AGU Advances最新文献

{"title":"Extreme Radiation Belt Dropout During the May 2024 Superstorm","authors":"Xingzhi Lyu,&nbsp;Dedong Wang,&nbsp;Bernhard Haas,&nbsp;Miroslav Hanzelka,&nbsp;Yixin Sun,&nbsp;Zikang Xie,&nbsp;Alwin Roy,&nbsp;Yoshizumi Miyoshi,&nbsp;Yihua Zheng,&nbsp;Christos Katsavrias,&nbsp;Sigiava Aminalragia-Giamini,&nbsp;Nana Higashio,&nbsp;Takefumi Mitani,&nbsp;Takeshi Takashima,&nbsp;Iku Shinohara,&nbsp;Yoshiya Kasahara,&nbsp;Shoya Matsuda,&nbsp;Atsuki Shinbori,&nbsp;Fuminori Tsuchiya,&nbsp;Atsushi Kumamoto,&nbsp;Ayako Matsuoka,&nbsp;Mariko Teramoto,&nbsp;Kazuhiro Yamamoto,&nbsp;Yuri Y. Shprits","doi":"10.1029/2026AV002476","DOIUrl":"https://doi.org/10.1029/2026AV002476","url":null,"abstract":"<p>The geomagnetic superstorm in May 2024 represents the most extreme space weather event over the past two decades, offering a unique opportunity to investigate radiation belt electron dynamics under exceptionally strong solar wind driving conditions. Observations from the Arase satellite show that relativistic electron fluxes dropped by several orders of magnitude during the storm main phase. Although magnetopause shadowing and wave-driven losses are established mechanisms, the response of radiation belt electrons to superstorm-level solar wind driving remains poorly constrained. Using the Versatile Electron Radiation Belt model, we present the first physics-based simulation of the May 2024 electron dropout. Utilizing multi-satellite and ground-based observations, we show that the decades-long, widely adopted Kp-driven radial diffusion parameterization fails to represent radial transport under superstorm conditions, substantially misrepresenting both the timing and magnitude of enhanced diffusion relative to observed ultra-low-frequency wave activity. Accurate modeling of the observed extreme dropout requires precise specification of the onset of enhanced radial diffusion, which should coincide with the nearly simultaneous storm-time magnetopause compression. These coupled processes drive the dramatic depletion, followed by scattering from whistler-mode plasma waves.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 6","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026AV002476","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brine Pool Microbes Enrich Metalliferous Sediments in Salt Giant Basins","authors":"Morgan I. Chakraborty,&nbsp;Hannah Shernisky,&nbsp;Clément G. L. Pollier,&nbsp;Amanda M. Oehlert,&nbsp;Arash Sharifi,&nbsp;Ali Pourmand,&nbsp;Bolton J. Howes,&nbsp;Benjamin Minch,&nbsp;Mohammad Moniruzzaman,&nbsp;Larissa Frühe,&nbsp;Mattie Rodrigue,&nbsp;Sam J. Purkis","doi":"10.1029/2026AV002570","DOIUrl":"https://doi.org/10.1029/2026AV002570","url":null,"abstract":"<p>We report the discovery of an extinct deep-sea brine pool in the Red Sea's Hume Deep, providing evidence that rift-shoulder pools are ephemeral on millennial timescales, and that the microbially-enriched metalliferous deposits produced during the pool's active phase persist into the stratigraphic record. Now devoid of brine, the Hume Deep retains signatures of activity, including a well-preserved Lagerstätte death assemblage, seafloor staining consistent with past inhabitation by extremophile microbes, and enrichment of metals associated with their metabolisms. Elemental analyses of seafloor sediments demonstrate that the high metal concentrations in the Hume Deep match those of the active NEOM brine pool, situated 90 km north. In the NEOM pool, metagenomics and metatranscriptomics, coupled with scanning electron microscopy and energy-dispersive spectroscopy, suggest that microbes drive metal enrichment via microbe-mineral interactions up to 117× higher than background values. These results suggest a role for microbial processes in metalliferous sediment formation in deep-sea brine pools. Uranium-thorium dating suggests the Hume pool was last active between two and 16 thousand years ago. We propose that rift-shoulder brine pools fill and drain in response to tectonically controlled hydrothermal circulation. Our findings suggest that: (a) microbes inhabiting ancient Red Sea brine pools radically enhanced the metalliferous content of the stratigraphy within and above the basin's Miocene evaporites, and (b) that the elemental composition of other salt giant basins might have been similarly microbially mediated. With implications for understanding early life on Earth, our results provide a framework for interpreting deep-sea metal enrichments in modern and ancient extremophile environments.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 6","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026AV002570","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyanobacteria Sustain Deep Ocean Carbon Sequestration Despite Eukaryotic Loss","authors":"Jingjing Zhang,&nbsp;Guangxi Chi,&nbsp;Hongliang Li,&nbsp;Tiantian Tang,&nbsp;Shuh-Ji Kao,&nbsp;Eric Achterberg,&nbsp;Wupeng Xiao,&nbsp;Bangqin Huang,&nbsp;Martin G. Wiesner,&nbsp;Niko Lahajnar,&nbsp;Jianfang Chen","doi":"10.1029/2025AV002148","DOIUrl":"https://doi.org/10.1029/2025AV002148","url":null,"abstract":"<p>The biological carbon pump exports phytoplankton-derived organic carbon to the deep ocean, regulating long-term carbon sequestration and climate. Yet how phytoplankton community composition controls the magnitude and efficiency of this process remains poorly understood. Using time-series sediment trap samples, we analyze compound-specific stable carbon isotopes of amino acids to trace taxon-specific sinking particulate organic carbon (POC), revealing stark contrasts in sequestration efficiency between cyanobacteria and eukaryotic microalgae. Despite pronounced seasonal variations in surface productivity and community structure, bulk POC sequestration efficiency remains statistically invariant. Mesopelagic sinking POC is persistently cyanobacteria-rich (67% ± 2%), even during high-productivity periods when surface dominant community shifts from cyanobacteria to eukaryotes. This decoupling arises because eukaryotic sequestration efficiency halves, while cyanobacterial efficiency nearly doubles. Elevated eukaryote-derived carbon, though produced by large ballasted algae, undergoes greater attenuation in the twilight zone, reflecting enhanced microbial remineralization. In contrast, small non-ballasted cyanobacteria benefit from aggregation–ballasting effects, thereby compensating for eukaryotic loss and stabilizing overall sequestration efficiency. Our findings challenge prevailing assumptions that overestimate eukaryotic contributions and highlight the pivotal, climate-sensitive role of cyanobacteria in marine carbon storage, underscoring the need for taxon-specific parameterization in modeling the ocean carbon sequestration capacity under global warming.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 6","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV002148","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global Circulation of Martian Ionospheric Currents Revealed by Magnetometer Data","authors":"T. Delcourt,&nbsp;A. Mittelholz","doi":"10.1029/2026AV002408","DOIUrl":"https://doi.org/10.1029/2026AV002408","url":null,"abstract":"<p>In the dynamo region of the Martian ionosphere, a large-scale current is generated by charge separation: ions collide with neutrals while electrons preferentially gyrate around local magnetic field lines. Using MAVEN magnetometer data and a physics-informed neural network constrained by Ampère's law and Gauss's law for magnetism (the Neural-Curlometer technique), we compute the first continuous and locally-resolved model of ionospheric currents. The reconstructed dynamo currents are concentrated between 125 and 220 km, with a Hall-to-Pedersen transition near 160 km. The current density scales with the crustal magnetic field, with a dayside correlation of 0.89, and is mostly active over regions where the crustal field ranges between 130 and 450 nT at 150 km. The proposed approach allows us to model the currents over time, revealing clear seasonal variability partially related to dust storm events. Furthermore, the modeled currents exhibit a smooth hemispheric vortex pattern consistent with independently predicted atmospheric wind circulation and Coriolis-driven transport associated with seasonal <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> condensation at the poles. As such, we provide a data-driven proxy for atmospheric circulation at ionospheric altitudes, providing new inputs for Martian general circulation models.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 6","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026AV002408","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Equatorial Extreme Convective Storms Are Expanding and Becoming More Persistent","authors":"Qi Zhuang,&nbsp;Nadav Peleg,&nbsp;Andreas F. Prein,&nbsp;Vladan Babovic,&nbsp;Simone Fatichi","doi":"10.1029/2026AV002370","DOIUrl":"https://doi.org/10.1029/2026AV002370","url":null,"abstract":"<p>Extreme rainfall is projected to intensify with climate warming, yet changes in the spatiotemporal structure of extreme-producing storms remain poorly understood in the tropics, as the most convectively active regions of the world are also the most data-scarce. We here leverage the first long-term, sub-kilometer, sub-hourly observational network in equatorial Singapore (730 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>k</mi>\u0000 <msup>\u0000 <mi>m</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> $mathrm{k}{mathrm{m}}^{2}$</annotation>\u0000 </semantics></math>), with 122 rain gauges reporting 5 min intensities for 2020–2024 and 82 stations with hourly accumulations for 1980–2024, combined with X-band radar (5 min, 100 m) to produce a high-resolution gridded rainfall reanalysis. Our findings indicate that extreme rainfall in Singapore is becoming larger and more persistent, with intensification resulting in higher storm rainfall volumes while rainfall peak intensities remain largely unchanged. Furthermore, extreme rainfall storms are strikingly compact, with spatial and temporal correlations halving over just 2 km and 4 min, decaying faster than previously recognized and observed elsewhere. This suggests that analyses based on coarse data sets or single stations may have misrepresented rainfall intensification under warming.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 5","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026AV002370","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Oceanic Mechanism for Geyser Formation on Enceladus","authors":"D. Y. Abdulah,&nbsp;W. Kang,&nbsp;A. Berne","doi":"10.1029/2026AV002539","DOIUrl":"https://doi.org/10.1029/2026AV002539","url":null,"abstract":"<p>The tiger stripes of Enceladus are a sequence of four parallel and evenly-spaced fissures 130 km long that erupt water from a global subsurface ocean into space. We present an ocean dynamical theory of their formation. Given one initial fissure, topography on the underside of the ice shell rubs periodically against the ocean due to the satellite's libration. This motion excites internal gravito-inertial waves that propagate downward and reflect at the seafloor before reimpacting the underside of the shell. Wave breaking upon impact generates thermal energy which promotes melting via a feedback mechanism, forming subsequent fissures in a chain of parallel stripes. Dissipation predicted by linear analytical theory matches nonlinear simulations using the MIT General Circulation Model, with stronger agreement when the topography is less steep. Sufficiently large topography and libration amplitude excite waves with enough energy to initiate the fissure formation process. For south polar ocean thickness between 30 and 60 km, we constrain the stratification (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>N</mi>\u0000 <mo>&lt;</mo>\u0000 <mn>4.6</mn>\u0000 <mo>×</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>5</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> $N&lt; 4.6times 1{0}^{-5}$</annotation>\u0000 </semantics></math> <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{s}}^{-1}$</annotation>\u0000 </semantics></math>) at which the resulting wave pattern replicates the observed 35 km spacing of the tiger stripes.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 5","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026AV002539","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Connectivity Between Primary and Secondary Subglacial Drainage Subsystems Beneath a Land-Terminating Outlet Glacier of the Greenland Ice Sheet","authors":"R. Ing,&nbsp;E. Bagshaw,&nbsp;J. Hawkins,&nbsp;M. Peacey,&nbsp;S. Doyle,&nbsp;S. Livingstone,&nbsp;M. Prior-Jones,&nbsp;S. Thorpe,&nbsp;A. Moffatt,&nbsp;A. Sole,&nbsp;G. Bianchi,&nbsp;A. Booth,&nbsp;S. Buzzard,&nbsp;T. Chudley,&nbsp;C. Clason,&nbsp;L. Craw,&nbsp;L. Edwards,&nbsp;F. Gimbert,&nbsp;A. Hepburn,&nbsp;A. Jones,&nbsp;T. Le Bris,&nbsp;S. Mann,&nbsp;A. Michel,&nbsp;N. Ross,&nbsp;R. Storrar,&nbsp;R. Veness,&nbsp;T. Young","doi":"10.1029/2026AV002403","DOIUrl":"https://doi.org/10.1029/2026AV002403","url":null,"abstract":"<p>The evolution and connectivity of subglacial drainage systems control basal sliding and therefore modulate ice motion, yet direct observations of these systems remain limited. Here, we investigate hydraulic connectivity and its influence on ice motion at Isunnguata Sermia, a large land-terminating outlet glacier of the Greenland Ice Sheet. We use “Cryoegg” wireless sensors to obtain moulin water pressure and electrical conductivity, in conjunction with passive seismics to measure glacio-hydraulic tremor and GNSS-derived measurements of ice motion. We identify rapid switching (&lt;24 hr) of subglacial hydraulic connectivity between distinct subsystems: a large, primary drainage axis located in a deep trough, and secondary subglacial channels. When surface melt inputs are high, the secondary subsystem fed by the instrumented moulins connects with the efficient primary drainage axis and exhibits smoothed diurnal variability and synchronization with regional ice motion and seismic tremor. When surface melt decreases, hydraulic connectivity is reduced, and the secondary subsystem becomes disconnected and responds sensitively to variations in local melt inputs, increasing local meltwater residence time. Regional ice motion is controlled by the characteristics of the primary drainage axis and is insensitive to local inputs into the secondary subsystem.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 5","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026AV002403","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transient Global Overturning Following the Shutdown of North Atlantic Deep Water Formation","authors":"Shantong Sun,&nbsp;Andrew F. Thompson","doi":"10.1029/2026AV002462","DOIUrl":"https://doi.org/10.1029/2026AV002462","url":null,"abstract":"<p>The Atlantic Meridional Overturning Circulation (AMOC), a key component of the climate system, is projected to weaken under climate warming, raising concerns about a potential collapse and its climatic consequences. However, it has recently been suggested that the wind-driven upwelling of the Southern Ocean may prevent the AMOC from collapsing even under climate extremes. Here we analyze a climate model under <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> quadrupling and show that North Atlantic Deep Water (NADW) formation can cease under extreme warming. Despite the shutdown of NADW formation, a cross-hemispheric overturning circulation persists for centuries, reflecting a transient adjustment of the global ocean that arises from progressive deepening of isopycnal surfaces rather than sustained diapycnal downwelling in the interior ocean. This adjustment explains the emergence of clockwise overturning circulation in the Indo-Pacific despite the absence of deepwater formation. These features are reproduced in an idealized 1.5-layer reduced-gravity model. The transient adjustment of ocean overturning has important implications for the climate system. In particular, it can effectively redistribute heat into intermediate depths, thereby mitigating surface warming, and reorganize ocean tracers, altering global patterns of nutrients and ventilation that may feed back to the climate system.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 5","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026AV002462","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148785009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining Harmful Field Interactions in Geoscience Fieldwork and Strategies for Change","authors":"Anne U. Gold,&nbsp;Maya Almaraz,&nbsp;Melisa Diaz,&nbsp;Amy Dunbar-Wallis","doi":"10.1029/2026AV002402","DOIUrl":"https://doi.org/10.1029/2026AV002402","url":null,"abstract":"<p>Field-based research can be central to geoscience training and research, yet field environments can heighten risks for interpersonal harm because of strong power differentials, blurred professional-social boundaries, close living conditions, and physical demands. These dynamics can undermine safety, belonging, and retention, particularly for scientists from historically excluded groups. We surveyed members of the American Geophysical Union (<i>n</i> = 289) to assess the prevalence, perceived impact, and reporting of harmful field interactions (HFIs), defined as 26 behaviors spanning incivility, microaggressions, and harassment. Eighty percent of respondents reported experiencing or witnessing at least one HFI. The most frequently reported categories were Aggression and Hostility, Undermining of Work, and Inappropriate Sexual Behavior. When asked to identify the most negatively impactful experiences, respondents most often selected professional conduct behaviors such as Undermining of Work, Aggression and Hostility, and Social Harassment, regardless of field setting. The most impactful HFIs were more often experienced personally than witnessed, and perpetrators were typically hierarchically above the affected individual. Underreporting was pervasive with 75% of HFIs not reported, often because incidents were perceived as “not serious enough,” fear of professional or social consequences, uncertainty about reporting pathways, and lack of confidence in follow-up. The findings show that improving field safety requires addressing everyday professional incivility and microaggressions alongside severe misconduct. Respondents suggested multi-level interventions including pre-field training, codes of conduct, and well-communicated reporting pathways. The results provide actionable evidence to guide field leaders, institutions, and funders toward culture changes that would strengthens safety, equity, and scientific participation.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 5","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026AV002402","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148784695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal Re-Entrainment of Respired Organic Matter Decouples Southern Ocean Surface Production and Annual Net Community Production","authors":"Shannon McClish,&nbsp;Seth Bushinsky,&nbsp;Nathan Briggs,&nbsp;Ivana Cerovečki,&nbsp;Clara Douglas","doi":"10.1029/2025AV002267","DOIUrl":"https://doi.org/10.1029/2025AV002267","url":null,"abstract":"<p>The long-term storage of carbon by the biological carbon pump depends on the amount of organic carbon produced in sunlit waters, the depth at which that organic carbon is respired, and the time until the respired carbon is again in contact with the atmosphere. In the Southern Ocean, estimates of organic carbon export, net community production (NCP), and export efficiency vary in their magnitude and variability. Results from different methods are often difficult to compare due to inconsistent time and depth scales. To address these discrepancies, we leveraged biogeochemical Argo float observations to explore the relationship between organic carbon production during seasonal phytoplankton blooms, estimated from a mixed layer nitrate budget, and the annual carbon removal from the mixed layer, estimated from oxygen-derived respiration rates calculated on isopycnals. We compared these estimates to a POC flux data set. Our findings reveal a median of 47 ± 21% of seasonal organic carbon production is respired and re-entrained into the mixed layer in the subsequent winter, decoupling surface seasonal NCP from annual NCP (ANCP). Due to this decoupling, satellite-derived estimates of export production are correlated with NCP during seasonal blooms but not with ANCP. The average fraction of organic carbon respired and re-entrained is similar across distinct regions due to compensation between respiration rates beneath the seasonal mixed layer and the depth of the winter mixed layer. These results quantify the importance of accounting for winter entrainment when estimating ANCP and assessing the strength and efficiency of the biological carbon pump.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"7 5","pages":""},"PeriodicalIF":7.4,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV002267","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148784681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}