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

{"title":"The genus Forcipatia (Tanaidacea) in the CCZ. Insights into recent speciation in abyssal plains","authors":"Patricia Esquete ,&nbsp;Marina R. Cunha ,&nbsp;Lénaïck Menot","doi":"10.1016/j.dsr.2026.104662","DOIUrl":"10.1016/j.dsr.2026.104662","url":null,"abstract":"<div><div>This paper deals with two new crustacean species of the genus <em>Forcipatia</em> (Tanaidacea: Leptognathidae) from two polymetallic nodules areas within the Clarion-Clipperton Fracture Zone (CCZ, central Pacific) designated as potential sites for future deep-sea mining activities. The diagnosis of <em>Forcipatia</em> provided by Larsen and Shimomura (2007) is amended and the genus is validated by designating a type species. Two new species are described based on molecular, morphological and distributional evidence: <em>Forcipatia arcana</em> and <em>F. cryptica</em>. The genus is characterized mainly by having a relatively short body (6.0 times as long as broad) and a cheliped with an elongated propodus about as long as or longer than the merus and carpus together, propodus with two ventral setae and dactylus deflexed over the fixed finger. Species of <em>Forcipatia</em> differ in the setation of the pereopods. Our results contribute to the knowledge of the biodiversity in the CCZ and provide insights on the speciation processes and diversification of small invertebrates with limited dispersal capacities in abyssal plains.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104662"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174170","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":"Shell trace elemental fingerprints of the deep-sea methane seep mussel Gigantidas childressi vary by depth, site, and shell growth region","authors":"Ian J. Grace ,&nbsp;Luciana Génio ,&nbsp;David B. Eggleston ,&nbsp;Brandon J. Puckett ,&nbsp;F. Joel Fodrie ,&nbsp;Adam N.H. Smith ,&nbsp;Craig M. Young","doi":"10.1016/j.dsr.2026.104655","DOIUrl":"10.1016/j.dsr.2026.104655","url":null,"abstract":"<div><div>Larval dispersal is a key driver of population persistence and resilience of numerous metapopulations and communities in marine ecosystems. Determining where and how larvae disperse in the deep sea is one of the most vexing challenges in deep-sea ecology. Laser ablation inductively coupled plasma mass spectrometry was used to evaluate the potential role of trace elemental fingerprints (TEFs) of deep-sea methane seep mussel <em>Gigantidas childressi</em> (n = 92 valves) in discriminating among collection depths, geographic regions (Gulf of Mexico and West Atlantic Margin; GOM and WAM), methane seep sites, and shell growth regions (larval VS settler shell). <em>A priori</em> permutational analyses of variance (PERMANOVA) discriminated among mussel valve TEFs across a depth gradient (650 m–2206 m), among eight methane seep sites, and among shell growth regions. <em>A priori</em> canonical analyses of principal coordinates (CAP) generally matched and additionally discriminated TEFs among geographic regions. Results for post-hoc analyses on individual shell growth regions varied by statistical approach (PERMANOVA VS CAP) and by shell growth region (larval prodissoconch I and prodissoconch II VS settler dissoconch shell). Broadly, post-hoc PERMANOVA discriminated only among sites, while post-hoc CAP discriminated among all study factors. Discrimination among depths was mainly driven by the elemental ratio Ba:Ca. Discrimination among geographic regions was mainly by Ba:Ca and Sr:Ca. Discrimination among sites and shell growth regions was driven by all three elemental ratios analyzed (Ba:Ca, Sr:Ca, and Mg:Ca). Overall, shell TEFs show potential to discern spatial distribution of larval population pools.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104655"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174175","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":"Radiocarbon constraints on the sources and fluxes of sinking particulate organic carbon to the deep Sargasso Sea","authors":"Charlotte Schnepper ,&nbsp;Rut Pedrosa-Pàmies ,&nbsp;Maureen H. Conte ,&nbsp;J.C. Weber ,&nbsp;Nicolas Gruber ,&nbsp;Negar Haghipour ,&nbsp;Timothy I. Eglinton","doi":"10.1016/j.dsr.2026.104663","DOIUrl":"10.1016/j.dsr.2026.104663","url":null,"abstract":"<div><div>The oceanic biological carbon pump (BCP) is thought to be driven by the vertical export of particulate organic carbon (POC) derived from fresh photosynthetically-fixed carbon in the surface waters to depth. Yet the chemical and isotopic composition of deep ocean POC is often inconsistent with this one-dimensional perspective of the BCP. Here, we investigate the sources and temporal dynamics of POC in the deep-sea using the concentration and carbon isotopic composition (Δ¹⁴C and δ¹³C) of POC intercepted by time-series sediment traps deployed in the Sargasso Sea near Bermuda over a 43-month time period. Seasonal variability in POC collected at 3200 m between 2012 and 2015 reveals a recurring springtime increase in Δ¹⁴C and δ¹³C, indicating rapid transfer of POC produced in the surface ocean to depth. In contrast, summer and autumn periods are characterized by lower Δ¹⁴C and δ¹³C values, reflecting higher contributions of millennial to centennial aged carbon sources. Isotopic mass balance calculations indicate that, on average, 63 ± 14 % of sinking POC originates from freshly produced surface-derived OC and 24 ± 15 % derives from mineral-free suspended pre-aged POC (partly surface-derived), while mineral-associated OC (8 ± 6 %), and DOC (5 ± 4 %) further contribute to the aged carbon signature. The contribution of surface-derived OC is highest during spring, while the fraction of aged mineral-bound OC, likely linked to Gulf Stream-driven lateral sediment transport from the Northwest Atlantic continental margin, is highest in autumn. Our findings highlight the complexity of the BCP in the open ocean, where pre-aged OC contributes significantly to deep-sea carbon sequestration, challenging traditional one-dimensional vertical perspectives of carbon export.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104663"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080586","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":"Environmental effects of Shenhu gas hydrate trial production: A perspective on carbon cycling in shallow sediments","authors":"Taiheng Lv ,&nbsp;Cuiling Xu ,&nbsp;Zhilei Sun ,&nbsp;Hong Cao ,&nbsp;Xilin Zhang ,&nbsp;Wei Geng ,&nbsp;Ye Chen ,&nbsp;Sinan Xu ,&nbsp;Dong Zhang ,&nbsp;Yucheng Zhou ,&nbsp;Shixing Li ,&nbsp;Yunbao Sun ,&nbsp;Bin Zhai","doi":"10.1016/j.dsr.2026.104652","DOIUrl":"10.1016/j.dsr.2026.104652","url":null,"abstract":"<div><div>The environmental issues associated with natural gas hydrate (NGH) production have become increasingly prominent. Additionally, gas hydrate systems in marine environments play a critical role in global carbon cycling and energy exchanges between the seafloor and the overlying water column. Though biogeochemical processes occurring in the shallow sediments are well studied, limited research focused on regions affected by NGH production. This study aims to fill this gap by investigating the geochemical characteristics of fluid-sediment interactions in the Shenhu NGH trial production area of the South China Sea. Sediment-water interface samples were collected from sites SH-1 and SH-2, both located near artificial vents in the Shenhu trial production area, using a visual multi-tube sampler. A combination of geochemical analysis and numerical simulations was used to examine the transport and transformation of dissolved carbon in the shallow sediments. The results indicate that artificial cold seeps caused by borehole-induced fluid leakage were observed in the Shenhu gas hydrate trial production area, exhibiting typical seep characteristics. The depth of the sulfate-methane transition zone (SMTZ) near the trial production well has risen from 18.9 mbsf in the background area to 10.8 mbsf. Organic sulfate reduction (OSR) dominated the biogeochemical processes in shallow sediments, with anaerobic oxidation of methane (AOM) contributing to DIC production, and a numerical model indicating a 7:3 sulfate consumption ratio of OSR to AOM in deeper sediments. Additionally, the sediment was found to be a net source of dissolved carbon to the bottom water, with inorganic carbon emission fluxes ranging from 5.7 to 9.1 mmol m⁻² a⁻¹ and organic carbon fluxes ranging from 0.65 to 0.71 mmol m⁻² a⁻¹. This study presents the first investigation into the biogeochemical carbon cycling mechanisms associated with artificial cold seep systems. The findings significantly improve our understanding of shallow sediment carbon dynamics in the Shenhu area and contribute a new perspective to gas hydrate-related carbon flux research.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104652"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025345","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":"MARS lander: Georeferencing landing and pop points of untethered ocean monitoring systems using fundamental physics","authors":"Marko Radeta ,&nbsp;Zahra Behboodi ,&nbsp;Vladimir Zekovic ,&nbsp;Décio Alves ,&nbsp;David Pestana ,&nbsp;Daniel Nunes ,&nbsp;Margarida Freitas ,&nbsp;Ankit Gupta ,&nbsp;João Pestana ,&nbsp;Dinarte Vieira ,&nbsp;Sílvia Almeida ,&nbsp;Morgado Dias ,&nbsp;João Canning Clode ,&nbsp;Rui Caldeira ,&nbsp;Paulo Relvas ,&nbsp;Antonio Vasiljevic","doi":"10.1016/j.dsr.2026.104650","DOIUrl":"10.1016/j.dsr.2026.104650","url":null,"abstract":"<div><div>Subsurface observations are crucial for understanding the ocean's role in Earth's climate and for refining climate models. However, existing aquatic monitoring systems that allow such insights remain complex and costly due to their high demands for deployment, sampling, and recapture. Since low-cost, easy-to-deploy deep-sea landers are scarce, and with the aim of facilitating more subsurface observations, this study provides a simple method for georeferencing small-sized untethered landers. Their underwater trajectories are modelled with fundamental physics, dead reckoning, lander geometry, and numerical simulations. Using free fall, upthrust, and ocean current dynamics, the proposed approach estimates their underwater trajectories, including landing (at the seabed) and pop (at the sea surface) points. The method relies on the lander's physical characteristics, including its vertical and horizontal cross-sectional areas, to calculate the drag force coefficients used to determine its trajectories during descent and ascent through the water column. Ocean currents' magnitudes are modelled using Ekman's exponential decay down to 90 m of the water column, while the depths until 900 m are modelled from prior ADCP surveys by varying ocean current headings with depth between −20 and 20°. Surface ocean and wind current headings are modelled with open datasets from satellite telemetry. Lander's velocity, displacement, and dive time to the landing and pop points, including the total radial excursion and uncertainty in heading, are analytically derived, numerically calculated, and empirically assessed a-posteriori until 90 m, yielding a ∼38 m radial excursion (40% error) against the obtained GNSS coordinates in field deployment, and 33° in heading uncertainty during a 138-s excursion. Additional random walk simulations are shown for full ocean depth obtaining radial excursion of 1038 m with 278 min total dive time. This approach is generalizable to any subsurface aquatic monitoring systems targeting deployments with diverse payloads from smaller sea vessels, not requiring cranes, radio, GNSS, or acoustic telemetry. Since it accounts for key nature factors, our method provides special benefits in planning and optimizing deployments. Additional discussion focuses on the method's practicality for full ocean depth deployments.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104650"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174176","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":"Multidecadal increase in microbial biomass and production along the western Antarctic Peninsula","authors":"Hugh W. Ducklow ,&nbsp;Oscar M. Schofield ,&nbsp;Sharon E. Stammerjohn ,&nbsp;David L. Kirchman","doi":"10.1016/j.dsr.2026.104653","DOIUrl":"10.1016/j.dsr.2026.104653","url":null,"abstract":"<div><div>Marine pelagic ecosystems around the world are changing in response to climate change. The marine pelagic ecosystem extending along the western Antarctic Peninsula (WAP) is a region of rapid warming and sea ice loss, and in response there have been conspicuous trends in the ecosystem ranging from phytoplankton to krill and penguins. Despite the many ecosystem responses observed globally for phytoplankton and other trophic levels, there have been only a few observations of trends in heterotrophic bacteria, the most numerically dominant organisms on the planet. Here we report on a sustained increase in bacterial biomass over 2003–2019 that occurred throughout a 140,000 km² area of the WAP. Concomitant with the rise in bacterial biomass, bacterial production, chlorophyll and primary production also increased throughout the region. The trends appear to be driven by the southward migration along the Peninsula of warm and moist conditions in the north into the cold and dry continental polar regime to the south. The extensive and sustained long-term increases in microbial biomass and activity are another sign of large changes in the WAP ecosystem.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104653"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145986736","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":"Hitchhiking in the deep: A new Amphisamytha species (Annelida: Ampharetidae) riding on widespread squat lobster at hydrothermal vents in the Okinawa Trough (NW Pacific)","authors":"Orlemir Carrerette ,&nbsp;Gilberto Bergamo ,&nbsp;Maurício Shimabukuro ,&nbsp;Naoto Jimi ,&nbsp;Yoshihiro Fujiwara ,&nbsp;Paulo Y.G. Sumida","doi":"10.1016/j.dsr.2026.104654","DOIUrl":"10.1016/j.dsr.2026.104654","url":null,"abstract":"<div><div>Deep-sea hydrothermal vents represent unique ecosystems characterized by extreme environmental conditions and high chemosynthetically-driven productivity. The annelid genus <em>Amphisamytha</em> is a key representative of deep-sea hydrothermal vent communities, exhibiting a wide distribution across chemosynthesis-based environments (CBEs) and diverse habitats, ranging from shallow coastal waters to deep-sea hydrothermal vents. While 13 species have been formally described, including those inhabiting both cold seeps and hydrothermal vents, the phylogeny and biogeography of the genus remain poorly understood, with gaps in molecular data, particularly for its type species, <em>A. japonica</em>. Recent research suggests <em>Amphisamytha</em> may have originated in shallow waters, with cryptic species contributing to its complexity. This study describes a new species, <em>Amphisamytha goemoncola</em> sp. nov., discovered in the hydrothermal vent fields of the Okinawa Trough, Northwestern Pacific, living symbiotically attached to the squat lobster <em>Shinkaia crosnieri</em>. The new species highlights the ecological versatility of the genus and provides new insights into the biodiversity of the region. By addressing key knowledge gaps in its evolutionary history, this work contributes to a better understanding of the biogeography and diversification of <em>Amphisamytha</em> across the Pacific.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104654"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174172","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":"Quadruple enhancement of surface chlorophyll growth by oceanic submesoscale temperature fronts","authors":"Hanrui Liu ,&nbsp;Bo Qiu ,&nbsp;Hailin Wang ,&nbsp;Zhengguang Zhang","doi":"10.1016/j.dsr.2026.104664","DOIUrl":"10.1016/j.dsr.2026.104664","url":null,"abstract":"<div><div>Submesoscale fronts have been recognized as important contributors to nutrient supply for oceanic primary production, which constrains the energy available to sustain marine ecosystems and the associated food chain. Their small spatiotemporal scales (1–10 km, 1–10 days) have hindered understanding of their spatial structure, temporal evolution and biogeochemical impact. Here, by combining global multi-platform observations, we find that submesoscale temperature fronts around oceanic eddies are characterized by enhancementd ageostrophic kinetic energy along the fronts. Stronger fronts increase the surface chlorophyll growth rate by fourfold on the warm side of the fronts, where the upwelling branch of a vertical secondary circulation develops. The temporal evolution of submesoscale temperature fronts of oceanic eddies is characterized by a peak in frontal intensity, with a lifecycle of approximately 10 days. These frontal processes induce biogeochemical impacts on a larger scale, which exhibits a net enhancement of surface chlorophyll concentration of the corresponding eddies during this lifecycle, and the strongest chlorophyll enhancement emerges when frontal intensity reaches its maximum. These biogeochemical signatures of submesoscale temperature fronts are associated with increased fishing hours, suggesting their potential contributions to the oceanic primary production and marine food chains.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104664"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174173","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":"Investigating the diversity and spatiotemporal dynamics of eukaryotic communities in hydrothermal vents at the Central Indian Ridge using environmental DNA metabarcoding","authors":"Eun-Bi Kim,&nbsp;Se-Jong Ju,&nbsp;Jonguk Kim,&nbsp;Yeon Jee Suh","doi":"10.1016/j.dsr.2026.104651","DOIUrl":"10.1016/j.dsr.2026.104651","url":null,"abstract":"<div><div>Deep-sea hydrothermal vent ecosystems along the Central Indian Ridge (CIR) are ecologically and biogeographically important; however, their biodiversity patterns remain poorly understood amid concerns over potential anthropogenic impacts. Here, we conducted the first comprehensive survey of eukaryotic community diversity across eight vent fields, including the newly discovered Saero and Maru, as well as a non-vent reference site unaffected by hydrothermal activity. Environmental DNA (eDNA) metabarcoding of seawater and sediment samples collected in 2023–2024, targeting the 18S rRNA V9 region, yielded 1569 and 1783 amplicon sequence variants (ASVs), representing 34 and 39 phyla and 78 and 85 classes, respectively. The results revealed high diversity and pronounced spatial heterogeneity in both sample types, with numerous unique ASVs at individual sites, suggesting potential local endemism. Notably, inactive vent fields displayed alpha diversity comparable to or exceeding that of active vents and the reference site, underscoring their ecological significance and the need for conservation. Community structures varied among vent fields, showing latitudinal organization along the CIR, and differed across years, particularly in diffuse vents, reflecting environmental and temporal influences. Seawater and sediment captured complementary aspects of community composition, highlighting the value of multi-substrate eDNA approaches for comprehensive biodiversity assessment. These findings establish a critical baseline for long-term monitoring and provide essential insights to guide conservation and management of CIR hydrothermal ecosystems.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104651"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025344","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":"Deep-sea bamboo corals: New Jasonisis species from Indian and Atlantic ridges and pan-oceanic genetic connectivity of Tridentisis candelabrum","authors":"Meiling Ge ,&nbsp;Xinlong Li ,&nbsp;Xin Tian ,&nbsp;Ningxia Xu ,&nbsp;Xuying Hu ,&nbsp;Yu Xu ,&nbsp;Zongling Wang ,&nbsp;Xuelei Zhang ,&nbsp;Qinzeng Xu","doi":"10.1016/j.dsr.2026.104648","DOIUrl":"10.1016/j.dsr.2026.104648","url":null,"abstract":"<div><div>Keratoisididae, a deep-sea family of Octocorallia, exhibits significant morphological and genetic diversity. Clade J3 comprises taxa diverse morphologic characteristics. This study reports two new species from clade J3: <em>Jasonisis guangdeensis</em> <strong>sp. nov.</strong> collected from the Central Indian Ridge and <em>Jasonisis rarispina</em> <strong>sp. nov.</strong> collected from the North Mid-Atlantic Ridge. Two new species are characterized by alternately and biserially arranged polyps, and scales with an obvious medial constriction in polyp body wall and coenenchyme, distinguishing them from the type species <em>J. thresheri</em>. <em>Jasonisis rarispina</em> <strong>sp. nov.</strong> differs from <em>J. guangdeensis</em> <strong>sp. nov.</strong> in its nearly smooth sclerites, fewer lobed-margined sclerites and larger inter-polyp distances. Phylogenetic analyses based on two single genes (the partial <em>mtMutS</em> and <em>28S</em>) and the complete mitogenome confirmed the monophyly of both new species. Meanwhile, <em>Tridentisis candelabrum</em> of clade I4 in Keratoisididae was recorded in the Indian Ocean for the first time. Mitochondrial genome analysis revealed that individuals of <em>T. candelabrum</em> from the Indian Ocean are more closely related to those from the Pacific, with identical mitochondrial genome sequences. In contrast, they exhibit 25 base substitutions compared to Atlantic individuals of <em>T. candelabrum</em>, primarily in two <em>rRNA</em> genes and the <em>mtMutS</em> gene. The discovery of these new species and new records of Keratoisididae enhances our understanding of deep-sea biodiversity and genetic connectivity across global ocean.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"228 ","pages":"Article 104648"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025958","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}