Deep-sea Research Part Ii-topical Studies in Oceanography最新文献

{"title":"Brachyuran and anomuran Decapoda of the Emperor Seamounts","authors":"Evgeniia Egorova,&nbsp;Tatiana Dautova","doi":"10.1016/j.dsr2.2025.105501","DOIUrl":"10.1016/j.dsr2.2025.105501","url":null,"abstract":"<div><div>The bathyal areas in the Emperor Seamount Chain (North Pacific) were investigated during two expeditions of the RV <em>Akademik M.A. Lavrentyev</em> in 2019 and 2021. Over 60 crustacean specimens, including true crabs, king crabs, and squat lobsters, were collected and more than 70 h of video data recorded. We present first information on the composition and distribution of deep-sea decapods (Brachyura and Anomura) of the Emperor Chain obtained with a remote operated vehicle. First data on the squat lobster (Chirostyloidea, Galatheoidea) fauna from the Emperor Seamounts are provided. The known geographic range of <em>Macroregonia macrochira</em> is broadened. The depth range of <em>Chaceon imperialis</em> was expanded and found to be bimodal. We have identified a species of king crab (<em>Neolithodes bronwynae</em>) previously unknown in the North Pacific. Overall, the diversity in the Emperor Seamount Chain region shows a relatively high level of endemism and a presence of species previously known from distant regions, suggesting that further biogeographical studies of the region and surrounding areas may elucidate migration routes.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"222 ","pages":"Article 105501"},"PeriodicalIF":2.3,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297872","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":"Assessment of oceanographic characteristics and water mass exchange in the Persian Gulf and Gulf of Oman","authors":"Siamak Jamshidi,&nbsp;Samad Hamzei","doi":"10.1016/j.dsr2.2025.105503","DOIUrl":"10.1016/j.dsr2.2025.105503","url":null,"abstract":"<div><div>Physical oceanography of the Persian Gulf (PG), Strait of Hormuz (SH), and Gulf of Oman (GO) waters is poorly understood, necessitating more extensive and long-term studies. The main goal of this research is to comprehend the oceanographic properties and water mass exchange in this region. The study evaluates the range and patterns of the changes in physical characteristics (salinity (S), temperature (T), and depth (D or pressure, P)) and structure, mixing and stratification, and circulation of water in the PG, SH and GO. The findings revealed that the maximum recorded sea surface temperature in the PG exceeded than that in the GO during the summer. Seawater temperature in the PG decreased from east to west in the winter. The maximum sound speed values were in the surface layer during the summer (approximately 1557.5 m/s). The maximum salinity gradient and winter halocline were found between depths of 40 and 60 m. The vertical structure of seawater indicates the formation of strong thermal and density stratifications in the summer. The Richardson Number (R_i No.) in the SH ranged from <span><math><mrow><msub><mrow><mn>0.5</mn><mo>&lt;</mo><mi>R</mi></mrow><mi>i</mi></msub><mspace></mspace><mi>N</mi><mi>o</mi><mo>.</mo><mo>&lt;</mo><mn>0.65</mn></mrow></math></span> in the summer and it varied between <span><math><mrow><msub><mrow><mn>0.03</mn><mo>&lt;</mo><mi>R</mi></mrow><mi>i</mi></msub><mspace></mspace><mi>N</mi><mi>o</mi><mo>.</mo><mo>&lt;</mo><mn>0.15</mn></mrow></math></span> during the winter. A dense water mass with a salinity more than 40 psμ (originating from the PG) was found below 150 m depth in the southwestern part of the GO. The stability and layering of the water column in the SH are under effect of the two-layer currents and the movement of water masses between the PG and GO. The static stability number (E) of the water column in the eastern part of the PG varied in the range of <span><math><mrow><mn>3</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup><mo>&lt;</mo><mi>E</mi><mo>&lt;</mo><mn>6</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math></span> during the winter, and between <span><math><mrow><mn>12</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup><mo>&lt;</mo><mi>E</mi><mo>&lt;</mo><mn>16</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math></span> in the summer. The maximum amount of the density anomaly occurs in the deep areas of the PG during the summer. During the winter, a two-layered water structure forms in the central areas of the SH. Horizontal and vertical gradients of the salinity and density facilitate the exchange of water masses between the PG and the GO through the SH. The average flushing time (Residence Time, T_Residence) of the PG is 1.82 years. The findings of the study offer an observational evaluation of the water mass exchange, seawater parameters, stratification, ","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"222 ","pages":"Article 105503"},"PeriodicalIF":2.3,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144510991","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":"New insights in benthic biodiversity of the saya de Malha Bank","authors":"L. Corbari ,&nbsp;P. Bouchet ,&nbsp;L. Le Gall ,&nbsp;S. Hourdez ,&nbsp;I. Frutos ,&nbsp;B. Gouillieux ,&nbsp;E. Vassard ,&nbsp;G. Moutardier ,&nbsp;W.-J. Chen ,&nbsp;S.-L. Ng ,&nbsp;R. Bhagooli ,&nbsp;S. Ramah ,&nbsp;D. Kaullysing ,&nbsp;V. Munbodhe ,&nbsp;C. Labonte ,&nbsp;R. Boone ,&nbsp;S. Bender","doi":"10.1016/j.dsr2.2025.105500","DOIUrl":"10.1016/j.dsr2.2025.105500","url":null,"abstract":"<div><div>In the South West Indian Ocean, a unique, remote and atypical geomorphological structure, the Saya de Malha Bank, is considered as an underwater 'island' that plays a key role in understanding benthic biodiversity and connectivity processes in the Indian Ocean. In 2022, the Saya de Malha Bank has been explored during the Indian Ocean expedition led by Monaco Explorations. A team of the Muséum national d’Histoire Naturelle (Paris) and collaborators have explored the benthic diversity of the bank by deploying a combination of sampling methods, such as towed gears (dredge, trawl, and sledge) or by scuba-diving (on-sight, brushing and suction device samplings). A total of 81 stations have been sampled, comprising 35 shallow stations on the summit of the bank (19–58 m depth) and 46 stations gaining depth on the flanks of the bank (73–1141 m depth). From these sampling events, a large collection of marine invertebrates, fish and algae has been preserved for taxonomic (morphological and molecular) studies. The inventory of the benthic biodiversity of Saya de Malha is underway, but it is a long-term process. We propose here to focus on the most represented taxonomic groups (algae, molluscs, crustaceans, annelids and fish) by compiling the primary taxonomic data for the diversity metrics and highlighting some discoveries and potential species new to science. Although the inventory is far from complete, these first results emphasize the endemicity of the fauna and flora of the Saya de Malha Bank.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"222 ","pages":"Article 105500"},"PeriodicalIF":2.3,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338555","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":"Diapycnal oxygen flux in the oxycline region of the core of the Arabian Sea Oxygen Minimum Zone","authors":"K. Ashin ,&nbsp;M.S. Girishkumar ,&nbsp;V.V.S.S. Sarma ,&nbsp;T.V.S. Udaya Bhaskar","doi":"10.1016/j.dsr2.2025.105499","DOIUrl":"10.1016/j.dsr2.2025.105499","url":null,"abstract":"<div><div>This study quantified the relative contributions of double diffusion and shear-driven mixing on the diapycnal oxygen flux in the oxycline region of the core of the Arabian Sea Oxygen Minimum Zone (OMZ), a critical oceanic region regulating the local ecosystem dynamics significantly. For that purpose, we used concurrent measurements of vertical profiles of dissolved oxygen and microstructure shear collected during the scientific cruise in May 2019. It was found that the presence of a moderately strong salt finger regime in the oxycline region enhanced the downward diapycnal oxygen flux (-7.0 ± 0.5x10^-2 μmol m^-2 s^-1) by an order of magnitude higher in contrast to traditionally considered shear-driven turbulence alone (-6.4 ± 0.7 x 10^-3 μmol m^-2 s^-1). This difference is solely attributable to the small magnitude of diapycnal diffusivity due to shear-driven turbulence (2.8 ± 1.1 x 10^-6 m² s^-1) compared to salt finger (10^-5 to 10^-4 m² s^-1). For the sake of comparison, the magnitude of lateral flux of oxygen due to horizontal circulation (3x10^-4 μmol m^-2 s^-1) and oxygen consumption rates due to biological processes estimated from observation (-3x10^-3 to -40 x 10^-3 μmol m^-2 s^-1) were much smaller than salt finger induced downward diapycnal oxygen flux in the oxycline region. As a result, there was a net downward oxygen flux from the oxycline into the OMZ. These findings highlighted the need to incorporate double diffusion processes in biogeochemical models to improve the accuracy of vertical oxygen distribution simulations in the Arabian Sea OMZ.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"222 ","pages":"Article 105499"},"PeriodicalIF":2.3,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270946","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":"On the sensitivity of Optimum Multiparameter Analysis: a California Current System case study","authors":"Mercedes Pozo Buil ,&nbsp;Isaac Schroeder ,&nbsp;Steven J. Bograd ,&nbsp;Michael G. Jacox ,&nbsp;Elliott L. Hazen ,&nbsp;Dianne Deauna ,&nbsp;Emanuele Di Lorenzo ,&nbsp;Nicole S. Lovenduski ,&nbsp;Samuel Mogen ,&nbsp;Ryan R. Rykaczewski","doi":"10.1016/j.dsr2.2025.105498","DOIUrl":"10.1016/j.dsr2.2025.105498","url":null,"abstract":"<div><div>Eastern boundary upwelling systems, like the California Current System (CCS), represent a confluence and mixing of water masses whose variability and composition play a key role in modulating their high biological productivity and ecosystem variability. In the southern CCS, the relative contribution (i.e. proportion) and variability of its source water masses was quantified previously using an extended Optimum MultiParameter (eOMP) analysis, which is an inverse modeling technique that solves a set of linear mixing equations using quasi-conservative and non-conservative properties. However, there are several oceanographic decisions implicit in eOMP analysis that can generate uncertainties in the representation of the mixing and proportions of the source waters in a region. Here we quantify the sensitivity of these previous eOMP results in the southern CCS to varying oceanographic assumptions based on the uncertainty of the water mass properties, modified Redfield ratios, and alternate locations of the eastern tropical Pacific source waters. We show that the mean relative contributions of the main CCS source waters are more sensitive to the location of their selected source region (∼20–25 %) and the Redfield ratio (∼15–20 %) than to the uncertainty in the source water properties (∼2–5 %). Understanding the uncertainties of the eOMP assumptions benefits similar studies in other regions, especially in other eastern boundary upwelling systems (EBUS) where water masses characteristics and composition strongly impact the ecosystem.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"222 ","pages":"Article 105498"},"PeriodicalIF":2.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297873","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 distribution and host utilization of octocoral infesting Ascothoracida (Crustacea, Thecostraca), including the discovery of a new species of Gorgonolaureus from the Emperor sea Mount Chain","authors":"Gregory A. Kolbasov ,&nbsp;Alexandra S. Savchenko","doi":"10.1016/j.dsr2.2025.105488","DOIUrl":"10.1016/j.dsr2.2025.105488","url":null,"abstract":"<div><div>Ascothoracida is a small group of exclusively parasitic crustaceans in the class Thecostraca. A new ascothoracidan, <em>Gorgonolaureus imperator</em> sp. nov., was collected from the Emperor Seamount Chain. Three females were found in permanent cysts detached from an undetermined octocoral of the family Acanthogorgiidae (Malacalcyonacea). We provide a description of the new species based on light and scanning electron microscopy together with its CO1 gene sequence and discuss taxonomic affinities of <em>Gorgonolaureus</em> and other closely related sessile genera. Host specificity, trophic ecology and host-parasite interactions of <em>Gorgonolaureus, Cardomanica, Isidascus</em> and <em>Thalassomembracis</em> are compared, providing new insights into the biology of these crustaceans. Previous records of all these octocoral infesting genera with their localities, depths and host taxonomy are summarized, showing the diversity of host taxa, and the wide geographical and vertical ranges of the parasites. The new species represents the northernmost and deepest record for the genus.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"222 ","pages":"Article 105488"},"PeriodicalIF":2.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297954","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":"Introduction to the Emperor Seamount Chain studies","authors":"Tatiana N. Dautova","doi":"10.1016/j.dsr2.2025.105486","DOIUrl":"10.1016/j.dsr2.2025.105486","url":null,"abstract":"<div><div>Seamounts are of interest to the scientific community as they occupy a significant part of the ocean floor area and are areas of high biodiversity and productivity. The Hawaiian-Emperor Chain, formed by the Hawaiian mantle plume, is crucial for understanding of the lithospheric plates’ movement in the past. The chain is the longest contiguous chain of islands, guyots and seamounts in the world, whose edges are located in contrasting climatic and biogeographic zones. It may provide stepping stones for dispersal of deep-sea fauna and serve as their refugia, as well as containing commercial resources. The geological features, plankton and fish stocks of this area have been studied since the 1970s, but bottom systems are poorly studied. With the development of deep-sea surveys and the use of ROVs, the bottom communities of the seamounts in the North Pacific and the Emperor Chain have been studied over the last 10 years.</div></div><div><h3>Results</h3><div>of three research cruises to the area performed in 2019 and 2021 are presented. Numerous new faunistic and biogeographic findings, including the biogeographic boundary between North Pacific and Central Pacific assemblages of species, are made. The feeding modes of the deep-sea corals in the Emperor Chain were surveyed. New data regarding high vertical mixing rates in the area (using Sr isotopes ratio) and possible influence of Aeolian dust input from Asia into the area were obtained. Although seamounts were not previously considered important regions for methane production, substantial methane generation at the Emperor Chain area was discovered. Given the large number of seamounts in the ocean, the global methane budget should be reconsidered.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"222 ","pages":"Article 105486"},"PeriodicalIF":2.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185103","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 life associated with sediments and polymetallic nodules from the Central Indian Ocean Basin: Insights from 18S metabarcoding","authors":"Dineshram Ramadoss ,&nbsp;Bharath Subramanyam Ammanabrolu ,&nbsp;Aneesha Acharya ,&nbsp;Jojy John ,&nbsp;Baban Ingole","doi":"10.1016/j.dsr2.2025.105487","DOIUrl":"10.1016/j.dsr2.2025.105487","url":null,"abstract":"<div><div>The eukaryotic diversity of ocean sediments and polymetallic nodules (PMN) from the Central Indian Ocean Basin (CIOB) is scarcely characterized and molecular studies are lacking, comprising a key research gap. This study aimed to leverage 18S rRNA gene amplicon metabarcoding of environmental DNA (eDNA) to describe the eukaryotic diversity of ocean sediments and PMN from the CIOB. Sediment and PMN samples were obtained at a depth of 5000 m from three CIOB ocean floor sites: Impact Reference Zone (IRZ), Preservation Reference Zone (PRZ), from the PMN International Seabed Authority Contract area of the Government of India, and a location outside the proposed mining zone named BC20. DNA was isolated and the 18S rRNA V9 region was amplified using primers 1391f and EukBr targeting approximately 150bp. Taxonomy was assigned using the reference databases: MZGDB database (MetaZoo WorldAtlas Database) for Animalia and SILVA138 release for Fungi and Protista. Alpha and beta diversities were calculated using the reads assigned to known phyla. In total, 11078041 paired-end reads were generated and 1327 ASVs were assigned to the kingdom level, while 297 were assigned to a minimum of phylum level for Animalia (213 ASVs), Fungi (66 ASVs), and Protista (18 ASVs). The taxa observed included Annelida, Arthropoda, Bryozoa, Chordata, Cnidaria and Mollusca; these are the phyla observed encompassing the 29 Animalia taxa. In total, 3 phyla from Fungi, Ascomycota, Basidiomycota, and Mucuromycota, and 8 other phyla, Amoebozoa, Apicomplexa, Ciliophora, Dinoflagellata, Euglenozoa, Heterolobosea, Orchrophyta and Retaria were noted. Sediment and nodule communities from the same sampling sites were clustered in ordination plots. This study is a pioneering effort to document deep-sea biodiversity in the Central Indian Ocean Basin (CIOB) using the eDNA metabarcoding method. With the hard substrates in the CIOB hosting a rich variety of flora and fauna, future mining activities could threaten these ecosystems. By providing a vital baseline for biodiversity assessments, the study highlights the necessity of extensive sampling to facilitate ongoing monitoring and mitigate potential impacts from exploration and mining.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"222 ","pages":"Article 105487"},"PeriodicalIF":2.3,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189689","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":"Spatial variation of future trends in Atlantic upwelling cells from two CMIP6 models","authors":"Raquel Flügel ,&nbsp;Steven Herbette ,&nbsp;Anne-Marie Treguier ,&nbsp;Robin Waldman ,&nbsp;Malcolm Roberts","doi":"10.1016/j.dsr2.2025.105483","DOIUrl":"10.1016/j.dsr2.2025.105483","url":null,"abstract":"<div><div>Eastern Boundary Upwelling Systems (EBUS) are characterized by wind-triggered upwelling of deep waters along the coast. They are hotspots of biological productivity and diversity and therefore have a high economic, ecological and social importance. In the past, different methods using surface data have been used to estimate upwelling. Recently, the IPCC has suggested directly assessing vertical velocities as a promising method. We use this method to study the two Atlantic EBUS from CMIP6 models from the HadGEM3-GC3.1 and the CNRM6-CM6 family, for both the historical period and a high-emission future scenario with spatial resolutions in the ocean component ranging from 1°to 1/12°. The two major upwelling regions are divided in subregions depending on their seasonality. The vertical transport index shows similar values to a wind-derived Ekman index. Directly evaluating upwelling from transport processes further provides information about the depth of the upwelling, which has previously been identified as an important factor for nutrient availability. We show that depending on the subregion of the upwelling system, different cell structures can be seen in terms of depth and distance to the coast of maximum velocities. When looking at possible future changes, high interannual variability limits the significance of the trends but could indicate a poleward shift of the upwelling regions. A detailed comparison of the spatial structures and the distinction in subregions is important to explain contradictory trends in previous works.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"221 ","pages":"Article 105483"},"PeriodicalIF":2.3,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143941074","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":"Growth rates and ages of the small bamboo coral Acanella arbuscula in the Northwest Atlantic","authors":"Laura F. Piccirillo ,&nbsp;Evan Edinger ,&nbsp;Bárbara de Moura Neves ,&nbsp;Meghan Burchell ,&nbsp;Graham D. Layne ,&nbsp;Vonda E. Hayes","doi":"10.1016/j.dsr2.2025.105485","DOIUrl":"10.1016/j.dsr2.2025.105485","url":null,"abstract":"<div><div><em>Acanella arbuscula</em> is a common deep-water bamboo coral in the Northwest Atlantic and is considered a Vulnerable Marine Ecosystems indicator. Growth rates and ages of <em>A. arbuscula</em> have not been confirmed, despite the importance of these metrics to understand the species recovery potential when disturbed. One-hundred and fifteen <em>A. arbuscula</em> samples were analyzed to examine the relationship between age, location, and depth, and how environmental conditions influence growth rates. Colonies were collected during scientific trawl or remotely operated vehicle surveys from the SW Grand Banks, Northern Labrador shelf, and SE Baffin shelf from depths of 178–1354 m. Skeletons were cross-sectioned at the proteinaceous nodes and examined under reflected light and fluorescence microscopy to quantify growth rings and determine age and growth rates. The species exhibited both major and minor growth rings. Major growth rings were confirmed to represent annual growth by comparing size metrics and age from a previously bomb-¹⁴C dated specimen of <em>A. arbuscula</em> versus specimens aged by growth rings. Minor (sub-annual) growth rings were not consistently observed across specimens and the cause of their formation is unknown. Ages ranged from 8 to 29 years, with radial growth rates of 0.025–0.160 mm/year and axial growth rates of 1.87–16.1 mm/year. Longevity for <em>A. arbuscula</em> is lower than the bamboo coral <em>Keratoisis grayi</em> in the NW Atlantic, but growth rates were consistent with other documented bamboo corals. Multiple regressions revealed that age influenced radial and axial growth rates, with no significant influence of bottom temperature or chlorophyll-a observed for radial growth rates. This study confirms frequency of ring formation in <em>A. arbuscula</em> and that growth rates for the species do not vary significantly based on geographic or bathymetric location.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"221 ","pages":"Article 105485"},"PeriodicalIF":2.3,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935732","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}