Regional Studies in Marine Science最新文献

{"title":"Population size estimates and migrations of the queen conch (Aliger gigas) in the nursery ground of the Xel-Há coastal inlet based on a mark-recapture and census surveys","authors":"Villegas-Hernández Harold ,&nbsp;Monroy-López Juan Carlos ,&nbsp;Pech-Puch Dawrin ,&nbsp;Manzanero-Vázquez Eddie Alejandro ,&nbsp;Raigoza-Figueras Rodolfo","doi":"10.1016/j.rsma.2024.103845","DOIUrl":"10.1016/j.rsma.2024.103845","url":null,"abstract":"<div><div>This project aims to analyze the spatiotemporal variations of the queen conch (<em>Aliger gigas</em>) population in the sanctuary of Xel-Há Inlet (Mexico). During 2022 and 2023, visual censuses (on 42 fixed transects per sampling) and biometrics (siphonal length SL and lip thickness LT) were carried out to estimate average densities and size-frequency distribution within four zones: Bocana (BO), Centro (CN), Brazo Norte (BN), and Brazo Sur (BS). In addition, the average population size (<span><math><msub><mrow><mover><mrow><mi>N</mi></mrow><mo>ˆ</mo></mover></mrow><mrow><mi>t</mi></mrow></msub></math></span>) and migrations were estimated following a mark-recapture methodology on 7 occasions, tagging 574 specimens (279 in 2022 and 295 in 2023). Regarding the ontogenetic phases (based on LT) of the organisms observed during censuses i<em>n</em> 2022 (<em>n</em> = 279), 81 corresponded to adults and 198 juveniles; meanwhile, in 2023 (<em>n</em> = 531), 36 were adults and 495 juveniles, indicating that the inlet is mostly a nursery ground. The overall mean densities have increased since Feb-2022 (0.543 ind./100 m²) up to Nov-2023 (5.079 ind./100 m²). Benthic variables and density of <em>A. gigas</em> varied spatially, i.e., CN and BO had higher benthic coverage of sand and seagrasses related to elevated densities of adults; meanwhile, BN and BS were dominated by turf and macroalgae and related to higher densities for juveniles. A total of 284 (54.2 % of tags) specimens were recaptured at another time, and based on the Jolly-Seber model, <span><math><msub><mrow><mover><mrow><mi>N</mi></mrow><mo>ˆ</mo></mover></mrow><mrow><mi>t</mi></mrow></msub></math></span> was estimated at 938 specimens (ranging from 538 to 1369). Regarding migrations, 79 tagged specimens that moved to other zones were identified, and 205 specimens were again observed in the same zone. Inter-annually, 108 tags in 2022 were later observed in 2023, and 36 specimens (earlier as juveniles) a year later were recaptured as adults; meanwhile, 72 adults in 2022 were again observed in 2023, thus indicating that queen conch used to return to breed within the inlet.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103845"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357662","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":"Functional traits and ecosystem implications in the Multiple Use Marine Protected Area Almirantazgo Sound: A baseline study of scallop banks and benthic communities","authors":"Taryn Sepúlveda ,&nbsp;Claudia Andrade ,&nbsp;Eduardo Almonacid ,&nbsp;Erik Daza ,&nbsp;Cristóbal Rivera ,&nbsp;Cristian Vargas ,&nbsp;Cristian Aldea","doi":"10.1016/j.rsma.2024.103836","DOIUrl":"10.1016/j.rsma.2024.103836","url":null,"abstract":"<div><div>Amid escalating environmental challenges confronting marine ecosystems, the proliferation of coastal and marine protected areas (MPAs) has emerged as a pivotal strategy for mitigating biodiversity loss and fostering sustainable resource management. This research advocates for a paradigm shift towards a trait-based approach to assess functional diversity (FD) within MPAs, with a specific focus on the ecologically crucial <em>Austrochlamys natans</em> banks in Parry Bay, MPA Almirantazgo Sound. By surveying 28 invertebrate species across eight phyla, a PCA using fuzzy-coded functional traits revealed five distinct groupings primarily based on feeding, movement, and reproductive modes. Mobile predators and scavengers clustered distinctly from sessile suspension feeders and limited-mobility grazers, indicating a scarcity of mobile predator species in Parry Bay, which impacts the ecosystem's dynamics. FD indices highlighted low functional α-diversity, emphasizing trait redundancy that enhances resilience but relies heavily on a few unique and specialized species. The potential extinction or migration of these species could directly affect unique ecosystem properties. While revealing the resilience of the benthic community, this research underscores its dependence on a handful of species that are crucial for both ecological functions and regional commercial significance. Urgent conservation and management measures are imperative to protect these species and maintain the delicate balance of this ecosystem.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103836"},"PeriodicalIF":2.1,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326844","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":"Microplastics contamination through a mighty estuarine island: Distribution, influencing factors, and risk assessment","authors":"Shahoriar Arefin ,&nbsp;Abu Reza Md. Towfiqul Islam ,&nbsp;Mehedi Hasan ,&nbsp;Al-Nure Mubin ,&nbsp;Md. Alinur Rahman ,&nbsp;Mir Mohammad Ali ,&nbsp;Md Abu Bakar Siddique ,&nbsp;Hazem Ghassan Abdo ,&nbsp;Abubakr M. Idris ,&nbsp;Subodh chandra Pal ,&nbsp;Guilherme Malafaia ,&nbsp;Venkatramanan Senapathi","doi":"10.1016/j.rsma.2024.103841","DOIUrl":"10.1016/j.rsma.2024.103841","url":null,"abstract":"<div><div>The global concern over microplastic (MP) contamination in diverse ecosystems is well-established, yet Nijhum Dwip Island (NDI), known for its ecological diversity, has not undergone a comprehensive study addressing the extent of MP pollution. This research aims to evaluate the spatial distribution, influencing factors, and ecological risks of MPs in both sediment and surface water surrounding NDI, situated in the Northern Bay of Bengal. A meticulous collection of 40 sediment and 40 tidal water samples from various sites facilitated a detailed analysis. The mean abundance of MPs in sediment was 138.39 ± 34.15 pieces/kg, while in water, it was 72.83 ± 30.76 pieces/m³. Various shapes observed on NDI included films, fragments, fibers, and foams, with fragments dominating in sediment (64.05 %) and water (61.51 %). Analysis of FTIR spectra identified two primary polymer types, namely polyethylene (PE) at 57 % and polypropylene (PP) at 40 %. The results indicated elevated pollution levels on NDI, with sediment and water pollution load index measuring 1.32 and 2.01, respectively, signifying significant MP contamination in both compartments. Given the island's rare biodiversity, the vicinity of wastewater sewages, anthropogenic activities, and atmospheric deposition, could be behind MP contamination in water and sediments. No strong correlation between MP and physiochemical properties in water and PCA biplots showed their similar distribution, whereas MP abundances in sediment were significantly correlated with pH and organic matter (p&lt;0.05), signifying a pivotal role in transporting MPs in the aquatic environment. Two canonical variables were identified as important by canonical correlation analysis, demonstrating the interdependence of MP contamination at the sample sites. This research contributes to better insights into the occurrence of MP in the rare islands, which are ecosystems that have been hardly examined for this type of pollution, and it can report sustainable interventions to lessen MP inputs to the Bay of Bengal.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103841"},"PeriodicalIF":2.1,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428199","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":"Warming events and their causes at the Bering Sea section B in summer of 1999–2019","authors":"Jiankang Liu ,&nbsp;Hongxia Chen","doi":"10.1016/j.rsma.2024.103843","DOIUrl":"10.1016/j.rsma.2024.103843","url":null,"abstract":"<div><div>Based on hydrological data for the Bering Sea from 1999 to 2019 during the Chinese National Arctic Research Expeditions (CHINAREs), along with oceanographic and meteorological data from the National Centers for Environmental Information (NCEI) and the European Centre for Medium-Range Weather Forecasts (ECMWF), we investigated trends in summer at the Bering Sea section B over the past 20 years and their underlying causes. The results revealed a pronounced rise in temperature at the Bering Sea section B in 2003, 2014, 2016, 2018, and 2019, suggesting a shift towards a new phase of warmth starting in 2014. In warm years (2003, 2014, 2016, 2018, and 2019), the mean maximum temperature in the upper layer in the basin north of 57°N and on the continental shelf were roughly 2.7 °C, 2.6 °C higher than that in cold years (1999, 2008, 2010, and 2012). Additionally, the mean minimum temperature of the cold water in the middle layer in the basin was roughly 0.7 °C higher in the warm years compared to the cold years. This difference between the warm and cold years was evident in the heat content: the average heat content in the upper to middle layers in the basin north of 57°N and on the continental shelf were about 1.2 and 0.9 GJ/m² higher, respectively, in the warm years than the cold years. However, there was a modest warming trend in the basin south of 57°N, and the temperature in the mid-layer on the continental shelf showed year-to-year stability, in contrast to the significant warming observed elsewhere. Further study suggested that temperature fluctuation in the basin was closely tied to seasonal 2-m air temperature. In addition, the southern basin, divided at 57°N, experienced larger positive or negative anomalous wind stress curl compared to the northern basin. This discrepancy resulted in differing causes of temperature variation between the two regions. Temperature change in the upper layer on the continental shelf was attributed to an increase in cumulative net heat flux resulting from reduced sea ice, while the temperature in the middle layer on the continental shelf was limited by the enhanced density gradient between the upper and middle layer caused by melt ice, preventing significant warming. Overall, the thermal state for the Bering Sea section B was influenced by a combination of factors, including net heat flux, sea ice, and atmospheric conditions, contributing to the year-to-year variation characterized by alternating cold and warm regimes.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103843"},"PeriodicalIF":2.1,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357581","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":"Predicting storm surge extremes on the Southeast Brazilian Coast: Long-term projections with neural networks","authors":"Clarisse Lacerda Gomes Kaufmann ,&nbsp;Marcos Nicólas Gallo ,&nbsp;Ricardo De Camargo","doi":"10.1016/j.rsma.2024.103846","DOIUrl":"10.1016/j.rsma.2024.103846","url":null,"abstract":"<div><div>Extreme sea level events, resulting from the confluence of tides and storm surges, pose a significant threat to coastal populations and economies. The escalating risks associated with these events are exacerbated by climate change, manifesting in heightened storm intensity, increased frequency, and rising sea levels. Precise estimation of the probability of extreme storm surges is crucial for effective coastal management and adaptation. However, utilizing historical storm data is challenging due to data scarcity and the imperative to consider potential non-stationarity induced by climate change in predicting such events. This study addresses these challenges by introducing two neural network-based machine learning systems: a Multilayer Perceptron (MLP) and a Long Short-Term Memory (LSTM). Leveraging local and remote atmospheric and oceanic conditions, these systems project storm surges until 2060, incorporating climate projections. Trained and evaluated using sea level data from Imbetiba Port in Macaé, Rio de Janeiro, Brazil, the models utilize dynamic regionalization data from the RegCM4 and WW3 models, forced by HadGEM2-ES and MPI climate models. Both neural network models exhibited similar performance patterns, demonstrating high agreement in predicting storm surge heights with a 100-year return value, based on Imbetiba Port data. Projections utilized peaks-over-threshold (POT) methods, and extremes were calculated using a generalized Pareto distribution (GPD). Long-term projections indicated a 28 % increase (MLP ANN) and a substantial 70 % increase (LSTM RNN) in estimating extreme values, surpassing the observed storm surge of 0.67 m. Projected mean values were 0.86 m for the MLP network and 1.15 m for the LSTM network, providing valuable insights into the potential amplification of extreme sea level events in the studied region.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103846"},"PeriodicalIF":2.1,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428603","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":"Spatio-temporal distribution and source analysis of nutrients and antibiotics in the waters of a mariculture area in Haizhou Bay, Yellow Sea","authors":"Liyuan Wang ,&nbsp;Wei Jin ,&nbsp;Siqi Xie ,&nbsp;Shuo Wang ,&nbsp;Ruilin Zhang ,&nbsp;Dong Xue ,&nbsp;Yangjun Chen ,&nbsp;Xinran He ,&nbsp;Zhihua Feng","doi":"10.1016/j.rsma.2024.103837","DOIUrl":"10.1016/j.rsma.2024.103837","url":null,"abstract":"<div><div>Due to the continuous expansion of China's urban areas, there has been a growing trend of discharging marine aquaculture tail water directly into the sea. This phenomenon has had a significant impact on the marine ecological environment.To determine the status of pollutant discharge from marine aquaculture tailwater and facilitate its treatment.This paper analyses the spatiotemporal distribution characteristics of nutrients and antibiotics in the pond culture mode of Penaeus monodon. The influent, tail water, and adjacent seawater of the aquaculture concentration area in the port industrial zone of Guanyun County, Lianyungang City were monitored. The study aims to explore potential correlations between the variables.The data indicates that nitrogen and phosphorus are the primary pollutants in the Lianyungang aquaculture sea area. In 2022, the average total nitrogen content was 104.475 mg/L, and the average total phosphorus content was 3.83 mg/L.Sulfanilamide and norethindrone antibiotics were found in the culture tailings. The residual content of sulfonamide antibiotics ranged from 0.6 to 33.4 ng/L, while the residual content of norethindrone antibiotics ranged from 0.15 to 1.0 ng/L.This paper analyses the monitoring data statistically to provide basic support for the protection of the marine ecological environment in Haizhou Bay. Additionally, to enhance the environmental management of China's coastal waters, it is necessary to formulate an environmental management policy for coastal waters and provide a scientific basis for the implementation of the total amount of pollutants discharged into the sea.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103837"},"PeriodicalIF":2.1,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322998","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":"Seasonal fluctuations in fatty acid profile and biochemical traits of edible deep-water shrimp Heterocarpus woodmasoni","authors":"A.P. Gayathri ,&nbsp;Rekha Devi Chakraborty ,&nbsp;Kajal Chakraborty ,&nbsp;Shubhajit Dhara ,&nbsp;Gyanranjan Dash","doi":"10.1016/j.rsma.2024.103817","DOIUrl":"10.1016/j.rsma.2024.103817","url":null,"abstract":"<div><div><em>Heterocarpus woodmasoni</em> is an edible deep-sea caridean shrimp that holds significant commercial importance and is sourced from the south-west coast of India in the Arabian Sea. In this research study, we extensively examined the biochemical, mineral and seasonal fatty acid compositions of <em>H. woodmasoni</em>. ANOVA tests, unveiled noteworthy disparities (p &lt; 0.05) in moisture, crude fat and protein content between male and female <em>H. woodmasoni</em>. In contrast, we observed no significant differences in ash, carbohydrate, and cholesterol levels. Regarding minerals, the prominent macro elements detected in <em>H. woodmasoni</em> included K, P, Na, Ca and Mg with Zinc (Zn) and manganese (Mn) emerging as the dominant micro elements followed by Copper (Cu) and Selenium (Se). Notably, these shrimp exhibited a well-balanced ratio of essential to non-essential amino acids. Within the n-6 series, linoleic acid (18:2n-6), dihomo-γ-linolenic acid (20:3n-6), and arachidonic acid (20:4n-6) were identified as the primary polyunsaturated fatty acids (PUFA), exhibiting distinct concentrations across sexes and seasons. Both male and female <em>H. woodmasoni</em> displayed lower atherogenicity and thrombogenicity indices, ranging between 0.4 and 0.6 and 0.2–0.4, respectively, indicating a favourable cardiovascular health profile. Principal component analysis resulted in a two-principal component model explaining 83.4 % and 67.3 % of the total data variance for amino acid and fatty acid indices, respectively. This comprehensive biochemical analysis of both male and female <em>H. woodmasoni</em> reaffirms the species' status as a valuable and healthful resource, characterized by its abundance of high-quality nutritional components.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103817"},"PeriodicalIF":2.1,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322995","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":"Macrobenthos community responses to tidal barrier in a sub-tropical river estuary: Insights for coastal management","authors":"Md. Riadul Jannah ,&nbsp;Debasish Saha ,&nbsp;Md. Maheen Mahmud Bappy ,&nbsp;As-Ad Ujjaman Nur ,&nbsp;Partho Banik ,&nbsp;Mohammed Fahad Albeshr ,&nbsp;Takaomi Arai ,&nbsp;M. Belal Hossain","doi":"10.1016/j.rsma.2024.103842","DOIUrl":"10.1016/j.rsma.2024.103842","url":null,"abstract":"<div><div>Understanding the impacts of tidal barriers on macrobenthos is essential for comprehending anthropogenic influences on coastal ecosystems and biodiversity. This study aimed to address two primary questions: firstly, whether there are differences in macrobenthos abundance and diversity between the protected (CPA) and non-protected areas (CNPA) characterized by the tidal barrier, and secondly, whether the environmental factors associated with tidal barriers influence the macrobenthos community structure. Samples collected from CPA and CNPA sites from a subtropical river-estuary revealed the presence of 16 taxa of soft-bottom invertebrates, with a predominant presence of Ampeliscidae, Capitellidae, Glyceridae, Oligochaeta, Mysidae, Mytilidae, Naticidae, Portunidae, and Insecta. Significant differences (p &lt; 0.05) in salinity and conductivity were observed between CPA and CNPA. In the CPA area, the average temperature was 23.21°C, dissolved oxygen was 4.81 mg/L, and pH was 7.91, all of which were higher compared to CNPA.Macrobenthos abundance was higher in CNPA (1506 ± 688 ind.m⁻²) compared to CPA (1330 ± 611 ind.m⁻²) (p &lt; 0.05) with distinct dominance patterns of Polychaeta and Malacostraca. CNPA showed lower species dominance index (0.10–0.24), higher species diversity index (1.52–2.38), slightly higher Margalef`s index (from 0.63 to 1.6), and lower Shannon Index (from 0.69 to 0.85) indicating a more balanced community structure with a more diverse assemblage of species than CPA and a moderately polluted area. Hierarchical cluster analysis (HCA), Non-metric multidimensional scaling (nMDS) analysis, and Canonical Correspondence Analysis (CCA) indicated that the tidal barrier negatively impacted the macrobenthic families. The findings indicated the influencing effect of the breakwater defensive system on the macrobenthos assemblage at the estuary and informed policymakers and environmental scientists to develop environment-friendly breakwater defense systems.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103842"},"PeriodicalIF":2.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428198","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":"Overall evaluation of microplastic exposure in oysters (Crassostrea gigas) in coastal areas of Viet Nam","authors":"Xuan Thanh Thao Le ,&nbsp;Viet M. Trinh ,&nbsp;Duy Thanh Nguyen ,&nbsp;Manh Van Do","doi":"10.1016/j.rsma.2024.103840","DOIUrl":"10.1016/j.rsma.2024.103840","url":null,"abstract":"<div><div>This study aimed to evaluate the presence of microplastics (MPs) in oysters (<em>Crassostrea gigas</em>) across the coastal area of Vietnam. Oyster samples were collected from sixteen coastal provinces across Vietnam, from North to South. Visual and chemical verification of microplastics were performed by the micro Fourier transform infrared (μFTIR) method using the Nicolet iN10 MX Infrared Imaging Microscope. The average concentration of MPs was 1.18 ± 0.59 MPs/g of wet weight or 11.55 ± 4.83 MPs/individual. Fragments were the dominant shape of MPs, followed by fibers and beads, corresponding to 62.40 %, 37.10 %, and 0.50 %, respectively. The detected MPs varied in size from 20 to 998 µm with an average size of 112 ± 125 µm. The majority of MPs size was smaller than 100 µm, accounting for 65.39 %. A total of twelve polymers were detected, of which Polyethylene terephthalate (PET) and high-density polyethylene (HDPE) were the two dominant types, accounting for 42.26 % and 31.95 %, respectively. This study provides valuable insights into the presence and potential risks posed by MPs from the oyster (<em>C.gigas</em>) in coastal areas of Vietnam.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103840"},"PeriodicalIF":2.1,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319483","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":"Numerical investigations on seasonal variation of waves in the Cat Ba – Ha Long coastal area (Vietnam) in 2021","authors":"Minh Hai Nguyen ,&nbsp;Duy Vinh Vu ,&nbsp;Duc Thinh Nguyen ,&nbsp;Thanh Duong Nguyen","doi":"10.1016/j.rsma.2024.103828","DOIUrl":"10.1016/j.rsma.2024.103828","url":null,"abstract":"<div><div>The Delft3D model, equipped with a high-resolution grid, was employed to simulate wave conditions in the Cat Ba-Ha Long coastal area by combining hydrodynamic and wave modules. The model was calibrated and validated using the measurement data at Hon Dau station, and demonstrated a good match between the data and simulation results (NSE = 0.55–0.69). In 2021, the simulation results revealed that wind waves are the primary type of waves in the Cat Ba-Ha Long coastal area. The lowest monthly-averaged wave heights were found in the January-February period (about 0.4 m), followed by a gradual increase, reaching its peak in the May-June period (1.18 m), and subsequent fluctuations throughout the rest. Wave heights ranging from 0.2 to 0.6 m were frequently observed in the majority of months, including January, February, March, April, July, November, and December. The wave heights ranging 0.6–0.8 m are primarily recorded during the months of August and October. The occurrence of high-altitude waves of 1.0–2.0 m in height was predominantly seen during the months of May and June. The areas with elevated wave heights (&gt;1 m) are primarily located in the southern part of Cat Ba and the southeast of Ha Long, accounting for around 30 % of the region. The areas characterized by gentle undulations are primarily concentrated in Ha Long Bay, where wave heights range from 0.2 to 0.6 m, accounting for 70 % of the region. The variations in wave height primarily result from the southern region of Cat Ba and the southeastern area of Ha Long Bay, which are more exposed and less influenced by the topography, hence facilitating the development of wind waves. Simultaneously, the Ha Long area is encircled by small islands, characterized by shallow depths, with waves that are diffused in direction and exhibit modest heights. In this area, the dominant wave directions are south-southeast (32.9 %) and east (29.7 %).</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"79 ","pages":"Article 103828"},"PeriodicalIF":2.1,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326843","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}