This study focuses on developing a comprehensive and reliable wind and wave hindcast for the Oman Sea and Arabian Sea, spanning a significant 45-year period (1979–2024). The objective is to capture the intricate wind and wave climate of the region, characterized by distinct monsoon cycles and occasional tropical cyclones. The availability of extensive wave data over four decades would be an irreplaceable tool for researchers and engineers, enabling improved accuracy in extreme value analysis, sediment transport studies, and wave-induced current simulations. Despite limited field observations, all available measured data within the region were collected, analyzed for configuration of the models and utilized for model calibration and validation. The hindcast data was generated using the Weather Research and Forecasting (WRF) model for winds and WAVEWATCH III (WW3) model for waves, and evaluated against observational and measured wind and wave parameters. A comprehensive statistical analysis of the hindcast model's performance reveals adequate agreement with measured data, as evidenced by root mean square errors (RMSEs) of 1.23 m/s for wind speeds and 0.37 m for significant wave heights in average. These results underscore the model's reliability for research and engineering applications, particularly in the Arabian Sea, with a focus on the northern coastlines of the Oman Sea. The specific model configuration employed in this study holds significant potential for future investigations in the northern Indian Ocean, offering a valuable tool for understanding and predicting climatical conditions in this region.
{"title":"A 45-year updating wind and wave hindcast over the Oman Sea and the Arabian Sea","authors":"Morteza Jedari Attari , Aref Farhangmehr , Arash Bakhtiari , Edris Delkhosh , Fatemeh Ameri , Ebrahim Hamidian Jahromi , Sarmad Ghader , S. Abbas Haghshenas","doi":"10.1016/j.rsma.2024.103882","DOIUrl":"10.1016/j.rsma.2024.103882","url":null,"abstract":"<div><div>This study focuses on developing a comprehensive and reliable wind and wave hindcast for the Oman Sea and Arabian Sea, spanning a significant 45-year period (1979–2024). The objective is to capture the intricate wind and wave climate of the region, characterized by distinct monsoon cycles and occasional tropical cyclones. The availability of extensive wave data over four decades would be an irreplaceable tool for researchers and engineers, enabling improved accuracy in extreme value analysis, sediment transport studies, and wave-induced current simulations. Despite limited field observations, all available measured data within the region were collected, analyzed for configuration of the models and utilized for model calibration and validation. The hindcast data was generated using the Weather Research and Forecasting (WRF) model for winds and WAVEWATCH III (WW3) model for waves, and evaluated against observational and measured wind and wave parameters. A comprehensive statistical analysis of the hindcast model's performance reveals adequate agreement with measured data, as evidenced by root mean square errors (RMSEs) of 1.23 m/s for wind speeds and 0.37 m for significant wave heights in average. These results underscore the model's reliability for research and engineering applications, particularly in the Arabian Sea, with a focus on the northern coastlines of the Oman Sea. The specific model configuration employed in this study holds significant potential for future investigations in the northern Indian Ocean, offering a valuable tool for understanding and predicting climatical conditions in this region.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554303","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}
Pub Date : 2024-10-19DOI: 10.1016/j.rsma.2024.103874
Vu Duy Vinh , Nguyen Minh Hai , Saheed Puthan Purayil , Geneviève Lacroix , Nguyen Thanh Duong
The COHERENS model is used to investigate the temporal and spatial variation of the coastal currents in 2021 at the Cat Ba - Ha Long, northern Vietnam. The findings indicate that tidal oscillation has a notable impact on the current fields in short-term variations (hours to days). Meanwhile, the wind field and river discharge are the decisive factors affecting the seasonal variation of the current fields in Cat Ba - Ha Long coastal area. Furthermore, the characteristics of residual currents are significantly affected by river discharges and wind patterns, which vary across different months and seasons. During the southwest monsoon season (May to August), the residual currents have a prevailing direction towards the sea, from the west and south-southwest towards the east and north-northeast, reaching maximum speeds of approximately 0.1–0.15 m/s. Conversely, in the transitional and northeast monsoon seasons, the directions of residual currents are from the east-northeast to the west-southwest, with peak speed up to 0.2–0.25 m/s. Notably, the residual currents in the bottom and surface layers in the eastern-southwestern area of Cat Ba Island and the north of Ha Long Bay are in opposite directions.
COHERENS 模型用于研究 2021 年越南北部 Cat Ba - Ha Long 沿岸海流的时空变化。研究结果表明，潮汐振荡对海流场的短期变化（数小时至数天）有显著影响。同时，风场和河流排水量是影响 Cat Ba - Ha Long 沿岸地区海流场季节变化的决定性因素。此外，不同月份和季节的河流排水量和风力模式对剩余海流的特征有很大影响。在西南季风季节（5 月至 8 月），残流的主要流向是向海，从西部和西南部流向东部和 东北部，最大流速约为 0.1-0.15 米/秒。相反，在过渡季风季节和东北季风季节，残余流的方向为东北偏东至西南偏西，最高流速可达 0.2-0.25 米/秒。值得注意的是，猫巴岛东西南部和下龙湾北部底层和表层的残余流方向相反。
{"title":"Seasonal variation of coastal currents and residual currents in the CAT BA – HA long coastal area (VIET NAM): Results of coherens model","authors":"Vu Duy Vinh , Nguyen Minh Hai , Saheed Puthan Purayil , Geneviève Lacroix , Nguyen Thanh Duong","doi":"10.1016/j.rsma.2024.103874","DOIUrl":"10.1016/j.rsma.2024.103874","url":null,"abstract":"<div><div>The COHERENS model is used to investigate the temporal and spatial variation of the coastal currents in 2021 at the Cat Ba - Ha Long, northern Vietnam. The findings indicate that tidal oscillation has a notable impact on the current fields in short-term variations (hours to days). Meanwhile, the wind field and river discharge are the decisive factors affecting the seasonal variation of the current fields in Cat Ba - Ha Long coastal area. Furthermore, the characteristics of residual currents are significantly affected by river discharges and wind patterns, which vary across different months and seasons. During the southwest monsoon season (May to August), the residual currents have a prevailing direction towards the sea, from the west and south-southwest towards the east and north-northeast, reaching maximum speeds of approximately 0.1–0.15 m/s. Conversely, in the transitional and northeast monsoon seasons, the directions of residual currents are from the east-northeast to the west-southwest, with peak speed up to 0.2–0.25 m/s. Notably, the residual currents in the bottom and surface layers in the eastern-southwestern area of Cat Ba Island and the north of Ha Long Bay are in opposite directions.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528573","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}
Pub Date : 2024-10-19DOI: 10.1016/j.rsma.2024.103883
Roberta Rodrigues das Chagas Pereira , Renan Ribeiro e Silva , Vinicius Peruzzi de Oliveira , Jean Louis Valentin
Marine heat waves are considered a threat to the cultivation of commercially important species because exposure to thermal stress may lead to mass mortalities of organisms. Investigating the upper thermal limits of marine species and their capacity for shifting these limits can contribute to securing the sustainability of aquaculture activities as exposure to heat extremes is increasing in frequency. The scallop Nodipecten nodosus and oyster Magallana [Crassostrea] gigas are two bivalve species commercially farmed in Brazil and production of spat is undertaken mainly at two hatcheries located in different regions subjected to distinct climate and seawater temperature conditions over the year. This study investigated the upper thermal tolerance of populations of N. nodosus and M. gigas sourced from temperate and tropical farming areas. Groups of N. nodosus and M. gigas farmed under warmer temperature regimes exhibited lower mortality rates when exposed to elevated temperatures compared to groups sourced from cooler waters and consequently displayed higher values of lethal temperature 50 (LT50). N. nodosus exhibited superior thermal tolerance than was previously known, however, commercial cultivation of this species is still at risk of mass mortalities depending on the duration and intensity of forecasted heat waves in both cultivation regions. M. gigas showed a high capacity to endure acute thermal stress at the resting stage of the reproductive cycle. To enhance the aquaculture sector's resilience to climate change, we recommend the development of cultivation methods that account for marine and atmospheric heat wave events, alongside continuous monitoring of abiotic factors at farming sites.
{"title":"Forecasting the impact of marine heat waves on farmed bivalves Nodipecten nodosus and Magallana gigas","authors":"Roberta Rodrigues das Chagas Pereira , Renan Ribeiro e Silva , Vinicius Peruzzi de Oliveira , Jean Louis Valentin","doi":"10.1016/j.rsma.2024.103883","DOIUrl":"10.1016/j.rsma.2024.103883","url":null,"abstract":"<div><div>Marine heat waves are considered a threat to the cultivation of commercially important species because exposure to thermal stress may lead to mass mortalities of organisms. Investigating the upper thermal limits of marine species and their capacity for shifting these limits can contribute to securing the sustainability of aquaculture activities as exposure to heat extremes is increasing in frequency. The scallop <em>Nodipecten nodosus</em> and oyster <em>Magallana</em> [<em>Crassostrea</em>] <em>gigas</em> are two bivalve species commercially farmed in Brazil and production of spat is undertaken mainly at two hatcheries located in different regions subjected to distinct climate and seawater temperature conditions over the year. This study investigated the upper thermal tolerance of populations of <em>N. nodosus</em> and <em>M. gigas</em> sourced from temperate and tropical farming areas. Groups of <em>N. nodosus</em> and <em>M. gigas</em> farmed under warmer temperature regimes exhibited lower mortality rates when exposed to elevated temperatures compared to groups sourced from cooler waters and consequently displayed higher values of lethal temperature 50 (LT50). <em>N. nodosus</em> exhibited superior thermal tolerance than was previously known, however, commercial cultivation of this species is still at risk of mass mortalities depending on the duration and intensity of forecasted heat waves in both cultivation regions. <em>M. gigas</em> showed a high capacity to endure acute thermal stress at the resting stage of the reproductive cycle. To enhance the aquaculture sector's resilience to climate change, we recommend the development of cultivation methods that account for marine and atmospheric heat wave events, alongside continuous monitoring of abiotic factors at farming sites.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554302","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}
The ability of planktonic and neustonic organisms to feed on microplastics and subsequently transfer it through the marine food web has been studied extensively. However, there are no studies on microplastic in the Northwestern Black Sea. The present study assesses the diversity and spatial distribution of microplastics and ichthyoplankton in two surface layers: 0–5 cm (neuston surface layer; NL) and 5–20 cm (hyponeuston layer; HL). The sampling was undertaken in June 2020 – October 2021 in the coastal (CW) and open (OW) waters of the Northwestern Black Sea. Microplastics was observed at all studied sites and was composed of fibres (75 %) and fragments (25 %). Black and red fibres were the most abundant type of fibre, and black particles dominated the fragments. Four types of polymers were identified by Raman spectroscopy: polyethylene, polyester, polyurethane, polypropylene. The concentration of microplastics near the coast significantly exceeded that of open waters; the average microplastics concentration in the CW reached 136±74 (±SE) and 46±30 particles.m-3 in the NL and HL, respectively, whereas it reached 18±3 and 2±0.8 particles.m-3 in the NL and HL of the OW, respectively. In the NL, ichthyoplankton was found only at 31 % of the sites, and at only 24 % of sites in the HL. In total, 6 species of fish were recorded. The most abundant species was the European anchovy, one of the main commercial species in the Black Sea. The ratio of microplastics to ichthyoplankton was 0.34 (or 1:2.87) for both layers, where ichthyoplankton was present. When considering all studied sites, the ratio of microplastics to ichthyoplankton was 1.07 (or 1:0.93). As ichthyoplankton is an ephemeral component of the neuston community, but microplastics is omnipresent, we may consider that comparable densities of microplastics:ichthyoplankton favour their interrelation, negative effect, and transport through the food web.
{"title":"Microplastic and ichthyoplankton in the Ukrainian waters of the Black Sea","authors":"A.O. Snigirova , R.V. Mihas , S.O. Khutornoi , A.K. Vinogradov , Ye.I Gazyetov , J.R. Gascooke , S.M. Snigirov , S.C. Leterme","doi":"10.1016/j.rsma.2024.103884","DOIUrl":"10.1016/j.rsma.2024.103884","url":null,"abstract":"<div><div>The ability of planktonic and neustonic organisms to feed on microplastics and subsequently transfer it through the marine food web has been studied extensively. However, there are no studies on microplastic in the Northwestern Black Sea. The present study assesses the diversity and spatial distribution of microplastics and ichthyoplankton in two surface layers: 0–5 cm (neuston surface layer; NL) and 5–20 cm (hyponeuston layer; HL). The sampling was undertaken in June 2020 – October 2021 in the coastal (CW) and open (OW) waters of the Northwestern Black Sea. Microplastics was observed at all studied sites and was composed of fibres (75 %) and fragments (25 %). Black and red fibres were the most abundant type of fibre, and black particles dominated the fragments. Four types of polymers were identified by Raman spectroscopy: polyethylene, polyester, polyurethane, polypropylene. The concentration of microplastics near the coast significantly exceeded that of open waters; the average microplastics concentration in the CW reached 136±74 (±SE) and 46±30 particles.m<sup>-3</sup> in the NL and HL, respectively, whereas it reached 18±3 and 2±0.8 particles.m<sup>-3</sup> in the NL and HL of the OW, respectively. In the NL, ichthyoplankton was found only at 31 % of the sites, and at only 24 % of sites in the HL. In total, 6 species of fish were recorded. The most abundant species was the European anchovy, one of the main commercial species in the Black Sea. The ratio of microplastics to ichthyoplankton was 0.34 (or 1:2.87) for both layers, where ichthyoplankton was present. When considering all studied sites, the ratio of microplastics to ichthyoplankton was 1.07 (or 1:0.93). As ichthyoplankton is an ephemeral component of the neuston community, but microplastics is omnipresent, we may consider that comparable densities of microplastics:ichthyoplankton favour their interrelation, negative effect, and transport through the food web.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528575","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}
Pub Date : 2024-10-19DOI: 10.1016/j.rsma.2024.103880
Pensiri Akkajit , Md Eshrat E. Alahi , Arsanchai Sukkuea
Microplastics (MPs) pose a growing environmental threat due to their accumulation and ecological impact. This study aimed to overcome the limitations of traditional methods, which are labor-intensive and prone to errors, in order to detect and classify MPs more effectively against marine pollution. We assessed object detection and classification algorithms: YOLOv8x, YOLOv8x (with augmentation), YOLOv8m, YOLOv8m (with augmentation), YOLO-NAS-L, and YOLO-NAS-L (with augmentation), focusing on four MP morphologies: fiber, film, fragment, and pellet. The dataset was divided into 80 % for training (320 images), 20 % for validation (80 images), and a fixed testing set of 200 images. The images were augmented using rotation (+25° and −25°), resizing (640 × 640 pixels), zooming, auto-orient strips, flipping, and noise application. This expanded the training set by 300 %, resulting in a total of 1400 images. The YOLOv8 models, particularly when augmented, outperformed the YOLO-NAS-L models in both [email protected] and precision across all categories. Notably, YOLOv8x achieved an exceptional 99.0 % in both precision and [email protected], with an impressive inference time of only 1.2 ms per image. The implementation of augmentation significantly enhanced detection accuracy across various models. With augmentation, YOLOv8x, YOLOv8m, and YOLO-NAS-L consistently achieved precision levels exceeding 99 %. For real-time applications, YOLOv8x was selected for the web application designed to detect and classify MPs, providing a more accurate and efficient solution compared to conventional methods. This model serves as a valuable resource for researchers in MP analysis, improving accuracy and reliability in environmental monitoring.
{"title":"Enhanced detection and classification of microplastics in marine environments using deep learning","authors":"Pensiri Akkajit , Md Eshrat E. Alahi , Arsanchai Sukkuea","doi":"10.1016/j.rsma.2024.103880","DOIUrl":"10.1016/j.rsma.2024.103880","url":null,"abstract":"<div><div>Microplastics (MPs) pose a growing environmental threat due to their accumulation and ecological impact. This study aimed to overcome the limitations of traditional methods, which are labor-intensive and prone to errors, in order to detect and classify MPs more effectively against marine pollution. We assessed object detection and classification algorithms: YOLOv8x, YOLOv8x (with augmentation), YOLOv8m, YOLOv8m (with augmentation), YOLO-NAS-L, and YOLO-NAS-L (with augmentation), focusing on four MP morphologies: fiber, film, fragment, and pellet. The dataset was divided into 80 % for training (320 images), 20 % for validation (80 images), and a fixed testing set of 200 images. The images were augmented using rotation (+25° and −25°), resizing (640 × 640 pixels), zooming, auto-orient strips, flipping, and noise application. This expanded the training set by 300 %, resulting in a total of 1400 images. The YOLOv8 models, particularly when augmented, outperformed the YOLO-NAS-L models in both [email protected] and precision across all categories. Notably, YOLOv8x achieved an exceptional 99.0 % in both precision and [email protected], with an impressive inference time of only 1.2 ms per image. The implementation of augmentation significantly enhanced detection accuracy across various models. With augmentation, YOLOv8x, YOLOv8m, and YOLO-NAS-L consistently achieved precision levels exceeding 99 %. For real-time applications, YOLOv8x was selected for the web application designed to detect and classify MPs, providing a more accurate and efficient solution compared to conventional methods. This model serves as a valuable resource for researchers in MP analysis, improving accuracy and reliability in environmental monitoring.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528037","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}
Pub Date : 2024-10-18DOI: 10.1016/j.rsma.2024.103857
Muhammad Abrar , Dietriech G. Bengen , Neviaty P. Zamani , Suharsono , Giyanto , Risandi D. Putra , Ni Wayan. P. Sari , Rikoh M. Siringoringo , Tri A. Hadi , Rizkie S. Utama , Bambang Hermanto , Ucu Y. Arbi , Frensly D. Hukom , La Ode Alifatri , Sam Wouthuyzen , Peter Harrison
Coral community structure exhibits variation at each stage of its life cycle, but the spatial distribution of corals in early life stages, including from juvenile to adult stages, is not well understood, especially at a larger scale. Spatially, our study compared the genera richness and abundance of juvenile and sub/adult corals at 9 locations and 83 sites along the coast and small islands of western and eastern Sumatra, Indonesia. Field surveys were conducted by recording juvenile corals measuring ≤5 cm in diameter in 1 ×1 m quadrat transects with 6 times randomly at each site, while those with diameters greater than 5–10 cm were categorized as transitional to sub/adult corals. A total of 52 genera from 16 juvenile coral families were recorded and identified, which is higher than the sub/adult level, where a total of 40 genera from 14 families were found. The most common genera came from the Acroporidae (23.0 %), Merulinidae (18.7 %), and Agariciidae (12.7 %) families. The genera richness at the juvenile stage showed variation between locations and regions in western and eastern Sumatra, except between locations in the eastern region, while at the sub/adult stage there was no variation between the western and eastern regions. Abundance at the juvenile stage also showed variation between locations, but did not differ between the western and eastern regions and at locations in the eastern region. In contrast, coral abundance at the sub/adult stage showed differences between locations and regions, but did not show variation at locations in the eastern region. The abundance of juvenile corals was influenced by live coral cover, the presence of herbivorous and corallivorous reef fish, and hard substrates of dead coral, limited to sandy or muddy bottoms and coral rubble. Genera richness was also influenced by live coral cover, but limited by sandy and rubble reef habitats, the cover of other biota such as soft corals, and the presence of herbivorous fish. Variations in water conditions and geomorphological forms between locations on the west and east sides of Sumatra impacted the diversity and abundance of corals in the early stages of life, affecting their success in becoming adult colonies. The transition from juvenile to sub/adult corals emerged as a critical phase in the early life stages of coral for population maintenance and sustainability.
{"title":"Spatial distribution of juvenile corals (Scleractinia) in the coastal and small islands of Sumatra, Indonesia","authors":"Muhammad Abrar , Dietriech G. Bengen , Neviaty P. Zamani , Suharsono , Giyanto , Risandi D. Putra , Ni Wayan. P. Sari , Rikoh M. Siringoringo , Tri A. Hadi , Rizkie S. Utama , Bambang Hermanto , Ucu Y. Arbi , Frensly D. Hukom , La Ode Alifatri , Sam Wouthuyzen , Peter Harrison","doi":"10.1016/j.rsma.2024.103857","DOIUrl":"10.1016/j.rsma.2024.103857","url":null,"abstract":"<div><div>Coral community structure exhibits variation at each stage of its life cycle, but the spatial distribution of corals in early life stages, including from juvenile to adult stages, is not well understood, especially at a larger scale. Spatially, our study compared the genera richness and abundance of juvenile and sub/adult corals at 9 locations and 83 sites along the coast and small islands of western and eastern Sumatra, Indonesia. Field surveys were conducted by recording juvenile corals measuring ≤5 cm in diameter in 1 ×1 m quadrat transects with 6 times randomly at each site, while those with diameters greater than 5–10 cm were categorized as transitional to sub/adult corals. A total of 52 genera from 16 juvenile coral families were recorded and identified, which is higher than the sub/adult level, where a total of 40 genera from 14 families were found. The most common genera came from the Acroporidae (23.0 %), Merulinidae (18.7 %), and Agariciidae (12.7 %) families. The genera richness at the juvenile stage showed variation between locations and regions in western and eastern Sumatra, except between locations in the eastern region, while at the sub/adult stage there was no variation between the western and eastern regions. Abundance at the juvenile stage also showed variation between locations, but did not differ between the western and eastern regions and at locations in the eastern region. In contrast, coral abundance at the sub/adult stage showed differences between locations and regions, but did not show variation at locations in the eastern region. The abundance of juvenile corals was influenced by live coral cover, the presence of herbivorous and corallivorous reef fish, and hard substrates of dead coral, limited to sandy or muddy bottoms and coral rubble. Genera richness was also influenced by live coral cover, but limited by sandy and rubble reef habitats, the cover of other biota such as soft corals, and the presence of herbivorous fish. Variations in water conditions and geomorphological forms between locations on the west and east sides of Sumatra impacted the diversity and abundance of corals in the early stages of life, affecting their success in becoming adult colonies. The transition from juvenile to sub/adult corals emerged as a critical phase in the early life stages of coral for population maintenance and sustainability.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528038","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}
Pub Date : 2024-10-18DOI: 10.1016/j.rsma.2024.103875
Puneet Kumar Mishra , R. Mani Murali , S. Santhosh Kumar , Jaya Kumar Seelam , Sila Tripati
Coastal formations, such as sandbars, play a vital role in shaping the environment and maintaining local and regional coastal morphology. This study deals with two noteworthy sandbars, namely Aguada and Reis Magos which are in the Mandovi estuary of the Goa region in the central west coast of India. They have attracted great attention because of their dynamics and their role in shaping the adjoining coast. This study employs a comprehensive approach, incorporating in-situ observations and remote sensing methods, to investigate the mechanisms underlying the emergence and dissipation of these sandbars and their linkage with adjoining navigational channels and coastline. During the intense wave conditions of the southwest monsoon (June to September), these sandbars undergo a temporary phase of dispersion. This phenomenon results in the accumulation of sand from both the sandbars and the neighbouring Miramar beach within the navigational channel. As a consequence, it obstructs maritime traffic and forms a unified shallow bar, obstructing maritime navigation in the area. However, following the attenuation of monsoon waves in October to November, the sandbar and beach initiate a gradual replenishment process, aimed at compensating for the sediment loss incurred during the monsoon season. This recurring trend has demonstrated persistent characteristics over an extended period. The presence of the sandbar may pose navigational challenges for large barges, cruise ships, and fishing boats but on the other hand, it serves as an effective barrier against incoming high-energy waves into the inner parts of the Mandovi estuary. Results revealed notable variations in the extent of the sandbar over the study period. The maximum recorded extent of the sandbar was 82.48 ha and 32.59 ha on May 04, 2021, while the minimum extent was measured at 36.68 ha and 7.14 ha on February 14, 2019, for Reis Magos and Aguada bar respectively. The sandbar promotes a calm environment along the shoreline and reduces erosion susceptibility by dissipating the wave energy before reaching the riverbanks. The absence of this protective sandbar would have significantly impacted the parts of the Goa region. Notably, the maximum erosion of 107 m was observed at the right bank of the estuary, while the maximum accretion of 141 m was recorded in the Caranzalem from 1975 to 2023. This study contributes valuable insights into the formation, dissipation, and environmental implications of sandbars within the estuary in Goa. The integration of in-situ observations and remote sensing data affords a comprehensive understanding of sandbar dynamics, highlighting the essential role that they play in coastal protection, navigation and the preservation of the local environment.
{"title":"Investigating the evolution of sand bars and natural channel formation in the Mandovi estuary along the central west coast of India","authors":"Puneet Kumar Mishra , R. Mani Murali , S. Santhosh Kumar , Jaya Kumar Seelam , Sila Tripati","doi":"10.1016/j.rsma.2024.103875","DOIUrl":"10.1016/j.rsma.2024.103875","url":null,"abstract":"<div><div>Coastal formations, such as sandbars, play a vital role in shaping the environment and maintaining local and regional coastal morphology. This study deals with two noteworthy sandbars, namely Aguada and Reis Magos which are in the Mandovi estuary of the Goa region in the central west coast of India. They have attracted great attention because of their dynamics and their role in shaping the adjoining coast. This study employs a comprehensive approach, incorporating in-situ observations and remote sensing methods, to investigate the mechanisms underlying the emergence and dissipation of these sandbars and their linkage with adjoining navigational channels and coastline. During the intense wave conditions of the southwest monsoon (June to September), these sandbars undergo a temporary phase of dispersion. This phenomenon results in the accumulation of sand from both the sandbars and the neighbouring Miramar beach within the navigational channel. As a consequence, it obstructs maritime traffic and forms a unified shallow bar, obstructing maritime navigation in the area. However, following the attenuation of monsoon waves in October to November, the sandbar and beach initiate a gradual replenishment process, aimed at compensating for the sediment loss incurred during the monsoon season. This recurring trend has demonstrated persistent characteristics over an extended period. The presence of the sandbar may pose navigational challenges for large barges, cruise ships, and fishing boats but on the other hand, it serves as an effective barrier against incoming high-energy waves into the inner parts of the Mandovi estuary. Results revealed notable variations in the extent of the sandbar over the study period. The maximum recorded extent of the sandbar was 82.48 ha and 32.59 ha on May 04, 2021, while the minimum extent was measured at 36.68 ha and 7.14 ha on February 14, 2019, for Reis Magos and Aguada bar respectively. The sandbar promotes a calm environment along the shoreline and reduces erosion susceptibility by dissipating the wave energy before reaching the riverbanks. The absence of this protective sandbar would have significantly impacted the parts of the Goa region. Notably, the maximum erosion of 107 m was observed at the right bank of the estuary, while the maximum accretion of 141 m was recorded in the Caranzalem from 1975 to 2023. This study contributes valuable insights into the formation, dissipation, and environmental implications of sandbars within the estuary in Goa. The integration of in-situ observations and remote sensing data affords a comprehensive understanding of sandbar dynamics, highlighting the essential role that they play in coastal protection, navigation and the preservation of the local environment.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528035","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}
Pub Date : 2024-10-18DOI: 10.1016/j.rsma.2024.103881
Gency L. Guirhem-Helican, Cristy S. Acabado
Chlorophyll-a (Chl-a) is often used as a substitute for marine primary productivity measurements in fishing grounds. Panay Gulf stands as one of the Philippines’ vital fishing grounds, however, there are limited studies on its Chl-a interannual and seasonal variability. As such, this study used remotely sensed Chl-a data from 2017 to 2023 to assess areas with high Chl-a concentrations, and high primary productivity. The relationship of Chl-a to location, month, year, and water current variables was evaluated using a generalized additive model (GAM). Chl-a value of >10 mg.m−3 was observed approximately <6.5, <2 km, and <1 km from the coast of Negros, Guimaras, and Panay Island respectively. During the Northeast Monsoon, short-term offshore pockets with elevated Chl-a levels were noted 13–24 km from the coast of Binalbagan, Negros Occidental that function as brief feeding grounds for marine organisms. These Chl-a pockets originated from the coast of Negros Occidental and were advected by the water currents to the center of the gulf. Furthermore, 2017 and 2022 have the highest Chl-a value in Panay Gulf, coinciding with the region's seasonal high fisheries production. Major peaks were regularly observed in January and December when offshore Chl-a pockets were present. A minor peak was observed in July corresponding to the Southwest Monsoon season and attributed to summer blooms. The lowest Chl-a values were observed in September during the transition months. Furthermore, high Chl-a values were found in low current speed near the coast and water moving west and southwest during the Northeast Monsoon. This study is the first to evaluate the Chl-a dynamics in Panay Gulf, which is valuable information to understand the influence of the environment on marine productivity. This study may prompt the local government to intensify monitoring efforts and coastal protection in these valuable areas within the municipal waters.
{"title":"Chlorophyll-a interannual and seasonal variability in Panay Gulf: Identification of potential productive sites in the municipal waters and offshore blooms aided by water currents","authors":"Gency L. Guirhem-Helican, Cristy S. Acabado","doi":"10.1016/j.rsma.2024.103881","DOIUrl":"10.1016/j.rsma.2024.103881","url":null,"abstract":"<div><div>Chlorophyll-a (Chl-a) is often used as a substitute for marine primary productivity measurements in fishing grounds. Panay Gulf stands as one of the Philippines’ vital fishing grounds, however, there are limited studies on its Chl-a interannual and seasonal variability. As such, this study used remotely sensed Chl-a data from 2017 to 2023 to assess areas with high Chl-a concentrations, and high primary productivity. The relationship of Chl-a to location, month, year, and water current variables was evaluated using a generalized additive model (GAM). Chl-a value of >10 mg.m<sup>−3</sup> was observed approximately <6.5, <2 km, and <1 km from the coast of Negros, Guimaras, and Panay Island respectively. During the Northeast Monsoon, short-term offshore pockets with elevated Chl-a levels were noted 13–24 km from the coast of Binalbagan, Negros Occidental that function as brief feeding grounds for marine organisms. These Chl-a pockets originated from the coast of Negros Occidental and were advected by the water currents to the center of the gulf. Furthermore, 2017 and 2022 have the highest Chl-a value in Panay Gulf, coinciding with the region's seasonal high fisheries production. Major peaks were regularly observed in January and December when offshore Chl-a pockets were present. A minor peak was observed in July corresponding to the Southwest Monsoon season and attributed to summer blooms. The lowest Chl-a values were observed in September during the transition months. Furthermore, high Chl-a values were found in low current speed near the coast and water moving west and southwest during the Northeast Monsoon. This study is the first to evaluate the Chl-a dynamics in Panay Gulf, which is valuable information to understand the influence of the environment on marine productivity. This study may prompt the local government to intensify monitoring efforts and coastal protection in these valuable areas within the municipal waters.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528576","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}
Rare earth elements (REEs) are emerging environmental contaminants that pose a threat to ecosystem health. Their accumulation in sediments and potential release into the water column can raise concerns. Understanding the factors influencing REE mobility is crucial. Furthermore, our knowledge of the risk and occurrence of REEs in wetland ecosystems is inadequate. This study investigated REE release from sediments under varying redox conditions (Eh). The different redox potential values were adjusted using a photoanode (Ti/TiO2) and a cathode (graphite). Also, to recognize the relationship between REEs and other parameters, Pearson correlation (PC) was employed. Results showed that increasing Eh initially enhanced REE mobility (until around 300 mV), followed by a decrease at higher Eh values. Among the studied REEs, lanthanum (La), cerium (Ce), and gadolinium (Gd) exhibited the highest release potential into water, with measured concentrations reaching 199.4, 93.1, and 31.2 µg/L, respectively. Moreover, according to several eco-geochemical risk assessment indices, the sediment of the study area was classified as minimal contamination. Statistical analyses revealed that Eh indirectly affects REE mobility by influencing linked changes in pH, salinity, and iron-manganese (Fe-Mn) chemistry, which in turn impacts REE solubility and release from sediments.
{"title":"Distribution, and mobility of rare earth elements in surface sediment of Gomishan Wetland","authors":"Fatemeh Kachoueiyan , Yusef Mehdizadeh , Armin Rajabi , Gabriel Enrique De-la-Torre , Abdolreza Karbassi","doi":"10.1016/j.rsma.2024.103879","DOIUrl":"10.1016/j.rsma.2024.103879","url":null,"abstract":"<div><div>Rare earth elements (REEs) are emerging environmental contaminants that pose a threat to ecosystem health. Their accumulation in sediments and potential release into the water column can raise concerns. Understanding the factors influencing REE mobility is crucial. Furthermore, our knowledge of the risk and occurrence of REEs in wetland ecosystems is inadequate. This study investigated REE release from sediments under varying redox conditions (Eh). The different redox potential values were adjusted using a photoanode (Ti/TiO<sub>2</sub>) and a cathode (graphite). Also, to recognize the relationship between REEs and other parameters, Pearson correlation (PC) was employed. Results showed that increasing Eh initially enhanced REE mobility (until around 300 mV), followed by a decrease at higher Eh values. Among the studied REEs, lanthanum (La), cerium (Ce), and gadolinium (Gd) exhibited the highest release potential into water, with measured concentrations reaching 199.4, 93.1, and 31.2 µg/L, respectively. Moreover, according to several eco-geochemical risk assessment indices, the sediment of the study area was classified as minimal contamination. Statistical analyses revealed that Eh indirectly affects REE mobility by influencing linked changes in pH, salinity, and iron-manganese (Fe-Mn) chemistry, which in turn impacts REE solubility and release from sediments.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528033","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}
Crude oil leakage occurs frequently during exploration, storage, transportation, production, and consumption. The spilling of crude oil has the potential to contaminate the ocean, soil, and groundwater. Oil spills during oil extraction and transportation, such as from drilling wells, rigs, transport tanks, and pipelines, are an important cause of extensive environmental damage because they significantly decrease the diversity of aquatic life and disrupt the biological equilibrium of the ocean. It also damages the world's energy economy. Cleaning crude oil spills from marine or ocean environments is a highly challenging task because of the spilt oil's properties and limited mobility to the accidental site. This article focuses primarily on the various technologies used in the cleanup of oil spillage in marine or ocean environments, as well as their recent trends and challenges. This research work begins with a discussion of the historical events and the primary roots of oil spills, the composition of the spilt oil, the effects they have on the surrounding environment, the governmental rules for oil spills, and methods for cleaning up marine oil spills such as physical, thermal, biological, and chemical are briefly covered along with their benefits and drawbacks. This work discusses the software and artificial intelligence-related technologies prevailing for oil spill modelling and their current limitations.
{"title":"Marine oil spill clean-up: A review on technologies with recent trends and challenges","authors":"B.K. Purohit , Saurabh Tewari , K.S.N.V. Prasad , Vijaya Kumar Talari , Niharika Pandey , Priyadarsani Choudhury , Sasank Shekhar Panda","doi":"10.1016/j.rsma.2024.103876","DOIUrl":"10.1016/j.rsma.2024.103876","url":null,"abstract":"<div><div>Crude oil leakage occurs frequently during exploration, storage, transportation, production, and consumption. The spilling of crude oil has the potential to contaminate the ocean, soil, and groundwater. Oil spills during oil extraction and transportation, such as from drilling wells, rigs, transport tanks, and pipelines, are an important cause of extensive environmental damage because they significantly decrease the diversity of aquatic life and disrupt the biological equilibrium of the ocean. It also damages the world's energy economy. Cleaning crude oil spills from marine or ocean environments is a highly challenging task because of the spilt oil's properties and limited mobility to the accidental site. This article focuses primarily on the various technologies used in the cleanup of oil spillage in marine or ocean environments, as well as their recent trends and challenges. This research work begins with a discussion of the historical events and the primary roots of oil spills, the composition of the spilt oil, the effects they have on the surrounding environment, the governmental rules for oil spills, and methods for cleaning up marine oil spills such as physical, thermal, biological, and chemical are briefly covered along with their benefits and drawbacks. This work discusses the software and artificial intelligence-related technologies prevailing for oil spill modelling and their current limitations.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528578","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}
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