Regional Studies in Marine Science最新文献

{"title":"Spatial suitability analysis for finfish aquaculture: A case study from center-east coast of Tunisia","authors":"Amel Mzoughi ,&nbsp;Naoufel Romdhane ,&nbsp;Mohamed Salah Azaza","doi":"10.1016/j.rsma.2025.104225","DOIUrl":"10.1016/j.rsma.2025.104225","url":null,"abstract":"<div><div>This paper outlines a methodology for selecting offshore sites for finfish cage farming, based on Spatial Multi-Criteria Evaluation and mathematical model (Degree of compatibility, DC). This approach is effective at the screening level, even in areas with limited field data, where informed decision-making is critical, or in conflict zones where marine spatial planning becomes essential. The case study was conducted at the center-east coast of Tunisia, Monastir’s Bay, where the central government plans to develop offshore aquaculture activities. The methodology consists of two steps. First, selection criteria are identified. Twenty-two factors were used to assess cage site suitability, including physical characteristics, and socioeconomic, and environmental conditions. These criteria were spatialized and classified into six macro-criteria: domain areas, hydrodynamics, environmental conservation, pollution prevention, interaction with existing coastal uses, and logistic efficiency. All criteria were spatially analyzed using GIS tools and multi-criteria analysis. In the second step, a degree of compatibility assessment model under two scenarios was applied to establish the most suitable areas for finfish aquaculture. The findings show that the procedure enables site selection by integrating the suitability of a site for aquaculture purposes with the conservation of the local receiving ecosystem under spatial restrictions set by existing activities. Few highly suitable sites (high DC value) exist, primarily constrained by intensive coastal usage and conflicts among various users. These smaller areas of suitability should be considered within the broader context of coastal activities. This study serves as a model to support sustainable aquaculture expansion and site selection methodologies that align with ecosystem-based approaches to aquaculture.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104225"},"PeriodicalIF":2.1,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069168","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":"Primary characterization of pCO2 in the three bays of Algiers coast","authors":"Mohamed Zerrouki,&nbsp;Ferial Louanchi,&nbsp;Mehdia Asma Keraghel,&nbsp;Malik AïtKaci,&nbsp;Romaissa Harid,&nbsp;Housseyn Otmani","doi":"10.1016/j.rsma.2025.104248","DOIUrl":"10.1016/j.rsma.2025.104248","url":null,"abstract":"<div><div>The carbonate system in Mediterranean coastal zones remains inadequately quantified, exhibiting substantial discrepancies in research on CO₂ partial pressure (<em>p</em>CO₂), particularly in the insufficiently studied Algero-Provencal sub-basin. This study addresses a critical knowledge gap by providing the first characterization of carbonate chemistry parameters along the Algerian coast, a region previously lacking published data. The findings contribute to enhancing the accuracy of regional and global ocean biogeochemical models, particularly for the southern Mediterranean.The Algiers coastline comprises three bays: Bou-Ismail Bay (BB) to the west, Algiers Bay (BA) at the center, and Zemmouri Bay (BZ) to the east. A detailed dataset was assembled from direct and indirect measurements of carbonate system parameters in the surface waters of the three bays collected during spring and summer campaigns from 2011 to 2017. The carbonate system exhibited significant heterogeneity.During the June 2014 campaign, <em>p</em>CO₂levels exhibited considerable variation among the three bays. BA exhibited the lowest <em>p</em>CO₂ at 284.6 µatm, whereas BB and BZ recorded markedly elevated values of approximately 516 µatm. The extensive spatial range of approximately 250 µatm was predominantly influenced by biological processes, with BA exhibiting greater photosynthetic activity and dissolved oxygen (DO) levels compared to BB and BZ. Sampling campaigns were conducted in BA and BB from 2011 to 2017. <em>p</em>CO₂ and DO levels in BA and BB demonstrated considerable temporal variability. In BA, <em>p</em>CO₂ fluctuated between a minimum of 227 µatm during a phytoplankton bloom in July 2013 (with DO supersaturation at 180 %) and a maximum of 466 µatm in April 2011, attributed to rainfall and respiratory processes(with DO undersaturation at 76 %). In BB, spring campaigns (March 2015 and 2017) exhibited DO saturation levels (102–112 %) and lower <em>p</em>CO₂ values (392 µatm), while summer campaigns demonstrated <em>p</em>CO₂ supersaturation (up to 541 µatm) and DO undersaturation (70 %) attributable to thermal and respiratory processes.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104248"},"PeriodicalIF":2.1,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070169","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":"Astaxanthin ameliorates Cr (VI) accumulation, antioxidant, digestive, apoptosis and inflammatory response","authors":"Lei Zhao ,&nbsp;Ying Zhang ,&nbsp;Jie Yu ,&nbsp;Yi-Han Liu ,&nbsp;Zhi-Hao Cai ,&nbsp;Mu-Yang Li ,&nbsp;Ming Liu","doi":"10.1016/j.rsma.2025.104240","DOIUrl":"10.1016/j.rsma.2025.104240","url":null,"abstract":"<div><div>Exposure to Cr (VI) can induce various adverse effects such as oxidative stress and inflammatory response in fish. Astaxanthin have been documented as a novel antioxidant and heavy metal antidote. This study was investigated potential protective effect of astaxanthin on Cr (VI) accumulation, antioxidant, digestive enzyme, glucocorticoid receptor (GR)-regulated inflammatory response and apoptosis in snakehead fish (<em>Channa argus</em>). In this study, 300 <em>C. argus</em> were randomly divided into three groups. The fish were exposed to waterborne Cr(VI) and/or dietary astaxanthin for 28 days. The results provided evidences that astaxanthin could inhibit Cr (VI) bioaccumulation, inflammatory response and apoptosis. Additionally, astaxanthin also exerted protective effects by increasing the activity of antioxidant, digestive enzymes and GR-related genes expression levels. Overall, our results suggest that administration of 100 mg/kg astaxanthin has the potential to combat Cr (VI) toxicity, antioxidant, digestive, anti-apoptosis.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104240"},"PeriodicalIF":2.1,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089064","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 abundance, characteristics, and associated ecological risk assessment in the selected coastal areas of Baybay City, Leyte, Philippines","authors":"Abu Sayed Al Helal ,&nbsp;Abu Bakar Siddique ,&nbsp;Teofanes A. Patindol ,&nbsp;Kleer Jeann G. Longatang ,&nbsp;Deejay M. Lumanao ,&nbsp;Anabella B. Tulin ,&nbsp;Molla Rahman Shaibur","doi":"10.1016/j.rsma.2025.104246","DOIUrl":"10.1016/j.rsma.2025.104246","url":null,"abstract":"<div><div>This study aimed to provide the first description of the distribution, characteristics, and ecological risk of microplastics in water and sediment of selected coastal areas of Baybay City, Leyte, Philippines. A total of 10 coastal villages were sampled, and they were selected based on spatial variation. This study found microplastic contamination levels ranging from 50.0 to 216.67 ± 28.9 Items/L in water and 233.3 ± 57.7–516.67 ± 28.9 Items/Kg in sediment. The most common types of MP shapes were Fiber, Film, Fragment, and Flakes. The dominant polymer types in this study were PS (polystyrene), PETE (polyethylene terephthalate), and polypropylene (PP). Black, blue, white, and transparent were the dominant colors found in this study. The major microplastic size found in water samples were Large (&gt;1.5 mm) and Medium (0.5–1.5 mm), and the dominant size in the sediment sample was small (&lt;0.5 mm). Four pollution parameters were measured in this study. The contamination factor value indicated that the samples were highly and considerably contaminated. The Pollution Load Index indicated all samples as polluted (&gt;1). The polymeric risk value indicated risk category level III, and finally Pollution risk assessment value for all samples indicated a high-risk category. All of these parameters were shown through a spatial distribution map using Geography and Information System (GIS). The findings of this study suggest that microplastics found in marine water and sediment are crucial in the context of MP pollution, highlighting the need for further research.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104246"},"PeriodicalIF":2.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069169","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":"Comparison of fishing performance of biodegradable and nylon gillnets with different twine diameter","authors":"Kristine Cerbule ,&nbsp;Roger B. Larsen ,&nbsp;Jørgen Vollstad ,&nbsp;Anja Helene Alvestad","doi":"10.1016/j.rsma.2025.104247","DOIUrl":"10.1016/j.rsma.2025.104247","url":null,"abstract":"<div><div>Gillnets are usually made of nylon (PA) due to suitable material properties making them an efficient and commonly used fishing gear worldwide. However, considering that such gear is widely used and made of material that can endure long time of being exposed to marine environment, gillnets are often considered harmful if abandoned, lost or otherwise discarded. Such gear can cause marine plastic pollution and continue capturing marine animals over a long time (ghost-fishing). Efforts to develop new biodegradable materials to replace nylon in gillnets have been conducted. However, studies testing biodegradable gillnets have often shown reduced catch efficiency, challenging their acceptance in commercial fisheries. In this study, gillnets made of a new biodegradable PBSA material were assessed under commercial fishing conditions targeting cod (<em>Gadus morhua</em>) to compare their fishing performance with that of nylon nets. Two different monofilament netting diameters were tested. The results showed that relative catch efficiency between Ø 0.70 mm biodegradable and nylon nets was not significantly different (<em>CRaverage</em> = 107.0 % (CI: 86.2–132.1 %) and 80.58 % (CI: 15.23—155.76 %)). Increase in material diameter resulted in decrease of catches of cod of lengths 100–120 cm in biodegradable compared to nylon gillnets. This study showed that biodegradable gillnets can have a potential to reduce ghost fishing and plastic pollution at sea caused by this fishery and should be followed by further future long-term testing of material performance.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104247"},"PeriodicalIF":2.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070171","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":"Multi-dimensional risk assessment (MDRA) of oil spills on the northern coasts of the Persian Gulf","authors":"Kameleh Aghajanloo ,&nbsp;Sam Mazaheri ,&nbsp;Farzad Ghatei Dargahi","doi":"10.1016/j.rsma.2025.104221","DOIUrl":"10.1016/j.rsma.2025.104221","url":null,"abstract":"<div><div>The assessment of oil spill risks in the marine environments is critical for decision-makers and coastal manager to mitigate adverse environmental, social, and economic impacts. This study developed a comprehensive multi-dimensional stochastic methodology to consider the oil spill risks through three integrated phases: occurrence, exposure, and susceptibility analyses. The northern coastline of the Persian Gulf (PG), an area of noteworthy economic and biological resources, is selected as a case study due to its vulnerability to oil pollution. By integrating historical spill data, environmental sensitivity indices, and a state-of-the-art oil trajectory model (GNOME/ADIOS), a high-resolution risk map is generated. The results indicate that approximately 46 % of the study area is categorized as high to very high-risk levels, highlighting the urgency of targeted mitigation efforts. Critical regions such as Qeshm and Kish Islands are prioritized for emergency response and preparedness resources, including spill containment and cleanup equipment (e.g., booms, skimmers)<strong>.</strong> The proposed methodology serves as a practical tool for coastal authorities, marine environmental managers, and response planning teams. It enables informed decision-making to enhance preparedness and response strategies. In addition, the framework presents a scalable approach of developing high-resolution risk maps for any coastal region anywhere in the world, which entails the assessment of environmental sensibilities, ecological vulnerabilities, and the integrated deterministic model of oil spills along with the hydrodynamic behavior.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104221"},"PeriodicalIF":2.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144106925","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":"Re-Os isotope constraints on the offshore extent of supra subduction zone along the NW continental margin of India","authors":"Anju Pandey ,&nbsp;Dhananjai K. Pandey","doi":"10.1016/j.rsma.2025.104230","DOIUrl":"10.1016/j.rsma.2025.104230","url":null,"abstract":"<div><div>The north-western continental margin of India (NWCMI) is juxtaposed with onshore supra-subduction zone (SSZ) type ophiolitic complexes (e.g. the Muslim Bagh and Bela) linked with protracted convergence between Indian and Eurasian plates. Prior studies envisaged that these N-S trending SSZ complexes, likely extend further south into the Arabian Sea. However, paucity of offshore basement sampling has impeded in-depth investigations into such propositions. In view of the recent findings from the scientific ocean drilling and coring in the Laxmi Basin (LB) of the northern Arabian Sea, here we assess offshore continuation of the onshore SSZ ophiolite complexes. We employ new geochemical and first report of Re-Os isotopic signatures of the LB basement from Site U1457 of the IODP Expedition 355. We report that the geochemical characteristics of the LB volcanics show unambiguous signatures of SSZ crust. These include low TiO₂ (0.63–1 ppm), low Zr (&lt;50 ppm), low Ti/V ratios (10−20) and uniform patterns of progressive depletion in high field strength elements, with typical negative anomalies of Nb and Zr, coupled with progressive enrichments in large ion lithophile elements (K, Rb, Sr and Ba). Using robust classification diagrams, the LB volcanics are categorised as forearc basalts (FAB) and boninitic FAB (B-FAB). The novel Re-Os isotope data from the Site U1457 show Re concentrations varying between 1.37 and 1.97 (ppb) and very low Os concentrations (0.06–0.18 ppb). The positive linear trend between suprachondritic ¹⁸⁷Os/¹⁸⁸Os ratios (0.1683–0.2484) with subduction derived fluid elements implies modification of original Os during subduction initiation process. Further, comparisons of ophiolites from NWCMI and Laxmi Basin allow us to infer that the onshore SSZ ophiolite belt continues into the Arabian Sea, at least till the LB. Our new findings would have significant implications towards paleo plate reconstructions of the final Gondwana dispersal.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104230"},"PeriodicalIF":2.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070168","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":"Habitat suitability of Thunnus spp. in the Northern South China Sea based on the MaxEnt species distribution model","authors":"Alma Alfatat,&nbsp;Hagai Nsobi Lauden,&nbsp;Shaoliang Lyu,&nbsp;Jiayi Chen,&nbsp;Jianyu Dong,&nbsp;Ning Chen,&nbsp;Xuefeng Wang","doi":"10.1016/j.rsma.2025.104238","DOIUrl":"10.1016/j.rsma.2025.104238","url":null,"abstract":"<div><div>Tuna (<em>Thunnus</em> spp.) are apex predators and vital fishery resources in the Northern South China Sea. This study assesses the habitat suitability of tuna (<em>Thunnus</em> spp.) in the northern South China Sea using the MaxEnt model to analyze seasonal shifts and key environmental drivers from 2016 to 2020. Tuna occurrence data from the Guangdong Fishery Resources Data Collection System, along with environmental variables (Chlorophyll-a, sea surface salinity, sea surface height, and temperature), were utilized. Model performance was validated using the AUC and verified with catch per unit effort (CPUE) data. The model demonstrated a satisfactory predictive performance, with AUC TRAIN values ranging from 0.805 to 0.864, AUC TEST values from 0.795 to 0.839. Chl-a was the primary driver in spring, whereas SSS had a greater influence in autumn, with optimal SST ranging from 24 °C to 27°C. Suitable habitat (HSI &gt; 0.8) reached its highest spatial coverage in April (7525 km²) and September (9656 km²), aligning with increased CPUE values during those periods. The model effectively captured seasonal variations in the species' spatial distribution; further refinement using additional predictors may lead to more accurate predictions. These findings provide important insights for adaptive fisheries management, supporting informed responses to climate-driven changes and promoting the future sustainability of regional tuna populations.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104238"},"PeriodicalIF":2.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070170","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":"Interannual variability in the distribution and biomass of five demersal fish species from shrimp bycatch and their relationship with environment in the Gulf of California","authors":"Jesús Leobardo Pérez-Burgos ,&nbsp;Juana López-Martínez ,&nbsp;Carlos Hiram Rábago-Quiroz ,&nbsp;Raúl Octavio Martínez-Rincón ,&nbsp;Ricardo García-Morales ,&nbsp;Emigdio Marín-Enríquez","doi":"10.1016/j.rsma.2025.104245","DOIUrl":"10.1016/j.rsma.2025.104245","url":null,"abstract":"<div><div>In the Gulf of California (GC), five fish species —<em>Balistes polylepis</em>, <em>Paralabrax maculatofasciatus</em>, <em>Sphoeroides annulatus</em>, <em>Haemulopsis elongatus</em>, and <em>Diapterus brevirostris</em>— are caught as bycatch in the industrial shrimp trawl fisheries. This study analyzed their distribution using the positive hauls from prospecting cruises, biomass through the swept area method, and environmental influences using multivariate methods from 2002 to 2018. The estimated absolute abundance was 52,181,219 individual organisms, with a total biomass of 4394.5 tons. The highest values were recorded in 2011, contributing more than 46 % of the total abundance and 54 % of the biomass, while the lowest values were observed in 2008 and 2018. <em>H. elongatus</em> (33 %) and <em>D. brevirostris</em> (25 %) were the most abundant species, whereas <em>B. polylepis</em> (41 %) and <em>H. elongatus</em> (22 %) dominated the biomass. According to our zoning of the GC, the North (N) zone contributed more than 50 % of the total abundance and biomass, followed by the Central (C) zone in the early years, with an increasing contribution from the South (S) and Southeast (SE) zones after 2015. Bathymetrically, the biomass in the SE and S zones was concentrated in the &lt; 20 m stratum, while the &gt; 40 m strata were relevant only in the N and S zones. <em>H. elongatus</em> and <em>D. brevirostris</em> exhibited a northward expansion, evidencing shifts in their geographic distribution. The PERMANOVA analysis indicated significant differences in biomass across years (F = 1.82, p = 0.00011) and zones (F = 1.95, p = 0.00141), but not across depth strata (p = 0.1971). Non-metric multidimensional scaling revealed temporal and spatial groupings, particularly for 2011, 2016, and 2005. Principal Component Analysis (PCA) explained 61.6 % of the variability, associating <em>H. elongatus</em> with the N zone and 2011, and <em>D. brevirostris</em> with the SE zone and 2016. Generalized Additive Models (GAMs) identified chlorophyll a (CHLA) and the Multivariate ENSO Index (MEI) as important environmental predictors of biomass variability in most species, explaining a significant portion of the deviance in their biomass patterns. These findings highlight the influence of environmental variability on biomass distribution, providing crucial insights for fisheries management in the GC region.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104245"},"PeriodicalIF":2.1,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070172","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":"Distribution characteristics and influencing factors of chlorophyll a in the Pearl River Estuary and surrounding waters during spring and summer of 2023","authors":"You LE ,&nbsp;Yuanliang ZHAO ,&nbsp;Xianjie LIU ,&nbsp;Yang LU ,&nbsp;Jin-Yu Terence YANG ,&nbsp;Shuqun SONG ,&nbsp;Jun SUN","doi":"10.1016/j.rsma.2025.104241","DOIUrl":"10.1016/j.rsma.2025.104241","url":null,"abstract":"<div><div>This study undertook cruise surveys in May and August 2023 in the Pearl River Estuary and its surrounding waters (21°N-23°N, 112.5°E-114.5°E) to investigate the spatial distribution characteristics of size-fractionated phytoplankton chlorophyll <em>a</em> (Chl <em>a</em>) and its environmental influencing factors. The distribution of Chl <em>a</em> in this region showed pronounced seasonal variations and spatial differences. The total Chl <em>a</em> concentration in summer was considerably higher than that in spring. In spring, pico-sized Chl <em>a</em> (55.66 %) was the main contributor to total Chl <em>a</em>, whereas in summer, the contribution ratios among different size-fractionated Chl <em>a</em> were more balanced (micro-sized Chl <em>a</em>: 39.38 %; nano-sized Chl <em>a</em>: 26.34 %; pico-sized Chl <em>a</em>: 36.88 %). In both spring and summer, the distribution of total Chl <em>a</em> in the Lingdingyang area demonstrated an initial increase from the estuary to the open sea, followed by a decrease. In the surrounding waters of the PRE outside Lingdingyang, the total Chl <em>a</em> showed a gradual decrease from the nearshore to the offshore areas, with the contribution of pico-sized Chl <em>a</em> gradually increasing to dominance. The study found that in the Lingdingyang area, the high nitrogen-to-phosphorus ratio indicated a pronounced imbalance in nutrient proportions, suggesting a potential phosphorus limitation. Studying different size-fractionated Chl <em>a</em> can facilitate a better understanding of the dynamic distribution of phytoplankton of varying sizes, aiding in improved management of water quality in the PRE.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"87 ","pages":"Article 104241"},"PeriodicalIF":2.1,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942624","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}