Journal of Geophysical Research-Oceans最新文献

{"title":"Synoptic Observations of Near-Inertial Motions in an Enclosed Basin","authors":"Erica L. Green, Samuel M. Kelly, Andrew J. Lucas, Jay A. Austin, Jonathan D. Nash","doi":"10.1029/2024JC021828","DOIUrl":"https://doi.org/10.1029/2024JC021828","url":null,"abstract":"<p>Near-inertial motions are common in the coastal ocean, producing significant currents, isopycnal displacements, and turbulent mixing. Unknown fractions of near-inertial energy are locally dissipated in the mixed layer and converted to offshore propagating internal waves along the coast. Here, we examine near-inertial motions from July to October 2017 at 10 moorings in Lake Superior, which provides a natural laboratory for the coastal ocean. The lake has an approximate two-layer structure and is dominated by near-inertial currents that reach 0.50 m <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> and isopycnal displacements that reach 10 m. Average mode-1 near-inertial kinetic energy (KE) and available potential energy (APE) are 320 J <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>m</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{m}}^{-2}$</annotation>\u0000 </semantics></math> and 10 J <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>m</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{m}}^{-2}$</annotation>\u0000 </semantics></math>, respectively. KE is inhibited near the coast and APE has no basin-wide structure. Velocity is separated into a basin-averaged inertial oscillation (IO) and a near inertial wave (NIW) residual. A slab model explains 87% of the IO variance, while the NIW field exhibits 5 W <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>m</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{m}}^{-1}$</annotation>\u0000 </semantics></math> offshore energy fluxes along the coasts, a group speed of 0.1 m <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 ","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021828","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689898","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 Wind and Buoyancy in a Turbulence-Resolving Model of the Atlantic Meridional Overturning Circulation","authors":"Bahman Ghasemi,&nbsp;Catherine A. Vreugdenhil,&nbsp;Bishakhdatta Gayen","doi":"10.1029/2024JC021790","DOIUrl":"https://doi.org/10.1029/2024JC021790","url":null,"abstract":"<p>The Atlantic meridional overturning circulation (AMOC) in the North Atlantic Ocean is shaped by mechanical and buoyancy forcing, with critical components like the Gulf Stream, gyres, dense water formation, and deep water upwelling. The AMOC is undergoing significant variability due to changes in forcing from the rapidly changing climate. However, limited understanding and resolution in capturing deep convection and boundary layer dynamics lead to inaccuracies in future ocean mass and heat transport estimations. This study employs novel turbulence- and convection-resolving simulations of an idealized, laboratory-scale North Atlantic Ocean model to investigate these effects. The simulation captures key features observed in the North Atlantic Ocean, including the AMOC, downwelling and upwelling, boundary currents, thermocline layers, gyres, fronts, and baroclinic eddies. With the presence of wind, two distinct thermocline layers form in the subtropics due to Ekman pumping: the “ventilated thermocline” near the surface and the “internal thermocline” below. We examine two scaling theories to quantify meridional and gyre transport based on these thermocline layers. Our findings indicate that meridional transport increases with both buoyancy and wind forcing, while zonal transport is enhanced by wind and shows some dependence on buoyancy forcing. We find that upwelling near the western boundary intensifies with increased wind and buoyancy forcing, while downwelling from convection occurs along the northeastern boundary and from Ekman pumping in the subtropics, highlighting the three-dimensional structure of the AMOC. Our results demonstrate the interconnectedness of gyres and deep overturning circulation, offering insights toward refining turbulence and convection parameterizations in ocean models.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021790","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689941","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":"Variability of the South Pacific Eastern Subtropical Mode Water and Associated Causal Mechanism During the Argo Period","authors":"Guimin Sun,&nbsp;Jifeng Qi,&nbsp;Tangdong Qu,&nbsp;Baoshu Yin","doi":"10.1029/2024JC022254","DOIUrl":"https://doi.org/10.1029/2024JC022254","url":null,"abstract":"<p>Variability of the South Pacific eastern subtropical mode water (SPESTMW) is investigated using Argo data and ERA5 reanalysis products, with particular attention paid to its connection to the El Niño-Southern Oscillation (ENSO). Our analysis shows significant seasonal variation in the SPESTMW volume, reaching its maximum (minimum) in November (July). Changes in the mixed layer depth (MLD) dominated by shortwave radiation are the main cause of this seasonal variation. In contrast, latent heat flux is primarily responsible for the MLD and SPESTMW variability on interannual timescales. There is a considerable association between the SPESTMW volume and ENSO, decreasing (increasing) during El Niño (La Niña) years. Further analysis of ERA5 reanalysis products indicates that anomalous winds associated with ENSO modulate surface latent heat flux via evaporation, which further alters the MLD and the SPESTMW volume. Our analysis also reveals significant differences in the SPESTMW response to the central and eastern Pacific El Niño, implying potential importance of the SPESTMW in regional ocean and climate variability.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689940","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":"A Divergence and Vorticity View of Nonlinear Oceanic Lee Wave Obtained by a Two-Vessel Survey","authors":"Tsai-Ling Chuang,&nbsp;Jia-Lin Chen,&nbsp;Ming-Huei Chang,&nbsp;Ren-Chieh Lien,&nbsp;Yu-Hsin Cheng,&nbsp;Yiing Jang Yang,&nbsp;Sen Jan,&nbsp;Anda Vladoiu","doi":"10.1029/2024JC021422","DOIUrl":"https://doi.org/10.1029/2024JC021422","url":null,"abstract":"&lt;p&gt;The spatial distribution of the flow field inferred from shipboard measurements often suffers from a spatial-temporal aliasing effect. This study examined a detailed view of the horizontal divergence and relative vertical vorticity captured by a two-vessel survey to characterize velocity gradients and the resulting process in the presence of nonlinear lee waves. The three-dimensional structure of the horizontal velocity gradients and turbulent mixing within a nonlinear internal lee wave behind a shallow seamount was investigated. Synchronous two-vessel Acoustic Doppler Current Profilers provide in-situ measurements of velocity vectors that significantly minimize the spatial and temporal aliasing effect. The magnitude of horizontal divergence and relative vertical vorticity normalized by the planetary vorticity (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;δ&lt;/mi&gt;\u0000 &lt;mo&gt;/&lt;/mo&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $delta /f$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;ζ&lt;/mi&gt;\u0000 &lt;mo&gt;/&lt;/mo&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $zeta /f$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; ∼ O (10)) is one order of magnitude greater than prior observations in the typical oceanic sub-mesoscale flow field using a two-vessel survey. Our analysis indicates that the spatial variations of horizontal divergence and relative vertical vorticity over the seamount are associated with flow-topography interactions. Owing to the bottom Ekman effect, the deflected Kuroshio enhances the relative vertical vorticity, &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;ζ&lt;/mi&gt;\u0000 &lt;mi&gt;z&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mo&gt;∂&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mi&gt;x&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mi&gt;V&lt;/mi&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mo&gt;∂&lt;/mo&gt;\u0000 &lt;mi&gt;y&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mi&gt;U&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${zeta }_{z},{=mathit{partial }}_{x}V-{mathit{partial }}_{y}U$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, and horizontal components of relative vorticity, &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;ζ&lt;/mi&gt;\u0000 &lt;mi&gt;x&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 ","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021422","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689934","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 Impacts of Two Types of El Niño on Interannual Variations of Marine Heatwaves in the South China Sea","authors":"Ningning Zhang,&nbsp;Jian Lan,&nbsp;Wenjin Sun,&nbsp;Changming Dong","doi":"10.1029/2024JC021991","DOIUrl":"https://doi.org/10.1029/2024JC021991","url":null,"abstract":"<p>This study utilizes multiple observational and reanalysis data sets to investigate the contrasting effects of Eastern Pacific (EP) and Central Pacific (CP) El Niño on interannual variations of marine heatwaves (MHWs) in the South China Sea (SCS) from the developing autumn to decaying summer of El Niño. EP El Niño is associated with more frequent, intense, and prolonged MHWs throughout its life cycle, while CP El Niño is linked to a general decrease in MHW characteristics, except in decaying summer. During EP El Niño, an anomalous anticyclone over the SCS during developing autumn induces warming mainly by increasing shortwave radiation and diminishing latent heat release, fostering MHW development. The anomalous warming persists into decaying summer, intensified by the influence of an anticyclone associated with the western North Pacific subtropical high (WNPSH). Reduced MHWs during CP El Niño are primarily attributed to cooling in developing autumn and early cessation of warming in decaying summer. This autumn cooling is connected to enhanced latent heat release, anomalous Ekman upwelling, and negative horizontal advection caused by an anomalous cyclone around the SCS. The early fade of summer warming in CP El Niño is due to the northeastward shift of the WNPSH compared to the EP El Niño scenario, which reduces its ability to warm the SCS. The sea surface temperature (SST) evolutions during CP El Niño events highlight the thermal status of developing autumn and decaying summer as critical factors for MHW occurrence and persistence, underscoring the necessity to assess the thermal state preceding SST increases in MHW research.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689935","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 and Decadal Geostrophic Pathways of Pacific and Atlantic Waters in the Arctic Amerasian Basin From Observations","authors":"Noémie Planat,&nbsp;L. Bruno Tremblay,&nbsp;Carolina O. Dufour,&nbsp;David Straub","doi":"10.1029/2024JC021560","DOIUrl":"https://doi.org/10.1029/2024JC021560","url":null,"abstract":"<p>We examine the geostrophic pathways of Pacific and Atlantic Waters along isopycnal surfaces of the Arctic Ocean from Montgomery potentials using two observation-based climatologies: the World Ocean Atlas and the Monthly Isopycnal &amp; Mixed-layer Ocean Climatology. The decadal mean circulation (2005–2017) shows an anticyclonic circulation for both the summer Pacific Waters (sPW) and winter Pacific Waters (wPW, although somewhat weaker) in the Canada Basin with subduction along the Chukchi plateau for both water masses. On the wPW layer, the diagnostics also highlight a year-long persistent flow from Herald Canyon on Chukchi Shelf to the Canadian Arctic Archipelago around the Canada Basin. Outflows are found at Nares and Fram Sraits at the density of sPW and wPW. These outflowing waters, previously reported as Pacific Waters, are found here to originate from the Eurasian shelf. Deeper, the Atlantic Waters flow anticyclonically around Northwind Ridge and cyclonically along the Alaskan shelfbreak forming a boundary current. The subduction of warm water along the Alaskan and Chukchi shelves is found to occur in summer on the sPW isopycnal layer, thus contributing to transferring heat into the center of the gyre. However, an advection of virtual Lagrangian particles from Pt. Barrow suggests that processes operating on timescales shorter than a month or at interannual timescales are the main contributors to the heat build up observed over the past two decades. This analysis supports the hypothesis that high frequency processes are key in shaping the subsurface heat reservoir of the Canada Basin.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021560","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689436","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":"Decadal Linkage of Sea Level Anomalies Between the South China Sea and Western Tropical Pacific","authors":"Qin Duan,&nbsp;Tianyu Wang,&nbsp;Yuhong Zhang,&nbsp;Yan Du","doi":"10.1029/2024JC021618","DOIUrl":"https://doi.org/10.1029/2024JC021618","url":null,"abstract":"<p>The decadal variability of sea level anomalies (SLA) in the South China Sea (SCS) is coherent with those in the Western Tropical Pacific (WTP), and both correlate with the Pacific Decadal Oscillation (PDO) with changing correlation across different decades, characterized by an enhanced relationship after 1993. This study analyzed the underlying factors in the relationship between SLA in the SCS and PDO based on observations and simple ocean model experiments. The results reveal that the key factor is the anomalous atmospheric anticyclonic circulation over the tropical western North Pacific (WNPAAC), which can induce positive decadal SLA responses. The WNPAAC index, defined as the regional mean Wind Stress Curl in the Tropical Western North Pacific (TWNP, 3°–18°N, 130°E–160°W), exhibits a negative correlation (<i>r</i> = −0.68 for 1940–2022, exceeding the 95% confidence level) with the decadal steric sea level first mode principal component of empirical orthogonal function. The index can thus characterize the decadal SLA variations in the SCS and the WTP well. Sensitivity experiments using a 1.5-layer nonlinear Reduced-Gravity Ocean model demonstrate that the TWNP wind field accounts for most of the decadal SLA variations in the SCS, with an explained variance percentage (skill) of 60.95%. This study suggests that the TWNP wind field, influenced by tropical central Pacific sea surface temperature anomalies through the Matsuno-Gill response after 1965, dominates decadal SLA variability in the SCS. This wind field functions as a subsystem within the PDO dynamics, showing relative independence from the PDO.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689381","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 Role of Dynamic Seepage Response in Sediment Transport and Tsunami-Induced Scour","authors":"Zhengyu Hu,&nbsp;Wen-Gang Qi,&nbsp;Yuzhu Pearl Li","doi":"10.1029/2024JC021084","DOIUrl":"https://doi.org/10.1029/2024JC021084","url":null,"abstract":"<p>Tsunamis have long been recognized to destabilize the seabed by causing severe erosion and potential liquefaction. However, the effect of the dynamic seepage response induced by tsunami loading on sediment transport remains elusive. Here, we explicitly quantify the role and mechanics of seepage response in field-scale tsunami-induced bed mobility and scour through theoretical analyses and fully coupled hydrodynamic and morphological simulations. The increased hydraulic gradient can lower the onset threshold of the sediment motion, thus facilitating sediment transport. In the meantime, it can also curtail the fluid–sediment momentum transfer, consequently weakening sediment transport. The competing effects of seepage response on the onset threshold and fluid agitation are such that the seepage response during the depression wave does not necessarily increase bed mobility. The suspended load transport can dominate the near-field scour processes, as demonstrated with the scour beneath a submarine pipeline. The seabed suction response to the elevation wave shows insignificant effects on the continuous exchange between the suspended load and bed load, although it inhibits the near-bed sediment concentration. The seabed injection response to the depression wave induces more bed load particles to be entrained into the water column, contributing to the increased concentration. This results in increased sediment transport and exacerbated scour, especially for the bed liquefaction scenario. The seepage response plays a critical role in the spatiotemporal variations of the seabed morphology and the sediment suspension. The outcomes significantly update the knowledge about the role of seepage in the progress of tsunami-induced sediment transport and scour.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689380","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":"Geochemical Fingerprinting of Siboglinid Tube Worms: Insights From Stable Isotopes (C, N, and S) and Trace Elements","authors":"Zice Jia,&nbsp;Niu Li,&nbsp;Jörn Peckmann,&nbsp;Xudong Wang,&nbsp;Junxi Feng,&nbsp;Bolin Zhuo,&nbsp;Na Cui,&nbsp;Zenggui Kuang","doi":"10.1029/2024JC022177","DOIUrl":"https://doi.org/10.1029/2024JC022177","url":null,"abstract":"<p>At marine methane seeps, siboglinid tube worms influence the exchange of elements between sediments and seawater and potentially represent a recorder of seep activity. The organ of siboglinids produces the chitin of the tube wall, facilitating the formation of tubes that protect the siboglinid's soft tissue. However, the mechanisms underlying element transfer and isotope fractionation between soft tissue and the chitinous tube are poorly constrained. This study analyzes the carbon, nitrogen, and sulfur isotopes as well as trace elements, including rare earth elements (REEs) and copper (Cu), compositions of tissues and tubes of the siboglinid tube worm <i>Paraescarpia echinospica</i> from the Haima seeps of the South China Sea. The stable isotope values of both tissue and the chitinous tube primarily reflect sulfur oxidation processes and carbon fixation by endosymbiotic sulfur-oxidizing bacteria. The trace element composition of the soft tissue suggests the utilization of light rare earth elements (LREEs) and Cu during aerobic oxidation of methane supposedly performed by epibiotic aerobic methanotrophic bacteria. In contrast, the trace element composition (e.g., REEs, Cu) of the chitinous tube primarily records the influence of diagenetic processes and source effects. The chitinous tube is therefore apparently not a straightforward archive of the local environment and metabolic characteristics of the tube worms. Still, the discrepancies between the information stored in tissue and the chitinous tube may offer some insight for the identification of fossil seep-dwelling tube worms if parts of the chitinous tube are preserved. Integrating element and isotope geochemistry within paleontological studies may consequently enhance our understanding of siboglinid evolution.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689529","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":"Infragravity Frequency Wave-Driven Bottom Boundary Layer Turbulence in Shallow Estuaries","authors":"Duncan C. Wheeler,&nbsp;Sarah N. Giddings,&nbsp;Mark Merrifield,&nbsp;Geno Pawlak","doi":"10.1029/2024JC021284","DOIUrl":"https://doi.org/10.1029/2024JC021284","url":null,"abstract":"<p>We use turbulent dissipation measurements from a small estuary to determine how and when infragravity (IG) waves (periods <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>25–250 s) increase turbulence due to bottom friction. The frequency of IG waves leads to a larger wave boundary layer than for sea and swell waves. Current methods for predicting turbulence from mean currents rely on observations in regions of the water column where oscillating velocities either have a logarithmic or depth-uniform profile. We develop a new approach for predicting turbulent dissipation in the unsteady boundary layer regime that combines a quasi-steady regime at the bottom of the water column and an outer regime above the wave boundary layer. Using a numerical model and observations from Los Peñasquitos Lagoon, we find that the new approach allows for calculation of average turbulent dissipation rates throughout the entire water column and performs better than existing methods when calculating turbulent dissipation within the wave boundary layer. Our observations indicate IG waves increase turbulent dissipation across a substantial fraction of the water column when the mean current amplitude is less than <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>3</mn>\u0000 <mo>/</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 <annotation> $3/2$</annotation>\u0000 </semantics></math> of the current standard deviation. These conditions were typically observed during neap flood tides or at the very beginning and the end of spring flood tides. In addition, we find that the wave boundary layer height can be estimated from the instantaneous bottom stress, consistent with existing scaling approaches. Finally, we show that IG wave-induced increases in turbulence appear associated with sediment transport inside the estuary.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021284","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689528","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}