, we estimated HR and AR in this region over 2000–2020 with 8-day timescale and 1 km spatial resolution. Validation with independent data showed improved accuracy compared with previous estimates. We estimated annual HR at 523 ± 381 g C m⁻² yr⁻¹ and AR at 254 ± 112 g C m⁻² yr⁻¹ (values represent mean ± SD). While previous HR estimates align well with our results, previous AR estimates are generally higher. Our estimates exhibited more detailed spatial patterns than existing data sets, particularly along altitudinal gradients, and showed significant increasing trends in both HR and AR driven by warming and greening, especially in high-rate region and during summer season. Soil temperature was the main driver for the interannual variation of HR especially in cold environments, while leaf area index mainly contributed to that of AR in most regions. Our results provide critical constraints on the estimates of HR and AR in subtropical forests and enhance our understanding of their contributions and spatiotemporal patterns under a changing climate.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770100","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":"Insect Herbivory Releases More Nutrients in Warmer and Drier Forests","authors":"Bernice C. Hwang,&nbsp;Christian P. Giardina,&nbsp;M. Noelia Barrios-Garcia,&nbsp;Haoyu Diao,&nbsp;Virginia Gisela Duboscq-Carra,&nbsp;Andreas Hemp,&nbsp;Claudia Hemp,&nbsp;Mylthon Jiménez-Castillo,&nbsp;Paulina Lobos-Catalán,&nbsp;Levan Mumladze,&nbsp;Ana C. Palma,&nbsp;Ion Catalin Petritan,&nbsp;Mariano A. Rodriguez-Cabal,&nbsp;Tommi Andersson,&nbsp;Kainana S. Francisco,&nbsp;Shelley A. Gage,&nbsp;Giorgi Iankoshvili,&nbsp;Seana K. Walsh,&nbsp;Daniel B. Metcalfe","doi":"10.1029/2024GB008367","DOIUrl":"https://doi.org/10.1029/2024GB008367","url":null,"abstract":"<p>Climate, forest successional stage, and soil substrate age can alter herbivore communities and their effects on biogeochemical cycling, but the size and spatial variability of these effects are poorly quantified. To address this knowledge gap, we established a globally distributed network of 50 broadleaved old-growth forests across six continents, encompassing well-constrained local-scale gradients in mean annual temperature (MAT), mean annual precipitation (MAP), succession, and soil substrate age. We used this network to investigate how these variables impact insect foliar herbivory and the associated carbon, nitrogen, phosphorus, and silica fluxes in forest ecosystems. Over 1 to 2 years, we measured stand-level foliar biomass production, leaf-level herbivory, and foliar element concentrations. At the global scale, insect herbivores liberated higher amounts of elements from the canopies of warmer and drier sites than those of cooler and wetter sites with patterns for phosphorus being most pronounced. MAT exerted a stronger influence over insect-mediated element fluxes than MAP. Foliar biomass production and leaf-level herbivory responses to MAT and MAP were mainly responsible for the observed changes in insect-mediated element fluxes; we also observed minor effects of foliar phosphorus concentration on phosphorus fluxes. Local-scale trends were mixed and successional stage or soil substrate age did not appear to influence insect herbivore-mediated element fluxes. These results demonstrate that climate effects on plant-herbivore interactions are stronger at large than small scales, at which herbivory rates and nutrient fluxes appear to be more strongly affected by a diversity of non-climate factors.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008367","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762240","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":"Quantifying Soil Gaseous Nitrogen Losses From Nitrification and Denitrification Based on Nitrogen Isotope Model","authors":"Haoming Yu,&nbsp;Wenxin Ba,&nbsp;Peter Dörsch,&nbsp;Wulahati Adalibieke,&nbsp;Yunting Fang,&nbsp;Longfei Yu,&nbsp;Chao Wang,&nbsp;Yihang Duan,&nbsp;Huayan Zhang,&nbsp;Benjamin Z. Houlton,&nbsp;Yan Bo,&nbsp;Yi Wei Jian,&nbsp;Xiao Qing Cui,&nbsp;Edith Bai,&nbsp;Feng Zhou","doi":"10.1029/2024GB008376","DOIUrl":"https://doi.org/10.1029/2024GB008376","url":null,"abstract":"<p>Gaseous nitrogen (N) losses from nitrification and denitrification (NO + N₂O + N₂) pathways contribute a significant fraction of the total N losses from cropland ecosystems. The N mass balance and process-based models are commonly applied to estimate the NO + N₂O + N₂ losses but have suffered from systematic error accumulations or model over-parameterization, leading to a large uncertainty in estimation, hindering effective management of the global N budget. Here, we proposed a novel N isotope model, which considers fertilizer, ammonia volatilization and harvest after testing steady-state assumption of soil δ¹⁵N and N pool for croplands, and justified if it could be successfully applied to constrain NO + N₂O + N₂ losses from cropland ecosystems. We compiled the first bulk-soil δ¹⁵N data set of 0–30 cm soils (<i>n</i> = 738) from croplands and produced a global map of cropland soil δ¹⁵N, which is crucial input data for an isotope model to quantify NO + N₂O + N₂ losses. The results show that the cropland soil δ¹⁵N ranges from 3.5 to 9.0‰, with a mean value of 6.6 ± 0.8‰ (mean ± standard deviation). The estimated NO + N₂O + N₂ losses accounted for an average of 17 ± 9% of N outputs and were 35.86 ± 24.17 kg N ha⁻¹ yr⁻¹ in China's rice paddies, with an increasing trend from Central China to South or North China. The estimations were comparable with the results from observation-constrained denitrification-decomposition modeling (38.9 ± 4.8 kg N ha⁻¹ yr⁻¹) and in good agreement with experimental observations at site scale (<i>R</i>² = 0.58). Our results suggest that soil N isotopes, as a quantitative tracer, provide a valuable alternative approach to constrain the NO + N₂O + N₂ losses in croplands at large geographic scales.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770235","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":"Hydrothermal Plumes Act as a Regional Boundary Sink of 230Th in the Equatorial Pacific","authors":"N. A. Redmond,&nbsp;C. T. Hayes,&nbsp;R. F. Anderson,&nbsp;E. E. Black,&nbsp;R. L. Edwards,&nbsp;M. Q. Fleisher,&nbsp;X. Li,&nbsp;P. J. Lam,&nbsp;K. C. Mateos","doi":"10.1029/2024GB008219","DOIUrl":"https://doi.org/10.1029/2024GB008219","url":null,"abstract":"<p>An important role in the cycling of marine trace elements is scavenging, their adsorption and removal from the water column by sinking particles. Boundary scavenging occurs when areas of strong particle flux drive preferential removal of the trace metals at locations of enhanced scavenging. Due to its uniform production and quick burial via scavenging, ²³⁰Th is used to assess sedimentary mass fluxes; however, these calculations are potentially biased near regions where net lateral transport of dissolved ²³⁰Th violates the assumption that the flux of particulate ²³⁰Th to the seabed equals its rate of production in the water column. Here, we present a water column transect of dissolved ²³⁰Th along 152° W between Alaska and Tahiti (GEOTRACES GP15), where we examine ²³⁰Th profiles across multiple biogeochemical provinces and, novelly, the lateral transport of ²³⁰Th to distal East Pacific Rise hydrothermal plumes. We observed a strong relationship between the slope of dissolved ²³⁰Th concentration-depth profiles and suspended particle matter inventory in the upper-mid water column, reinforcing the view that biogenic particle mass flux sets the background ²³⁰Th distribution in open ocean settings. We find that, instead of the region of enhanced particle flux around the equator, hydrothermal plumes act as a regional boundary sink of ²³⁰Th. At 152° W, we found that the flux-to-production ratio, and thereby error in ²³⁰Th-normalized sediment flux, is between 0.80 and 1.50 for hydrothermal water, but the error is likely larger approaching the East Pacific Rise.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717292","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":"Modeling Terrestrial Dissolved Organic Carbon and Its Effect on the Carbonate System in the Sunda Shelf Seas, Southeast Asia","authors":"Bernhard Mayer,&nbsp;Stefan Hagemann,&nbsp;Yongli Zhou,&nbsp;Yuan Chen,&nbsp;Shawn Bing Hong Ang,&nbsp;Johannes Pätsch,&nbsp;Patrick Martin","doi":"10.1029/2024GB008433","DOIUrl":"https://doi.org/10.1029/2024GB008433","url":null,"abstract":"&lt;p&gt;The flux of dissolved organic carbon (DOC) from land to sea is an important transfer within the global carbon cycle. The biogeochemical fate of this terrestrial DOC (tDOC) remains poorly understood and is usually neglected in ocean models. Southeast Asia accounts for around 10% of global tDOC flux, mostly from tropical peatland-draining rivers discharging onto the Sunda Shelf. We developed a new light-driven parameterization of tDOC remineralization that accounts for photochemical, microbial, and interactive photochemical–microbial degradation, and simulated the transport and remineralization of tDOC through the Sunda Shelf seas using the regional 3D hydrodynamical HAMSOM and biogeochemical ECOHAM models (only for the carbonate system). Our realistic hindcast simulations for 1958–2022 show that about 50% of riverine tDOC is remineralized before leaving the shelf. This lowers seawater pH across the entire inner Sunda Shelf by an average of 0.005 (by up to 0.05 in the Malacca Strait). Correspondingly, seawater &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;pCO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{pCO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; is raised, increasing yearly &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;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; outgassing from the shelf by 19% (3.1 Tg C &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;, 0.14 mol &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{m}}^{-2}$&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;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","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008433","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717221","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":"Tracing Pan-Canadian Arctic Water Masses and Dissolved Inorganic Carbon Cycling Using Stable and Radiocarbon Isotopes","authors":"L. Jasperse,&nbsp;B. G. T. Else,&nbsp;L. A. Miller,&nbsp;G. Nickoloff,&nbsp;J. Walker,&nbsp;A. E. Fox,&nbsp;B. D. Walker","doi":"10.1029/2024GB008179","DOIUrl":"https://doi.org/10.1029/2024GB008179","url":null,"abstract":"<p>The Canadian Arctic is warming four times faster than the global average, yet the impact of this perturbation on the marine carbon cycle remains unknown. Dissolved inorganic carbon (DIC) stable isotope (δ¹³C) and radiocarbon (Δ¹⁴C) values are powerful tools for tracing water mass transport, residence times and carbon cycling. While the hydrography of the Canadian Arctic Archipelago (CAA) is well documented, few DIC δ¹³C and Δ¹⁴C values exist for the region. Here, we present new DIC δ¹³C and Δ¹⁴C depth profiles from 19 stations across the CAA sampled in 2021 and place them into the context of five recently published Baffin Bay values. CAA DIC δ¹³C and Δ¹⁴C values ranged from −0.68‰ to +1.86‰, and −90.7 to +49.5‰, respectively. Several negative DIC Δ¹⁴C values (−44.7‰ and −51.9‰) were observed near the Mackenzie River, indicating riverine permafrost carbon is actively incorporated into the nearshore DIC pool. “Bomb” DIC Δ¹⁴C values in the Kitikmeot Sea were attributed to enhanced tidal mixing and heterotrophy together with high regional water mass residence times. A comparison of historical DIC Δ¹⁴C depth profiles from 2009 to 2021 reveals significant dilution of “bomb” ¹⁴C and minor contributions (2.1%–4.4%) of fossil anthropogenic CO₂ within Pacific Summer Water (PSW), Pacific Winter Water (PWW) and Atlantic Fram Strait Water (ATL_FS) in the Beaufort Sea. Finally, the contrast between deep Beaufort Sea and Baffin Bay DIC δ¹³C and Δ¹⁴C values reveal differences in residence time and carbon sources in the two regions.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 4","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008179","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707360","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}