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

{"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}

{"title":"Ecopath modelling Unravels the food web of the Gulf of Corinth, a deep Mediterranean important marine Mammal area","authors":"Nikolaos Raptis ,&nbsp;Georgia Papantoniou ,&nbsp;Dionysios E. Raitsos ,&nbsp;Dimitrios Damalas ,&nbsp;Konstantinos Tsagarakis","doi":"10.1016/j.dsr.2025.104466","DOIUrl":"10.1016/j.dsr.2025.104466","url":null,"abstract":"<div><div>The Mediterranean Sea, recognized as a biodiversity hotspot, is facing significant impacts from human-induced stressors such as overfishing and climate change, which exert pressure on its ecosystems. The Gulf of Corinth (eastern Mediterranean Sea, Greece) encompasses a deep ecosystem that has not been extensively studied, despite its rich biodiversity and the presence of Protected, Endangered, and Threatened (PET) species. An Ecopath trophic model was implemented for the baseline period 2014–2016 to outline its ecological structure, with special emphasis on (i) dolphins (bottlenose, striped, and common) and other PET species, as the Gulf is an Important Marine Mammal Area; (ii) deep-living groups such as mesopelagic fishes, due to their wide distribution and high abundance; and (iii) commercial species to assess the impact of fishing. Model outputs reveal a complex food web structure with numerous links among functional groups, with detritus serving as dominating energy source, particularly in the pelagic zone. Dominant species, such as mesozooplankton, and keystone species, including squid, sharks, and hake, shape the trophic relationships in the water column, with keystone prey groups such as shrimps and mesopelagic fish contributing significantly. Model statistics align with those of other modeled ecosystems in Greece, consistent with productivity patterns and other ecological features; however, ecological indicators suggest a relatively immature ecosystem state despite low fishing pressure. Due to spatio-temporal bans on semi-industrial fisheries and the absence of extensive suitable trawling grounds and small pelagic fish populations, small-scale fisheries exert the highest fishing pressure. The estimated probability of sustainable fisheries in the ecosystem is high (estimated at 94%), while trophic competition among fisheries and PET species is moderate to low, with the exception of bottlenose dolphins. The model was developed to enhance understanding of species trophic relationships and energy flows in the system, making it a critical tool for effective management and conservation initiatives in the Gulf of Corinth.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"218 ","pages":"Article 104466"},"PeriodicalIF":2.3,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429058","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":"Abundant taxa can better indicate seasonal and depth variations of pelagic microbial communities in the tropical open ocean","authors":"Dong Sun ,&nbsp;Qianwen Shao ,&nbsp;Yunzhi Feng ,&nbsp;Chunsheng Wang","doi":"10.1016/j.dsr.2025.104463","DOIUrl":"10.1016/j.dsr.2025.104463","url":null,"abstract":"<div><div>Understanding seasonal and depth variations of microbial communities is essential to predict the impact of climate change on pelagic ecosystem. Unfortunately, a major barrier to this knowledge is that long-term deployed automated equipment meets the low-cost requirement for obtaining time-series data in pelagic oceans far from land, but these techniques hardly obtain diversity data covering the whole community. To test whether monitoring abundant taxa can better capture variations of pelagic microbial communities in the tropical open ocean, the seasonal and depth variations of prokaryotic and microeukaryotic communities throughout the water column over three seasons were studied using 16S rRNA and 18S rRNA gene amplicon sequencing in the western Pacific Warm Pool, where is the most stable open ocean marine environment on earth. Our results showed that photic and aphotic layers were comprised of distinct microbes, and seasonal changes of microbes occurred at all depths, which were strongest at 200 m. Specificity and occupancy indicated that most of seasonal or depth specialists were abundant taxa. The community similarity distributions of abundant taxa and the whole microbial community were similar, while that of rare taxa was completely different. These results suggested abundant taxa can better indicate seasonal and depth variations of pelagic microbial communities compared to rare taxa, which provide a basis for the future development of autonomous platforms for long time-series monitoring of microbial community dynamics using a minimal number of taxa.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"218 ","pages":"Article 104463"},"PeriodicalIF":2.3,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429056","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":"Potential carbon sources and sinks in frontal zones dominated respectively by mesoscale and submesoscale processes in the Luzon Strait","authors":"Sihai Liu ,&nbsp;Qibin Lao ,&nbsp;Guangzhe Jin ,&nbsp;Shuwen Zhang ,&nbsp;Chunqing Chen ,&nbsp;Shangjun Cai ,&nbsp;Fajin Chen","doi":"10.1016/j.dsr.2025.104461","DOIUrl":"10.1016/j.dsr.2025.104461","url":null,"abstract":"<div><div>The Luzon Strait experiences active ocean fronts resulting from the intrusion of the Kuroshio water, accompanied by substantial mesoscale and submesoscale processes. These processes induce variable patterns of upwelling and downwelling where submesoscale dynamics are often more intense than their mesoscale counterparts, profoundly affecting phytoplankton production and sedimentation. However, the ultimate role of these processes in the production and export of carbon remains unclear. We analyzed daily satellite and reanalysis data from 1999 to 2019, revealing the climatological patterns and spatial variations of mesoscale and submesoscale processes during both summer and winter, thereby identifying distinct frontal zones dominated by either mesoscale or submesoscale processes. Our results show that the cyclonic front area on the eastern side of the strait and anticyclonic front area along the Kuroshio axis, are significantly influenced by submesoscale processes. These areas are identified as potential carbon sinks due to enhanced nutrient availability and elevated sedimentation rates. Conversely, although mesoscale fronts contribute more significantly to Chlorophyll-<em>a</em>, the cyclonic front area on the western side of the strait, dominated by mesoscale processes, serves as a potential carbon source. This difference is attributed to the slower sedimentation rate of organic matter in the mesoscale region, which prolongs the decomposition of both <em>in-situ</em> and horizontally transported matter. These findings deepen our understanding of the impacts of mesoscale and submesoscale processes within frontal zones on the global carbon cycle.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"217 ","pages":"Article 104461"},"PeriodicalIF":2.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420604","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":"Marine porewater dissolved organic matter linked to the paleoclimate and archaeal communities on glacial-interglacial timescales","authors":"Minchun Li ,&nbsp;Wei Xie ,&nbsp;Xizheng Lin ,&nbsp;Chuanlun Zhang ,&nbsp;Kedong Yin","doi":"10.1016/j.dsr.2025.104460","DOIUrl":"10.1016/j.dsr.2025.104460","url":null,"abstract":"<div><div>Although dissolved organic matter (DOM) in marine sediments is one of the most important carbon reservoirs, its distribution, characterization, and associated biogeochemical processes in marine sediments have not been fully investigated, especially in the deep ocean. In this study, we sampled a deep-sea gravity core from the northern South China Sea (SCS) to investigate the characterization and distribution of porewater DOM, which is the most dynamic part of the sedimentary DOM pool, as well as its correlations with other environmental components in sediments during glacial-interglacial cycles. The gravity core covers a period from Marine Isotope Stage (MIS) 3 to Holocene. Overall, the fluorescence intensity of porewater DOM increased with depth along the core expect the sample belonging to MIS 2, indicating the accumulation of fluorescence DOM (FDOM) with geological age. The abnormally high value of FDOM intensity occurred in MIS 2, which might be attributed to the enhanced marine primary productivity and favorable preservation conditions during this glacial period. Despite a longer degradation time since MIS 3, the molecular weight (MW) of porewater DOM remained relative constant among all stages. Compared to MIS 1, higher paleo-productivity and stronger upper marine mixing in MIS 3 may be responsible for this relatively constancy in MW, leading to an increase in marine autochthonous labile DOM with high MW. The composition of the sedimentary archaeal communities as well as archaeal functions were significantly different between MIS 1 and MIS 3. These differences implied that there were variations in DOM-microbe interactions along the core, thus could influence the vertical profile of porewater DOM. The findings in this study elucidate the close connection between porewater DOM and geological events as well as microbial communities in deep-sea sediments.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"217 ","pages":"Article 104460"},"PeriodicalIF":2.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402619","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":"Dissolved selenium in the Northeastern Indian Ocean","authors":"Jing Zhang ,&nbsp;Wan Wan Cao ,&nbsp;Yan Chang ,&nbsp;Wei Zheng ,&nbsp;Shuo Jiang ,&nbsp;Jie Jin","doi":"10.1016/j.dsr.2025.104459","DOIUrl":"10.1016/j.dsr.2025.104459","url":null,"abstract":"<div><div>Selenium is considered as one of essential micronutrients in marine ecosystems, and is involved in a number of enzymatic reactions, and hence plays an important role in various metabolic pathways. However, the biogeochemistry of selenium in the ocean is still poorly described in the literature because of lack of observational data. In this study, we reported the concentration and chemical speciation of dissolved selenium in the Eastern Indian Ocean (EIO) based on observations and sample analyses made in 2017 and 2018. In surface waters, concentration of Se(IV), Se(VI) are all low relative to dissolved organic selenium (DOSe), being related to the biological uptake in the euphotic zone. The regeneration of Se in the mesopelagic waters induces that concentration increases with depth for inorganic fraction of dissolved pool, with a systematic change in species ratio, indicating active transformations there. In the deep part of vertical profiles, spatial structure of Se shows a similar trend with dissolved oxygen (DO) and is consistent to the pattern of deep water circulation.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"217 ","pages":"Article 104459"},"PeriodicalIF":2.3,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395598","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}