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

{"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":"Diversity and biogeography of mesophotic and bathyal Onuphidae (Annelida: Eunicida) of the Western Mediterranean sea","authors":"Sara Verni ,&nbsp;Joachim Langeneck ,&nbsp;Andrea Silverj ,&nbsp;Sergio Stefanni ,&nbsp;Luigi Musco ,&nbsp;Alberto Castelli","doi":"10.1016/j.dsr.2025.104476","DOIUrl":"10.1016/j.dsr.2025.104476","url":null,"abstract":"<div><div>The Mediterranean Sea is extensively studied from a biological point of view and known for its high diversity, however benthic macro- and meiofauna of its deep ecosystems remain largely unexplored. Polychaetes are among the most abundant deep-sea benthic invertebrates, yet they are poorly understood in terms of taxonomy and biogeography. The Onuphidae family is known for its diversity in deep-sea environments, but most European studies focus on shallow-water species, with no molecular data for specimens collected at depths below 100 m in the Mediterranean. In this study, 88 specimens from 10 morphotypes were morphologically characterised. Samples came from Canyon Dohrn, Salerno bathyal plain, and Palinuro and Marsili seamounts of the Western Mediterranean Sea, as well as from the historical collections of the Natural History Museum of the University of Pisa. Phylogenetic reconstruction was performed using concatenated markers 16S rDNA, 18S rDNA and, separately, cytochrome <em>c</em> oxidase subunit I. This study provides the first thorough molecular phylogeny for Onuphidae in the deep Mediterranean. The combined morphological and molecular data revealed three potentially endemic <em>Nothria</em> species: <em>Nothria</em> sp. 1 (over 600 m depth off Corsica and in the Northern Tyrrhenian Sea), <em>Nothria</em> sp. 2 (35–90 m), and <em>Nothria</em> cf. <em>jourdei</em> (80–230 m). This study also identified <em>Paradiopatra</em> species with different biogeographical affinities: <em>P. bihanica</em> (Senegalese) and <em>P. fiordica</em> (Lusitanian) at different depths. Our study reveals that the overlap of Northern and Southern species ranges in shallow Mediterranean waters, known as the \"biodiversity pump\" effect, may also influence the deep Mediterranean biota, though further research across more invertebrate groups is needed. The deep Mediterranean polychaete fauna is likely influenced by the neighbour biogeographic districts, including Senegalese and Lusitanian, but it also includes a significant endemic component reflecting the basin's unique environmental conditions. This complex biogeographic composition of the deep-sea Mediterranean fauna should be considered when planning conservation and management of these unique and diverse ecosystems.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"220 ","pages":"Article 104476"},"PeriodicalIF":2.3,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816948","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}

{"title":"Trophic partitioning and mercury accumulation in deep-sea fishes of the East China Sea","authors":"Xinyu Chen ,&nbsp;Zezheng Li ,&nbsp;David Mboglen ,&nbsp;Yunkai Li","doi":"10.1016/j.dsr.2025.104473","DOIUrl":"10.1016/j.dsr.2025.104473","url":null,"abstract":"<div><div>The deep sea, characterized by darkness, low temperatures, limited food availability, and extreme pressure, harbors a diverse array of life forms. Deep-sea fish, which have evolved unique adaptations to thrive in these harsh conditions, play a crucial role in marine ecosystems and biogeochemical cycles. This study investigated the trophic ecology and mercury (Hg) dynamics of eleven deep-sea fish species in the East China Sea (ECS) using stable isotope analysis (SIA) and total mercury (THg) concentration. Our findings revealed significant overlap in trophic niches among the examined species, with notable exceptions indicating instances of competition and resource partitioning. <em>Coelorhynchus anatirostris</em> exhibited a relatively broader trophic niche, suggesting a generalist feeding strategy, while <em>Chlorophthalmus albatrossis</em> and <em>Neoscopelus microchir</em> displayed more specialized niches. We identified four distinct trophic guilds based on δ¹³C and δ¹⁵N values, as well as THg concentrations, which underscore the complex interactions of niche differentiation and resource sharing within the deep-sea community. The incorporation of Hg as an additional bioindicator provided valuable insights into feeding strategies and trophic levels, highlighting its effectiveness in distinguishing ecological niches. Positive correlations between THg concentration and total length were observed in certain species, but not across all. At the community level, THg concentrations were closely associated with trophic level and habitat. Notably, THg concentrations in demersal fish were significantly lower than those in mesopelagic fish, likely attributable to the intricate distribution of THg within the ECS, suggesting the complexity of THg variation with depth. Our results demonstrate how vertical habitat partitioning and dietary preferences mediate competition and coexistence among deep-sea fish species in the ECS. These findings advance our understanding of deep-sea ecosystem trophic structure and function while providing insights for conservation and management strategies.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"218 ","pages":"Article 104473"},"PeriodicalIF":2.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474609","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":"Stable connections in the deep sea: Temporally consistent larval pathways for the deep-sea coral, Lophelia pertusa (=Desmophyllum pertusum) in the Northwest Atlantic Ocean","authors":"Graeme Guy ,&nbsp;Anna Metaxas ,&nbsp;Martha Nizinski ,&nbsp;Zeliang Wang","doi":"10.1016/j.dsr.2025.104462","DOIUrl":"10.1016/j.dsr.2025.104462","url":null,"abstract":"<div><div>Population connectivity facilitates genetic exchange and increases resilience of populations promoting long-term persistence. For sessile benthic invertebrates, larval dispersal provides the main mechanism to achieving population connectivity. Here, we use biophysical modelling of larval dispersal to elucidate potential connections between populations and quantify dispersal pathways, which we combine with network-theoretic analyses to evaluate their potential importance to the stability of the entire network. Because the necessary parameters for these analyses are difficult to quantify for deep-sea species with unresolved life-history traits, we explore multiple scenarios using a range of likely life-history trait values. Focussing on the deep-water coral <em>Lophelia pertusa</em> (=<em>Desmophyllum pertusum</em>) over its North American range in the Northwest Atlantic Ocean, we used a high-resolution ocean circulation model in combination with larval parameters to project larval dispersal for each season over 14 years from 2005 to 2018. We then use the larval dispersal pathways to identify connections between populations, and network theory to uncover network structure and quantify the importance of each population to the overall connectivity within the network. Larval retention was strongest in the northern domain and within the Gulf of Mexico, suggesting these populations could persist without larval influence from other areas. The two dominant transport pathways occurred following the Gulf Stream from Florida north towards the eastern United States and following the Labrador Current travelling southwestwards from the Canadian EEZ with little exchange between northern and southern domains. Our network-theoretic analysis suggested that the populations of <em>L. pertusa</em> in Norfolk Canyon are primarily responsible for exchange between northern and southern populations, with no northward connections. Our community detection analysis based on population connectivity agrees well with previous patterns based on estimates of genetic connectivity in the area. This is the first study to analyse potential connectivity of <em>L. pertusa</em> in the NW Atlantic Ocean, and projects consistency in the dominant connection pathways throughout spawning seasons, years, and for biological parameters. Our results are integral in assessing a populations susceptibility to anthropogenic disturbance and are directly applicable to other deep-sea species in our domain with similar life-history traits to those within the modelled ranges.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"218 ","pages":"Article 104462"},"PeriodicalIF":2.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562789","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":"An inverse modelling approach to constrain 7Be cycling in the subpolar North Atlantic","authors":"Paul Lerner ,&nbsp;Mélanie Grenier ,&nbsp;Olivier Marchal ,&nbsp;Pieter van Beek","doi":"10.1016/j.dsr.2025.104465","DOIUrl":"10.1016/j.dsr.2025.104465","url":null,"abstract":"<div><div>Beryllium-7 is a short-lived cosmogenic radionuclide that has been used as a tracer of atmospheric deposition at the sea surface and of physical processes in the upper ocean. These applications generally assume that (i) the fraction of marine ⁷Be in particulate form is negligible, and/or (ii) the interactions between the particulate and dissolved forms of ⁷Be in seawater can be neglected. In this study, we test different steady-state models of upper ocean ⁷Be cycling from measurements of total ⁷Be and particulate ⁷Be activities collected at two stations of the GEOVIDE cruise in the subpolar North Atlantic (May–June 2014). The most complete model includes vertical advection, vertical diffusion, gravitational settling, radioactive decay, atmospheric deposition, and the reversible exchange between dissolved ⁷Be (⁷Be_d) and particulate ⁷Be (⁷Be_p). This model reproduces the measured ⁷Be activities at both stations to within their uncertainties (±1 standard deviation). In the East Greenland-Irminger Current (station 51/60), models that do not consider adsorption and/or desorption can still reproduce the measured activities, while in the southern Labrador Sea (station 69) models that neglect reversible exchange or desorption poorly fit the data. Thus, ⁷Be_d at station 51/60 could have been supplied entirely by surface deposition, whereas ⁷Be_d at station 69 originated at least partly from the release of particulate ⁷Be into solution. The subsurface ⁷Be_p maxima, present at both stations, seem to require a flux of ⁷Be between particles and solution at station 69 but not at station 51/60. At both stations, most of the total ⁷Be deposited at the ocean surface was removed by radioactive decay, with at most 5% removed by sinking of ⁷Be_p, suggesting that reversible exchange can be neglected in applications of total ⁷Be as a tracer for atmospheric deposition. However, reversible exchange is important to consider in applications of ⁷Be_d as a deposition tracer, with a maximum bias of 40% when reversible exchange is neglected. The steady state assumption does not alter our results regarding the solid-solution exchange of ⁷Be, but it does result in a significant bias when deriving atmospheric ⁷Be_tot deposition fluxes from water column ⁷Be_tot inventories. Overall, our findings suggest that reversible exchange could significantly influence the oceanic cycling of ⁷Be at some locations, and should not be systematically neglected when using ⁷Be_d as an oceanic tracer.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"220 ","pages":"Article 104465"},"PeriodicalIF":2.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715157","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":"Quantifying the contribution of modern Asian dust to the southern Yap trench and its southeastern region","authors":"Xiaoqiang Guo ,&nbsp;Yanyan Zhao ,&nbsp;Zhishun Zhang ,&nbsp;Guangyao Cao ,&nbsp;Lei Yang ,&nbsp;Guanglu Zhang ,&nbsp;Jishang Xu ,&nbsp;Guangxue Li ,&nbsp;Sanzhong Li","doi":"10.1016/j.dsr.2025.104464","DOIUrl":"10.1016/j.dsr.2025.104464","url":null,"abstract":"<div><div>Dust plays a vital role in the Earth system, yet its contribution to the tropical West Pacific is still under-quantified. This gap limits the ability to assess the impacts of dust on the biogeochemical cycles in this region. In this study, we analyzed grain size distribution, the contents of major and trace elements in lithogenic components isolated by sequential leaching and in three grain-size fractions of surface sediments from the southern Yap Trench and its southeastern region in the tropical West Pacific, along with the characteristics of the climatological surface and subsurface current fields. Our results initially identified that the provenances of lithogenic components comprise not only Asian dust and volcanic material but also continental material from northern New Guinea rivers. Furthermore, the Rare Earth Elements-based dust fractions within the lithogenic components, derived from a binary mixing model and correction formula, range from 0.08 to 0.70, with an average of 0.39. This is highly consistent with the ⁸⁷Sr/⁸⁶Sr-based results and ratios of illite to smectite. In bulk sediment samples, the dust contents vary from 0.82% to 49.42%, with an average of 18.82%. Spatially, dust is enriched in the southern Yap Trench, West Caroline Basin, and Sorol Trough, while it was depleted on the West Caroline Ridge. This pattern may result from the potential redistribution induced by bottom current and/or dilution effect of authigenic smectite and carbonate on the West Caroline Ridge. Ultimately, although traditional geochemical methods and diagrams comparing illite/kaolinite and kaolinite/chlorite ratios, corrected for fluvial input, proved insufficient in distinguishing dust source regions and relevant transport media, dust aerosol analysis based on the MERRA-2 database suggests contributions from both Central Asian and East Asian deserts, with the former potentially playing a more prominent role. However, further studies are required to validate the aerosol-based method and these implications, as they are essential for reconstructing paleoatmospheric circulation from paleodust records. Hopefully, this study would contribute to a more comprehensive understanding of the global dust cycle and its interplay with biogeochemical cycles in abyssal trenches and basins.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"218 ","pages":"Article 104464"},"PeriodicalIF":2.3,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438002","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}