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

{"title":"Variability of bottom dissolved oxygen on the southern Senegalese shelf at intraseasonal to interannual time scales using a modelling approach","authors":"Abdoul Wahab Tall ,&nbsp;Vincent Echevin ,&nbsp;Xavier Capet ,&nbsp;Eric Machu","doi":"10.1016/j.dsr2.2025.105464","DOIUrl":"10.1016/j.dsr2.2025.105464","url":null,"abstract":"<div><div>Recent in-situ measurements on the west African continental shelf have shown that the bottom waters undergo episodic hypoxia and even anoxia. In this study, we investigate the variability of bottom dissolved oxygen (DO) over the southern Senegalese shelf at seasonal, intraseasonal and interannual time scales over the period 2015–2019 using a high-resolution (2 km) regional coupled dynamical-biogeochemical model. The model is forced by daily winds to represent synoptic variability during the upwelling-favourable cold season (November-May). Near-bottom DO evaluation using data from the Melax mooring located over the mid shelf indicates that the model represents well the seasonal and intraseasonal variability. A bottom DO budget shows that advection of deep, low-oxygenated waters over the shelf edge during the upwelling season generates a DO loss, which is overcompensated by ventilation of the entire shelf due to vertical mixing. Biogeochemical processes compensate this DO supply: DO is consumed by organic matter and zooplankton respiration, slightly compensated by regenerated and new primary production. Because of a sluggish shelf circulation during the summer season (July–September, JAS), oxygen concentration declines in parts of the outer shelf bottom layer, in spite of a weaker surface primary production and organic matter export than during the heart of the cold season (February–April, FMA). Analysis of the synoptic variability reveals the complexity of the DO response to the duration and intensity of upwelling and relaxation events, with the largest DO decrease of <span><math><mrow><mo>∼</mo><mn>110</mn><mi>μ</mi><mi>m</mi><mi>o</mi><mi>l</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><msup><mrow><mi>L</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> associated with a strong upwelling event (cumulative upwelling index <span><math><mrow><mo>∼</mo><mn>2</mn><msup><mrow><mi>Nm</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><mi>d</mi><mi>a</mi><mi>y</mi></mrow></math></span>) obtained in 2016. Year to year variability indicates two periods of enhanced hypoxia in FMA 2017 and JAS 2016 characterized by a high retention of bottom waters over the shelf.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"221 ","pages":"Article 105464"},"PeriodicalIF":2.3,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519959","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":"Impact of desalination plant brine discharge on macrobenthic communities in the Persian Gulf","authors":"Moslem Sharifinia,&nbsp;Mehrzad Keshavarzifard,&nbsp;Parisa Hosseinkhezri","doi":"10.1016/j.dsr2.2025.105465","DOIUrl":"10.1016/j.dsr2.2025.105465","url":null,"abstract":"<div><div>This research investigates the ecological impacts of desalination plant discharges on sediment quality and macrobenthic communities in the coastal waters of Bushehr City, Iran, located within the Persian Gulf. Spanning from November 2019 to October 2020, the study involved meticulous sampling of 288 sediment samples from 24 strategically selected stations—half of which were influenced by brine discharges from a desalination facility releasing approximately 45,000 cubic meters of treated wastewater daily, while the other half served as controls. The study employed a comprehensive methodology that integrated fieldwork focused on macrobenthos as biological indicators. A total of 62 macrobenthic taxa were identified, with a notable diversity of mollusks, including 35 gastropod taxa, which represented 56% of the total abundance. The application of ecological indices, including the AZTI Marine Biotic Index (AMBI), Margalef's richness, Shannon-Wiener diversity, and Pielou's evenness, revealed significant declines in biodiversity metrics near discharge points, highlighting the detrimental effects of pollution. Statistical analyses confirmed a negative correlation between the AMBI index and both the Shannon and Margalef indices, while a positive association was observed between the AMBI index and total organic matter (TOM), highlighting its effectiveness in assessing organic enrichment. These findings emphasize the complex interplay between ecological health indicators and environmental stressors, such as salinity, and highlight the importance of utilizing biological indices within coastal management frameworks. Ultimately, this research provides critical insights for developing targeted strategies to enhance the sustainable management of coastal ecosystems, ensuring the preservation of biodiversity and ecological integrity in the face of anthropogenic pressures.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"221 ","pages":"Article 105465"},"PeriodicalIF":2.3,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471556","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":"Introducing a new method to determining the capacity of heavy metal absorption by macro algae on the coast of Persian Gulf based on Kullback-Leibler cumulative information","authors":"Mehdi Bibak ,&nbsp;Saeid Tahmasebi ,&nbsp;Eisa Safavi ,&nbsp;Najmaldin Ezaldin Hassan","doi":"10.1016/j.dsr2.2025.105466","DOIUrl":"10.1016/j.dsr2.2025.105466","url":null,"abstract":"<div><div>Researchers have continuously sought effective and affordable ways to address contamination. Application of both live and deceased algae biomass has emerged as a highly effective and promising approach for remediation. In this study, the efficacy of macroalgal species (<em>Padina gymnospora</em>, <em>Cladophoropsis membranacea</em>, and <em>Hypnea hamulosa</em>) harvested from the northern coast of the Persian Gulf was evaluated for their capacity to biosorb heavy metals, with a focus on nickel, lead, cadmium, and mercury. The study encompassed two key components. Firstlythe experimental methodology was meticulously design using Design-Expert software. Secondly, a novel approach involving – the analysis of scanning electron microscope (SEM) images of the algae was introduced, employing a measure known as cumulative Kullback–Leibler information. The results showed that <em>P. gymnospora</em> is capable of removing 50% of Pb. The highest percentage of Cd removal was observed in <em>H. hamulosa</em> (86.44%), while the highest percentage of Hg removal was recorded in <em>C. membranacea</em> (50%). Both, the experimental and analysis of image methods yielded consistent findings, corroborating their reliability. Based on the findings of this study, image analysis employing cumulative Kullback–Leibler information presents a novel and cost effective means of assessment, contributing to the arsenal methods available for contamination treatment.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"221 ","pages":"Article 105466"},"PeriodicalIF":2.3,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487678","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":"Uncovering the hidden amphipod biodiversity and its drivers in the Persian Gulf","authors":"Farzaneh Momtazi ,&nbsp;Abdolvahab Maghsoudlou ,&nbsp;Hanieh Saeedi","doi":"10.1016/j.dsr2.2025.105463","DOIUrl":"10.1016/j.dsr2.2025.105463","url":null,"abstract":"<div><div>The Persian Gulf (PG), an epicontinental sea at the northwestern corner of the Indian Ocean presents a challenging environment in which species confront the upper limits of their environmental tolerance. Previous hypotheses suggested that the PG is a homogeneous ecosystem characterized by low species diversity and a limited number of endemic species. We investigated these hypotheses by studying the amphipods' distribution pattern and environmental drivers, a dominant benthic group in the PG. We compiled an extensive database of amphipod distribution by integrating the open-access data including the Ocean Biodiversity Information System (OBIS) and Global Biodiversity Information Facility (GBIF), literature mining on amphipods, as well as the author's sampling database from the Persian Gulf and the Gulf of Oman. Following careful data cleaning and quality control, the final dataset comprised 1411 distribution records of 134 accepted marine amphipod species collected from depths ranging from 0 to 100 m. The environmental variables were extracted from the Bio-ORACLE database for the benthic layer with the maximum depth. Species richness per hexagonal cells (alpha species richness), and ES15 (expected number of species per 15 random samples) were calculated. Our findings revealed higher-than-expected species richness and non-homogeneous amphipod distribution across the region. Two biodiversity hotspots were identified in the northern and northwestern parts of the PG and a lowspot of amphipod species diversity in the southern half. Beta diversity cluster analysis exhibited three distinct compositions of amphipod assemblages: a northwestern community near the Arvand (Shat AL-Arab) river, a northern assemblage along Iranian coasts and the Strait of Hormuz region, and a southern assemblage along Arabian coasts. Generalized Additive Models (GAMs) and General Linear Models (GLMs) outputs showed that all environmental variables, pH, and temperature were the most important drivers in delimiting the benthic species distributions and richness. Our findings emphasize the need for a detailed approach to understanding the distribution and diversity of marine organisms in the PG where data and knowledge are less shared openly. This region should not be treated as a homogeneous ecosystem, as it harbors many endemic and rare species threatened by anthropogenic activities such as oil extraction and ocean warming.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"220 ","pages":"Article 105463"},"PeriodicalIF":2.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421546","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":"Diet of deep-sea octocorals from the Emperor Seamount Chain inferred by fatty acid trophic markers","authors":"S.A. Rodkina,&nbsp;T.N. Dautova","doi":"10.1016/j.dsr2.2025.105462","DOIUrl":"10.1016/j.dsr2.2025.105462","url":null,"abstract":"<div><div>Despite the important role that octocorals (Cnidaria: Octocorallia) play in creating and maintaining deep-sea communities known as coral gardens, little is known about their diet. We analyzed the fatty acid compositions of deep-sea octocorals collected from Koko Guyot, located in the southern Emperor Seamount Chain, to identify their main food sources. The data suggests that octocorals feed mainly on zooplankton. However, the contribution of zooplankton to their diet varies greatly among different species and is determined by different zooplankton groups (herbivores, carnivores, or omnivores). This is evidenced by the increased content of some monounsaturated fatty acids (FA) and the different ratios of polyunsaturated fatty acids in corals. In bamboo coral <em>Isidella</em>, we observed the maximum enrichment in calanoid copepod markers (20:1n-9 and 22:1n-1). In addition to the copepod markers, most corals showed a high level of the carnivore marker (18:1n-9), which indicates a significant contribution of other (non-calanoid copepods) items to the diet. The high level of n-3 polyunsaturated fatty acids (PUFA) such as the diatom marker 20:5n-3 suggests that corals of the family Primnoidae take up more freshly produced material. However, the high level of n-6 PUFA (especially, 20:4n-6), found in Paramuriceidae and <em>Keroeides</em> corals may indicate the involvement of detrital links in their diet. FA analysis is useful for identifying the diet of cold-water octocorals and provides a basis for prediction of future potential changes of the bottom ecosystems in the Emperor Seamount Chain.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"220 ","pages":"Article 105462"},"PeriodicalIF":2.3,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395369","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":"Brought to the surface from obscurity: The distribution and biology of Coelorhinchus gilberti (Macrouridae, Gadiformes, Teleostei) off the Emperor Seamounts (Northwestern Pacific)","authors":"Nikolai B. Korostelev ,&nbsp;Igor V. Volvenko ,&nbsp;Igor V. Maltsev ,&nbsp;Alexei M. Orlov","doi":"10.1016/j.dsr2.2025.105461","DOIUrl":"10.1016/j.dsr2.2025.105461","url":null,"abstract":"<div><div><em>Coelorinchus gilberti</em> is a member of the grenadier family (Macrouridae) found off the Pacific coast of Japan (from Shikoku Island to Hokkaido Island), the Kyushu-Palau submarine ridge, and the Emperor Seamounts. This species is a common bycatch in the longline fishery for the skilfish <em>Erilepis zonifer</em> (Anoplopomatidae) and some rockfishes (Sebastidae). However, there is no published information on its distribution and biology. Based on observations on commercial longlines between 2014 and 2018, the catch distribution, size and sex, size of otoliths, age and growth, sex ratio and sexual maturity of <em>C. gilberti</em> in the waters of the Emperor Seamounts (NW Pacific) are presented. This species has been caught from Nintoku Seamount in the north to Kammu Seamount in the south and is most commonly found off the Jingu, Ojin, and Kammu seamounts. The species has been recorded from 215 to 1840 m, which significantly extends its known bathymetric range. The catches included individuals from 34 to 93 cm (mean 53.2 cm), weight 140–5240 g (mean 688.2 g) and age from 24 to 48 years (mean 37.9 years). The females were significantly longer, heavier and older than the males and generally dominated the catches (the proportion of males &lt;40%). The growth of <em>C. gilberti</em> is best described by a von Bertalanffy growth function (VBGF), and the parameters of the von Bertalanffy growth equation were L∞ = 61.6, k = 0.09, t₀ = −1.4. Spawning individuals were recorded in catches only in April, which is the end of spawning. Further research with year-round trawl samples is needed to obtain more detailed information on the life cycle of <em>C. gilberti</em>.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"220 ","pages":"Article 105461"},"PeriodicalIF":2.3,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386454","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":"Phytoplankton communities distribution along a physical gradient in the eastern Indian Ocean based on their pigments and absorption properties","authors":"Chandanlal Parida,&nbsp;David Antoine","doi":"10.1016/j.dsr2.2025.105460","DOIUrl":"10.1016/j.dsr2.2025.105460","url":null,"abstract":"<div><div>Phytoplankton pigments and absorption properties were measured along 110° E in the southeast Indian Ocean during a research voyage carried out on R/V Investigator in May–June 2019. The data set was collected along a 3300 km transect starting from mesotrophic conditions around 40° S (chlorophyll concentration of about 0.5 mg m⁻³) to oligotrophic conditions (0.04 mg m⁻³) near 10° S. A cluster analysis was applied to phytoplankton absorption data, in which the absorption-based clusters serve as a reference for identifying different phytoplankton pigment assemblages and their depth in the water column. The resulting clusters reflect variations in phytoplankton pigment compositions and degrees of pigment packaging, categorised into distinct groups: mesotrophic waters, surface oligotrophic waters, deeper waters near the deep chlorophyll maxima and low-chlorophyll waters at depths exceeding 100 m. Our results confirm that pigment composition has a significant impact on the absorption spectra for given chlorophyll concentrations. In oligotrophic conditions, the proportions of photosynthetic and photoprotective pigments show large variations along depth. We also found that the phytoplankton absorption coefficient in the blue is lower than predicted by relationships previously established with Chl-<em>a</em>. When pico- and micro-phytoplankton are generally expected to vary in opposite ways from oligo-to meso-trophic waters, with the contribution of nano-phytoplankton remaining quite stable, we here found that pico- and nano-phytoplankton were the varying fractions along the transect, with the contribution of micro-phytoplankton remaining stable and low (about 10%). Our results support the use of optical properties, which are linked to pigment composition, cell size, and intracellular pigment concentration to study phytoplankton communities across varied oceanographic regimes.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"220 ","pages":"Article 105460"},"PeriodicalIF":2.3,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479396","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":"Estimating quantitative gear and taxa specific encounter thresholds for commercial fisheries bycatch of vulnerable marine ecosystem indicator taxa","authors":"Christopher N. Rooper ,&nbsp;Kayleigh Somers ,&nbsp;Pamela Goddard ,&nbsp;Glenn Campbell","doi":"10.1016/j.dsr2.2024.105448","DOIUrl":"10.1016/j.dsr2.2024.105448","url":null,"abstract":"<div><div>Corals and sponges are often a component of vulnerable marine ecosystems (VMEs) in the deep sea. These taxa can be impacted and removed by bottom contacting fishing gear and protecting VMEs is an important component of managing ecosystems. One of the tools that is routinely used to manage VME impacts from fishing gear is move-on rules triggered by bycatch thresholds (encounter thresholds) of VME. Usually, these bycatch thresholds are set with little information regarding the level of impact on the benthic habitat. The objective of this analysis was to develop and apply methods for quantifying threshold catches of VME indicator taxa by gear type and VME indicator taxa grouping. Three previously used methods based on cumulative bycatch distributions and one novel method based on percentile regression of fishery bycatch and density from underwater camera surveys were applied to data from the northeast Pacific Ocean to determine data-based encounter thresholds that could trigger spatial fishery closures. The percentile regression method suggested encounter thresholds of ∼40–65 kg of Antipatharia, &lt;20 kg of gorgonians and 78–131 kg of Porifera would equate to a density of 0.2 VME indicator taxa per <span><math><mrow><msup><mi>m</mi><mn>2</mn></msup></mrow></math></span> for bottom trawl bycatch. Threshold values were lower for longline and pot gear (generally &lt;10 kg per set). Using the percentile regression method allowed for the definition of VME encounter thresholds to be expressed in terms of density of the taxa of interest, an improvement over examination of break points in the cumulative bycatch data alone. This improvement allows the ecological importance (e.g. density of VME) to be defined and used to estimate encounter thresholds, rather than assuming that the natural break points in cumulative bycatch represent an ecological break point.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105448"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161548","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 seasonal patterns of hydrographic and biogeochemical variables in the Ross Sea: A BGC-Argo analysis","authors":"Ruobing Cao ,&nbsp;Walker O. Smith Jr. ,&nbsp;Yisen Zhong ,&nbsp;Stephen Riser ,&nbsp;Kenneth S. Johnson ,&nbsp;Lynne Talley","doi":"10.1016/j.dsr2.2024.105436","DOIUrl":"10.1016/j.dsr2.2024.105436","url":null,"abstract":"<div><div>Seasonal patterns in seasonally frozen waters have usually been derived from composites of analyses conducted in different years and largely have been confined to ice-free periods. We present the first continuous measurements of hydrographic and biogeochemical variables collected over an entire year by Biogeochemical-Argo (BGC-Argo) profiling floats on the continental shelf of the Ross Sea. Analyses were divided into two periods: autumn/winter and spring/summer. Mixed layers increased rapidly upon ice cover, and nitrate, oxygen, and dissolved inorganic carbon vertical distributions were strongly influenced by this deeper mixing. Rates of nitrification in autumn were substantial and similar to rates measured in other areas of the ocean. Organic carbon disappearance was also most rapid in March. Changes in all variables slowed considerably after May. The largest mixed layer depths occurred at the southern floats and reached 400–500 m. Spring/summer patterns were similar to those observed during individual cruises, with rapid nitrate removal beginning in November, continuing through early January, but ceasing during austral summer. The most rapid accumulations of chlorophyll occurred prior to complete ice retreat. Substantial spatial differences were noted that were likely related to both mixed layer depths and phytoplankton composition. Particulate matter accumulated throughout the summer below 100 m, although the rates of change suggested substantial remineralization in the water column. The temporal patterns observed show the importance of relatively short periods that markedly influence the vertical distribution of biogeochemical parameters.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105436"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161545","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":"The relative contribution of deep and shallow benthic sources to iron supply in the Ross sea, with specific emphasis on Ross Bank","authors":"Blair J.W. Greenan ,&nbsp;Michael S. Dinniman ,&nbsp;Dennis J. McGillicuddy Jr. ,&nbsp;Peter N. Sedwick ,&nbsp;Stefanie L. Mack ,&nbsp;Walker O. Smith Jr.","doi":"10.1016/j.dsr2.2024.105450","DOIUrl":"10.1016/j.dsr2.2024.105450","url":null,"abstract":"<div><div>Summer primary productivity in the Ross Sea is limited by the availability of dissolved iron (DFe) in the euphotic zone. Previous studies have suggested that benthic sources dominate the supply of DFe to the upper water column in the southern Ross Sea polynya. The purpose of this study is to investigate whether these benthic sources are derived from shallow banks or deeper areas of the continental shelf. Our study combines analysis of <em>in situ</em> observations near Ross Bank with a physical ocean model simulation in an overlapping summertime period to investigate the vertical supply of DFe. Two passive tracer dyes were employed in the ocean model with the first (second) being input in the bottom model layer over seabed depths of less (greater) than 400 m. The tracer dyes provide temporal (March 2011–January 2012) and spatial estimates of the advection, mixing and diffusion throughout the Ross Sea model domain, and enable estimates of the relative contributions of shallow and deep benthic iron sources to the upper ocean DFe inventory. A comparison of the model output with a ship-based survey and a mooring deployed on Ross Bank in January 2012 provides confidence that the model simulations produce a sufficiently accurate representation of ocean conditions to support estimates of benthic DFe supply to surface waters. The results demonstrate that for Ross Bank the local (on-bank) benthic supply is important during the early winter period, whereas for most of the year the deep (off-bank) benthic iron is the predominant source supplying the upper ocean over this shallow region.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"219 ","pages":"Article 105450"},"PeriodicalIF":2.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161547","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}