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

{"title":"Biogenic Si cycling along the Cocos Ridge: differences between in situ and ex situ extracted pore waters imply rapid rates of dissolved Si uptake upon core recovery","authors":"Matthew P. Quinan ,&nbsp;William M. Berelson ,&nbsp;Jaclyn E.P. Cetiner ,&nbsp;Nick E. Rollins ,&nbsp;Frank J. Pavia ,&nbsp;Sijia Dong ,&nbsp;Janice L. Jones ,&nbsp;Mark A. Brzezinski ,&nbsp;Jess F. Adkins","doi":"10.1016/j.dsr.2025.104554","DOIUrl":"10.1016/j.dsr.2025.104554","url":null,"abstract":"<div><div>The cycling of silicon (Si) in marine sediments can have major impacts on global ocean nutrient dynamics and productivity. Si cycling in the sediment of the Cocos Ridge and overlying waters of the eastern equatorial Pacific was investigated using unique <em>in situ</em> and traditional <em>ex situ</em> pore water collection techniques as well as solid phase analysis, core incubation, and sediment trap collection. Si remineralization and burial fluxes show little variation between the four sites investigated, regardless of a ∼1600 m difference in water depth among stations. Dissolved Si concentrations in pore water from sediment depths &gt;10 cm collected <em>in situ</em> were significantly and consistently higher than those collected <em>ex situ</em> implying a previously unrecognized sampling artifact associated with sediment core recovery and processing. The loss of dissolved Si in the <em>ex situ</em> pore waters is also associated with the fractionation of Si isotopes. <em>In situ</em> pore water δ³⁰Si is lighter than <em>ex situ</em> pore water δ³⁰Si at three of the four stations, though only significantly lighter at one. The preferential loss of light Si in <em>ex situ</em> pore waters is attributed to authigenic clay formation during core collection and transport from the cold, high pressure benthos to the ocean's surface. However, consistency between <em>in situ</em> and <em>ex situ</em> pore water Si gradients within 10 cm of the sediment water interface indicates remineralization fluxes previously determined using sediment core-derived pore waters remain accurate.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104554"},"PeriodicalIF":2.3,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589074","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":"The in situ Mg/Ca ratios of planktonic foraminifera shells in the northeastern South China Sea: an attempt to get efficient and reliable proxies","authors":"Guanglu Zhang ,&nbsp;Yanyan Zhao ,&nbsp;Jun Yang ,&nbsp;Sheng Liu ,&nbsp;Zhishun Zhang ,&nbsp;Xiaoqiang Guo ,&nbsp;Guangyao Cao ,&nbsp;Lei Yang ,&nbsp;Sanzhong Li ,&nbsp;Li Zou","doi":"10.1016/j.dsr.2025.104553","DOIUrl":"10.1016/j.dsr.2025.104553","url":null,"abstract":"<div><div>Planktonic foraminifera are one of the important carriers of the physico-chemical environments. Recent advances in <em>in situ</em> microanalysis techniques provide new insights into the spatial distribution and variations of trace element concentrations of individual foraminifera shells. In this study, we focus on the variations of the <em>in situ</em> Mg/Ca ratios of four planktonic foraminifera species, which live in the different depths, from the surface sediments of the northeastern slope of the South China Sea (SCS). Both electron microprobe mapping and LA-ICP-MS results indicate that <em>Globigerinoides ruber</em> exhibits periodic bands with high Mg contents and Mg/Ca ratios, which may be attributed to symbionts. In contrast, <em>Neogloboquadrina dutertrei, Pulleniatina obliquiloculata, and Globorotalia inflata</em> exhibit thick calcite layers with low Mg/Ca ratios, potentially associated with calcite crusts. Meanwhile, high Mg/Ca ratios may be attributed to the contaminants, especially on the shell surface. These findings demonstrate that the variations of Mg/Ca ratios in foraminifera shells are controlled not only by the surrounding seawater temperature but also by other factors.</div><div>Applying this method, we reconstructed Mg/Ca-SST in the northeastern SCS over the past ∼3000 years. The results indicate that the reconstructed SST trend aligns with the previous regional records, which validates the robustness of the method. We hope that this method can be widely applied in the future due to the efficiency, rapid processing, and high spatial resolution with minimal sample requirements.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104553"},"PeriodicalIF":2.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144564072","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":"An unexpected journey – the arctic deep-sea halicreatid trachymedusa Botrynema brucei ellinorae off Florida: a reassessment under an integrative taxonomic approach","authors":"Javier Montenegro ,&nbsp;Jessica Kolbusz ,&nbsp;Yakufu Niyazi ,&nbsp;Joan J. Soto-Angel ,&nbsp;Aino Hosia ,&nbsp;Allen G. Collins ,&nbsp;Alan J. Jamieson ,&nbsp;Dhugal J. Lindsay","doi":"10.1016/j.dsr.2025.104551","DOIUrl":"10.1016/j.dsr.2025.104551","url":null,"abstract":"<div><div>The study of the trachymedusa <em>Botrynema</em> has a long history of research, encompassing over 120 years of exploration in the deep sea. Two distinct morphotypes are recognized within <em>Botrynema</em>: one with a characteristic apical knob and another without it. Both morphotypes are present in the subspecies <em>B. brucei ellinorae</em>, while only specimens with a knob are known for the remainder of <em>B. brucei</em>. Specimens with a knob have been reported across all oceans and latitudes, whereas specimens without a knob are only known from Arctic and Subarctic regions. In this study, we use historical records, molecular tools and phylogenetic analyses to challenge the widely accepted notion of a cosmopolitan distribution for <em>B. brucei</em> as traditionally understood. We propose a range expansion to the subtropical western Atlantic Ocean for <em>B. brucei ellinorae</em> based on molecular data and hypothesize the existence of a mesopelagic soft barrier in the North Atlantic region as a plausible explanation to emerging biogeographical patterns revealed in this study.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104551"},"PeriodicalIF":2.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579332","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":"Constraining sulfur and iron cycling in seep systems: insights from authigenic pyrite signatures","authors":"Qinyi Zhang ,&nbsp;Daidai Wu ,&nbsp;Yanting Ling ,&nbsp;Xuan Chen ,&nbsp;Shengyi Mao ,&nbsp;Jie Liu ,&nbsp;Guangrong Jin","doi":"10.1016/j.dsr.2025.104552","DOIUrl":"10.1016/j.dsr.2025.104552","url":null,"abstract":"<div><div>Seep activity has emerged as a critical area of research for understanding biotic communities and elemental cycling (e.g., carbon, sulfur and iron) in deep extreme environments. While previous studies have predominantly focused on sulfur isotopes in pyrite as a proxy for seep activity, recent advancements highlight the potential of iron isotopes as an additional indicator. However, the detailed mechanism of how sulfur and iron coupled in seep environment is still unclear and thus hamper the further constraint of seep activity by these two key elements. For this reason, the authors analyzed 25 samples from three sediment cores which are collected from seepage sites in the Taixinan Basin (core 973–4) and the Pearl River Mouth Basin (cores GG03 and Z22-3) in the Northern South China Sea. By using SEM-EDS analysis and in-situ sulfur (δ³⁴S) and iron (δ⁵⁶Fe) isotope measurements, also combining with results from previous studies, the evolution patterns of sulfur and iron in seep environments is explored. The δ³⁴S values of pyrite in core 973–4 range from −18.79 ‰ to 27.26 ‰, indicating a closed-system seep activity. In contrast, pyrite in cores GG03 and Z22-3 exhibit significantly negative δ³⁴S values (−49.75 ‰ to −46.29 ‰ and −53.88 ‰ to −37.11 ‰, respectively), characteristic of more open-system seep activities. Additionally, the δ⁵⁶Fe values of pyrite are consistently negative across all cores (−1.39 ‰ to −0.31 ‰ in core 973–4, −1.59 ‰ to −0.24 ‰ in core GG03, and −1.10 ‰ to −0.20 ‰ in core Z22-3), suggesting the absence of a heavy iron isotope pool. By integrating these findings with previous results, this study demonstrates that the δ⁵⁶Fe values of pyrite are influenced by the position of the sulfate-methane transition zone, diverse microbial reduction processes, and varying iron sources. Therefore, this study provides valuable data to decipher how coupled sulfur and iron evolving in seep environments by pyrite, enhancing the further understanding of elemental cycles in extreme settings.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104552"},"PeriodicalIF":2.3,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556734","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":"Microplastic accumulation visually and fluorescently undetectable within deepwater corals of the remote equatorial Pacific","authors":"Maxwell S. Helmberger ,&nbsp;Steven Auscavitch ,&nbsp;Justin Linehan ,&nbsp;Timothy M. Shank ,&nbsp;Erik Cordes ,&nbsp;Randi D. Rotjan","doi":"10.1016/j.dsr.2025.104550","DOIUrl":"10.1016/j.dsr.2025.104550","url":null,"abstract":"<div><div>Microplastic abundance in aquatic environments is a well-established phenomena, with the potential to disrupt ecological processes, including food webs and vector diseases via contaminated water and sediments. With the call for increasing ocean protection in remote and deep-waters, it is important to establish baselines of relative contamination, and to identify whether or not there are places relatively free from microplastic impact. Deep-sea corals are heterotrophic ecosystem engineers that have the potential to capture and ingest microplastic particles. In this study, we asked whether or not deep-sea corals in humanly remote, fully-protected, locations demonstrate evidence of microplastic ingestion using visual and fluorescence-enabled techniques. We found no strong evidence for microplastic accumulation. Despite these specific results, maintaining plastic-free environments in remote deep-sea systems will benefit from increased protections that limit or prevent anthropogenic activities. As such, open ocean and deep-water marine protected areas should consider including decreased pollution risk among their potential benefits.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104550"},"PeriodicalIF":2.3,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556735","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":"Evidence of vertical stratification in marine environments: insights from passive acoustic monitoring in French Polynesia","authors":"Xavier Raick ,&nbsp;Mélanie Vendrame ,&nbsp;David Lecchini ,&nbsp;Éric Parmentier","doi":"10.1016/j.dsr.2025.104548","DOIUrl":"10.1016/j.dsr.2025.104548","url":null,"abstract":"<div><div>The stratification of species distribution in marine environments is well-documented, reflecting the influence of depth-related factors such as light availability, temperature, pressure, and habitat structure on the organization of marine communities. This study aimed to determine whether this stratification can also be highlighted using Passive Acoustic Monitoring (PAM), a technique proven effective in the study of various marine habitats. Sounds were recorded at 300 m in July 2022 off Moorea Island (French Polynesia) using a SNAP acoustic recorder. These data were compared to both those collected at shallower depths at Moorea Island (20, 60, and 120 m) and to data from other Polynesian islands obtained during a previous, non-concurrent study. Fish sounds in the recordings were manually identified. Richness and abundance of sounds from 20 m to 300 m depth were compared to assess whether fish communities in the altiphotic reef, upper mesophotic reef, lower mesophotic reef, and rariphotic zone could be distinguished based on the sounds they produce. Comparisons between zones over a 24-h period revealed for the first time the existence of acoustic stratification, with a fourfold decrease in species richness, from the altiphotic reef to the rariphotic zone, along with a general decline in sound abundance. However, this general pattern was not uniform in terms of abundance throughout the day, as sound abundance increased with depth at dusk from 950 sounds per hour at 20 m to 3600 at 300 m. It further confirms that diel activity patterns were also evident in light-deprived zones. This first exploration of vertical acoustic stratification based on fish sounds highlights the undeniable contribution of PAM to studies on the ecology of deep-sea communities.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104548"},"PeriodicalIF":2.3,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of the isotope (δ18O, δ2H) composition and salinity of the seawater surface layer in polar regions: Application for the East and European arctic","authors":"E.O. Dubinina,&nbsp;S.A. Kossova,&nbsp;Yu.N. Chizhova,&nbsp;A.S. Avdeenko","doi":"10.1016/j.dsr.2025.104547","DOIUrl":"10.1016/j.dsr.2025.104547","url":null,"abstract":"<div><div>The surface sea water salinity and isotope (δ¹⁸O, δ²H) composition in polar regions are determined by the balance between freshening and freezing-related processes. Due to sea ice formation and its melting, the relation between the salinity and δ¹⁸O(δ²H) values does not correspond entirely to an additive process. We propose the dynamic model of surface layer (DMSL), which considers the fluxes corresponding to the freshening, freezing, and sea ice melting in order to describe the δ¹⁸O(δ²H)–salinity and δ¹⁸O–δ²H relations in Arctic seawater. The DMSL shows that the slope in the δ–salinity space is a complex function of melting and freezing fluxes, freshwater flux, salinity, and isotope composition of marine and freshwater endmembers. The model can be applied to salinity and isotope signatures both for any whole water region and for single water samples. The testing of the DMSL was done for water areas covered with different freezing–melting activity, located both in shelf areas influenced of continental runoff and in areas isolated from it. The data used for test calculations were obtained for surface (0–15 m) seawater collected in the Eastern and European Arctic in 2017, 2018, and 2021 (70°–82.7° N, and −4° W to 168° E) at the end of ice-free seasons. The calculations show that the model is capable of adequately estimating both the isotope signature of fresh water and the ratio of the main fluxes that form the surface layer: freshening, modification, and the contribution from melting sea ice.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104547"},"PeriodicalIF":2.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517570","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":"Bacterial community characterization and relationship in the gut of deep-sea holothurians and sediment from the Northern Indian Ocean","authors":"Xinlong Li ,&nbsp;Anning Mou ,&nbsp;Yue Dong ,&nbsp;Jing Mo ,&nbsp;Xiaomei Liao ,&nbsp;Xiao Wang ,&nbsp;Zongling Wang ,&nbsp;Xuelei Zhang ,&nbsp;Qinzeng Xu","doi":"10.1016/j.dsr.2025.104546","DOIUrl":"10.1016/j.dsr.2025.104546","url":null,"abstract":"<div><div>Sea cucumbers, widely distributed benthic invertebrates in diverse deep-sea habitats, rely on their gut bacterial communities for essential functions including energy metabolism, biological adaptation, and health. However, the gut bacterial community of deep-sea holothurians in the Indian Ocean remains poorly understood. We used 16S rRNA gene sequencing to characterize bacterial communities in the guts of sea cucumbers and surrounding sediments from two distinct regions of the northern Indian Ocean: the Ninety-East Ridge and the Arabian Sea Basin. This study investigates the composition, diversity, predicted functions, co-occurrence networks, and assembly processes of gut bacterial communities. Alpha diversity of gut bacterial communities did not differ significantly between the two regions. Based on principal coordinate analysis, the bacterial communities of gut formed a distinct cluster from the sediment communities. Actinobacteriota, Proteobacteria, Firmicutes, Chloroflexi, and Bacteroidota were the dominant phyla in both gut and sediment bacterial communities. In the Ninety-East Ridge, the gut microbial network exhibited a higher proportion of positive correlation than the sediment network, suggesting a greater potential for cooperative interactions. Compared to sediment communities, functional predictions indicated that gut communities were enriched in metabolic pathways, including those for amino acid, glycan, vitamin, and lipid metabolism. Stochastic processes were predominant in gut bacterial community assembly, whereas deterministic processes dominated in sediment bacterial communities. This study provides critical insights into the gut microbiota of deep-sea holothurians, advancing our understanding of microbial ecology in extreme marine environments.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104546"},"PeriodicalIF":2.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321085","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":"Decadal change in deep-ocean dissolved oxygen in the North Atlantic Ocean and North Pacific Ocean","authors":"Henry A. Ruhl ,&nbsp;Christine L. Huffard ,&nbsp;Monique Messié ,&nbsp;Thomas P. Connolly ,&nbsp;Thomas Soltwedel ,&nbsp;Frank Wenzhöfer ,&nbsp;Rodney J. Johnson ,&nbsp;Nicholas R. Bates ,&nbsp;Susan Hartman ,&nbsp;Anita Flohr ,&nbsp;Edward W. Mawji ,&nbsp;David M. Karl ,&nbsp;James Potemra ,&nbsp;Fernando Santiago-Mandujano ,&nbsp;Tetjana Ross ,&nbsp;Kenneth L. Smith","doi":"10.1016/j.dsr.2025.104534","DOIUrl":"10.1016/j.dsr.2025.104534","url":null,"abstract":"<div><div>Declining dissolved oxygen concentrations are documented at upper and mid ocean depths, but less is known about the deep ocean. Long time-series measurements of dissolved oxygen analyzed with Winkler titration over several decades reveal regional differences at six stations in the abyssal North Atlantic Ocean and North Pacific Ocean. A significant decline in dissolved oxygen was evident at two stations in the northeast Pacific Ocean at 4000–4200 m depth (Stations PAPA and M). A similar decreasing but insignificant trend was recorded in the Arctic region of the North Atlantic Ocean (HAUSGARTEN). However, there was no significant decrease in dissolved oxygen at two temperate stations in the North Atlantic Ocean (PAP, BATS) and at one tropical station in the central North Pacific Ocean (ALOHA) all at similar depths &gt;4000 m over similar time periods. Continued long time-series observations will be needed to monitor global deep ocean processes and the impact of changing climate. We compare these rare long-term observations with model estimations from historical (1850–2014) and projected (2015–2100) forcing under a continued high greenhouse gas emission scenario.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104534"},"PeriodicalIF":2.3,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470622","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":"Evolutionary affinity of a novel deep-sea coral from the Central Indian Ridge seamount, and its links to Pacific Ocean species","authors":"Rengaiyan Periasamy ,&nbsp;Baban Ingole","doi":"10.1016/j.dsr.2025.104543","DOIUrl":"10.1016/j.dsr.2025.104543","url":null,"abstract":"<div><div>The family Victorgorgiidae Moore et al., 2017 comprises deep-sea gorgonian corals typically characterized by purple colonies and distinctive josephinae clubs in their polyp tentacles. Despite this, the family exhibits low species diversity and the ones from the deep Indian Ocean remain poorly unknown, remarking the need for more research to better understand their ecological role and evolutionary history. A new species, <em>Victorgorgia indica</em> sp. nov., was discovered on a seamount along the Central Indian Ridge (CIR) at depths of 1917–2053 m, representing the first record of Victorgorgiidae in the Indian Ocean. Among the nine known species of <em>Victorgorgia</em> López-González and Briand, 2002), <em>V. indica</em> sp. nov. is morphologically most similar to <em>V. flabellata</em> Li et al., 2020 and <em>V. iocasica</em> Li et al., 2020, particularly in the arrangement of the calyx, which is mainly isolated in three sides of the branches. However, this arrangement can vary in different parts of a colony and may be influenced by local habitat conditions. <em>V. indica</em> sp. nov. differs from these species by having tuberculate rods, a thorn club in the tentacle rachis, and curved rodlets with tall tubercules along their edges in the pinnules. Phylogenetic analysis at the family level using the MutS-like protein (MutS) gene supports Victorgorgiidae as a monophyletic group. The evolutionary relationships of the new CIR species suggest a close affinity with its Pacific Ocean congeners, including <em>V. flabellat</em><em>a</em>, <em>V. iocasica</em> and <em>V. eminens</em> Moore et al., 2017. This points to the CIR seamount system potentially acting as a link for gene flow between the Indian and Pacific Oceans. Analyses of the reproductions of these species showed that <em>V. indica</em> sp. nov. is a brooder, with planula larvae developing within clumped autozooids—the only mature polyps—and settling on dead deep-sea coral. Here we presented also the complete mitochondrial genome of <em>V. indica</em> sp. nov., which is 18,715 base pairs in size, and includes 14 protein-coding genes (PCGs), two ribosomal RNA genes (rrnS and rrnL), and one transfer RNA gene. The gene order of the mitogenome is identical to that of other sequenced Victorgorgiidae species.</div></div>","PeriodicalId":51009,"journal":{"name":"Deep-Sea Research Part I-Oceanographic Research Papers","volume":"223 ","pages":"Article 104543"},"PeriodicalIF":2.3,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502790","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}