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

{"title":"Remineralisation signals in the western South Indian Ocean thermocline: diagnosing local biogeochemical processes from nutrient stoichiometry","authors":"Tanya A. Marshall ,&nbsp;Eesaa Harris ,&nbsp;Sarah E. Fawcett","doi":"10.1016/j.dsr2.2025.105549","DOIUrl":"10.1016/j.dsr2.2025.105549","url":null,"abstract":"<div><div>The western South Indian Ocean is a highly dynamic region where tropical and subtropical waters converge. As in other ocean areas, the nutrient conditions of its thermocline play a critical role in setting regional productivity, yet they remain largely unstudied. Here, we investigate local biogeochemical processes that alter thermocline nutrient ratios in the western South Indian Ocean by applying a regional optimum multiparameter analysis to WOCE data collected across the northern and southern entrances to the Mozambique Channel, the Southeast Madagascar Current, and the Agulhas Current. We first quantify the relative contributions of three proximate source waters (Equatorial, Tropical, Subtropical) to the regional thermocline (∼100–900 m), along with the nutrient (i.e., nitrate and phosphate) inventories expected from isopycnal mixing of these source waters. We then use the difference between the expected and observed nutrient concentrations and ratios to diagnose the occurrence of local biogeochemical processes such as organic matter remineralization and N₂ fixation. We find that distinct regimes characterize the two entrances to the Mozambique Channel, with nutrient-rich Tropical source waters dominating the northern entrance (&gt;55%) while nutrient-poor Subtropical source waters dominate the south (&gt;80%). At the northern entrance, overlapping nutrient addition and removal processes drive only minor changes to the thermocline nutrient inventory relative to the nutrients supplied by the proximate source waters, with no evidence of local N₂ fixation. By contrast, south of the Mozambique Channel (&gt;25°S), including across the Southeast Madagascar Current and Agulhas Current, a strong local remineralization signal indicates nutrient addition to the Subtropical thermocline. These nutrients have a high nitrate-to-phosphate ratio relative to those supplied by the proximate and underlying source waters, which we interpret as evidence of local N₂ fixation. Our analysis shows that N₂ fixation occurs locally in the subtropical southwest Indian Ocean where it will fuel regional productivity and carbon export.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105549"},"PeriodicalIF":3.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263093","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":"Studying the impact of sea surface temperature (SST) changes and El Niño phenomenon on coral reefs bleaching around Kish Island in the northern Persian Gulf: A remote sensing approach","authors":"Fatemeh Shabani ,&nbsp;Mohammad Raie ,&nbsp;Keivan Kabiri","doi":"10.1016/j.dsr2.2025.105550","DOIUrl":"10.1016/j.dsr2.2025.105550","url":null,"abstract":"<div><div>Coral reefs are among the most biodiverse marine ecosystems but are increasingly threatened by environmental stressors, particularly coral bleaching caused by rising Sea Surface Temperature (SST). Monitoring SST changes is therefore critical for coral conservation. This study investigates thermal anomalies around Kish Island in the northern Persian Gulf using the Degree Heating Weeks (DHW) index, which quantifies cumulative thermal stress on corals. SST and DHW data from 1982 to 2022 were obtained from the National Oceanic and Atmospheric Administration (NOAA). Trends were analyzed using the Mann-Kendall test and Sen's slope estimator, while the Pierce Skill Score was employed to estimate the DHW threshold indicating coral bleaching risk. The relationship between the El Niño phenomenon and DHW was also assessed. Spatial and temporal SST changes were examined using MODIS Aqua satellite data processed via the Google Earth Engine. Results show maximum SST and DHW values of 35.17 °C and 13.6°C-weeks in August–September 2017, respectively, with DHW exhibiting an upward trend of 0.025°C-weeks per year. The DHW threshold was estimated at 5.3°C-weeks. Spatial analyses suggest increasing thermal stress along the southern and northern coasts of the Persian Gulf, particularly near Kish Island. Finally, El Niño events corresponded with elevated DHW values, highlighting their influence on coral bleaching. These findings underscore the importance of long-term monitoring to mitigate climate-induced threats to coral ecosystems.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105550"},"PeriodicalIF":3.0,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263170","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":"Offshore demersal fish community structure and habitat associations in Amundsen Gulf, Canadian Arctic","authors":"Andrew R. Majewski ,&nbsp;Krystal Woodard ,&nbsp;Andrea Niemi ,&nbsp;Sheila Atchison ,&nbsp;Jane Eert ,&nbsp;Shannon MacPhee ,&nbsp;James D. Reist","doi":"10.1016/j.dsr2.2025.105548","DOIUrl":"10.1016/j.dsr2.2025.105548","url":null,"abstract":"<div><div>Marine fishes occupy a range of trophic positions, all of which play integral roles in energy pathways within and amongst habitats. Understanding marine fish community structure and habitat associations is prerequisite to understanding ecosystem structure and function in the western Canadian Arctic, and the lack of regional-scale information impedes effective regulation of emerging industrial activities and climate adaptation strategies. Our study documented 46 demersal fish species from 29 genera, recording eight new species occurrences for Amundsen Gulf. The demersal fish community of Amundsen Gulf is largely structured by the depth-mediated water masses of the region where they interface with seafloor habitats. The fish assemblages appeared stable over the seven-year span of the study, while interannual fluctuations in abundance reflected species-level variability. Species richness was higher in Amundsen Gulf relative to the adjacent Canadian Beaufort Shelf and slope, but indexes for evenness and species dominance in Amundsen Gulf were skewed by the pervasiveness of <em>Boreogadus saida</em>. The average abundance of <em>B. saida</em> was 4.7 times higher at stations where fishing occurred within Atlantic waters relative to Pacific waters, with peak average abundance documented in Minto Inlet. The deep <span>Atlantic</span> water and large embayments of Amundsen Gulf support high abundances of <em>B. saida</em> across life-history stages and warrant special consideration for industrial planning and conservation initiatives. Our results provide contemporary baselines on marine fish community structure and diversity for the Amundsen Gulf region and provide a basis for evaluating future change and comparisons with neighboring regions.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105548"},"PeriodicalIF":3.0,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145120043","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":"Microbial food web dynamics in tropical waters of the bluefin tuna spawning region off northwestern Australia","authors":"Michael R. Landry ,&nbsp;Michael R. Stukel ,&nbsp;Natalia Yingling ,&nbsp;Karen E. Selph ,&nbsp;Sven A. Kranz ,&nbsp;Christian K. Fender ,&nbsp;Rasmus Swalethorp ,&nbsp;Ria I. Bhabu","doi":"10.1016/j.dsr2.2025.105547","DOIUrl":"10.1016/j.dsr2.2025.105547","url":null,"abstract":"<div><div>Whereas recruitment success for many fisheries depends on coincident timing of larvae with abundance peaks of their prey, less can be more in the tropical/subtropical spawning areas of bluefin tunas if lower but steady food resources are offset by reduced larval vulnerability to pelagic predators. To understand larval habitat characteristics for Southern Bluefin Tuna (SBT), we quantified microbial community carbon flows based on growth and grazing rates from depth profiles of dilution incubations and carbon biomass assessments from microscopy and flow cytometry (FCM) during their peak spawning off NW Australia (Indian Ocean) in February 2022. Two Chl<em>a</em>-based estimates of phytoplankton production gave differing offsets due to cycling or mixotrophy, exceeding ¹⁴C net community production on average (677 ± 98 versus 447 ± 43 mg C m⁻² d⁻¹). Productivity was higher than in the Gulf of Mexico spawning area for Atlantic Bluefin Tuna but less than similar studies of oceanic upwelling regions. Microzooplankton grazing averaged 482 ± 63 mg C m⁻² d⁻¹ (71 ± 13 % of production). Two measurement variables for <em>Prochlorococcus</em> gave average production and grazing rates of 282 ± 36 and 248 ± 32 mg C m⁻² d⁻¹ (86 ± 6 % grazed). <em>Prochlorococcus</em> comprised almost half of production and grazing fluxes in the upper (0–25 m) euphotic zone where SBT larvae reside. <em>Prochlorococcus</em> declined and eukaryotic phytoplankton and heterotrophic bacteria increased in relative importance in the lower euphotic zone. These results describe relatively classic open-ocean oligotrophic conditions as the food web base for nutritional flows to SBT larvae.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105547"},"PeriodicalIF":3.0,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107591","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":"Temporal stability in genetic origin of juvenile green turtle recruits at remote western Indian Ocean islands","authors":"Jérôme Bourjea ,&nbsp;Quentin Schull ,&nbsp;Sylvie Lapègue ,&nbsp;Corinne Bouvier ,&nbsp;Stéphane Ciccione ,&nbsp;Claire Jean ,&nbsp;Katia Ballorain ,&nbsp;Phillipe Gaspar ,&nbsp;Julien Temple Boyer ,&nbsp;Christopher Jones ,&nbsp;Annabelle Constance ,&nbsp;Mayeul Dalleau ,&nbsp;Michael Jensen","doi":"10.1016/j.dsr2.2025.105545","DOIUrl":"10.1016/j.dsr2.2025.105545","url":null,"abstract":"<div><div>The increasing anthropogenic and climatic pressures on marine ecosystems raise concerns about the sustainability of their functions, uses and conservation. Marine megafauna such as marine turtles are particularly vulnerable to these pressures due to their life cycle and the variability of habitats they occupy during their life cycle. Understanding how juvenile population dynamics respond to environmental conditions is crucial for designing effective conservation strategies. The present study investigates whether the genetic composition of juvenile green turtles at recruitment sites changes over time. A total of 346 juveniles were sampled at four key recruitment sites in the South Western Indian Ocean - SWIO (Glorieuses, Mayotte, Reunion and Aldabra) during two sampling phases at an interval between 6 and 17 years depending on the site. Based on mtDNA control region sequences, genetic structures were compared between periods within each site. Even if subtle changes in genetic composition may not be detectable with current genetic resolution, our results suggest that the structure of the juvenile green turtle population has not significantly changed over the course of the study period. Such stability in population structure may be correlated with the stability of regional oceanic currents over the last decades in the SWIO, as well as the dynamics of nesting populations in the different regional genetic stocks contributing in regional juvenile green turtle production.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105545"},"PeriodicalIF":3.0,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263171","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":"Enhanced eddy kinetic energy in the southeastern Arabian Sea during winter: the influence of surface currents and wind force","authors":"Ullas M. Pillai ,&nbsp;Ajith Joseph K ,&nbsp;Roshin P. Raj ,&nbsp;Ola M. Johannessen","doi":"10.1016/j.dsr2.2025.105537","DOIUrl":"10.1016/j.dsr2.2025.105537","url":null,"abstract":"<div><div>Eddy kinetic energy (EKE) in the southeastern Arabian Sea (SEAS) during the relatively least explored winter season spanning 28 years (1993–2020) was studied using satellite observational and reanalysis data from the Copernicus Marine Service Data Center. The generation and enhancement of EKE resulting from current instabilities are discussed, and the significant role of barotropic energy conversion in the SEAS, is further examined, considering the roles of surface currents and wind forcing obtained from ERA5 reanalysis dataset. The strong EKE observed during winter within the Laccadive Sea in the SEAS is partly attributed to dominant barotropic instability arising from horizontal shear in surface currents driven by strong negative wind stress curl. Furthermore, EKE shows a significant positive correlation with chlorophyll-<em>a</em> (Chl-<em>a</em>) concentration during winter in the SEAS, highlighting the influence of physical-biological coupling associated with eddies and the zonal advection of Bay of Bengal waters by the northeast monsoon current.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105537"},"PeriodicalIF":3.0,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047400","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":"Diatom assemblages in coral patches of the Northwestern Persian Gulf: Community structure across substrates and proximity to oil sites","authors":"Mahtab Azari ,&nbsp;Ali Nasrolahi ,&nbsp;Mohammad Reza Shokri ,&nbsp;Roksana Majewska","doi":"10.1016/j.dsr2.2025.105535","DOIUrl":"10.1016/j.dsr2.2025.105535","url":null,"abstract":"<div><div>Diatoms, essential primary producers in coral reef ecosystems, are highly sensitive to environmental changes, making them effective bioindicators of ecosystem health. This study investigates diatom assemblages in northwestern Persian Gulf coral reefs, comparing communities in oil-polluted sites around Kharg Island with those in less-impacted conditions near Khargoo Island. A total of 86 diatom taxa from 37 genera were identified across live and dead coral tissues and coral rubble. The most abundant species across all samples (average ± SD) were <em>Halamphora coffeiformis</em> (8.43 ± 1.4 %), <em>Nitzschia dissipata</em> (5.94 ± 2.11 %), and <em>H</em>. <em>borealis</em> (5.75 ± 1.39 %). Statistical analyses revealed that substrate type significantly influenced species richness, with dead corals hosting more diatom species than live corals and coral rubble. While no significant difference in species richness was observed between the oil-polluted and control sites, the assemblages differed compositionally. Diatom communities growing on living corals from the polluted site showed the highest level of within-group dissimilarity, which may indicate habitat instability and a state of dysbiosis. These findings suggest that community differences may be associated with chronic oil exposure, and that substrate type plays an important role in shaping diatom communities. The results also signal the potential of certain diatom species as indirect bioindicators responding not only to the pollutants present at the sampling location but also to the condition of a possibly more sensitive host. Further research is needed to assess the long-term effects of oil pollution on coral reef health and diatom-coral interactions.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"223 ","pages":"Article 105535"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144921529","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":"Impacts of barite and bentonite sedimentation on the behaviour, mucus production and cnidocytes of the deep-sea coral Flabellum (Ulocyathus) alabastrum","authors":"Kathryn Murray ,&nbsp;Bárbara de Moura Neves ,&nbsp;Jean-François Hamel ,&nbsp;Johanne Vad ,&nbsp;Vonda Hayes ,&nbsp;Annie Mercier","doi":"10.1016/j.dsr2.2025.105536","DOIUrl":"10.1016/j.dsr2.2025.105536","url":null,"abstract":"<div><div>As oil and gas exploration expands in deep-sea environments, understanding the impacts of wastes produced by this industry is urgent. One of the main wastes of offshore drilling is the discharge of drill muds, commonly including barite and bentonite clay. Here, we investigated the effects of these two byproducts on the expansion behaviour, mucus secretion and cnidocyte density of the solitary cup coral <em>Flabellum</em> (<em>Ulocyathus</em>) <em>alabastrum</em>. A total of 96 live corals were exposed over 10 days to one of three treatments (barite, bentonite, or barite and bentonite combined) or assigned as an untreated control. Daily waste additions aimed to reach a total sedimentation depth of 6.3 mm (common ‘probable no-effects threshold’). Photography was used to monitor behavioural changes and mucus production, and histology was used to assess changes in tentacle cnidocytes. Overall, responses of <em>F. alabastrum</em> in the form of excessive polyp expansion (swelling) and mucus production were more severe under the barite and bentonite combined treatment, followed by barite alone, bentonite alone and lowest/absent in the control. Moreover, elevated nematocyte densities were measured under exposure to the mix of barite and bentonite. However, <em>F. alabastrum</em> returned to baseline metrics during a 10-day recovery period. The results suggest that sedimentation of common drill mud ingredients to &lt;6.3 mm depth can cause observable and non-lethal responses in <em>F. alabastrum</em>, but remain conservative relative to what may be experienced <em>in situ</em>. As the most adverse effects were observed under the barite and bentonite combination treatment (tested together for the first time here), potential synergistic effects of the two should be considered in future research. Understanding long-term consequences, as well as impacts of more abrasive drilling waste (drill cuttings) on <em>F. alabastrum</em> requires further study.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"223 ","pages":"Article 105536"},"PeriodicalIF":3.0,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144913671","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":"Distribution of free–Living marine nematodes along environmental gradients in the strait of hormuz","authors":"Mehrshad Taheri ,&nbsp;Mohammad Ali Hamzeh ,&nbsp;Abolfazl Saleh ,&nbsp;Maryam Yazdani Foshtomi ,&nbsp;Ahmad Radmanesh","doi":"10.1016/j.dsr2.2025.105532","DOIUrl":"10.1016/j.dsr2.2025.105532","url":null,"abstract":"<div><div>Understanding the drivers of nematode community structure in subtidal ecosystems is critical for assessing marine biodiversity and ecosystem health. As sensitive bioindicators of environmental change, marine nematodes provide crucial insights into ecosystem dynamics; however, their spatial distribution patterns in the Persian Gulf's subtidal zones remain poorly understood. This study investigates the spatial variability of free–living nematode communities across five distinct transects in this understudied region. A total of 2189 specimens, representing 60 different genera, were identified. Nematode density showed significant variation, ranging from 16.7 to 92.6 individuals in 10 cm², with the highest densities typically found at the shallowest stations. The average number of genera per sample ranged from 1 to 18.67. The Shannon diversity indices varied significantly, with a maximum of 2.58 and a minimum of 0, while evenness scores ranged from 0.76 to 1. Notable differences in nematode community structure were observed across the various transects and stations. The overall nematode community was dominated by genera such as <em>Actinonema</em>, <em>Axonolaimus</em>, <em>Dorylaimopsis</em>, <em>Gnomoxyala</em>, <em>Halalaimus</em>, <em>Hopperia</em>, <em>Marylynnia</em>, <em>Pierrickia</em>, <em>Sabatieria</em>, <em>Subsphaerolaimus</em>, and <em>Terschellingia</em> across different transects. According to DistLM analysis, depth, salinity, mean grain size, pH, and temperature together explained 22.9 % of the total variance in the nematode community, with depth accounting for 9.3 % and the other significant variables contributing an additional 13.6 %. Further research is essential to clarify the relationship between nematode communities and environmental conditions in underexplored ecosystems like this region.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"223 ","pages":"Article 105532"},"PeriodicalIF":3.0,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889520","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":"Mesozooplankton community responses to environmental stressors in Kuwait's first marine protected area","authors":"Rakhesh Madhusoodhanan,&nbsp;Turki Al-Said,&nbsp;Faiza Al-Yamani,&nbsp;Gopikrishna Mantha,&nbsp;Takahiro Yamamoto,&nbsp;Loreta Fernandes,&nbsp;Ayaz Ahmed,&nbsp;Nithyanandan Manickam,&nbsp;Amit Sarkar,&nbsp;Sabeena Habeebullah Koduvayur Habeebullah,&nbsp;Fathima Thuslim,&nbsp;Waleed Al-Zekri,&nbsp;Jessy Sebastian,&nbsp;Maryam Al-Enezi","doi":"10.1016/j.dsr2.2025.105533","DOIUrl":"10.1016/j.dsr2.2025.105533","url":null,"abstract":"<div><div>Understanding mesozooplankton (MSP) dynamics in nursery habitats is crucial for assessing ecosystem health and trophic interactions, particularly in anthropogenically stressed yet ecologically significant areas, such as Sulaibikhat Bay – home to Kuwait's first Marine Protected Area (MPA) in the northwestern Arabian/Persian Gulf (NWG). This study examines MSP community dynamics and environmental interactions over 26 months (October 2018–March 2021) across five fixed stations, including sites influenced by desalination and sewage outfalls. Seasonal fluctuations in water temperature, salinity, and nutrients significantly influenced MSP community structure. Copepods dominated, with cyclopoids (<em>Oithona</em> spp.) peaking in summer and fall, while calanoids (<em>Parvocalanus crassirostris</em>, <em>Acartia</em> spp.) were more prevalent in winter and spring. The cyclopoid-to-calanoid ratio, a potential indicator of trophic shifts, varied significantly across seasons, with cyclopoids prevailing in warmer months. Diversity and dispersion patterns, assessed through Venn diagrams and PERMDISP analysis, revealed higher species turnover near polluted sites and greater stability within the MPA. Taxonomic relatedness indices (AvTD, VarTD) indicated reduced diversity in chronically stressed areas. BIOENV and RELATE analyses identified temperature, dissolved oxygen, turbidity, and nanophytoplankton chlorophyll <em>a</em> as key drivers of the MSP community. Significant negative correlations between fish larvae and cyclopoids near the Al-Ghazali sewer outlet suggested potential prey-predator interactions, reinforcing the ecological implications of MSP composition shifts in this nursery habitat. While the MPA supports high MSP diversity, ongoing stressors, such as brine discharge and sewage, continue to shape the MSP community and trophic interactions. This study provides critical insights for ecosystem-based management of marine resources in and around Kuwait's first MPA in the NWG.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"223 ","pages":"Article 105533"},"PeriodicalIF":3.0,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890809","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}