Marine environmental research最新文献

{"title":"Size fraction, behavior, and fate of trace metals along the river-estuary-coastal ocean continuum of Shandong Peninsula, northern China","authors":"Yuxi Lu ,&nbsp;Yongsheng Luan ,&nbsp;Zhiwei Zhang ,&nbsp;Jinglin Ding ,&nbsp;Dawei Pan","doi":"10.1016/j.marenvres.2025.107324","DOIUrl":"10.1016/j.marenvres.2025.107324","url":null,"abstract":"<div><div>In this study, hydrological parameters, dissolved organic carbon (DOC), nutrients, and dissolved metal distribution in the coastal waters around the Shandong Peninsula (SP) were systematically explored. DOC concentration varied (196.81–691.18 μmol L⁻¹, avg. 345.96 μmol L⁻¹), with &lt;1 kDa fraction 48–99 %, showing human impact. Dissolved metals followed the pattern of Mn &gt; Zn &gt; Cu &gt; Fe &gt; Pb &gt; Cd. Mn (13.81–1821.60 nmol L⁻¹, 570 times that of Cd on average) was ∼57 % colloidal. Over 63 % of Fe, Cu, Zn, Cd, and Pb were in the &lt;1 kDa phase. Contamination factor (CF) values were low (0–4.59). Cu (with an average CF of 0.74) was the main pollution contributor. The ecological risk (ERI) was low, but Cu contributed 44 % to the ERI. Temperature affected many metals, salinity correlated with Cd, while DO and pH had weak impacts. Under the 0–30 salinity gradient, in the total dissolved (TD) fraction, Mn, Fe, Cu, and Zn mixed conservatively with non-conservative additions in the 15–25 zones. Cd and Pb increased non-conservatively. In the 1 kDa-0.45 μm fraction, Cd grew exponentially like Pb, and the Mn, Fe, Cu, and Zn declined with rising salinity. The &lt;1 kDa Mn, Fe, and Cu were stable, &lt;1 kDa Zn and Pb had no consistent trend, and &lt;1 kDa Cd behaved similarly. DOC influenced metal fractions via organic ligands, showing organic sources, yet &lt;1 kDa DOC had weak effects. It is suggested that NO₂⁻ may be related to the denitrification effects of Mn and Pb, while NO₃⁻ may promote metal consumption and NH₄⁺ may promote the chelation of Cd. DIP might have been related to &lt;1 kDa Fe, Cu, and Pb by competitive adsorption.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107324"},"PeriodicalIF":3.0,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying the influence of environmental factors on elasmobranch distribution and abundance in a high-use marine protected area","authors":"Pascal Sebastian ,&nbsp;Serena Jane Stean ,&nbsp;Ahmad Ilham Rabbani Erawan ,&nbsp;Rinaldi Gotama ,&nbsp;I Nengah Swarya ,&nbsp;Lauren Dawn Sparks ,&nbsp;Rahmadi Prasetijo ,&nbsp;Andhika Prima Prasetyo","doi":"10.1016/j.marenvres.2025.107317","DOIUrl":"10.1016/j.marenvres.2025.107317","url":null,"abstract":"<div><div>Elasmobranchs, comprising sharks and rays, are vital indicators of marine ecosystem health but face increasing threats from anthropogenic pressures such as overfishing, habitat degradation, and tourism-related disturbances. Marine Protected Areas (MPAs) are widely promoted as conservation tools to mitigate these threats, yet their effectiveness, particularly in multi-use zones, remains uncertain. This study employed Baited Remote Underwater Video (BRUV) surveys across four MPA zones in Nusa Penida to assess elasmobranch distribution, relative abundance, and habitat associations. From 212 BRUV deployments between 2018 and 2023, we recorded 119 elasmobranch individuals across 13 species, with a sightings per unit effort (SPUE) of 0.48 MaxN per hour, reflecting only a marginal increase from the 2016 baseline of 0.39 MaxN per hour. Elasmobranch distribution varied across regions, with the highest species diversity observed in the northern and western areas where BRUV sites were associated with hard coral, rubble, and key invertebrates such as sponges, ascidians, and anemones. The southern region was characterized by repeated sightings of reef manta rays, reinforcing its function as a key aggregation site. In contrast, the eastern region recorded very few elasmobranch encounters, though the presence of endangered pelagic species suggests it may warrant further monitoring and protection. These findings suggest that biological and environmental conditions may influence elasmobranch presence independently of protection status. The limited change in relative abundance highlights the urgent need for improved enforcement, refined fisheries and tourism regulation, and habitat-based management strategies to strengthen the MPA's role in regional elasmobranch conservation.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107317"},"PeriodicalIF":3.0,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Does incidental fisheries bycatch in Canadian waters have population level impacts for northern fulmars breeding in Arctic Canada?","authors":"S.E. Gutowsky ,&nbsp;A. Morrill ,&nbsp;H.L. Major ,&nbsp;M.L. Mallory ,&nbsp;C.M. Francis ,&nbsp;J.F. Provencher","doi":"10.1016/j.marenvres.2025.107285","DOIUrl":"10.1016/j.marenvres.2025.107285","url":null,"abstract":"<div><div>Northern fulmar (<em>Fulmarus glacialis</em>) populations breeding in Arctic Canada are vulnerable to incidental seabird bycatch due to their ecology and overlapping foraging range with fisheries activities. The Greenland halibut (<em>Reinhardtius hippoglossoides</em>) fishery off eastern Baffin Island, Nunavut, catches fulmars incidentally in numbers that may have population-level implications for this species within Canada. We provide an assessment of the potential impacts of fisheries on fulmars that incorporates recent results from genetics, colony censuses, bycatch data from fisheries in the eastern Canadian Arctic and farther south in Atlantic Canada, and assessments of bycatch reporting error. We use Population Viability Analysis (PVA) incorporating biological removal from multiple fulmar source populations across a range of probable levels of bycatch removal. We demonstrate that, relative to conservatively optimistic baseline PVA models, low to average levels of probable bycatch taken between two distinct fisheries regions across fulmar source populations are likely to severely impede recovery or cause long-term declines of the total northern fulmar population in Arctic Canada. Importantly, it was necessary to consider the cumulative impacts of both southern and northern Canadian fisheries; models considering fisheries separately might suggest the impact is sustainable, whereas the combined impact is not. Given the high likelihood that bycatch in Canadian fisheries is having negative impacts on the Arctic northern fulmar population, we suggest that targeted bycatch mitigation strategies should be implemented.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107285"},"PeriodicalIF":3.0,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scale habitat modelling reveals contractions of harbour porpoise distribution within the northeast Atlantic","authors":"Tiffany Goh ,&nbsp;Oriol Giralt Paradell ,&nbsp;Mark Jessopp ,&nbsp;Emer Rogan ,&nbsp;Enrico Pirotta","doi":"10.1016/j.marenvres.2025.107320","DOIUrl":"10.1016/j.marenvres.2025.107320","url":null,"abstract":"<div><div>In the northeast Atlantic, large-scale changes in marine ecosystems are resulting in an ecological regime shift characterised by the degradation and loss of habitats, alterations to the food web, and ultimately, the redistribution and loss of species. Given the complexity and scale of these environmental changes, there is a critical need to reliably detect and monitor changes in species’ distribution. Here, we used a multi-year and multi-season dataset to model harbour porpoise (<em>Phocoena phocoena</em>) summer and winter distribution in the Irish Atlantic, using a multi-scale modelling approach to identify the best spatio-temporal scales of oceanographic variables. Porpoise sightings data were collected during dedicated line-transect aerial surveys from 2015 to 2017 and 2021–2023. Binary generalised additive models were used to assess the relationships between porpoise presence and oceanographic variables at different spatial (5, 20 and 40 km) and temporal (daily, monthly, and average across survey period) scales. Porpoises were present in coastal waters around Ireland across years and seasons. Rising sea surface temperature was negatively associated with porpoise presence, and models predicted a decline in occurrence probability for the summer and winter seasons after 2016, alongside a contraction in distribution to the Irish Sea, which remained a key habitat throughout the study. As their range contracts, porpoises are likely to be exposed to increased human-induced stressors, highlighting the need for targeted conservation measures. This study demonstrates the value of distribution datasets covering multiple years and different seasons for assessing the responses of large vertebrate species to environmental change.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107320"},"PeriodicalIF":3.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced hermit crabs detection using super-resolution reconstruction and improved YOLOv8 on UAV-captured imagery","authors":"Fan Zhao,&nbsp;Yijia Chen,&nbsp;Dianhan Xi,&nbsp;Yongying Liu,&nbsp;Jiaqi Wang,&nbsp;Shigeru Tabeta,&nbsp;Katsunori Mizuno","doi":"10.1016/j.marenvres.2025.107313","DOIUrl":"10.1016/j.marenvres.2025.107313","url":null,"abstract":"<div><div>Hermit crabs are vital to coastal ecosystems, serving as environmental health indicators and contributing to seed dispersal, debris cleanup, and soil disturbance. Traditional hermit crabs survey methods, like quadrat sampling, are labor-intensive and environmentally dependent. This study presents an innovative approach combining UAV (Unmanned Aerial Vehicles)-based remote sensing with Super-Resolution Reconstruction (SRR) and the CRAB-YOLO detection network, a modification of YOLOv8s, to monitor hermit crabs effectively. SRR enhances image quality by addressing motion blur and insufficient resolution, significantly improving detection accuracy over conventional low-resolution fuzzy images. CRAB-YOLO integrates three improvements for accuracy, hermit crab characteristics, and computational efficiency, achieving state-of-the-art (SOTA) performance. The Residual Dense Network (RDN) demonstrated the best image reconstruction performance, and CRAB-YOLO achieved a mean average precision (mAP) of 69.5 % on the SRR test set, a 40 % improvement over the conventional Bicubic method with a magnification factor of 4. These results prove the effectiveness of the proposed method for cost-effective, automated hermit crab monitoring supporting coastal benthos conservation efforts.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107313"},"PeriodicalIF":3.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of phytoplankton in the deep chlorophyll maximum CO2 dynamics along a zonal section (34.5°S) in South Atlantic Ocean","authors":"João Vitor Langorte Bueno ,&nbsp;Rodrigo Kerr ,&nbsp;Andréa da Consolação de Oliveira Carvalho ,&nbsp;Carlos Rafael Borges Mendes","doi":"10.1016/j.marenvres.2025.107314","DOIUrl":"10.1016/j.marenvres.2025.107314","url":null,"abstract":"<div><div>Marine phytoplankton acts directly on the carbon biogeochemical cycle as key mediators of the biological carbon pump, and its efficiency is dependent on the composition of phytoplankton communities. Therefore, in the present study, we aimed to investigate the composition of phytoplankton communities in the deep chlorophyll maximum and the role of the different phytoplankton groups in CO₂ dynamics and biogeochemical processes along the South Atlantic Ocean. Environmental and biological data were collected in the deep chlorophyll maximum in 59 stations along a zonal section (34.5°S) in the South Atlantic Ocean. Sampling stations were grouped into Brazil, South Atlantic Gyre and Africa provinces. We identified the chemotaxonomic phytoplankton groups using the HPLC-CHEMTAX approach and evaluated the thermal and non-thermal effects on CO₂ partial pressure (<em>p</em>CO₂) variability in the region. The relationship between biogeochemical variables and phytoplankton groups was investigated using a canonical correspondence analysis. Our results showed strong gradients in the distribution of biogeochemical parameters among the different provinces, with higher <em>p</em>CO₂ and thermal effects in the coastal regions due to the influence of ocean circulation processes, and lower <em>p</em>CO₂ and higher non-thermal effects in the open ocean due to the upwelling of deeper waters rich in dissolved inorganic carbon and nutrients associated to mesoscale eddies. Haptophytes and <em>Prochlorococcus</em> dominated the deep chlorophyll maximum in the study area, with the highest phytoplankton biomass being recorded in the Africa province. Haptophytes were associated with mixed nutrient-rich waters, and showed higher influence in <em>p</em>CO₂ variation, whereas <em>Prochlorococcus</em> were associated with stratified oligotrophic waters. The results found in this study elucidate the variability in the role of the different phytoplankton groups on CO₂ dynamics across the different biogeochemical provinces of the South Atlantic Ocean. Thus, further investigations on the spatial and temporal patterns of phytoplankton distribution are encouraged to better decouple the thermal and non-thermal effects driving <em>p</em>CO₂ variations in subsurface waters in the region.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107314"},"PeriodicalIF":3.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of feeding on microbial community structure and pathogen abundance in marine aquaculture ponds","authors":"Lun Song ,&nbsp;ChaoKui Hu ,&nbsp;Xiansheng Zhang ,&nbsp;Yin Liu ,&nbsp;GuangJun Song ,&nbsp;JinHao Wu ,&nbsp;ZhaoHui Wang ,&nbsp;Ming Sun","doi":"10.1016/j.marenvres.2025.107319","DOIUrl":"10.1016/j.marenvres.2025.107319","url":null,"abstract":"<div><div>Microbial communities in aquaculture ponds play a vital role in regulating water quality, driving nutrient cycling, and maintaining ecological balance. In 2023, we conducted a study to evaluate how feeding affects microbial communities by comparing the microbial composition and water quality in both fed and unfed aquaculture ponds. Metagenomic sequencing indicated that feeding significantly elevated the relative abundance of bacteria within the microbial community. Ecological similarity analysis showed that bacterial community in the ponds predominantly originated from internal pond sources, rather than from adjacent coastal waters. Furthermore, the relative abundance of pathogenic bacteria was significantly higher in fed ponds, with <em>Vibrio parahaemolyticus</em> levels reaching 1.6 times those in unfed ponds. In addition, water quality assessments further showed that feeding elevated nutrient concentrations, leading to eutrophication. Analyses of redundancy and correlation showed a notable positive link (<em>p</em> &lt; 0.05) between the levels of pathogenic bacteria and the concentration of organic nutrients. These results suggest that excessive feeding contributes to eutrophication, which promotes the growth of bacteria, including pathogenic strains, thereby increasing the risk of disease outbreaks in aquaculture systems.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107319"},"PeriodicalIF":3.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the impact of 4-nonylphenol and 17β-estradiol on growth, steroidogenesis and vitellogenin expression in juvenile manila clams: Implications for endocrine disruption","authors":"Peipei Liu ,&nbsp;Qichao Fan ,&nbsp;Jingjing Miao ,&nbsp;Lu Wang ,&nbsp;Shanshan Jiang ,&nbsp;Luqing Pan","doi":"10.1016/j.marenvres.2025.107303","DOIUrl":"10.1016/j.marenvres.2025.107303","url":null,"abstract":"<div><div>The contamination of marine sediments by endocrine-disruptive contaminants (EDCs) represents a global threat to marine ecosystems. Among these pollutants, 4-nonylphenol (4-NP) and 17β-estradiol (E2) are particularly noted for their potent endocrine-disrupting effects in aquatic organisms. This study employed juvenile Manila clams (<em>Ruditapes philippinarum</em>), with genetically determined sexes, as model organisms in a 14-day exposure experiment. The clams were exposed to 4-NP and E2 at concentrations of 0 (control), 0.1, 1, and 10 μg/L. We primarily investigated the effects on steroidogenesis and <em>vitellogenin</em> (<em>VTG</em>) expression, which are key factors in assessing endocrine disruption. Results showed that 4-NP inhibited shell growth at all tested concentrations, and increased free E2 in tissues levels were observed in clams exposed to 0.1 μg/L of 4-NP on both the 7th and 14th days. Conversely, E2 did not significantly affect free E2 in tissues levels. Notably, exposure to 1 μg/L 4-NP significantly upregulated mRNA expression of genes involved in the steroidogenesis pathway (<em>GnRH</em>, <em>CYP17</em>, and <em>17β-HSD</em>) in genetically female juveniles. Both male and female juveniles showed increased <em>VTG</em> mRNA expression after 4-NP exposure. These findings confirm the endocrine-disrupting potential of 4-NP, particularly affecting genetically female juveniles. The alterations in key genes involved in steroidogenesis and the upregulation of <em>VTG</em> expression highlight the vulnerability of bivalves to EDCs. This study underscores the importance of <em>VTG</em> expression as a reliable biomarker for assessing the estrogenic impacts and action mechanisms of EDCs in juvenile bivalves.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107303"},"PeriodicalIF":3.0,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biochemical properties and vertical distribution of particulate organic carbon in the northern Chukchi Sea","authors":"Jonghyuck Lee ,&nbsp;Eun Jin Yang ,&nbsp;Kyoung-Ho Cho ,&nbsp;Jinyoung Jung ,&nbsp;Sanghoon Park ,&nbsp;Jaesoon Kim ,&nbsp;Myeong Seop Kim ,&nbsp;Jae Ha Jeon ,&nbsp;Sang Heon Lee","doi":"10.1016/j.marenvres.2025.107311","DOIUrl":"10.1016/j.marenvres.2025.107311","url":null,"abstract":"<div><div>The vertical dynamics of biopolymeric carbon (BPC) components are essential for understanding their role in the biological pump and carbon cycling. However, little research has addressed their distribution and transformation across the epipelagic, mesopelagic, and bathypelagic zones, particularly in the northern Chukchi Sea. This study investigated the contributions to particulate organic carbon (POC), reduction rates, and vertical distribution of BPC components, including carbohydrate carbon (CHO-C), protein carbon (PRT-C), and lipid carbon (LIP-C), across the Mendeleev Ridge (MR), Chukchi Basin (CB), and Northwind Basin (NB), along with analyzing potential factors influencing the distribution patterns of BPC components and POC. In all three regions (MR, CB, and NB), LIP-C was the dominant BPC component, exhibiting the highest contribution to POC and the lowest reduction rate as depth increased, highlighting its significant role in carbon cycling and export. In the MR and CB regions, elevated POC concentrations were observed at specific depths, corresponding to high LIP-C levels. These findings indicate that BPC components, particularly LIP-C, play a substantial role in influencing POC distribution in these regions. In contrast, the NB displayed distinct POC distribution, with consistently high concentrations extending from the epipelagic to bathypelagic zones. Unlike the MR and CB, POC distributions in the NB appeared less influenced by autochthonous BPC sources, suggesting additional contributions from external factors such as lateral transport. These findings highlight the pivotal role of BPC components in driving POC dynamics and carbon cycling in the northern Chukchi Sea.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107311"},"PeriodicalIF":3.0,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental controls on chlorophyll-a and dissolved oxygen variability in contrasting Basins of the Northern Indian ocean","authors":"Kunal Chakraborty ,&nbsp;Linta Rose ,&nbsp;B. Rohith ,&nbsp;Sanjiba Kumar Baliarsingh ,&nbsp;Alakes Samanta","doi":"10.1016/j.marenvres.2025.107316","DOIUrl":"10.1016/j.marenvres.2025.107316","url":null,"abstract":"<div><div>This study examines the contrasting environmental processes driving spatio-temporal variations in chlorophyll-<em>a</em> (Chl-<em>a</em>) and dissolved oxygen (DO) across latitudes in the north Indian Ocean, focusing on the roles of mesoscale eddies and Rossby waves, using biogeochemical Argo profiles and outputs from a high-resolution coupled ocean-ecosystem model. The model effectively reproduces the observed upper-ocean variability of temperature, salinity, Chl-<em>a</em>, and DO on seasonal to interannual timescales. Analysis of biogeochemical Argo profiles reveals that anticyclonic eddies (ACEs) deepen the oxycline, facilitating DO ventilation into deeper waters. The extent of this deepening varies linearly with eddy strength, with ACE-induced DO ventilation being more pronounced in the Arabian Sea (AS) than in the Bay of Bengal (BoB). While the model captures DO ventilation reasonably well, except for a few mild eddies. Nevertheless, mesoscale eddies contribute to DO replenishment in deeper waters across both basins. Chl-<em>a</em> and deep chlorophyll maximum (DCM) depth variability exhibit distinct regional patterns. ACEs cause a rapid downward movement of Chl-<em>a</em>, followed by immediate shoaling, creating a vertically homogeneous Chl-<em>a</em> column with unusually high surface concentrations across most of the AS, but this does not occur in the BoB. The DCM depth in the AS shoals progressively northward from the equator due to regional physical processes, whereas in the BoB, mesoscale eddies play a dominant role in controlling its variability. Rossby wave propagation also plays a crucial role in deeper oxygen ventilation, with these waves occurring more frequently in the BoB. In the AS, thermocline, oxycline, and DCM depth variability are influenced by Rossby waves propagating across different latitudinal bands. In contrast, in the BoB, Rossby wave effects are largely confined to the southern region, while eddy activity dominates variability in the central and northern regions.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"210 ","pages":"Article 107316"},"PeriodicalIF":3.0,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}