Journal of Geophysical Research-Oceans最新文献

{"title":"Marine Mammal-Based Observations of Subsurface-Intensified Eddies in the Seasonally Sea Ice-Covered Southern Ocean","authors":"Jennifer A. Kosty, Ken X. Zhao, Andrew L. Stewart, Daniel E. McCoy, Daniele Bianchi, Georgy E. Manucharyan","doi":"10.1029/2024JC021781","DOIUrl":"https://doi.org/10.1029/2024JC021781","url":null,"abstract":"<p>Submesoscale coherent vortices (SCVs) are long-lived subsurface-intensified eddies that advect heat, salt, and biogeochemical tracers throughout the ocean. Previous observations indicate that SCVs are abundant in the Arctic because sea ice suppresses surface-intensified mesoscale structures. Regional observational and modeling studies have indicated that SCVs may be similarly prevalent beneath Antarctic sea ice, but there has been no previous systematic attempt to observe these eddies. This study presents the discovery of eddies in the Southern Ocean's seasonally sea ice-covered region using the Marine Mammals Exploring the Oceans Pole to Pole (MEOP) hydrographic measurements. Eddies are identified via a novel algorithm that utilizes anomalies in spice, isopycnal separation, and dynamic height along MEOP seal tracks. This algorithm is tested and calibrated by simulating the MEOP seal tracks using output from a 1/48<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math> global ocean/sea ice model, in which subsurface eddies are independently identified via the Okubo–Weiss parameter. Approximately 60 detections of cyclonic and over 100 detections of anticyclonic SCVs are identified, with typical dynamic height anomalies of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>0.05</mn>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>m</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${sim} 0.05,{mathrm{m}}^{2},{mathrm{s}}^{-2}$</annotation>\u0000 </semantics></math>, core depths of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>200</mn>\u0000 <mspace></mspace>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 <annotation> ${sim} 200,mathrm{m}$</annotation>\u0000 </semantics></math>, and vertical half-widths of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>100</mn>\u0000 <mspace></mspace>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 <annotation> ${sim} 100,mathrm{m}$</annotation>\u0000 </semantics></math>, similar to their Arctic counterparts. The eddies exhibit a pronounced geographical asymmetry: cyclones are exclusively observed in the open ocean, ","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021781","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793913","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 Role of Local Wind Stress Curl in Modulating Kuroshio Extension Latitudinal Variability","authors":"Mingshun Fan,&nbsp;Xiaohui Liu,&nbsp;Tongya Liu,&nbsp;Dake Chen","doi":"10.1029/2024JC021742","DOIUrl":"https://doi.org/10.1029/2024JC021742","url":null,"abstract":"<p>The Kuroshio Extension (KE) exhibits a typical interannual to decadal latitudinal shift. Previous studies have proposed that eastern/central North Pacific wind and oceanic intrinsic variability are responsible for the KE variability. In this study, we define a KE index using Empirical Orthogonal Function analysis based on subsurface temperature to quantify the variability of the KE shift caused by thermocline migration. The KE region exhibits positive (negative) temperature anomalies and clockwise (anti-clockwise) circulation anomalies in the north (south) phase of the KE. A lead correlation analysis indicates that, in addition to a 3–4 years leading correlation between the eastern/central North Pacific wind stress curl anomalies and the KE index, a significant linear correlation is revealed in the local region when the wind stress curl anomalies lead the KE index 0–1 year. By conducting a series of sensitivity experiments using both a global circulation model and a reduced gravity model, we suggest that both local wind and (broad) remote wind are responsible for the interannual to decadal variability of the KE, with their contributions being comparable. Regarding the local wind forcing process, when the wind stress curl anomalies are positive (negative) in the western North Pacific, they generate negative (positive) local Sea Surface Height anomalies and temperature anomalies through Ekman divergence (convergence), resulting in the southward (northward) shift of the KE.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143801273","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":"Decreased Air-Sea \u0000 \u0000 \u0000 \u0000 CO\u0000 2\u0000 \u0000 \u0000 ${mathbf{text{CO}}}_{mathbf{2}}$\u0000 Flux During the Persistent Marine Heatwaves in the Yellow Sea and East China Sea","authors":"Guozhi Ren,&nbsp;Rong Na,&nbsp;Shaoqing Zhang,&nbsp;Zengrui Rong,&nbsp;Wentao Ma,&nbsp;Fei Chai,&nbsp;Yongjun Tian,&nbsp;Yang Gao,&nbsp;Lv Lu","doi":"10.1029/2024JC021525","DOIUrl":"https://doi.org/10.1029/2024JC021525","url":null,"abstract":"&lt;p&gt;Marine heatwaves (MHWs) exert a significant influence on marine ecosystem, especially in marginal seas where carbonate processes are intricately linked to temperature variations. However, how MHWs affect the carbonate processes in marginal seas, such as the Yellow Sea (YS) and East China Sea (ECS), remains unclear. Here, we employ a physical-biogeochemical model to simulate marine ecosystem, aiming to systematically quantify impacts of persistent MHWs (PMHWs) on air-sea &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; flux (&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;FCO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{FCO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) anomaly in YS and ECS. Results reveal that due to reduced wind speed and elevated temperature during PMHWs, ocean &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; reservoir experiences dramatic decrease. In summer when the ocean releases CO&lt;sub&gt;2&lt;/sub&gt; to the atmosphere, suppressed ocean CO&lt;sub&gt;2&lt;/sub&gt; outgassing induced by decreased wind speed counteracts elevated ocean CO&lt;sub&gt;2&lt;/sub&gt; outgassing resulted from high temperature. In winter, both wind speed and temperature factors suppress ocean CO&lt;sub&gt;2&lt;/sub&gt; absorption from the atmosphere to the ocean. In addition, the spatial pattern of &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;FCO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{FCO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; is dominated by partial pressure of &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; in the surface water (&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;). While thermal effects have a contribution of 61% and 33% in YS and ECS to positive &lt;span&gt;&lt;/span&gt;&lt;m","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143801598","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":"On the Impact of Southeastern Pacific-Generated Storm Surges on the Southwestern Atlantic Continental Shelf: Interoceanic Connections Through Coastally Trapped Waves","authors":"Matías G. Dinapoli,&nbsp;Claudia G. Simionato","doi":"10.1029/2024JC021685","DOIUrl":"https://doi.org/10.1029/2024JC021685","url":null,"abstract":"<p>The storm surge in the Southwestern Atlantic Continental Shelf (SWACS) has been characterized as a process forced regionally by migrating atmospheric Rossby waves. When they produce alongshore winds, Ekman transport drives a sea level anomaly that then propagates northward as a Kelvin wave. Here, we explore the hypothesis that Rossby waves on the polar jet stream could generate additional surges in the southeastern Pacific by inverted barometer effect and/or Ekman transport, that then propagate to the SWACS as remotely forced signals connecting both oceans, by means of process-oriented numerical simulations. We find that atmospheric waves initially force a sea level anomaly over the South Pacific Ocean by inverted barometer effect; it increases by the action of alongshore winds when the signal interacts with the coast, and finally enters the SWACS. Remotely generated surge displays strong pseudo-periodicity in a band around 7.5 days and amplitudes of the order of 10% of the regional one. Although remotely and local forced events are independent, they can overlap originating more extreme events. Activity shows a statistically significant seasonal cycle (with mean kinetic energy in winter almost doubling that in summer) and interannual variability (with mean yearly activity almost doubling in some years) at 2–7 years that has increased since 1997, probably due to modulation of the storm tracks by climate variability. Incorporating this process in ocean simulations reduces the forecast/hindcast error of the oceanic surge by 50%.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787025","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 Wind-Driven Time-Variable Circulation in the Arctic Mediterranean","authors":"A. L. P. Sjur,&nbsp;P. E. Isachsen,&nbsp;J. Nilsson,&nbsp;J. H. LaCasce,&nbsp;M. D. Ryseth","doi":"10.1029/2024JC021713","DOIUrl":"https://doi.org/10.1029/2024JC021713","url":null,"abstract":"<p>The Arctic Ocean is a key component of Earth's climate system, and an understanding of ocean dynamics in this region is central for predicting how the Arctic is responding to a changing climate. In this study, we examine the ocean circulation in a high-resolution numerical model of the Arctic Ocean and Nordic Seas. Based on what is observed in this simulation, we reexamine an existing idealized linear model estimating the time-variable large-scale circulation in ocean basins, and test it against the highly nonlinear numerical model. The idealized model is an integral relation derived from the linear momentum equations and assumes that the circulation around a closed depth contour is driven by surface stresses and regulated by bottom friction. We show that the idealized model estimates agree very well with the numerical simulations. This indicates that much of the variability of the large-scale circulation can be explained by linear processes. In particular, a correct description of the net surface stress over partially ice-covered areas improves the correlation between linear model and numerical simulations significantly in the Arctic Ocean compared to a previous study. However, undetected in that previous study, we now find that the linear model might be lacking a cyclonic tendency.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021713","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787026","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":"Separation Timescales of Vertically Migrating Zooplankton and Other (a)Biotic Materials in the Benguela System","authors":"Darshika Manral,&nbsp;Laura Gómez-Navarro,&nbsp;Michael C. Denes,&nbsp;Doroteaciro Iovino,&nbsp;Pier Giuseppe Fogli,&nbsp;Simona Masina,&nbsp;Ismael Hernández-Carrasco,&nbsp;Linda Amaral-Zettler,&nbsp;Marcello Vichi,&nbsp;Erik van Sebille","doi":"10.1029/2024JC021701","DOIUrl":"https://doi.org/10.1029/2024JC021701","url":null,"abstract":"<p>Plankton, plastics, nutrients, and other materials in the ocean can exhibit different dispersion patterns depending on their individual transport properties. These dispersion patterns can provide information on the effective timescales of interaction between different types of materials in a highly dynamic ocean environment, such as the Benguela system in the southeast Atlantic Ocean. In this study, we compare the timescales and spatial distribution of separation for zooplankton performing Diel Vertical Migration (DVM) while drifting with currents to those of other materials: (a) positively buoyant plastics or planktonic organisms passively floating near the ocean's surface; (b) nutrients or pollutants passively advecting in the three-dimensional flow; and (c) sinking biogenic particulate matter. We apply the drift properties of each material type in Lagrangian flow modeling to simulate the movement of virtual particles across the Benguela system. Our results indicate faster separation between zooplankton performing DVM and the other particle types during the upwelling season in the austral spring and summer. We also observe a decrease in the separation timescales between zooplankton performing DVM and other particle types as the zooplankton migration depth increases. Despite the differences in separation timescales across seasons, different particle types can become trapped in coherent features such as eddies, fronts, and filaments, indicating prolonged exposure of zooplankton to prey and pollutants in these coherent ocean features.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021701","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784281","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 Role of Long-Term Hydrodynamic Evolution in the Accumulation and Preservation of Organic Carbon-Rich Shelf Sea Deposits","authors":"S. L. Ward,&nbsp;S. L. Bradley,&nbsp;Z. A. Roseby,&nbsp;S.-B. Wilmes,&nbsp;D. F. Vosper,&nbsp;C. M. Roberts,&nbsp;J. D. Scourse","doi":"10.1029/2024JC022092","DOIUrl":"https://doi.org/10.1029/2024JC022092","url":null,"abstract":"<p>Understanding and mapping seabed sediment distribution in shelf seas is essential for effective coastal management, offshore developments, and for blue carbon stock assessments and conservation. Fine-grained marine sediments, particularly muds, play a key role in long-term organic carbon sequestration, so knowledge of the spatial extent of these carbon-rich deposits is important. Here, we consider how changes in shelf sea tidal dynamics since the Last Glacial Maximum have influenced the development of three mud depocenters in the northwest European shelf seas: the Fladen Ground, the Celtic Deep, and the Western Irish Sea Mud Belt. Using a new high-resolution paleotidal model, we demonstrate how the evolution of simulated tidal parameters, including bed shear stress and bottom boundary layer thickness, differ across these sites. Geological data support our findings, indicating that long-term mud sedimentation continues to the present in the Celtic Deep and Western Irish Sea Mud Belt, while in the Fladen Ground, accumulation cannot be fully explained by contemporary hydrodynamics. In the latter, mud deposition is relict, deposited during quiescent tidal conditions between 17,000 and 5,000 years ago. We suggest that simulating paleoceanographic conditions can contribute to understanding first-order sediment dynamics over large spatial and temporal scales, a key input for predictive mapping and regional blue carbon inventories. This approach is a valuable first step in data-poor regions to identify potential fine sediment deposits. By illustrating the temporal evolution of organic carbon-rich deposits, we provide a broader context for managing organic carbon storage in shelf sea sedimentary environments.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022092","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770178","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 Effects of a Storm Surge Event on Salt Intrusion: Insights From the Rhine-Meuse Delta","authors":"Avelon Gerritsma,&nbsp;Martin Verlaan,&nbsp;Marlein Geraeds,&nbsp;Ymkje Huismans,&nbsp;Julie Pietrzak","doi":"10.1029/2024JC021520","DOIUrl":"https://doi.org/10.1029/2024JC021520","url":null,"abstract":"<p>The Rhine-Meuse Delta is a low-lying delta in the Netherlands that is subject to both salt intrusion events and storm surges. Typically, storm surges only temporarily cause increased salt intrusion and do not cause severe problems for freshwater availability. However, during the storm surge of December 2013, salt reached the closed southern branch of the delta and higher salinities were observed for weeks after the storm surge. The purpose of this study is to examine the mechanisms controlling salt intrusion in the Rhine-Meuse Delta during and after a severe storm surge event. A three-dimensional hydrodynamic model (Delft3D-FM) of the Rhine-Meuse Delta was developed that successfully reproduces salt intrusion for both normal and storm surge conditions. During the storm, high water levels in the northern branch caused a salt flux toward the southern branch. The southern branch of the Rhine-Meuse Delta is closed off by an estuarine dam, consequently salt was retained landward of the dam. Local stratification in the southern branch caused salt to remain in the deeper parts, limiting the effectiveness of flushing after the storm surge. In the post-storm period, salt was gradually released from the southern branch, raising salinity levels in an adjacent channel. The river discharge was only just below the yearly average, showing prolonged salt intrusion can also occur outside of dry periods.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021520","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770176","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":"Interaction Between Organic Carbon Conversion and Microbial Metabolism in Marginal Seas Sediments During Hydrodynamic Sorting Processes","authors":"Ziyang Yang,&nbsp;Lei Xing,&nbsp;Yangli Che,&nbsp;Nan Wang,&nbsp;Haiyue Ma,&nbsp;Siqi Zhao,&nbsp;Anna Chen,&nbsp;Haoshuai Li,&nbsp;Rui Bao","doi":"10.1029/2024JC021994","DOIUrl":"https://doi.org/10.1029/2024JC021994","url":null,"abstract":"<p>Hydrodynamic sorting processes control the transport of marine sediments in benthic environments of marginal seas, affecting the distribution of associated microbes and organic carbon (OC) composition in marine sediments. However, microbial characteristics variations and their impacts on OC stability during hydrodynamic sorting processes remain insufficiently understood. Here, we analyzed the concentrations and carbon isotopes of phospholipid fatty acids (PLFAs), and conducted the thermal stability analysis on OC in grain-size fractionated sediments retrieved along the classical transport pathway from the Yellow River delta to the Yellow Sea. We find that the relative abundance of anaerobic bacterial PLFAs has positive correlations with the proportion of pre-aged OC and negative correlations with the proportion of refractory OC compounds, and bioavailable OC become more limited along the transport pathway. We suggest that the decreasing refractory OC and the increasing pre-aged OC may facilitate the increasing abundance of anaerobic bacteria, and the metabolism of microbes can utilize the refractory OC during resuspension of marine sediments. The metabolism of microbes attached to resuspension sediments may produce by-products including pre-aged OC, which may promote the pre-aged OC burial in benthic environments, with important environmental implications such as carbon sequestration in marginal seas sediments.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143770177","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":"Under Ice-Shelf Eddy at the Stancomb-Wills Ice Tongue","authors":"C. Hancock,&nbsp;K. Speer,&nbsp;M. Janout,&nbsp;O. Boebel","doi":"10.1029/2024JC021393","DOIUrl":"https://doi.org/10.1029/2024JC021393","url":null,"abstract":"<p>Eddies are considered important for the dynamics within the Antarctic Slope Current but are difficult to observe due to the often year-round ice cover in the southern Weddell Sea. Here we present novel findings from acoustically tracked profiling floats, which observed the spin-down of an eddy under an ice shelf. Two profiling floats were deployed at 8°W in the Antarctic Slope Current and drifted westward along the slope at 800 m depth. One of the floats was captured by an anticyclonic eddy in the wake of the Riiser-Larsen Ice shelf. We postulate the eddy was generated by baroclinic instability due to the interaction of the Antarctic Slope Current with floating ice shelves. Float trajectories show the eddy propagated westward along the slope and ultimately became trapped under the Stancomb-Wills Ice Tongue, where the eddy spun down because of ocean-ice shelf stresses. Simple bulk mixing calculations were fitted to observations to explore the role of eddies under the ice shelf, in relation to an “Eddy-Ice-Pumping” mechanism, and revealed that significant basal melting occurred. Subsequent vertical mixing of the eddy's cold and fresh core, due to the Eddy-Ice-Pumping mechanism, resulted in a cold and fresh subsurface signal which was still evident downstream at the Filchner Trough 3 months later. Estimates of eddy contributions to basal melt and freshwater transport show eddies could have a significant impact on the stratification and thermocline depth downstream, potentially affecting the inflow of modified Warm Deep Water into the Filchner Trough.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021393","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762276","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}