Regional Studies in Marine Science最新文献

{"title":"Ecotoxicological assessment of polycyclic aromatic hydrocarbons and fish biomarkers in a marine protected area","authors":"André Vieira Kuhn ,&nbsp;João Henrique Alliprandini da Costa ,&nbsp;Ursulla Pereira Souza ,&nbsp;Gislaine Vanessa de Lima ,&nbsp;Pedro Henrique Cipresso Pereira ,&nbsp;Rafael Garrett Dolatto ,&nbsp;Caio Rodrigues Nobre ,&nbsp;Marco Tadeu Grassi ,&nbsp;Augusto Cesar ,&nbsp;Giorgi Dal Pont ,&nbsp;Antônio Ostrensky ,&nbsp;Camilo Dias Seabra Pereira ,&nbsp;Helen Sadauskas-Henrique","doi":"10.1016/j.rsma.2025.104155","DOIUrl":"10.1016/j.rsma.2025.104155","url":null,"abstract":"<div><div>From 2019–2020, oil slicks were reported in more than a thousand coastal locations along the Brazilian Atlantic coast. The Marine Protected Area Costa dos Corais (MPACC), located in the states of Pernambuco and Alagoas, Brazil, was among the most affected regions. This study investigates the feeding behavior of fish species, the presence of polycyclic aromatic hydrocarbons (PAHs) in sediments and white muscle, PAHs-like metabolites in bile, and oxidative damage to DNA (deoxyribonucleic Acid), proteins, and lipids in the liver, gills, and muscle of three fish species collected from the MPACC. The results indicate low to moderate levels of PAHs in sediments, originating from both pyrolytic and petrogenic sources. <em>Mugil curema</em> primarily ingested sand, followed by algae; <em>Eugerres brasilianus</em> consumed animal-derived items and algae, while <em>Odontoscion dentex</em> fed on fish fragments (such as scales), detritus, and crustaceans. The sum of four PAHs (benzo[<em>a</em>]pyrene, chrysene, benzo[<em>b</em>]fluoranthene, and benzo[<em>a</em>]anthracene) in white muscle exceeded the European Union’s recommended threshold for safe human consumption (30 ng g⁻¹; EU Regulation No. 835/2011). <em>Eugerres brasilianus</em> and <em>Mugil curema</em> exhibited significant positive correlations between lipid damage in liver and naphthalene-type metabolites in bile and PAHs concentrations in white muscle, respectively. Additionally, the set of biomarkers (PAH-type metabolites in bile, DNA damage, TBARs, and carbonyl proteins) collectively demonstrates their potential for assessing fish species inhabiting contaminated tropical aquatic environments, as they were found to be inter-correlated. The findings of this study provide valuable insights into the ecological impacts of tropical environments contamination and can support the development of management and recovery strategies for Brazilian marine protected areas affected by oil spills.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104155"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"ESG is conducive to improving the operating efficiency of fishery enterprises -- Based on DEA model and Tobit regression analysis","authors":"Lanlan Sun ,&nbsp;Xuanxuan Zhang ,&nbsp;Zhuming Zhao ,&nbsp;Jianying Zhang","doi":"10.1016/j.rsma.2025.104158","DOIUrl":"10.1016/j.rsma.2025.104158","url":null,"abstract":"<div><div>Fisheries have a strategically significant position in the national economy as a major component of agricultural and rural economies. The establishment of a rational and efficient method for assessing operational efficiency contributes to a more profound understanding of the developmental state of publicly traded the fishing firms, thereby promoting the sustainable and sound growth of fishing industry. The operational efficiency of Chinese listed fishing firms was assessed in the study using the data envelopment analysis (DEA) approach in conjunction with Malmquist index, both in a static and dynamic manner, over the period between 2012 and 2022. Furthermore, in order to ascertain the impact of environmental, social, and governance (ESG) performance on fishery-listed firms, the Tobit regression model was employed. The findings indicated that (1) although the overall comprehensive resource utilization efficiency of the industry is relatively high, it has not yet reached the optimal production frontier, and the low comprehensive efficiency of ZONECO is the most important reason for the ineffective average comprehensive efficiency of the fishery industry. (2) Dynamically, although technical efficiency shows an upward trend, the decline in the industry’s technical progress index still leads to a downward trend in total factor productivity. (3) ESG performance contributes to the operating efficiency of listed fishery companies.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104158"},"PeriodicalIF":2.1,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 pollution and ecological risks of potentially toxic elements in surface sediments of the north-central Persian Gulf","authors":"Fakhteh Zare ,&nbsp;Alireza Vaezi ,&nbsp;Vahid Tavakoli ,&nbsp;Razyeh Lak","doi":"10.1016/j.rsma.2025.104159","DOIUrl":"10.1016/j.rsma.2025.104159","url":null,"abstract":"<div><div>This study investigates pollution levels and ecological risks of potentially toxic elements (PTEs) in surface sediments of the North-Central Persian Gulf, a region heavily influenced by industrial activities. Sediment samples were systematically collected from 109 stations at depths ranging from 0 to 78 m. Analysis revealed a predominance of silt and clay (∼70 % of total composition). Concentrations of 14 major and trace elements followed the order: Ca &gt; Al &gt; Fe &gt; Sr &gt; Mn &gt; Ba &gt; Cr &gt; Ni &gt; V &gt; Zn &gt; Cu &gt; Pb &gt; As &gt; Cd. The modified degree of contamination (mCd) indicated generally low contamination, though elevated pollution levels were detected near Bushehr Port, the Bushehr Nuclear Power Plant, and Khark Island, likely due to anthropogenic inputs. Significant enrichment of As and Cd was observed, alongside moderate enrichment of Cr and Ni, while Cu, Fe, Mn, Pb, V, and Zn exhibited minimal enrichment. Ecological risk assessment suggested low overall risk, with localized moderate risks at certain stations. Notably, Cd contributed 56 % of the total ecological risk, highlighting concerns near industrial zones. Geochemical analysis revealed that Al, Ni, Zn, Cr, V, Fe, and Cu primarily originated from terrestrial sources, reflecting regional geological background. Moderate enrichment of Ni and Cr aligns with naturally high soil concentrations in southern Iran. In contrast, elevated As and Cd levels point to significant anthropogenic influence, particularly near industrial sites, with Cd linked to oil tanker operations and industrial wastewater discharge. These findings underscore the urgent need for mitigation strategies such as (1) stricter controls on industrial and shipping-related discharges, (2) remediation of Cd and As hotspots near high-risk zones (e.g., Bushehr Port and Khark Island), and (3) long-term monitoring of benthic ecosystems to assess bioaccumulation risks.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104159"},"PeriodicalIF":2.1,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 water physicochemical factors, plankton, and biological composition of Penaeus vannamei guts in the salt-field ponds","authors":"Changjian Li ,&nbsp;KeKe Lei ,&nbsp;Xinhua Wu ,&nbsp;Xiangli Tian ,&nbsp;Hongwei Shan ,&nbsp;Ziying Li","doi":"10.1016/j.rsma.2025.104156","DOIUrl":"10.1016/j.rsma.2025.104156","url":null,"abstract":"<div><div>The shrimp farming in salt-field has attracted people’s attention due to the high quality of the shrimp being farmed. In this study, four salt-field ponds with salinity of 33 ± 5 (HS33), 40 ± 5 (HS40), 47 ± 5 (HS47), and 52 ± 7 (HS52) were selected and their water physicochemical factors, plankton, and gut food organism composition of shrimp (<em>Penaeus vannamei</em>) from May to September were analyzed. The results showed a time difference between the peak of nutrients and the peak of phytoplankton bloom in the water. Total nitrogen and phosphorus concentrations increased and then decreased, with peaks in July. Phytoplankton density increased and then decreased, with a peak in August. In contrast, the zooplankton densities in all groups decreased and then increased over time, with a minimum in June. Besides, diatoms are the main phytoplankton, and copepods and rotifers are the main zooplankton in salt-field ponds during the investigation period. The main phytoplankton in salt-field ponds are not affected by culture time. The zooplankton exhibited a decrease in average size from July to September due to the decrease in copepods and the increase in rotifers. In addition, phytoplankton density was not affected by the salinity gradient in the salt-field ponds, whereas zooplankton density increased with increasing salinity from 33 to 47, decreasing at 52 salinity. The plankton consumed by shrimp in all salt-field ponds is mainly dominated by green algae and copepods and is less affected by salinity and culture time, except in August. These results indicated that the plankton structure of the salt-field pond is reasonable and relatively stable. Zooplankton may be feeding selectively and act as mediators of green algae into the shrimp intestine. An appropriate increase in salinity (from 33 to 47) can enhance zooplankton abundance and is more suitable for the growth of shrimp. The results of this study will provide useful information for the development of shrimp farming in salt-fields.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104156"},"PeriodicalIF":2.1,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Influence of sediment on the chemical properties of water in coastal environment and their potential effect on heterotrophic prokaryotic growth","authors":"Clara Dignan ,&nbsp;Benjamin Misson ,&nbsp;Véronique Lenoble ,&nbsp;Nicole Garcia ,&nbsp;Benjamin Oursel ,&nbsp;Virginie Sanial","doi":"10.1016/j.rsma.2025.104145","DOIUrl":"10.1016/j.rsma.2025.104145","url":null,"abstract":"<div><div>This work aims to carry out a field diagnosis of the sedimentary column influence on the spatial variability of the surface waters chemical composition in an urbanized bay. The spatial distributions of nutrients, dissolved organic matter, and radium isotopes used as sediment tracers were determined. Additionally, laboratory incubations were performed to evaluate the influence of the sedimentary column on the growth of heterotrophic prokaryotes (HP). To do so, a natural HP community was exposed to dissolved substances collected from the bay. First, radium concentrations were positively correlated with concentrations of some fluorescent compounds in the dissolved organic matter, dissolved inorganic phosphorus and dissolved organic nitrogen, suggesting that sediment inputs caused chemical alterations. Second, HP growth was strongly stimulated by dissolved substances derived from sediments, identified by correlation with radium, leading to an abundance up to 34 times that of the maximum observable with dissolved substances without recent influence from sediments.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104145"},"PeriodicalIF":2.1,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decapod community composition is seasonally driven by different environmental factors in an estuarine-coastal gradient (Eastern Brazil)","authors":"Ronaldo R. Oliveira-Filho ,&nbsp;Mariana Antunes ,&nbsp;Joelson Musiello-Fernandes ,&nbsp;Rodrigo Guéron ,&nbsp;Helen Audrey Pichler ,&nbsp;Ciro Colodetti Vilar ,&nbsp;Fernando L. Mantelatto ,&nbsp;Jean-Christophe Joyeux ,&nbsp;Julien Chiquieri ,&nbsp;Maurício Hostim-Silva ,&nbsp;David Bauman","doi":"10.1016/j.rsma.2025.104135","DOIUrl":"10.1016/j.rsma.2025.104135","url":null,"abstract":"<div><div>Crustacean communities are shaped by a series of ecological processes, but the degree to which different spatial and environmental dimensions affect them in surrounding estuarine-coastal gradients remains unclear. Here we analyzed decapod community data (crabs and shrimps) from the Doce River estuary and its adjacent marine coast, to test and quantify the effects that spatial and environmental factors have had on these communities three years after the Fundão mining dam failure of November 2015. We sampled communities monthly from October 2018 to September 2019 in 18 sampling sites distributed in three zones (estuary, nearshore, and offshore), resulting in 216 samples and 29 recorded taxa. Spatial eigenvector-based methods and variation partitioning approaches were used to test and quantify the pure and joint effects of spatial and environmental processes on the communities over different seasons. The spatial structures of the community composition presented differences among the four studied seasons, being driven by environmental heterogeneity as well as spatial processes unrelated to our measured variables (temperature, salinity, depth, turbidity, dissolved oxygen and pH). Specifically, the species composition and species richness responded the most to turbidity, pH, and depth during the rainy seasons, as well as salinity during the dry seasons. The variability of decapod composition surrounding the Doce River mouth is seasonally affected by a different set of environmental and spatial factors, with low intrusions of saltwater in the estuarine sector impacting the distribution of stenohaline marine species. Our results both partly uncover and emphasize the complexity resulting from environmental heterogeneity and anthropic pressures, stressing the need for further studies on local spatio-temporal dynamics of decapod fauna and other organisms to inform conservation and management actions.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104135"},"PeriodicalIF":2.1,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Microplastic pollution in marine bivalves, surface water and sediments from an aquaculture in Portugal and possible intake by humans","authors":"Daniela C.C. Silva ,&nbsp;Ana Borba ,&nbsp;Hermínio C. de Sousa ,&nbsp;João C. Marques ,&nbsp;Ana M.M. Gonçalves","doi":"10.1016/j.rsma.2025.104146","DOIUrl":"10.1016/j.rsma.2025.104146","url":null,"abstract":"<div><div>The abundance and types of microplastics (MP) were assessed in different tissues of <em>Magallana gigas</em> (diploid and triploid oysters) and <em>Ruditapes philippinarum</em> (clams), surface water and sediments in a Portuguese shellfish farm. The daily MP intake by humans through the consumption of these organisms was estimated. Diploid oysters (0.33–5.00 MP particles/tissues) and clams (0.00–3.33 MP particles/tissues) showed higher MP abundances than triploid oysters (0.00–1.00 MP particles/tissues). Seasonal differences in MP abundance were observed in diploid oysters (visceral mass: winter lower than autumn, spring and summer; digestive gland: autumn and winter lower than summer; gills: autumn, spring and summer lower than winter), triploid oysters (gills: summer lower than autumn) and clams (digestive gland and gills: autumn, winter and summer lower than spring; foot: autumn lower than spring and summer). The highest MP abundances were observed in the visceral mass (5.00 MP particles/tissue in diploid oysters), digestive gland (3.33 MP particles/tissue in clams) and gills (1.00 MP particles/tissue in triploid oysters). Pink MP films (1–100 µm) were predominantly found in these bivalves. MPs were detected in surface water (0.00–5.33 MP particles/L) and sediments (15.47–114.55 MP particles/kg). Temporal variations in MP abundance were observed in surface water (low tide: Oct19, Nov19, Jan20, Feb20, Mar20, Aug20 and Sep20 lower than Sep19 and Dec19; high tide: Nov19 lower than Dec19, Ap20 and May20) and sediments (low tide: Sep19, Oct19, Jan20, Jun20, Jul20, Aug20 and Sep20 lower than Dec19 and Apr20). Tidal variations were detected in sediments (Nov19, Dec19 and May20: high tide lower than low tide). MPs in surface water were predominantly transparent fibers (100–2500 µm), while those observed in sediments were blue fragments (100–2500 µm). The main polymers identified were poly(propylene) and poly(ethylene). The highest daily MP intake values were observed in adults, very elderly and pregnant women.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104146"},"PeriodicalIF":2.1,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How does the Natuna Cyclonic Eddy form in the Southern South China Sea, and what are its implications?","authors":"Apriansyah ,&nbsp;Agus Saleh Atmadipoera ,&nbsp;Dwiyoga Nugroho ,&nbsp;Bayu Priyono ,&nbsp;Risko","doi":"10.1016/j.rsma.2025.104154","DOIUrl":"10.1016/j.rsma.2025.104154","url":null,"abstract":"<div><div>This study investigates the Natuna Cyclonic Eddy (NCE) in the South China Sea, focusing on its formation processes, circulation characteristics, and impact on essential oceanographic parameters such as sea surface temperature (SST), chlorophyll-a concentration (CHL), and sea level anomaly (SLA). Through an analysis of an extensive 11-year dataset derived from satellite observations and ocean models, we identify that the NCE is primarily formed through the interaction between the Vietnam Coastal Jet and the sea topography of the Natuna Islands region. With its cyclonic circulation reaching maximum speeds of 0.6 m/s, the NCE promotes the vertical transfer of nutrients from deeper layers to the surface, thus boosting biological productivity in the surrounding waters. Additionally, our results indicate that the variability of the NCE is notably influenced by both annual and semi-annual cycles, as well as the El Niño-Southern Oscillation (ENSO); specifically, La Niña events result in a more intense NCE compared to conditions during El Niño. These findings are vital for effectively managing fishery resources and conserving marine ecosystems within the area.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104154"},"PeriodicalIF":2.1,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Single-use plastic free islands: The case study of Donousa","authors":"Irina Kandylioti,&nbsp;Elefteria Psillakis","doi":"10.1016/j.rsma.2025.104151","DOIUrl":"10.1016/j.rsma.2025.104151","url":null,"abstract":"<div><div>This study investigates the impact of the four-year cleaning and awareness raising program implemented on Donousa, the first island in Greece to ban single-use plastics. Despite the relatively low marine macro-litter recorded levels, approximately 90 % of the collected items were composed of artificial polymer materials. According to the plastic’s Clean Coast Index analysis, the surveyed beaches transitioned from “very clean” or “clean” state in 2018 to a “moderate” state in 2021, mostly influenced by items transferred by sea currents, like plastic fragments ≥ 2.5 cm, which ranked as the primary litter type on Donousa. While most of the collected marine litter were of uncertain origin (55.7 %), land-based sources (2.5 %) found to be the least prominent, with fishing activity (16.8 %) and beach users (26.0 %) contributing significantly. Regarding the single-use plastic (SUP) items, that the program specifically targeted to reduce by transitioning to alternative options, their contribution to the total plastic marine litter load decreased by 11.2 % by the end of the program, with plastic bottles nearly eliminated. Notably, beach S₄ recorded a 34.6 % reduction in SUPs_. However, challenges persist with item categories such as caps/lids, cigarette butts and plastic bags, highlighting the urgency for more drastic preventive measures and coordinated interventions on a larger scale.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104151"},"PeriodicalIF":2.1,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term trends in eutrophication in the inner part of Tokyo Bay, Japan, from 1998 to 2023","authors":"Shinji Hashimoto ,&nbsp;Kie Mizuno","doi":"10.1016/j.rsma.2025.104153","DOIUrl":"10.1016/j.rsma.2025.104153","url":null,"abstract":"<div><div>Nutrient loading is a critical issue in coastal waters that leads to eutrophication and anoxic water masses and impacts production in fisheries. In this study, therefore, long-term and seasonal variations in the eutrophication index (EI) using dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and chemical oxygen demand (COD) were investigated from 1998 to 2023 in the inner part of Tokyo Bay. Furthermore, the contribution of DIN, DIP, and COD to eutrophication was analyzed. The DIN concentrations showed a significant long-term decreasing trend, whereas DIP and COD showed no trend. EI also showed no long-term trend. The DIN and DIP concentrations showed a significant negative correlation with salinity, suggesting that the DIN and DIP concentrations in the inner part of Tokyo Bay were influenced by river water. COD showed a significant positive correlation with chlorophyll <em>a</em> concentration, suggesting that the COD in the inner part of Tokyo Bay was largely caused by endogenous factors. The EI was higher during the seasons with higher DIN and DIP concentrations and a lower salinity. The EI in the inner part of Tokyo Bay appeared to be higher during the season and at locations which the influence of river water was greater. The highest contribution to the EI was found for COD (&gt; 40 %), followed by DIN and DIP, suggesting that COD is an important factor in the eutrophication process.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104153"},"PeriodicalIF":2.1,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}