Deep-Sea Research Part I-Oceanographic Research Papers最新文献

{"title":"Bio-optical properties and radiant heating rates in the borderlands region of the Chukchi Sea: The roles of phytoplankton biomass and sea ice cover","authors":"Xingyuan Zhu ,&nbsp;Tao Li ,&nbsp;Lee W. Cooper ,&nbsp;Eun Jin Yang ,&nbsp;Jinyoung Jung ,&nbsp;Kyoung-Ho Cho ,&nbsp;Yubin Yao ,&nbsp;Yamei Tang","doi":"10.1016/j.dsr.2025.104458","DOIUrl":"10.1016/j.dsr.2025.104458","url":null,"abstract":"<div><div>Hydrographic, irradiance, nutrient and chlorophyll-a concentration data were collected in the Chukchi Borderlands region of the northern Chukchi Sea 2011 and 2015 during Korean Arctic program research cruises. Goals included investigation of the spatial and temporal variability of optical and radiant heating properties in the water column, with a focus on the roles of phytoplankton and sea ice. The distribution of phytoplankton in the Chukchi Borderlands exhibits significant east-west variations, derived from two distinct water body types: Type-C and Type-M. Type-C water is influenced by the relatively low-nutrient Pacific Summer Water and upper layers of the central Beaufort Gyre, while Type-M water is associated with relatively higher-nutrient waters found in upwelling and shelf regions. In addition, the differences between these two water types are also reflected in their thermohaline properties, sea ice concentration, optical properties, and radiant heating rates. Under conditions of high sea ice concentration, we observed that phytoplankton are concentrated in the upper layers where more light is available, which in turn concentrates radiative energy at the surface. This mechanism partly reduces the impact of sea ice cover and increases radiant heating in early melt season, aiding further sea ice melt. The near-surface temperature maximum (NSTM) <span><math><mrow><msub><mi>T</mi><mi>max</mi></msub></mrow></math></span> is strongly correlated with the radiant heating rate (R² = 0.79; p &lt; 0.001), and the presence of sea ice decreases the heating rate. On balance, as Arctic sea ice continues to decline, we estimate that the heat stored in the NSTM would contribute to melting 35.3 cm thickness of existing sea ice. These findings highlight the crucial roles of phytoplankton and sea ice in the dynamics of Arctic Ocean radiant heating.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"218 ","pages":"Article 104458"},"PeriodicalIF":2.3,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid chemistry evolution in deep-sea hydrothermal environments: Unraveling mineral-fluid-microorganism interactions through continuous culture experiment","authors":"Lise Artigue ,&nbsp;Valérie Chavagnac ,&nbsp;Christine Destrigneville ,&nbsp;David François ,&nbsp;Françoise Lesongeur ,&nbsp;Anne Godfroy","doi":"10.1016/j.dsr.2025.104456","DOIUrl":"10.1016/j.dsr.2025.104456","url":null,"abstract":"<div><div>This study investigates minerals and microorganisms effects on fluid chemistry through a continuous enrichment culture in a gas-lift bioreactor during the MoMARsat’19 cruise. A sulfate-based chimney and buoyant hydrothermal fluid, both collected <em>in situ</em> at the Aisics vent of the Lucky Strike hydrothermal field, were incubated for 18 days under physico-chemical conditions simulating those of diffuse hydrothermal vents. We present the evolution of elemental and Sr, and Li isotopic compositions of the bioreactor fluid, alongside Bacteria and Archaea diversity, and analyze the mineral saturation state of the fluid through geochemical modeling. Our results show that the microbial diversity in the bioreactor reflects that of the sulfate-based chimney. During the initial 168 h, minerals precipitation/dissolution primarily controlled the elemental and Sr isotopic composition of the fluid. From 168 h to 264 h, sulfate-reducing Archaea (Archaeoglobi) disappeared in favor of sulfur-reducing Archaea (Thermoprotei and Thermococci). This shift coincides with a drastic increase in trace element concentrations and less radiogenic ⁸⁷Sr/⁸⁶Sr ratios, suggesting a possible microbial influence on the fluid. From 264 h onwards, with stable sulfur-reducing archaeal diversity, mineral saturation state primarily controls the elemental composition of the fluid. However, the observed increase in the ⁸⁷Sr/⁸⁶Sr ratio and δ⁷Li correlates with changes in bacterial diversity, notably an increase in Deinococci abundance. This study reveals that in a bioreactor simulating diffuse vent environments related to the sulfur cycle: (i) both microorganism and mineral influence fluid chemistry over time, (ii) shift in microbial diversity appear to affect trace metal concentrations and isotopic signatures, and (iii) the ⁸⁷Sr/⁸⁶Sr ratio serves as a tracer for mineral-fluid interactions and may be a tracer for microorganism-fluid interactions.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"218 ","pages":"Article 104456"},"PeriodicalIF":2.3,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Origin and propagation of M2 internal tides in the Arabian Sea","authors":"Hua Zheng ,&nbsp;Min Wang ,&nbsp;Tao Zhang ,&nbsp;Ruibin Ding ,&nbsp;Ying Jin ,&nbsp;Kun Zhang ,&nbsp;Deng Zhang ,&nbsp;Binjie Wu ,&nbsp;Yiwei Zhang","doi":"10.1016/j.dsr.2024.104441","DOIUrl":"10.1016/j.dsr.2024.104441","url":null,"abstract":"<div><div>Internal tides (ITs) generated by the interaction of barotropic tides and rough topography in stratified oceans play a significant role in turbulent mixing and thermohaline circulation. The baroclinic modes, propagation, energy, and origin of M₂ ITs in the Arabian Sea are analyzed using Multivariate Inversion of Ocean Surface Topography Internal Tide Model product (MIOST-IT). The M₂ ITs are generated in the northeast Arabian Sea, around the Socotra Island, and around the Maldive Islands, dominated by the mode-1 component with a wavelength of approximately 110 km. The most energetic M₂ ITs radiate from the continental shelf of the northeast Arabian Sea for more than one thousand kilometers with mode-1 and mode-2 energy of approximately 0.56 GW and 0.04 GW, respectively. M₂ ITs generated around the ridges southeast of the Gulf of Oman propagate southeastward, whereas they radiate in all directions from the Socotra Island. The northeastward-propagated M₂ ITs from the Socotra Island and the southwestward-propagated M₂ ITs from the continental shelf form standing waves. The M₂ ITs propagate westward on the western side of the Maldive Islands and eastward on the eastern side, dominated by mode-1 with energy of 0.17 GW and 0.08 GW, respectively. The study presents the characteristics of multi-directionally propagated and multi-modally M₂ ITs in the Arabian Sea, which addresses the characteristics of M₂ ITs in the region, therefore contributing to the understanding of the Arabian Sea's role in regional and global overturning circulation, energy budget, climate dynamics, and ecological environments.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"216 ","pages":"Article 104441"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pteropod assemblages in the oceanic waters of the southern Gulf of Mexico (June 2015)","authors":"H.S. López-Arellanes ,&nbsp;J.A. Cruz-Barraza ,&nbsp;E.D. Ruvalcaba-Aroche ,&nbsp;C.A. Silva-Segundo","doi":"10.1016/j.dsr.2024.104431","DOIUrl":"10.1016/j.dsr.2024.104431","url":null,"abstract":"<div><div>The pteropod community structure in the oceanic waters of the southern Gulf of Mexico (sGoM) was analyzed in June 2015. For the first time, we used an integrative morphological and molecular approach for pteropod identification in the sGoM. A total of 32 pteropod taxa were morphologically identified from the oceanic waters of which 12 were successfully sequenced, at least for one of the loci implemented (COI and 28S). The molecular data support the taxonomic identity of half of them. However, despite the morphological differences in the other six taxa, the molecular evidence displayed low genetic variability, resulting in a resolution to the genus level. During the sampling campaign, the oceanographic conditions were very homogeneous in all the sampled areas, with high surface temperatures (SST &gt;27.5 °C) and low chlorophyll (CHL &lt;0.5) concentrations. Nevertheless, CHL presented a positive and significant correlation with total pteropod abundance, herbivores abundance and carnivores abundance, suggesting a bottom-up control of the pteropod community. The ecological analysis showed that four species accounted for 63% of the pteropod abundance: <em>Heliconoides inflatus</em>, <em>Creseis conica</em>, <em>Limacina trochiformis</em> and <em>Creseis acicula</em>. The cluster analysis showed the presence of four assemblages, named after their distribution and species composition. The oceanic assemblage presented a wide distribution over the sampled area, characterized by a set of oceanic species such as <em>H. inflatus</em>, <em>Styliola subula</em> and <em>Limacina lesueurii</em>, with no apparent correlation with the measured environmental variables. The coastal oceanic assemblage presented the highest pteropod abundances; it was characterized by the dominance of the neritic species <em>C. conica</em> and <em>L. trochiformis</em>, and significant positive correlation with CHL concentration. The other two assemblages were distributed in the vicinity of an anticyclonic eddy with high stratification and low CHL values in the northwest, and presented a mixed dominance among the oceanic species <em>H. inflatus</em>, <em>C. acicula</em> and <em>S. subula</em>. The oceanic assemblage is suggested as the basal pteropod community in the sGoM. It is modified by the deflection of the coastal current in the southeast that transports nutrients and biota into the oceanic domain and produce relative enrichment of the CHL concentration. The presence of a Loop Current anticyclonic eddy in the northwest, increases the stratification and accentuates the oligotrophic conditions, leading to a different pteropod community well adapted to those oligotrophic conditions.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"216 ","pages":"Article 104431"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bathymetric distribution of abyssal and hadal amphipod families and genera in the Japan Trench and the southernmost Kuril-Kamchatka trench","authors":"Daiki Yamamoto,&nbsp;Takuya Yahagi,&nbsp;Shigeaki Kojima","doi":"10.1016/j.dsr.2024.104438","DOIUrl":"10.1016/j.dsr.2024.104438","url":null,"abstract":"<div><div>Amphipoda, belonging to superorder Peracarida, represents a conspicuous proportion of benthic fauna occurring across multiple depth zones. Extensive sampling has been conducted to understand the composition and distribution of benthic organisms, particularly in the Northwest Pacific. However, logistical challenges and limited opportunities have restricted our understanding of benthic fauna diversity and distribution. Using two types of trawls and an epibenthic sledge, abyssal and hadal benthic fauna were collected across 55 sampling sites from both the Japan Trench and the Kuril-Kamchatka Trench, at depths between 3689 m and 8010 m. A collection of 3126 deep-sea amphipods was obtained and the animals were assigned to at least 76 genera belonging to 37 families during the two expeditions. The most abundant family was Phoxocephalidae, followed by Ampeliscidae, Lysianassoidea and Oedicerotidae in descending order of abundance. In addition, high numbers of genera of the Pardaliscidae, Oedicerotidae, Stegocephalidae and Synopiidae families were identified. In the two trenches, the number of genera showed a weak inverse correlation with depth at both abyssal and hadal depths. Amphipod diversity and abundance were highest in the landward slopes, whereas those observed in the trench axes were the least diverse and abundant. High productivity, in addition to proximity to the Japanese archipelago, may explain the amphipod assemblage characteristics observed in our study areas. Our findings present novel data on the global depth records for eight identified and one unidentified amphipod genera, belonging to nine families.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"216 ","pages":"Article 104438"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Descriptions of two new deep-sea nemertean species from the genera Alvinonemertes and Sagornya gen. nov. (Hoplonemertea, Oerstediina) with discussion on close genetic relationship between deep-sea species","authors":"Alexei V. Chernyshev,&nbsp;Vasiliy G. Kuznetsov","doi":"10.1016/j.dsr.2024.104439","DOIUrl":"10.1016/j.dsr.2024.104439","url":null,"abstract":"<div><div>In a recent study by Sagorny et al. (2022), nine new species of deep-sea hoplonemerteans, including five from the new genus <em>Alvinonemertes</em> Sagorny, von Döhren, Rouse &amp; Tilic, 2022, have been described from off the Pacific coast of Costa Rica and the Oregon margin. The new species <em>Alvinonemertes tilici</em> sp. nov., found during the research cruise #94 aboard the R/V <em>Akademik M.A. Lavrentyev</em> in the Emperor Seamounts, has proven to be very close morphologically and genetically to <em>A. dariae</em> Sagorny et al., 2022 from the methane Parrita Seep, off Costa Rica. As a phylogenetic analysis based on five gene markers (cytochrome <em>c</em> oxidase subunit I, 1<em>6S</em> rRNA, <em>18S</em> rRNA, <em>28S</em> rRNA, and histone H3) has shown, the genus <em>Alvinonemertes</em> is not monophyletic. Four species of <em>Alvinonemertes</em> are here segregated into a new genus, <em>Sagornya</em> gen. nov. The new species <em>Sagornya iturupica</em> sp. nov. is described based a specimen collected from the bathyal zone in the Sea of Okhotsk. This species is close genetically to <em>S. tatjanae</em> (Sagorny et al., 2022) comb. n. from seeps along the Oregon margin. The family Oerstediidae is divided into two sister groups: the subfamilies Oerstediinae and Tetranemertinae subfam. nov. To date, the new clade <em>Gononemertes</em> is the largest clade in the family Oerstediinae in terms of number of deep-sea and symbiotic species. Examples of close genetic similarity between deep-sea species from the genera <em>Nemertovema</em>, <em>Tetrastemma, Alvinonemertes, Sagornya</em>, and <em>Carinina</em> are considered. The study has shown that the genetic differences between deep-sea hoplonemerteans from the western and eastern Pacific Ocean are lower than those between sibling hoplonemertean species from Pacific shallow waters off North America and Asia. A hypothesis is advanced here that species with limited geographical ranges are frequently found among deep-sea nemerteans. The wide distribution of deep-sea hoplonemerteans can be provided by long-swimming lecithotrophic larvae, as in Cratenemertidae sp. MCZ IZ 45644.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"216 ","pages":"Article 104439"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling mesoscale circulation and potential fish larvae transport at the entrance of a semi-enclosed sea under different periods","authors":"Laura Sánchez-Velasco ,&nbsp;Jorge Montes-Arechiga ,&nbsp;Emmanuel Romero ,&nbsp;Erick D. Ruvalcaba-Aroche ,&nbsp;Victor M. Godínez ,&nbsp;Leonardo Tenorio-Fernández ,&nbsp;Emilio Beier ,&nbsp;Lydia B. Ladah","doi":"10.1016/j.dsr.2024.104430","DOIUrl":"10.1016/j.dsr.2024.104430","url":null,"abstract":"<div><div>Data from three oceanographic cruises at the entrance to the Gulf of California (April 2012, June 2015, and October 2020) were used to model the transport of preflexion fish larvae associated with the mesoscale eddies that dominated the surface circulation during the study periods. Hydrographic transects crossed sections of various eddies of different life histories (origin, rotation, dimensions). A lagrangian particle tracking model (HYCOM) was applied to a cross-Gulf transect using six key locations over the mesoscale structures. The 14-day simulations showed that most particles were retained within the eddies. In April 2012, 85% of the particles remained at the entrance to the Gulf of California until day 7, and one week later, 34% arrived at the north side of the boundary between the entrance to the Gulf of California and the southern Gulf (with no free transport to north). In October 2022, no particles arrived at the southern Gulf of California during the 14 days. In June 2015, however, &gt;90% of the particles were transported to the north by day 14, and 56% of these, to the southern Gulf of California, corresponding with the detection of the poleward Mexican Coastal Current on the mainland side. Dominant fish species in the region with seasonal changes in abundance included <em>Benthosema panamense</em> (mesopelagic), <em>Auxis</em> spp. (epipelagic), <em>Bregmaceros bathymater</em> (pelagic neritic) and <em>Syacium ovale</em> (soft-demersal). Extrapolating the modeling results to preflexion fish larvae distributions, it appears that these mesoscale structures may trap most of the larvae spawned in the Gulf of California entrance. June 2015 was the exception when the fish larvae could disperse from the entrance to the Gulf of California towards the north, corresponding with the period of spawning for some soft-demersal fish species in the region. We conclude that the high mesoscale activity that occurs most of the year at the entrance to the Gulf of California might be a dynamic barrier that controls the dispersal of fish larvae and other planktonic organisms in the region, and might occur in other semi-enclosed seas as well.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"216 ","pages":"Article 104430"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical and seasonal variations in stable oxygen isotope ratio of living planktonic foraminifera and estimation of habitat depth in the western tropical Pacific","authors":"Tae Wook Ko ,&nbsp;Kyung Eun Lee ,&nbsp;Ryoung Ah Kim","doi":"10.1016/j.dsr.2024.104440","DOIUrl":"10.1016/j.dsr.2024.104440","url":null,"abstract":"<div><div>To verify the habitat depth of planktonic foraminifera, the variability of foraminiferal δ¹⁸O (δ¹⁸O_pforam) by depth, season, day and night was investigated over a water depth of 0–600 m in the western tropical Pacific region. Species that inhabit the surface mixed layer in April include <em>Globigerinoides sacculifer, Globigerinoides ruber</em> white<em>, Globigerinoides conglobatus, Globigerinella siphonifera,</em> and <em>Orbulina universa</em> (δ¹⁸O_pforam, −2.2‰ to –2.9‰). Meanwhile, <em>Globorotalia hirsuta</em> and <em>Globorotaloides hexagonus</em> inhabit the upper thermocline (δ¹⁸O_pforam, −0.3‰to –1.2‰) and lower thermocline (δ¹⁸O_pforam, 1.2‰), respectively. In August, various species inhabit the uppermost thermocline during the day (<em>G. sacculifer</em>, <em>G. ruber</em> white, <em>G. siphonifera</em>, <em>G. conglobatus</em>, <em>O. universa</em>, <em>Globorotalia menardii</em>, <em>Hastigerina pelagica</em>, <em>Neogloboquadrina dutertrei</em>, <em>Pulleniatina obliquiloculata</em>, and <em>Globoquadrina conglomerata</em>) (δ¹⁸O_pforam, −2.2‰ to –3.2‰). At night, <em>G. sacculifer</em> without sac and <em>G. menardii</em> appear to inhabit the surface mixed layer (δ¹⁸O_pforam, −2.9‰ to –3.4‰). <em>G. hexagonus</em> inhabits the lower thermocline (δ¹⁸O_pforam, 1.3‰) in August. The vertical distribution of δ¹⁸O_pforam in December was similar to that of April δ¹⁸O_pforam. The habitat depths inferred from δ¹⁸O_pforam were mostly consistent with those estimated from species abundance. Species that did not match were <em>Globorotalia truncatulinoides</em> (in April), <em>Globigerinoides elongatus</em> (in December), <em>G. hirsuta</em> (in August), and <em>G. hexagonus</em> (in December). The results of δ¹⁸O analysis suggest that <em>G. truncatulinoides</em> lives in the uppermost thermocline, and <em>G. elongatus</em> in the surface mixed layer. In the case of <em>G. hirsuta</em> and <em>G. hexagonus</em>, they inhabit the upper thermocline and lower thermocline, respectively. Our results contribute to research on reconstructing past thermocline structure using geochemical analysis of planktonic foraminifera in marine sediments in this region.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"216 ","pages":"Article 104440"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the influence of stratification and background currents on Internal Solitary Waves in the northern South China Sea based on the Wavefront model","authors":"Zijian Cui ,&nbsp;Chujin Liang ,&nbsp;Beifeng Zhou ,&nbsp;Feilong Lin ,&nbsp;Tao Ding ,&nbsp;Weifang Jin","doi":"10.1016/j.dsr.2025.104442","DOIUrl":"10.1016/j.dsr.2025.104442","url":null,"abstract":"<div><div>Internal Solitary Waves (ISWs) are nonlinear internal waves generated within vertically stratified oceans, characterized by large amplitudes and strong destructive capabilities. Previous studies have shown that background currents significantly affect the propagation process of ISWs. However, the background currents can also induce changes in stratification, and the specific manner in which they influence ISWs remains unclear. This study, based on the Wavefront model, independently investigates the effects of oceanic stratification and background currents on the nonlinear phase velocity, crest line morphology, and energy distribution of ISWs in the northern South China Sea. The results show that compared to stratification, background currents are more likely to alter the nonlinear phase speed of ISWs. The background currents also significantly alter the generation locations and propagation directions of ISWs. Furthermore, this study analyzes the propagation characteristics of ISWs under different Kuroshio circulation patterns and points out that the Kuroshio primarily regulates ISWs through background currents. The Wavefront model serves as a powerful tool for accurately forecasting ISWs in the northern South China Sea and holds great potential for studying other characteristics of ISWs.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"216 ","pages":"Article 104442"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143092920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forecasting summer marine heatwaves in the South China Sea using explainable machine learning models","authors":"Chaorong Mi ,&nbsp;An Yi ,&nbsp;Jingyuan Xue ,&nbsp;Changming Dong ,&nbsp;Haixia Shan","doi":"10.1016/j.dsr.2025.104457","DOIUrl":"10.1016/j.dsr.2025.104457","url":null,"abstract":"<div><div>Marine Heatwaves (MHWs), classified as extreme oceanographic meteorological phenomena, have profound effects on ecological systems and socio-economic activities within the South China Sea (SCS). Multiple machine learning (ML) algorithms, specifically Random Forest (RF) and Ridge models, are employed to predict summer Sea Surface Temperature Anomalies (SSTA) and occurrence of MHWs in the SCS. The ML forecast results are also compared with climatology forecasts, persistence forecasts, and the European Centre for Medium-Range Weather Forecasts Sub-seasonal to Seasonal (ECMWF S2S) hindcasts. The results reveal that for regression forecasting with a one-week lead time, the Ridge model performs the best among all models. However, for longer lead times, all models tend towards climatology forecasts. When it comes to the classification forecasting, the RF model demonstrates superior performance to predict extreme MHWs compared to typical MHWs. Moreover, the feature importance is measured via the mean decrease in impurity (MDI) incorporated in the RF model to identify the predictors that contribute to predicting the MHWs. The SHapley Additive exPlanation (SHAP) algorithm is additionally employed to evaluate both the positive and negative impacts of these predictors on the model. SSTA and the Indian Ocean Basin-Wide (IOBW) index are the most two critical forecasting factors influencing the occurrence of MHWs, exhibiting a pronounced positive contribution to the model. The insights derived from this study are expected to provide strong support for the MHWs early warning system in the SCS and provide essential information for the conservation of marine ecosystems and the management of fisheries resources.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"218 ","pages":"Article 104457"},"PeriodicalIF":2.3,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}