Global Biogeochemical Cycles最新文献

{"title":"Oligotrophic Ocean New Production Supported by Lateral Transport of Dissolved Organic Nutrients","authors":"Zhou Liang,&nbsp;Robert T. Letscher,&nbsp;Angela N. Knapp","doi":"10.1029/2024GB008345","DOIUrl":"https://doi.org/10.1029/2024GB008345","url":null,"abstract":"<p>Dissolved organic nitrogen (DON) and phosphorus (DOP) are potential nutrient sources to sustain productivity in the oligotrophic ocean where inorganic nutrient concentrations are low. Variations in the carbon(C):nitrogen(N):phosphorus(P) stoichiometry of surface ocean dissolved organic matter (DOM) can trace patterns of DON and DOP production and consumption; however, concurrent dissolved organic carbon (DOC), DON, and DOP concentration observations are limited. Using new global ocean DOM concentration data sets, we develop inverse DOC and DON models to obtain global ocean DOC and DON concentration fields and associated biogeochemical fluxes. Including autotrophic DON uptake improves the model fit to observations. Combining our modeled DOC and DON concentration fields with a global ocean DOP concentration field from our previous inverse DOP model, we obtain a modeled global ocean DOM stoichiometry field. We further evaluate the lateral transport of semi-labile DON (SLDON) and semi-labile DOP (SLDOP) to the oligotrophic low latitudes (15° to 40°) and identify the equatorial Pacific and Atlantic as important sources of SLDON and SLDOP. We also quantify the preferential loss of DON and DOP relative to DOC from the surface to 500 m, which, with physical circulation, may retain nutrients in the gyres, further enhancing productivity. Our findings highlight two modes by which DON and DOP serve as organic nutrient sources to sustain productivity in the oligotrophic low latitudes, with lateral transport more important and capable of supporting ∼6–15% of export production in these regions.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008345","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144232245","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":"Microbial Carbon Accumulation Efficiency in Global Soils Resolved via 13C-Glucose Amendment Experiments","authors":"Wanjia Hu,&nbsp;Yue Cai,&nbsp;Xingqi Li,&nbsp;Cheng Wang,&nbsp;Juan Jia,&nbsp;Xiaojuan Feng","doi":"10.1029/2025GB008553","DOIUrl":"https://doi.org/10.1029/2025GB008553","url":null,"abstract":"<p>Accurately assessing the efficiency of microbial carbon (C) conversion and accumulation associated with soil “microbial C pump” (MCP) is essential for understanding microbial-mediated soil C sequestration. Conventional assessments based on microbial C use efficiency (CUE) hinge on living biomass only and do not include microbial necromass, which may not depict microbial C accumulation. Here we propose a simple and rapid approach based on ¹³C-glucose amendment experiment to assess microbial C accumulation efficiency (CAE) in a relatively short term. We first validated the approach by showing negligible sorption of glucose to soils with a wide range of edaphic properties. Glucose-derived ¹³C may hence be considered to represent microbial C (including biomass and residues) after a few days of addition, given the rapid uptake of glucose by microbes. Microbial CAE may thus be assessed as the recovery of glucose-derived ¹³C in the soil. By further conducting a meta-analysis of literature data involving isotopically labeled glucose amendment experiments, we revealed distinct variation patterns and influencing factors of CAE and CUE across various terrestrial ecosystems. Compared to CUE, which is mainly regulated by factors influencing microbial physiological processes (particularly substrate availability), CAE is jointly regulated by factors that influence microbial growth and residue persistence (e.g., clay content). These findings underscore that CAE is decoupled from CUE. Given the potential divergence in microbial biomass and residue responses to environmental perturbations, CAE provides a more accurate measure of microbial C conversion and accumulation efficiency than CUE, enabling a clearer understanding of MCP dynamics under global changes.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206679","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":"Fish Carbonates in the North Atlantic and Their Potential Role in the Carbon Cycle","authors":"Mohammed S. Hashim,&nbsp;Maureen H. Conte,&nbsp;Michael A. Salter,&nbsp;Rut Pedrosa-Pamies,&nbsp;J. C. Weber,&nbsp;Matthew G. Hayden,&nbsp;Rod W. Wilson,&nbsp;Chris T. Perry,&nbsp;Stephen F. Crowley,&nbsp;Paul F. Dennis,&nbsp;David Bish,&nbsp;Adam V. Subhas","doi":"10.1029/2024GB008387","DOIUrl":"https://doi.org/10.1029/2024GB008387","url":null,"abstract":"<p>Marine fish precipitate carbonates in their intestines that they subsequently excrete as part of an osmoregulatory strategy. While fish carbonates are proposed to be volumetrically significant to the global carbonate budget, no study has presented direct evidence of fish carbonates in the open ocean. Here we examine sediment trap material collected by the Oceanic Flux Program (OFP) in the North Atlantic and observe the episodic occurrence of enigmatic blue particles since 1992. The blue particles are comprised of calcite with unusually high magnesium content (up to 46 mol%) with distinctively depleted δ¹³C and enriched δ¹⁸O compared with calcite produced by common marine calcifiers. Based on the mineralogical, isotopic, and textural similarities between the blue particles and fish carbonates, we propose that the blue particles are produced by pelagic fish. Our data suggest that fish modify their intestinal fluids to create a concentrated, highly supersaturated, ¹³C depleted solution capable of precipitating calcite with high magnesium content and low δ¹³C. Collectively, our data imply that fish carbonate production is an open-ocean phenomenon, opening up the possibility that fish contribute to the production, dissolution, and export of carbonates globally.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190874","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":"The Global Biogeochemical Cycle of Chromium at the Earth's Surface","authors":"David J. Janssen,&nbsp;Kohen W. Bauer,&nbsp;Sylvie Bruggmann,&nbsp;Sean A. Crowe","doi":"10.1029/2025GB008525","DOIUrl":"https://doi.org/10.1029/2025GB008525","url":null,"abstract":"<p>The biogeochemistry of Cr and its cycling in Earth's surface environments is reviewed. A synthesis and critical evaluation of the major processes controlling Cr mobility and isotope composition (δ⁵³Cr) is presented, taking a source to sink view beginning with Cr mobilization from Earth's crust. Transport and cycling in inland waters and input to the oceans are discussed. Anthropogenic mobilization of Cr results in contributions to the atmosphere and inland waters that are of similar orders of magnitude as natural processes. The principal sources of Cr to the oceans are rivers and diffusive fluxes from marine sediments. Internal cycling of Cr in the ocean is largely controlled by reductive removal onto particles, particularly in O₂-depleted waters, and redistribution through ocean circulation. Chromium removal from the oceans occurs primarily in organic carbon-rich, O₂-poor shelf sediments. Despite theoretically poor mobility of Cr(III), reductive removal in anoxic waters is non-quantitative. As a result, isotope fractionation drives δ⁵³Cr offsets in removed Cr as well as residual dissolved Cr(III), which accumulates in anoxic water, compared to the corresponding source. The implications for δ⁵³Cr-based reconstructions are discussed, along with an outlook for future proxy applications based on the processes controlling Cr incorporation into sediments. The roles of different source and sink processes are quantified in an updated mass balance for the global ocean. Finally, priority topics for future research are suggested, which at present are the primary uncertainties of the modern Cr biogeochemical cycle and aspects of the Cr isotope mass balance.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171958","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":"Methane Emissions and Dynamics in the Weddell and Scotia Seas","authors":"Evelyn Workman,&nbsp;Anna E. Jones,&nbsp;Rebecca E. Fisher,&nbsp;James L. France,&nbsp;Katrin Linse,&nbsp;Bruno Delille,&nbsp;Freya A. Squires","doi":"10.1029/2024GB008425","DOIUrl":"https://doi.org/10.1029/2024GB008425","url":null,"abstract":"&lt;p&gt;The Southern Ocean's role in the global methane (&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;CH&lt;/mtext&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CH}}_{4}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) cycle remains uncertain due to limited measurement data from this remote region. It is unclear if the Southern Ocean acts as a source or sink of atmospheric &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;CH&lt;/mtext&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CH}}_{4}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, and climatic changes can have consequences on the amount of marine &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;CH&lt;/mtext&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CH}}_{4}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; released due to the acceleration of glacial melting and uncertain consequences on seabed &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;CH&lt;/mtext&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CH}}_{4}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; reservoirs. Monitoring &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;CH&lt;/mtext&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CH}}_{4}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; here is essential to understanding its impact on the global &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;CH&lt;/mtext&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CH}}_{4}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; budget now and in the future. This study measured &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;CH&lt;/mtext&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CH}}_{4}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; concentrations in both ocean and atmosphere during an expedition in the Scotia Sea, Weddell Sea, and South Georgia shelf, linking seabed activity, water column concentrations, sea-air fluxes, and atmosphe","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 5","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008425","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144118144","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":"Global Patterns of Leaf Litter C:N:P Stoichiometry Under Current and Future Climate Scenarios","authors":"Ji Yuan,&nbsp;Qiqian Wu,&nbsp;Zimin Li,&nbsp;Josep Peñuelas,&nbsp;Jordi Sardans,&nbsp;Changhui Peng,&nbsp;Yan Peng,&nbsp;Yuexin Fan,&nbsp;Petr Heděnec,&nbsp;Chaoxiang Yuan,&nbsp;Nannan An,&nbsp;Fuzhong Wu,&nbsp;Kai Yue","doi":"10.1029/2024GB008431","DOIUrl":"https://doi.org/10.1029/2024GB008431","url":null,"abstract":"<p>Plant litter carbon (C), nitrogen (N), and phosphorus (P) stoichiometry can indicate ecosystem nutrient use efficiency and limitation. Yet, a comprehensive quantification of plant litter C:N:P ratios at the global scale remains elusive, limiting our understanding of how their variation responds to future climate change. We constructed a database comprising 11,807 records of leaf litter C:N:P ratios, quantifying their global patterns under current and future (2041–2100) climate scenarios using the random forest method. We found that global mean leaf litter C:N, C:P and N:P ratios were 46.5, 669.4 and 16, respectively, while they were dependent on mycorrhizal association, taxonomic division, and/or plant functional type. Leaf litter C:N and N:P ratios showed opposite latitudinal patterns, being larger in high and low latitude regions, respectively, while the C:P ratio remained relatively stable in low latitude regions but increased significantly toward the poles. Our simulations further revealed that increasing climate warming decreased the leaf litter C:N ratio but increased the C:P and N:P ratios in terrestrial plants, despite the fact that their variations were largely dependent on ecosystem type. These findings clearly benefit us to understand the role of leaf litter in regulating the cycling of C and nutrients, responding to ecosystem plant development with climate change.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 5","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144085303","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":"Stable Iron Isotopes Constrain the Sedimentary Input of Dissolved Iron to the Ocean","authors":"Ying Ye,&nbsp;Christoph Völker","doi":"10.1029/2024GB008373","DOIUrl":"https://doi.org/10.1029/2024GB008373","url":null,"abstract":"<p>Iron is a key micronutrient for marine biota and potentially one of the main drivers of ocean feedback to changing climate. There is however no consensus on the relative role of different external iron sources to the ocean, hampering our ability to predict how the oceanic iron cycle and biological carbon pump will react to climate change. For the last two decades, stable iron isotopes have been increasingly used in field studies to track contributions of different iron sources and modeling studies started to help interpreting isotope observations. However, measured isotopic compositions of iron sources can vary substantially, and the isotopic signatures of different sources can overlap, leading to high uncertainty in constraining the magnitude of the sources. This study aims to examine the sensitivity of seawater iron isotopes to the uncertainty in the sedimentary source. An existing box model of the marine carbon cycle is extended with a description of the cycle of iron and its stable isotopes. Experiments have been done with variable isotopic end-member signature and strength of the sedimentary source, and fractionation through biological uptake and binding to organic ligands. The model results reveal the necessity to consider spatially distinct isotopic end-member signatures for the sedimentary source and fractionations so as to reproduce observed spatial gradients of seawater iron isotopic composition. By assuming a sedimentary input of 7.5–15 Gmol Fe <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mtext>yr</mtext>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${text{yr}}^{-1}$</annotation>\u0000 </semantics></math>, the model is able to reproduce observed concentrations of dissolved iron and its isotopes in large ocean regions, providing useful constraints for complex global biogeochemistry models.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 5","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008373","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144085501","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":"Contrasting Drivers of Bacterial Metabolism in the Euphotic and Mesopelagic Zones of Tropical Oligotrophic Oceans","authors":"Wenxin Fan,&nbsp;Wupeng Xiao,&nbsp;Chao Xu,&nbsp;Zengchao Xu,&nbsp;Yao Liu,&nbsp;Weinan Li,&nbsp;Jiayu Guo,&nbsp;Chengwen Xue,&nbsp;Jixin Chen,&nbsp;Xin Liu,&nbsp;Bangqin Huang","doi":"10.1029/2024GB008388","DOIUrl":"https://doi.org/10.1029/2024GB008388","url":null,"abstract":"<p>Microbial metabolism plays a critical role in global carbon cycling; however, our understanding of bacterial metabolic processes across the full depth of tropical oligotrophic oceans remains incomplete. The South China Sea (SCS) and Western Pacific (WP), as contrasting oligotrophic environments, provide an ideal setting to investigate this unresolved issue. This study presented a comprehensive analysis of bacterial carbon demand (BCD) from the euphotic to the mesopelagic zone in both regions, revealing distinct drivers of bacterial metabolism at different depths. In the euphotic zone, BCD was closely linked to biotic factors such as bacterial abundance and net primary production, with the SCS exhibiting higher bacterial metabolic activity compared to the WP. Below the euphotic zone, dissolved organic carbon availability became the critical limiting factor, with the WP supporting stronger bacterial metabolism due to more efficient organic matter retention. These findings highlighted the regional variability in carbon sequestration efficiency between the SCS and WP, offering new insights into the marine biological carbon pump. As climate change intensifies, understanding how microbial metabolism modulates carbon export and long-term storage is increasingly critical for predicting shifts in the carbon sink capacity of marine ecosystems.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 5","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074268","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":"The Unaccounted Oceanic Sink of Anthropogenic Nitrous Oxide and Its Relationship With Anthropogenic Carbon Dioxide","authors":"Mercedes de la Paz,&nbsp;Antón Velo,&nbsp;Reiner Steinfeldt,&nbsp;Fiz F. Pérez","doi":"10.1029/2024GB008417","DOIUrl":"https://doi.org/10.1029/2024GB008417","url":null,"abstract":"<p>Since 1800, the concentration of greenhouse gases like nitrous oxide (N₂O) and carbon dioxide (CO₂) has significantly increased due to anthropogenic activities. Oceanic anthropogenic CO₂ (C_ant) uptake from the atmosphere has been quantified and periodically re-evaluated given the implications for climate change. However, the potential oceanic uptake of N₂O has been largely overlooked. This study quantifies the uptake of N₂O of anthropogenic origin (N₂O_ant) taken up by the global ocean and how it relates with the anthropogenic CO₂. The oceanic inventory of N₂O_ant has been quantified using two approaches which consider the anthropogenic perturbation of N₂O and CO₂ as conservative tracers: first, a direct approach using the Transient Time Distribution (TTD) method; and second, indirectly through a novel method, founded on the direct proportionality between the excess of both N₂O and CO₂ in the atmosphere since 1800. Our results show that the North Atlantic Ocean is a key region of maximum accumulation of N₂O_ant due to the confluence of cold and ventilated waters. The global oceanic uptake of N₂O_ant from the pre-industrial times to 2010 was estimated to be 11.5 ± 2.3 Tg-N, with an annual uptake rate of 0.23 ± 0.05 Tg-N yr⁻¹. The study shows that oceanic sequestration contributes to a small portion of global N₂O inventories, but it is comparable to other N₂O oceanic budget numbers derived from atmospheric nitrogen deposition. Furthermore, connecting the N₂O_ant and C_ant oceanic distributions is a valuable tool for linking the perturbation of the Anthropocene on the N and C cycles in the ocean.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 5","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008417","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074270","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":"Deforestation Increases Vegetation Vulnerability to Drought Across Biomes","authors":"Chenwei Xiao,&nbsp;Sönke Zaehle,&nbsp;Stephen Sitch,&nbsp;Gregory Duveiller,&nbsp;Daniel E. Pabon-Moreno,&nbsp;Anthony P. Walker,&nbsp;Jürgen Knauer,&nbsp;Fabienne Maignan,&nbsp;Christiane Schmullius,&nbsp;Ana Bastos","doi":"10.1029/2024GB008378","DOIUrl":"https://doi.org/10.1029/2024GB008378","url":null,"abstract":"<p>Land use and land cover changes have altered terrestrial ecosystem carbon storage, but their impacts on ecosystem sensitivity to drought and temperature fluctuations have not been evaluated spatially over the globe. We estimate drought and temperature sensitivities of ecosystems using vegetation greenness from satellite observations and vegetation biomass from dynamic global vegetation model (DGVM) simulations. Using a space-for-time substitution with satellite data, we first illustrate the effects of vegetation cover changes on drought and temperature sensitivity and compare them with the effects estimated from DGVMs. We also compare simulations forced by scenarios with and without land cover changes to estimate the historical land cover change effects. Satellite data and vegetation models both show that converting forests to grasslands results in a more negative or decreased positive sensitivity of vegetation greenness or biomass to drought. Significant variability exists among models for other types of land cover transitions. We identify substantial effects of historical land cover changes on drought sensitivity from model simulations with a generally positive direction globally. Deforestation can lead to either an increased negative sensitivity, as drought-tolerant forests are replaced by grasslands based on model ensemble mean, or a decreased negative sensitivity, since forests under current land cover are predicted to exhibit greater drought resistance compared to those under pre-industrial land cover. Overall, our findings emphasize the critical role of forests in maintaining ecosystem stability and resistance to drought and temperature fluctuations, thereby implying their importance in stabilizing the carbon stock under increasingly extreme climate conditions.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 5","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008378","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950292","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}