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

{"title":"On Anguillosyllis cf. hessleri Maciolek, 2020 – A species complex from the Clarion-Clipperton zone, abyssal central Pacific","authors":"Regan Drennan ,&nbsp;Lenka Neal ,&nbsp;Helena Wiklund ,&nbsp;Eva C.D. Stewart ,&nbsp;Muriel Rabone ,&nbsp;Corie Boolukos ,&nbsp;Innes Clatworthy ,&nbsp;Zuzana Jungmanova ,&nbsp;Thomas G. Dahlgren ,&nbsp;Adrian G. Glover","doi":"10.1016/j.dsr.2025.104453","DOIUrl":"10.1016/j.dsr.2025.104453","url":null,"abstract":"<div><div>The benthic annelid fauna of polymetallic nodule fields in the eastern Clarion-Clipperton Zone (CCZ) has recently been the subject of taxonomic investigations aiming to document the biodiversity of this region. While investigating the annelids, a particularly high diversity was discovered within the genus <em>Anguillosyllis</em> Day, 1963 using a combination of morphological and molecular approaches. Initially, 38 specimens of <em>Anguillosyllis</em> were assigned to the known CCZ species <em>Anguillosyllis hessleri</em> Maciolek, 2020 based on morphological examination, including examination of the type specimen. However, our genetic data revealed that these specimens represent four distinct lineages (putative species) based on COI and 16S markers. Further morphological investigation using SEM revealed a complex structure of the prostomium, which could potentially differentiate these lineages. However, as no molecular or SEM data are available from the type specimen of <em>A. hessleri</em>, we cannot ascertain which, if any, of these lineages represent the known species described by Maciolek (2020). Thus, currently, we can only assign CCZ specimens to <em>Anguillosyllis</em> cf. <em>hessleri</em> and further distinguish the lineages by assigning each a unique code in the form of “NHM_####”. The SEM observations are the first reported for <em>Anguillosyllis</em>, revealing new taxonomic characters that may be used to disentangle the <em>A. hessleri</em> species complex and be of use in taxonomy of <em>Anguillosyllis</em> in general.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"220 ","pages":"Article 104453"},"PeriodicalIF":2.3,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747775","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":"The near-bottom turbulence induced resuspension of seabed material in deep sea","authors":"Cong Hu ,&nbsp;Ting Zhang ,&nbsp;Chunsheng Ji ,&nbsp;Yonggang Jia","doi":"10.1016/j.dsr.2025.104491","DOIUrl":"10.1016/j.dsr.2025.104491","url":null,"abstract":"<div><div>Marine seabed material resuspension holds significant importance across various fields, from ocean engineering to environmental science. However, it has been seldom explored in deep-sea environments. In this study, we conducted an in-situ field observation using a lander at the toe of Shenhu Canyon (1405 m). A sediment resuspension event and down-slope current were simultaneously recorded. The suspended particulate concentration synchronously varied with current velocity. Despite the occurrence of resuspension, the velocity and near-bed shear stress were below their critical values. This phenomenon was attributed to the resuspension of loose aggregates, which required a low current velocity exceeding 0.1 m/s and small near-bed shear stress. Sweep was identified as the primary contributor to resuspension, followed by ejection, while the contributions of down-deceleration and up-acceleration were negligible. An intriguing observation was the bimodal characteristic of both near-bed shear stress and sweep. At the highest suspended particulate concentration, both parameters decreased to small values. Additionally, the amplitude of acoustic backscatter increased with distance from the seabed in the near-bed vertical profile. This can be explained by the slow settling of the resuspended loose aggregates, shedding light on the formation of giant bottom nepheloid layers in the South China Sea.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"219 ","pages":"Article 104491"},"PeriodicalIF":2.3,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697712","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":"Occurrence of vent-derived organic falls and associated fauna at hydrothermal vents on the Indian ridge: Implications for an underestimated food source at hydrothermal vent fields","authors":"Klaas Meyn ,&nbsp;Terue C. Kihara ,&nbsp;Andrew K. Sweetman ,&nbsp;Pedro Martínez Arbizu ,&nbsp;Thomas Kuhn","doi":"10.1016/j.dsr.2025.104489","DOIUrl":"10.1016/j.dsr.2025.104489","url":null,"abstract":"<div><div>Organic falls, hydrothermal vent fields and seeps rely primarily on chemosynthetic organic production leading to a carbon enriched habitat set against the oligotrophic deep-sea background. These habitats are typically inhabited by novel faunal assemblages with similar functional characteristics and often show harsh environmental gradients over relatively small scales with severe effects on diversity and density compared to the benthic background fauna. While the importance of particulate organic matter (POM) has been pointed out, the presence of POM as local accumulated organic deposits within hydrothermal vent fields has not been studied.</div><div>Here, we present the first observations of organic deposits within active vents in the Indian Ocean including observations of giant capitellid worms inhabiting these organic mats with a length of up to 30 cm. This potential new species occurred in shrimp carcasses, the exuvia of <em>Rimicaris kairei</em>, on two hydrothermal vent sites from the Indian Ocean. We used imagery to build a high-resolution 3D reconstruction model of one side of a chimney complex, including the 4.8 m² surface area of the exuvia deposit. The capitellids occurred in dense aggregations and may contribute significantly to the food web of active hydrothermal vent fields, representing a possible overlooked food source for benthic and demersal predators. In addition, we report on observations on further organic deposit types and compare their associated epifauna along the mid-ocean ridges of the Indian Ocean. The exuvia deposits where capitellids were present appeared to be compacted and compressed implicating a potential role in stabilizing seafloor habitat. This is the first record of the family Capitellidae in organic deposits at hydrothermal vent fields, where they may serve as ecosystem engineers.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"220 ","pages":"Article 104489"},"PeriodicalIF":2.3,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776985","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":"The trapping of Agulhas Rings in the South Brazil Bight","authors":"Piero S. Bernardo ,&nbsp;Cauê Z. Lazaneo ,&nbsp;Ilson C.A. da Silveira ,&nbsp;João P.M. Amorim ,&nbsp;Milton Borges-Silva ,&nbsp;Pedro W.M. Souza-Neto ,&nbsp;Marcelo Dottori ,&nbsp;Wellington C. Belo ,&nbsp;Renato P. Martins ,&nbsp;Luiz A.A. Guerra ,&nbsp;Daniel L. Moreira","doi":"10.1016/j.dsr.2025.104486","DOIUrl":"10.1016/j.dsr.2025.104486","url":null,"abstract":"<div><div>The South Brazil Bight is a section of the Brazilian margin mainly dominated by the poleward Brazil Current flow, its meanderings and eddies. We evaluated the mean mesoscale activity for the region, and an anticyclonic feature was highlighted over the São Paulo Plateau. Around that feature, cyclonic eddies were also accentuated. The combination of these structures dominate the region, forming an eddy corridor. Using eddy detection dataset, we reveal that the filtered positive-<span><math><mi>Ψ</mi></math></span>-signal on the plateau was related to the presence of anticyclones. The cyclones in the region originate both locally and remotely, whereas most anticyclones predominantly have remote origins. More than 95% of these anticyclones were Agulhas Rings, which could or could not have been subjected to splitting or merging processes. On the plateau we observe an average of 5.3 anticyclones per year. However, this rate is related not only to the number of anticyclones but also to the time they remain there. We observe that Agulhas Rings reside individually in the region for 50.8 days on average, consequently, they occupy the plateau for almost 75% of the year. During half of the residence time, there is a multi-pattern interaction with cyclonic eddies. This relationship between eddies of opposite polarity creates a shielding process. The anticyclones become shielded and trapped by the cyclones, have their progress delayed, and their course deflected towards the Brazil Current.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"219 ","pages":"Article 104486"},"PeriodicalIF":2.3,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682382","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":"Scale worm diversity in abyssal and hadal environments (Aphroditiformia, Annelida)","authors":"Brett C. Gonzalez ,&nbsp;Alejandro Martínez ,&nbsp;Alan J. Jamieson","doi":"10.1016/j.dsr.2025.104490","DOIUrl":"10.1016/j.dsr.2025.104490","url":null,"abstract":"<div><div>The deep sea is dominated by diverse invertebrate communities, of which annelids are among the most prolific. Within such annelids, scale worms (Aphroditiformia) have long been recognized as a major component to the composition of deep-sea communities, yet their overall diversity and distribution is unknown. To better understand this diversity, we provide the first comprehensive census of scale worms inhabiting depths at or below 3000 m. Our literature analyses across all species recognized by the World Register of Marine Species (WoRMS) revealed 418 records and 122 species spread across Aphroditidae, Polynoidae and Sigalionidae, of which the second was the most species rich. Within Polynoidae, 12 species were identified as hadal zone exclusives. Caveats of the dataset are discussed. Historical, recently published, and new <em>in situ</em> observations of Aphroditiformia at hadal depths are also presented. These results provide a baseline for future investigations across deep sea Aphroditiformia.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"220 ","pages":"Article 104490"},"PeriodicalIF":2.3,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724216","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":"Assessment of the effects of climate change on dissolved oxygen in the Gulf of Oman","authors":"Shirin Farkhani,&nbsp;Nasser Hadjizadeh Zaker","doi":"10.1016/j.dsr.2025.104487","DOIUrl":"10.1016/j.dsr.2025.104487","url":null,"abstract":"<div><div>In this paper, we investigated the impacts of climate change on dissolved oxygen (DO) concentration in the Gulf of Oman using numerical modeling. We simulated and compared the DO concentration of the Gulf of Oman through the historical (1980–2000) and future (2080–2100) periods. Results demonstrated that in the future climate, the DO concentration levels in the upper 400 m of the Gulf of Oman will decrease. In the surface mixed layer, the mean DO concentration will decrease by 0.4, 0.5, and 0.7 mg/l in summer, and by 0.2, 0.3, and 0.4 mg/l in winter. Below the surface mixed layer, the mean DO concentration will decrease by 0.5, 0.6, and 0.8 mg/l in summer, and by 0.6, 0.7, and 1 mg/l in winter. The ventilation effect of the Persian Gulf outflow on the Gulf of Oman's water will also decrease in the future. The future climate deoxygenation will expand hypoxic waters upward. In summer, the mean thickness of the surface layer with DO &gt; 2 mg/l will decrease from 40 m in the historical period to approximately 32, 26, and 23 m in the RCP 2.6, RCP 4.5, and RCP 8.5 scenarios, respectively. In winter, the hypoxic boundary will shift from 100 m depth in the historical period to about 91, 84, and 80 m in RCP 2.6, RCP 4.5, and RCP 8.5 scenarios, respectively.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"219 ","pages":"Article 104487"},"PeriodicalIF":2.3,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682384","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":"Mg/Ca from mussel shells rather than δ18O as a promising temperature proxy for hydrothermal vent ecosystems","authors":"V. Mouchi ,&nbsp;K. Nedoncelle ,&nbsp;O. Bruguier ,&nbsp;Z. Garmirian ,&nbsp;N. Le Bris ,&nbsp;F. Lartaud","doi":"10.1016/j.dsr.2025.104485","DOIUrl":"10.1016/j.dsr.2025.104485","url":null,"abstract":"<div><div>Minor and trace metal fluctuations in biogenic carbonates have been demonstrated to be important potential environmental tracers in coastal areas, but remained poorly studied in deep-sea environments. For the first time, this study assesses the use of Mg/Ca signal as a thermometer proxy in hydrothermal vent ecosystems together with the analysis of oxygen stable isotope composition. <em>Bathymodiolus azoricus</em> and <em>B. thermophilus</em> mussels were collected at three hydrothermal vent fields from the mid-Atlantic ridge (Rainbow, Menez Gwen) and the East Pacific Rise (EPR 9°50N), presenting contrasted temperature and chemical habitat conditions. The variation of Mg/Ca was analysed via LA-ICP-MS and is revealed suitable to reconstruct temperature variations in these ecosystems, presumably due to stable Mg compositions of the seawater surrounding hydrothermal systems. Temperature anomalies inferred from Mg/Ca ratios can be good tracers of fluid pulses. Important fluid emissions appear however to generate major growth cessation in shell mineralization. Temperatures inferred from Isotope Ratio Mass Spectrometry (IRMS) δ¹⁸O analyses systematically underestimated the measured values in the environment. The isotopic disequilibrium is likely due to pH fluctuations in the mussel habitat, in the vicinity of vent fluid discharges, and/or interactions with the symbiotic chemosynthetic bacteria. Those results will first benefit to the ecological study of deep-sea mussels, but also provide a promising contribution for the study of the environmental dynamic in hydrothermal systems at short (daily) to long-term (pluri-annual) scales, recorded in the calcite material of bivalves.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"219 ","pages":"Article 104485"},"PeriodicalIF":2.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636618","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":"Crustal recycling and mantle heterogeneity beneath the Central Indian ridge, Indian Ocean","authors":"Arghya Hazra ,&nbsp;Abhishek Saha ,&nbsp;Nilanjana Sorcar ,&nbsp;A. Keshav Krishna ,&nbsp;Aditya Peketi ,&nbsp;Kotha Mahender","doi":"10.1016/j.dsr.2025.104484","DOIUrl":"10.1016/j.dsr.2025.104484","url":null,"abstract":"<div><div>This study presents a new database including mineral chemistry, whole rock geochemistry and Sr-Nd isotopic compositions for basalts recovered from the Central Indian Ridge (CIR) with a view to evaluate melt generation processes, source characteristics and tectonic controls on Indian Ocean mantle evolution. The salient geochemical characteristics of the subalkaline, tholeiitic to transitional Central Indian Ridge Basalt (CIRB) are marked by relatively higher abundances of LILE and LREE over HFSE, depletion in HFSE abundances with respect to primitive mantle compositions corroborated by negative Nb, Zr, Hf anomalies and Nb/Nb∗&lt;1, Zr/Zr∗&lt;1, Hf/Hf∗&lt;1; depleted to moderate enrichment of LREE and MREE over HREE and trace element variations reflecting distinct deviation from N-MORB to E-MORB with very low Nb/Y (avg.: 0.08) and Zr/Y (avg.: 3.00) values with respect to OIB (Nb/Y: 1.66, Zr/Y: 9.66). The CIRB samples showing Ba/Nb&gt;6, Rb/Nb&gt;0.6, Nb/U&lt;42 and Ce/Pb&lt;22 conform to the BABB filter thereby preserving past subduction signals and validating the evidence for a subduction-modified source mantle. The Sr-Nd isotopic ratios yielded the following ranges: ⁸⁷Sr/⁸⁶Sr: 0.702810–0.703518 and ¹⁴³Nd/¹⁴⁴Nd: 0.512831–0.513118 (Ɛ_Nd: +3.77 to +9.37), reflecting an enriched heterogeneous mantle end-member source mantle. Isotopic mixing calculations identify major HIMU-EM1 signature with minor EM2 component for CIR basalts attesting to the chemical heterogeneity of the Indian Ocean mid oceanic ridge (MOR) mantle. The major HIMU-EM1 isotopic trend, distinct deviation from DMM-N-MORB with lower Nb/Y, Nb/Yb, Nb/U, Nb/Th and higher Ba/Nb, Ba/Th, Ba/La, Nd/Hf, Ce/Nb for CIRB in comparison with OIB and N-MORB suggest that OIB component or deep mantle plume sources had no influence on the compositional diversity of the mantle source. Instead, these features attribute the fertility of CIRB source mantle to: (i) convection driven recycling of ancient, subducted, metasomatized oceanic crust (HIMU) and (ii) delamination, dispersion and dilution of Gondwanan SCLM, LCC and UCC. This study equates the chemical evolution of the Indian Ocean MOR mantle and its pervasive heterogeneity with polychronous tectonic events involving cyclic amalgamation and disintegration of supercontinents synchronized with ocean basin closure and opening that systematically recycled ancient lithospheric components into the mantle.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"219 ","pages":"Article 104484"},"PeriodicalIF":2.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682383","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":"Unique gastropods dominate the fauna on inactive vent sulfide features in the eastern Pacific","authors":"Lauren S. Mullineaux ,&nbsp;Stace E. Beaulieu ,&nbsp;Susan W. Mills ,&nbsp;Rose Jones ,&nbsp;Johanna N. J. Weston ,&nbsp;Ayinde C. Best ,&nbsp;Rodrigo Zúñiga Mouret ,&nbsp;Michael J. Meneses ,&nbsp;Margaret K. Tivey ,&nbsp;Mikayla J. Harris ,&nbsp;Amanda M. Achberger ,&nbsp;Jason B. Sylvan","doi":"10.1016/j.dsr.2025.104475","DOIUrl":"10.1016/j.dsr.2025.104475","url":null,"abstract":"<div><div>Understanding the extent of habitat adaptation and endemism is essential for assessing resilience to natural and human disturbances. In the deep sea, a habitat of heightened interest is inactive vent sulfide features that form when hydrothermal vent activity ceases, changing the physical and chemical environment and shifting the microbial and animal community. Limited prior sampling of macrofauna (&lt;1 cm) living on these features has suggested that some invertebrate species may be endemic and uniquely adapted to inactive sulfides. Here, we characterize the macrofaunal community composition across different sulfide rock surface types from two inactive sulfide features near the 9°47–50′N vent field of the East Pacific Rise (EPR). Using macrofauna identification, and image analysis of faunal density, we found a dense macrofaunal community dominated by gastropods. Most of the gastropod species appear uniquely associated with inactive sulfide features on the EPR. Further, the composition, diversity, and density of gastropods varied with rock surface characteristics, suggesting a trophic web driven by rock-based microbial chemosynthesis. As metal-rich inactive sulfide deposits are a target for seafloor mining, this discovery of a unique community highlights the need to better understand this type of fauna and its contribution to functional and taxonomic biodiversity in the world's oceans.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"219 ","pages":"Article 104475"},"PeriodicalIF":2.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705847","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":"Spatial and temporal variability of the Brazil current path: Diagnostics from satellite-derived altimetry and a global reanalysis product","authors":"Thiago Pires de Paula ,&nbsp;Wilton Zumpichiatti Arruda ,&nbsp;Jose Antonio Moreira Lima ,&nbsp;Victor Bastos Daher ,&nbsp;Nelson Violante-Carvalho","doi":"10.1016/j.dsr.2025.104474","DOIUrl":"10.1016/j.dsr.2025.104474","url":null,"abstract":"<div><div>The Brazil Current (BC) exhibits significant spatial and temporal variability, forming meanders and eddies off Cabo de São Tomé (22°S) and Cabo Frio (24°S) due to baroclinic instability and topographic influences. The BC presents considerable annual and interannual transport variability, affecting its trajectory and cross-sectional attributes. However, the connection between temporal variations in stream structure and its spatial distribution is often overlooked. This study investigates the long-term spatio-temporal variations of the position and structure of the BC between 21°S and 28°S, along the south-southeast Brazilian coast, using 28 years of altimetry and global reanalysis data. Results indicate that the width, depth, core velocity, and position of the BC are sensitive to transport changes, depending on latitude. The current path is more influenced by topographic gradients north of 24°S and less so to the south. At this latitude, the energy exchange between the mean flow and eddies correlates with transport increase, leading to a rise in downstream eddy kinetic energy (EKE) after two months. The BC intensification and path changes are influenced by broader phenomena, including the position and strength of the South Atlantic Subtropical Gyre, the wind stress associated with coastal upwelling (lagged by two months), and El Niño events (lagged by eight months). Rotated Empirical Orthogonal Function analysis at two cross-stream sites near Cabo Frio confirms that variations in strength and transport of the BC are key factors driving velocity variance, along with the growth of eddies due to baroclinic instability and the propagation of continental shelf waves.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"219 ","pages":"Article 104474"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578519","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}