Journal of Geophysical Research-Oceans最新文献

{"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}

{"title":"Seasonality of Internal Tides in the Strait of Hormuz: Observations and Modeling","authors":"M. P. Subeesh,&nbsp;Hajoon Song,&nbsp;Yacine Addad,&nbsp;Jeffery R. Scott,&nbsp;John Marshall,&nbsp;Maryam R. Al Shehhi","doi":"10.1029/2024JC021007","DOIUrl":"https://doi.org/10.1029/2024JC021007","url":null,"abstract":"<p>The seasonality of internal tides in shallow seas is primarily controlled by changes in stratification. This study explores how semidiurnal and diurnal internal tides respond differently to seasonal stratification, using mooring observations and numerical modeling in the Strait of Hormuz, the gateway for hypersaline Arabian Gulf waters. Semidiurnal internal tides are weak during winter, which is attributed to relatively weak stratification, whereas diurnal internal tides are enhanced. In the remaining seasons, internal tides are strong in both bands. Estimates of energy flux and barotropic-to-baroclinic conversion rates from observations and modeling show a likely generation site near the mooring location. In winter, this generation site turns subcritical at semidiurnal frequencies and supercritical at diurnal frequencies. In addition, barotropic tides show significant amplification at the diurnal frequency during winter. Thus, supercritical topography along with strong barotropic tidal forcing enhances the diurnal internal tides. In the remaining seasons, the topography becomes either critical or supercritical for the semidiurnal frequency and supercritical for the diurnal frequency, resulting in strong internal tide generation. The results of our model show that low-frequency currents significantly influence stratification in the strait, thus playing a crucial role in modulating internal tides. In turn, vertical mixing orchestrated by those tides may be important in setting water mass transformation rates, stratification, and exchange through the strait.</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/10.1029/2024JC021007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761867","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":"Estimation of Eulerian Sea Surface Currents and Lagrangian Trajectory Using Ocean Color Elements From GOCI Images in Turbid Coastal Water","authors":"Xiaoping Xu,&nbsp;Bin Ai,&nbsp;Jun Zhao,&nbsp;Yuxun Liu","doi":"10.1029/2024JC022666","DOIUrl":"https://doi.org/10.1029/2024JC022666","url":null,"abstract":"&lt;p&gt;In turbid coastal waters, sea surface currents often exhibit frequent spatiotemporal variability, retrieving them from optical satellite data remains challenging due to the saturated signal caused by suspended particles. This study uses the maximum cross-correlation (MCC) method to retrieve Eulerian currents and Lagrangian trajectories in turbid nearshore areas, and the performance of MCC with different correlation coefficients and tracers are evaluated. Current vectors calculated using the Cosine correlation coefficient show the highest consistency with high frequency radar currents. The minimum average magnitude error and average angular error were 0.51 and 23.98°, respectively. They also demonstrate strong statistical correlations of 0.99 for direction and 0.8 for speed with measured tidal currents, surpassing results calculated using Pearson and Tanimoto correlation coefficients. Eulerian currents and Lagrangian trajectories can effectively be derived from the tracers inverted from Rayleigh-corrected reflectance. The number of valid current vectors from total suspended matter (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;_&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${R}_{rc}{_}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;TSM) and chlorophyll-a concentration (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;_&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${R}_{rc}{_}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;Chl) is more than double that estimated with the tracers inverted from thoroughly atmospheric corrected reflectance. The fusion of these two tracers further enhances the reliability and consistency of the estimated currents. In tidal-dominant regions, Lagrangian trajectories from &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;_&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${R}_{rc}{_}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;TSM and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;_&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 ","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749589","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":"Seasonal Source Water Changes and Winds Contribute to the Development of Hypoxia in St Helena Bay Within the Southern Benguela Upwelling System","authors":"A. J. Carlson,&nbsp;S. A. Siedlecki,&nbsp;J. Granger,&nbsp;J. Veitch,&nbsp;G. C. Pitcher,&nbsp;G. Fearon,&nbsp;F. Soares,&nbsp;M. Zhou,&nbsp;R. F. Flynn,&nbsp;S. E. Fawcett","doi":"10.1029/2024JC021702","DOIUrl":"https://doi.org/10.1029/2024JC021702","url":null,"abstract":"<p>St Helena Bay (SHB), a retentive zone in the productive southern Benguela Upwelling System off western South Africa, experiences seasonal hypoxia and episodic anoxic events that threaten local fisheries. To understand the drivers of oxygen variability in SHB, we queried 25 years of dissolved oxygen (DO) observations alongside high-resolution wind and hydrographic data, and dynamical data from a high-resolution model. At 70 m in SHB (mid-bay), upwelling-favorable winds in spring drove replenishment of cold, oxygenated water. Hypoxia developed in summer, becoming most severe in autumn. Bottom waters in autumn were replenished with warmer, less oxygenated water than in spring—suggesting a seasonal change in source waters upwelled into the bay. Downwelling and deep mixing in winter ventilated mid-bay bottom waters, which reverted to hypoxic conditions during wind relaxations and reversals. In the nearshore (20 m), hypoxia occurred specifically during periods of upwelling-favorable wind stress and was most severe in autumn. Using a statistical model, we extended basic hydrographic observations to nitrate and DO concentrations and developed metrics to identify the accumulation of excess nutrients on the shelf and nitrogen-loss to denitrification, both of which were most prominent in autumn. A correspondence of the biogeochemical properties of hypoxic waters at 20 m to those at 70 m implicates the latter as the source waters upwelled inshore in autumn. We conclude that wind-driven upwelling drives the replenishment of respired bottom waters in SHB with oxygenated waters, noting that less-oxygenated water is imported later in the upwelling season, which exacerbates hypoxia.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740976","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":"Does Wind-Driven Mixing Sustain Post-Bloom New Production in the Barents Sea?","authors":"J. S. Braun,&nbsp;J. P. Rodgers,&nbsp;T. Brand,&nbsp;K. Davidson,&nbsp;S. F. Henley,&nbsp;M. Inall,&nbsp;M. Porter,&nbsp;E. J. Venables,&nbsp;F. Cottier","doi":"10.1029/2024JC021081","DOIUrl":"https://doi.org/10.1029/2024JC021081","url":null,"abstract":"<p>Wind-driven mixing is one of the primary factors likely to regulate changes in primary production in the future Arctic Ocean with reduced sea ice coverage. Quantifying this effect requires an understanding of whether this mechanism will resupply nutrients to surface waters during the post-bloom season. We therefore investigated the role of wind-driven mixing events in initiating new production in the Barents Sea by combining measurements of turbulence, nitrate fluxes, and proportional uptake of nitrate during primary production. We calculated the resupply of nitrate, and the relationship between nitracline and wind-driven mixing depths was evaluated to investigate mechanisms for resupply of nitrate over the post-bloom summer. In the weakly stratified waters of the central Barents Sea, wind-driven resupply of nitrate to the surface was not found at the time of sampling. Nor was such resupply predicted based on empirical modeling of wind-driven mixing depth and the depth of the upper boundary of the nitracline for the post-bloom summer season. In the strongly stratified waters of the northern Barents Sea, new production was low at the time of sampling, but modeling suggests that wind-driven nitrate resupply is likely to occur during the post-bloom summer, differing from previous findings. The highest nitrate fluxes were found over the shelf slope north of Svalbard, which were 10 times higher than in the central Barents Sea, supporting 47% of the net primary productivity, accounted for as new production. Our model suggested that wind-driven nitrate resupply is to be expected for the shelf slope during the post-bloom season.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741566","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 Arctic Beaufort Gyre in CMIP6 Models: Present and Future","authors":"Marylou Athanase,&nbsp;Raphael Köhler,&nbsp;Céline Heuzé,&nbsp;Xavier Lévine,&nbsp;Ryan Williams","doi":"10.1029/2024JC021873","DOIUrl":"https://doi.org/10.1029/2024JC021873","url":null,"abstract":"<p>The Beaufort Gyre (BG) is an important feature of the Arctic Ocean. By accumulating or releasing freshwater, it influences ocean properties both within the Arctic and as far as the North Atlantic. Yet, its future remains uncertain: the gyre could strengthen as sea ice declines and allows increased wind stress on the ocean, or weaken along with the Beaufort High (BH) pressure system. Here, we provide a first evaluation of the BG in historical and climate-change simulations from 27 available global climate models. We find that the vast majority of models overestimate the gyre area, strength, and northward extent. After discarding the models with too inaccurate a gyre and its drivers—namely, the sea ice cover and BH—we quantify changes in the BG under two emission scenarios: the intermediate SSP2-4.5 and the high-warming SSP5-8.5. By the end of the 21st century, most models simulate a significant decline or even disappearance of the BG, especially under SSP5–8.5. We show that this decline is mainly driven by a simulated future weakening of the BH, whose influence on the BG variations is enhanced by the transition to a thin-ice Arctic. The simulated gyre decline is associated with an expected decrease in freshwater storage, with reduced salinity contrasts between the gyre and both Arctic subsurface waters and freshwater outflow regions. While model biases and unresolved processes remain, such possible stratification changes could shift the Atlantic-Arctic meridional overturning circulation northward.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021873","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741567","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":"Mercury Distribution and Speciation Along the U.S. GEOTRACES GP15 Pacific Meridional Transect","authors":"Lindsay D. Starr,&nbsp;Yipeng He,&nbsp;Robert P. Mason,&nbsp;Chad R. Hammerschmidt,&nbsp;Silvia E. Newell,&nbsp;Carl H. Lamborg","doi":"10.1029/2024JC021672","DOIUrl":"https://doi.org/10.1029/2024JC021672","url":null,"abstract":"<p>Mercury (Hg) is a bioaccumulative neurotoxin that can concentrate to potentially harmful levels in higher levels of marine food webs following conversion to methylmercury (MeHg). This is of public health concern as seafood is a main protein source for many in the Pacific region. To better understand Hg partitioning and transformations in the Pacific Ocean, Hg species and phases were measured along a meridional section from Alaska to Tahiti in 2018. This allowed the description of Hg concentrations and speciation under a variety of biogeochemical conditions such as the Alaskan shelf, the oligotrophic North Pacific gyre, and near the hydrothermally active Loihi seamount. Filtered HgT concentrations were elevated below 1,000 m near the Loihi Seamount with an average concentration of 1.45 pM, possibly indicating enrichment from hydrothermal venting. Filtered MeHg concentrations were notably higher at depth at the equator and generally lower south of the equator. Total Hg in suspended particles was greatest in the upper 1,000 m near the Alaskan Shelf and decreased in concentration southward. Suspended particle MeHg was greatest in the surface ocean in the upper 300 m near the Intertropical Convergence Zone (ITCZ). For both HgT and MeHg, particle-associated concentrations appear to be related to organic fraction, and concentrations decreased southward. In general, all measured Hg species had greater concentrations in the northern than southern Pacific Ocean consistent with prior measurements.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 4","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021672","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143735509","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}