Pub Date : 2024-10-28DOI: 10.1016/j.seares.2024.102550
Rikke Petri Frandsen , Ludvig Ahm Krag , Bent Herrmann
Common sole (Solea solea) is an economically important species in several European trawl fisheries, yet little is known about the size selective properties of codends used in bottom trawl fisheries targeting sole. This study presents results from a sea trial conducted in the inner Danish waters where common sole is fished in a seasonal trawl fishery using a 90 mm diamond mesh codend with a mandatory large mesh escape panel. To improve understanding of the selectivity in this gear, we in addition tested a plain 90 mm diamond mesh codend without an escape panel. This combination of codend mesh size and large mesh escape panel is part of an ambitious management plan aimed at eliminating bycatch of cod (Gadus morhua) in trawl fisheries in the inner Danish waters. In the fishery for common sole, we found a severe mismatch between gear regulations and minimum conservation reference size of the target species. The outcome is a highly inefficient fishery in which only 22 % (CI: 18–27 %) by weight of the marketable sole is retained in the 90 mm diamond mesh codend. Further, we estimated that 25 % (CI: 16–35 %) of the sole entering the codend would contact the mandatory escape panel and escape, resulting in a total loss of 83 % (CI: 79–87 %) of marketable sole through the mandatory gear. The inefficiency in this fishery demonstrates the need for other means than gear specifications to regulate this type of fishery.
{"title":"The challenge of harvesting common sole (Solea solea) in highly selective trawl fisheries","authors":"Rikke Petri Frandsen , Ludvig Ahm Krag , Bent Herrmann","doi":"10.1016/j.seares.2024.102550","DOIUrl":"10.1016/j.seares.2024.102550","url":null,"abstract":"<div><div>Common sole (<em>Solea solea</em>) is an economically important species in several European trawl fisheries, yet little is known about the size selective properties of codends used in bottom trawl fisheries targeting sole. This study presents results from a sea trial conducted in the inner Danish waters where common sole is fished in a seasonal trawl fishery using a 90 mm diamond mesh codend with a mandatory large mesh escape panel. To improve understanding of the selectivity in this gear, we in addition tested a plain 90 mm diamond mesh codend without an escape panel. This combination of codend mesh size and large mesh escape panel is part of an ambitious management plan aimed at eliminating bycatch of cod (<em>Gadus morhua</em>) in trawl fisheries in the inner Danish waters. In the fishery for common sole, we found a severe mismatch between gear regulations and minimum conservation reference size of the target species. The outcome is a highly inefficient fishery in which only 22 % (CI: 18–27 %) by weight of the marketable sole is retained in the 90 mm diamond mesh codend. Further, we estimated that 25 % (CI: 16–35 %) of the sole entering the codend would contact the mandatory escape panel and escape, resulting in a total loss of 83 % (CI: 79–87 %) of marketable sole through the mandatory gear. The inefficiency in this fishery demonstrates the need for other means than gear specifications to regulate this type of fishery.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102550"},"PeriodicalIF":2.1,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Silver croaker (Pennahia argentata) is an important economic species in the East China Sea (ECS); however, its population has been declining, and studies on its status are scarce. This study collected biological data, including length, weight, and gonadal maturity of silver croaker from the southern coastal waters of Zhejiang Province between 2015 and 2021, to evaluate its life history and assess stock status. Methods from the TropFishR package were employed to estimate population growth and natural mortality parameters. Two widely used length-based data-limited models, length-based bayesian biomass estimation method (LBB) and length-based spawning potential ratio method (LBSPR), were applied to assess the stock status of silver croaker in the ECS. The results indicated that with a maximum age (Amax) of 4 years, the asymptotic length (Linf) was 23.80 cm, growth rate (K) was 0.74/year, and natural mortality coefficient (M) ranged from 1.068 to 1.376. Under the assumption of Amax = 5 years, Linf was 26.77 cm, K was 0.63/year, and M ranged from 0.818 to 1.193. The LBB and LBSPR models showed that, except for scenarios with L∞ = 23.8 cm, M/K = 1.46, and L∞ = 26.77 cm, M/K = 1.30, 1.38, or 1.48, the selectivity at length parameters and for silver croaker exhibited an increasing trend over the years. In the LBB model, for different years consistently fell below the optimum length (Lc_opt), indicating that most individuals did not reach the size at first sexual maturity or optimal catch length. Moreover, under high fishing pressure, the Spawning Potential Ratio (SPR) and the unfished biomass ratio (B/B0) for silver croaker showed a decreasing trend, despite some stability or recovery in recent years. However, in all scenarios, SPR values were below 0.2, and B/B0 values were below 0.5, suggesting a significant risk of population collapse for silver croaker in the ECS due to intense fishing pressure. Therefore, it is recommended to reduce the current fishing pressure and increase the minimum catch size of this species for effective conservation and management in this region.
{"title":"Stock exploitation status of silver croaker (Pennahia argentata) from the East China Sea","authors":"Shiqing Zhao , Richard Kindong , Chunxia Gao , Njomoue Achille Pandong , Siquan Tian","doi":"10.1016/j.seares.2024.102549","DOIUrl":"10.1016/j.seares.2024.102549","url":null,"abstract":"<div><div>Silver croaker (<em>Pennahia argentata)</em> is an important economic species in the East China Sea (ECS); however, its population has been declining, and studies on its status are scarce. This study collected biological data, including length, weight, and gonadal maturity of silver croaker from the southern coastal waters of Zhejiang Province between 2015 and 2021, to evaluate its life history and assess stock status. Methods from the TropFishR package were employed to estimate population growth and natural mortality parameters. Two widely used length-based data-limited models, length-based bayesian biomass estimation method (LBB) and length-based spawning potential ratio method (LBSPR), were applied to assess the stock status of silver croaker in the ECS. The results indicated that with a maximum age (<em>A</em><sub><em>max</em></sub>) of 4 years, the asymptotic length (<em>L</em><sub><em>inf</em></sub>) was 23.80 cm, growth rate (<em>K</em>) was 0.74/year, and natural mortality coefficient (<em>M</em>) ranged from 1.068 to 1.376. Under the assumption of <em>A</em><sub><em>max</em></sub> = 5 years, <em>L</em><sub><em>inf</em></sub> was 26.77 cm, <em>K</em> was 0.63/year, and <em>M</em> ranged from 0.818 to 1.193. The LBB and LBSPR models showed that, except for scenarios with <em>L</em><sub><em>∞</em></sub> = 23.8 cm, <em>M/K</em> = 1.46, and <em>L</em><sub><em>∞</em></sub> = 26.77 cm, <em>M/K</em> = 1.30, 1.38, or 1.48, the selectivity at length parameters <span><math><msubsup><mi>L</mi><mn>50</mn><mi>S</mi></msubsup><mspace></mspace></math></span>and<span><math><mspace></mspace><msubsup><mi>L</mi><mn>95</mn><mi>S</mi></msubsup></math></span> for silver croaker exhibited an increasing trend over the years. In the LBB model, <span><math><msubsup><mi>L</mi><mn>50</mn><mi>S</mi></msubsup></math></span> for different years consistently fell below the optimum length (<em>L</em><sub><em>c_opt</em></sub>), indicating that most individuals did not reach the size at first sexual maturity or optimal catch length. Moreover, under high fishing pressure, the Spawning Potential Ratio (SPR) and the unfished biomass ratio (<em>B/B</em><sub><em>0</em></sub>) for silver croaker showed a decreasing trend, despite some stability or recovery in recent years. However, in all scenarios, SPR values were below 0.2, and <em>B/B</em><sub><em>0</em></sub> values were below 0.5, suggesting a significant risk of population collapse for silver croaker in the ECS due to intense fishing pressure. Therefore, it is recommended to reduce the current fishing pressure and increase the minimum catch size of this species for effective conservation and management in this region.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102549"},"PeriodicalIF":2.1,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.seares.2024.102548
Yang Deng , Xiaoguang Xu , Jie Xu , Wenlin Wang , Ruijie Lu , Haihua Zhuo , Yingcai Wang , Yunbing Liu , Xi Liu , Xiaolong Huang
While the spatiotemporal dynamics of phytoplankton community structures in river ecosystems have been extensively studied, their primary driving factors remain elusive, particularly at the watershed scale. This research examined the phytoplankton community structure across three watersheds of an island and concurrently analyzed its response to water level fluctuations (WLFs). The phytoplankton density was notably higher at elevated water levels, registering an increase of 1.29 times in Nandu River, 1.34 times in Changhua River, and 1.28 times in Wanquan River. Notably, the middle reaches of the Changhua River recorded the highest phytoplankton density (4.46 × 108 cells/L). Broadly speaking, Cyanophyta, Chlorophyta, and Bacillariophyta remained the predominant phytoplankton across varied water levels. Dominant phytoplankton species varied with water levels; however, the most prevalent species consistently belonged to the Cyanophyta group, primarily Microcystis or Merismopedia, with dominance ranging between 0.17 to 0.38 (low water level) and 0.18 to 0.32 (high water level). Enhanced phytoplankton diversity and richness were observed at higher water levels, correlating with increased concentrations of NH4+-N, NO3−-N, and PO43− in the river water. Consequently, nutrient fluctuations driven by hydrodynamics significantly influence the phytoplankton community structure in island river ecosystems.
{"title":"Hydrological-driven changes in the phytoplankton community structure under nutrient stress in island river ecosystems","authors":"Yang Deng , Xiaoguang Xu , Jie Xu , Wenlin Wang , Ruijie Lu , Haihua Zhuo , Yingcai Wang , Yunbing Liu , Xi Liu , Xiaolong Huang","doi":"10.1016/j.seares.2024.102548","DOIUrl":"10.1016/j.seares.2024.102548","url":null,"abstract":"<div><div>While the spatiotemporal dynamics of phytoplankton community structures in river ecosystems have been extensively studied, their primary driving factors remain elusive, particularly at the watershed scale. This research examined the phytoplankton community structure across three watersheds of an island and concurrently analyzed its response to water level fluctuations (WLFs). The phytoplankton density was notably higher at elevated water levels, registering an increase of 1.29 times in Nandu River, 1.34 times in Changhua River, and 1.28 times in Wanquan River. Notably, the middle reaches of the Changhua River recorded the highest phytoplankton density (4.46 × 10<sup>8</sup> cells/L). Broadly speaking, Cyanophyta, Chlorophyta, and Bacillariophyta remained the predominant phytoplankton across varied water levels. Dominant phytoplankton species varied with water levels; however, the most prevalent species consistently belonged to the Cyanophyta group, primarily Microcystis or Merismopedia, with dominance ranging between 0.17 to 0.38 (low water level) and 0.18 to 0.32 (high water level). Enhanced phytoplankton diversity and richness were observed at higher water levels, correlating with increased concentrations of NH<sub>4</sub><sup>+</sup>-N, NO<sub>3</sub><sup>−</sup>-N, and PO<sub>4</sub><sup>3−</sup> in the river water. Consequently, nutrient fluctuations driven by hydrodynamics significantly influence the phytoplankton community structure in island river ecosystems.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102548"},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-28DOI: 10.1016/j.seares.2024.102547
Guozhen Zha , Zhongbiao Chen , Zhijia Lin , Lin Peng , Jie Zhang , Weiye He
Nautical X-band radars are used to continuously monitor large ocean surface areas with high temporal and spatial resolution. The signatures of ocean surface waves in nautical X-band radar images are typically present as straight or curved stripes with distinct directional and frequency characteristics. Curvelet transform (CT) is a multi-resolution technique with the capability of locational and directional resolving. This study presents a new method for enhancing the signatures of ocean surface waves in nautical X-band radar images. A radar image is decomposed at different scales, directions, and locations using forward CT. The surface wave signals are distributed in the curvelet coefficient (CC) of certain directions and scales. The signals of surface waves are extracted by retaining the CCs in specific directions and scales, whereas the CCs in other directions and scales are all set to zero. Wave signatures are enhanced by adding the extracted signals back to the original image. The proposed method is also feasible for enhancing signatures of surface waves in synthetic aperture radar or optical remote sensing images.
航海 X 波段雷达用于以较高的时间和空间分辨率连续监测大面积海面。在航海 X 波段雷达图像中，海洋表面波的特征通常表现为具有明显方向和频率特性的直线或曲线条纹。小曲线变换（CT）是一种多分辨率技术，具有定位和方向分辨能力。本研究提出了一种增强航海 X 波段雷达图像中海洋表面波特征的新方法。使用前向 CT 对雷达图像进行不同尺度、方向和位置的分解。面波信号分布在特定方向和尺度的小曲线系数（CC）中。通过保留特定方向和尺度上的小曲线系数，提取面波信号，而其他方向和尺度上的小曲线系数则全部置零。通过将提取的信号添加回原始图像来增强波浪特征。所提出的方法也适用于增强合成孔径雷达或光学遥感图像中的表面波特征。
{"title":"A new method for enhancing signatures of ocean surface waves in nautical X-band radar images","authors":"Guozhen Zha , Zhongbiao Chen , Zhijia Lin , Lin Peng , Jie Zhang , Weiye He","doi":"10.1016/j.seares.2024.102547","DOIUrl":"10.1016/j.seares.2024.102547","url":null,"abstract":"<div><div>Nautical X-band radars are used to continuously monitor large ocean surface areas with high temporal and spatial resolution. The signatures of ocean surface waves in nautical X-band radar images are typically present as straight or curved stripes with distinct directional and frequency characteristics. Curvelet transform (CT) is a multi-resolution technique with the capability of locational and directional resolving. This study presents a new method for enhancing the signatures of ocean surface waves in nautical X-band radar images. A radar image is decomposed at different scales, directions, and locations using forward CT. The surface wave signals are distributed in the curvelet coefficient (CC) of certain directions and scales. The signals of surface waves are extracted by retaining the CCs in specific directions and scales, whereas the CCs in other directions and scales are all set to zero. Wave signatures are enhanced by adding the extracted signals back to the original image. The proposed method is also feasible for enhancing signatures of surface waves in synthetic aperture radar or optical remote sensing images.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102547"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.seares.2024.102546
Hyun Yang , Suk Yoon , Hyeong-Tak Lee , Kwang Seok Kim , Hee-Jeong Han , Young-Je Park
The abnormally high-water temperature (AHWT) phenomena have caused the mass stranding of farmed fish in the Korean coastal waters, leading to a substantial monetary loss in recent decades. It is most important to predict the HWT occurrence and take responsive measures before the HWT arrival to prevent such loss, we proposed a methodology to predict HWT occurrences using a deep-learning technology. Firstly, we trained a long short-term memory (LSTM) deep-learning model using the sea surface temperature data from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 product to estimate future water temperature in advance. Secondly, we used the estimated water temperature data to predict HWT occurrences from 1 day to 7 days later. We computed root mean square error (RMSE), mean absolute percentage error (MAPE) metrics, and F1-scores to evaluate the accuracy of the proposed LSTM model. In the cases of 1-day and 7-day water temperature predictions, RMSE and MAPE values between the estimated data and the sea-truth data were 0.293 degrees Celsius with 1.313 % and 0.854 degrees Celsius with 4.175 %, respectively. The F1-scores of the classification algorithm of 1- and 7-day HWT predictions were 0.96 and 0.74, respectively. This study contributes to developing measures to reduce the monetary loss of HWT damage on fish farms.
{"title":"Abnormal high water temperature prediction in nearshore waters around the Korean Peninsula using ECMWF ERA5 data and a deep learning model","authors":"Hyun Yang , Suk Yoon , Hyeong-Tak Lee , Kwang Seok Kim , Hee-Jeong Han , Young-Je Park","doi":"10.1016/j.seares.2024.102546","DOIUrl":"10.1016/j.seares.2024.102546","url":null,"abstract":"<div><div>The abnormally high-water temperature (AHWT) phenomena have caused the mass stranding of farmed fish in the Korean coastal waters, leading to a substantial monetary loss in recent decades. It is most important to predict the HWT occurrence and take responsive measures before the HWT arrival to prevent such loss, we proposed a methodology to predict HWT occurrences using a deep-learning technology. Firstly, we trained a long short-term memory (LSTM) deep-learning model using the sea surface temperature data from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 product to estimate future water temperature in advance. Secondly, we used the estimated water temperature data to predict HWT occurrences from 1 day to 7 days later. We computed root mean square error (RMSE), mean absolute percentage error (MAPE) metrics, and F1-scores to evaluate the accuracy of the proposed LSTM model. In the cases of 1-day and 7-day water temperature predictions, RMSE and MAPE values between the estimated data and the sea-truth data were 0.293 degrees Celsius with 1.313 % and 0.854 degrees Celsius with 4.175 %, respectively. The F1-scores of the classification algorithm of 1- and 7-day HWT predictions were 0.96 and 0.74, respectively. This study contributes to developing measures to reduce the monetary loss of HWT damage on fish farms.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102546"},"PeriodicalIF":2.1,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.seares.2024.102544
Caitlin Yoo , Tim J.G. Wilms , Svenja A. Stoehr , Linda Latuta , Karen Timmermann , Maria Moltesen , Jon C. Svendsen
Coastal ecosystems worldwide face increasing anthropogenic pressures, with implications for the local ecological status and biodiversity. Using a temperate coastal ecosystem in poor ecological condition, this study revealed the importance of blue mussel (Mytilus spp.) reefs in supporting mobile marine fauna (e.g., fish). Using baited remote underwater video systems (BRUVS), we compared mobile marine fauna associated with A) high coverage mussel reefs in shallow and deeper parts of the area and B) corresponding low coverage soft-bottom sites. Our BRUVS findings demonstrate that blue mussel reefs harbor a higher taxonomic diversity of mobile fauna compared to the corresponding soft-bottom sites. Furthermore, the species community associated with mussel reefs exhibits distinct composition from the soft-bottom sites. Despite efforts to mitigate harmful eutrophication, the poor ecological status of the coastal ecosystem highlights ongoing challenges in coastal management. Our results have important implications for management of coastal resources and conservation of marine biodiversity. Despite its environmental challenges, the examined ecosystem serves as a representative case for many temperate waterbodies emphasizing the need for improved management outcomes. Incorporating mussel reef conservation and restoration into temperate water body management actions could enhance ecosystem resilience and local biodiversity in many coastal ecosystems subjected to anthropogenic pressures.
{"title":"Mussel reefs promote taxonomic biodiversity and host a unique assemblage of mobile marine fauna in a coastal area of poor ecological status","authors":"Caitlin Yoo , Tim J.G. Wilms , Svenja A. Stoehr , Linda Latuta , Karen Timmermann , Maria Moltesen , Jon C. Svendsen","doi":"10.1016/j.seares.2024.102544","DOIUrl":"10.1016/j.seares.2024.102544","url":null,"abstract":"<div><div>Coastal ecosystems worldwide face increasing anthropogenic pressures, with implications for the local ecological status and biodiversity. Using a temperate coastal ecosystem in poor ecological condition, this study revealed the importance of blue mussel (<em>Mytilus</em> spp.) reefs in supporting mobile marine fauna (e.g., fish). Using baited remote underwater video systems (BRUVS), we compared mobile marine fauna associated with A) high coverage mussel reefs in shallow and deeper parts of the area and B) corresponding low coverage soft-bottom sites. Our BRUVS findings demonstrate that blue mussel reefs harbor a higher taxonomic diversity of mobile fauna compared to the corresponding soft-bottom sites. Furthermore, the species community associated with mussel reefs exhibits distinct composition from the soft-bottom sites. Despite efforts to mitigate harmful eutrophication, the poor ecological status of the coastal ecosystem highlights ongoing challenges in coastal management. Our results have important implications for management of coastal resources and conservation of marine biodiversity. Despite its environmental challenges, the examined ecosystem serves as a representative case for many temperate waterbodies emphasizing the need for improved management outcomes. Incorporating mussel reef conservation and restoration into temperate water body management actions could enhance ecosystem resilience and local biodiversity in many coastal ecosystems subjected to anthropogenic pressures.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102544"},"PeriodicalIF":2.1,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Thriving life beneath: Biodiversity and functioning of macrobenthic communities within two human-shaped European estuaries","authors":"Romain Lécuyer , Anik Brind'Amour , Anne-Laure Barillé , Bastien Chouquet , Hervé Le Bris","doi":"10.1016/j.seares.2024.102545","DOIUrl":"10.1016/j.seares.2024.102545","url":null,"abstract":"","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102545"},"PeriodicalIF":2.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Southern Indonesian (SI) region is known for its high-intensity coastal upwelling caused by monsoonal wind. Interannual phenomena such as El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) also influence upwelling activity in this region. This study analyzed the relationship between upwelling intensity (UIsst) and those variables and their impact on oceanographic features such as Sea Surface Temperature (SST) and chlorophyll-a concentration. We used satellite imagery data, including SST from the National Oceanic and Atmospheric Administration (NOAA) and chlorophyll-a from MODIS, to analyze the aforementioned issue. To identify the impact of wind patterns on coastal upwelling, we analyzed using zonal wind stress from ERA-5 Data. Quantification of UIsst is defined as the SST gradient between the coastal and open ocean waters. Linear and partial correlation analysis between UIsst with the Ocean Niño Index (ONI) and Dipole Mode Index (DMI) were conducted to see the influence of ENSO and IOD phenomena. Anomaly analysis was also conducted on SST, chlorophyll-a concentration, zonal windstress and UIsst to see how large the values were during the years of the ENSO and IOD events. Upwelling in the SI region typically occurs during southeast monsoon (SEM) periods, starting earlier in the East side (Nusa Tenggara Islands) and moving towards the West side (South Coast of Java). The correlation analysis (both linear and partial) indicates that the IOD has a stronger influence on UIsst in the SI region compared to ENSO, especially during June to October (SEM periods). This finding is confirmed by anomaly analysis, which reveals significant changes in SST, chlorophyll-a concentration, zonal windstress, and UIsst during ENSO and IOD events. The magnitude of the anomalies is generally stronger during IOD events than those observed under ENSO conditions.
{"title":"Dynamic of upwelling variability in southern Indonesia region revealed from satellite data: Role of ENSO and IOD","authors":"Herlambang Aulia Rachman , Martiwi Diah Setiawati , Zainul Hidayah , Achmad Fachruddin Syah , Muhammad Rizki Nandika , Jonson Lumban-Gaol , Abd. Rahman As-syakur , Fadli Syamsudin","doi":"10.1016/j.seares.2024.102543","DOIUrl":"10.1016/j.seares.2024.102543","url":null,"abstract":"<div><p>The Southern Indonesian (SI) region is known for its high-intensity coastal upwelling caused by monsoonal wind. Interannual phenomena such as El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) also influence upwelling activity in this region. This study analyzed the relationship between upwelling intensity (UI<sub>sst</sub>) and those variables and their impact on oceanographic features such as Sea Surface Temperature (SST) and chlorophyll-a concentration. We used satellite imagery data, including SST from the National Oceanic and Atmospheric Administration (NOAA) and chlorophyll-a from MODIS, to analyze the aforementioned issue. To identify the impact of wind patterns on coastal upwelling, we analyzed using zonal wind stress from ERA-5 Data. Quantification of UI<sub>sst</sub> is defined as the SST gradient between the coastal and open ocean waters. Linear and partial correlation analysis between UI<sub>sst</sub> with the Ocean Niño Index (ONI) and Dipole Mode Index (DMI) were conducted to see the influence of ENSO and IOD phenomena. Anomaly analysis was also conducted on SST, chlorophyll-a concentration, zonal windstress and UI<sub>sst</sub> to see how large the values were during the years of the ENSO and IOD events. Upwelling in the SI region typically occurs during southeast monsoon (SEM) periods, starting earlier in the East side (Nusa Tenggara Islands) and moving towards the West side (South Coast of Java). The correlation analysis (both linear and partial) indicates that the IOD has a stronger influence on UI<sub>sst</sub> in the SI region compared to ENSO, especially during June to October (SEM periods). This finding is confirmed by anomaly analysis, which reveals significant changes in SST, chlorophyll-a concentration, zonal windstress, and UI<sub>sst</sub> during ENSO and IOD events. The magnitude of the anomalies is generally stronger during IOD events than those observed under ENSO conditions.</p></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102543"},"PeriodicalIF":2.1,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1385110124000765/pdfft?md5=68cb95fa1ef611cc84c343aaca6d9005&pid=1-s2.0-S1385110124000765-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142232135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1016/j.seares.2024.102540
Yuan Zhang , Fang Shen , Haiyang Zhao , Xuerong Sun , Qing Zhu , Mengyu Li
<div><p>Different phytoplankton types play distinct roles in marine ecosystems, biogeochemical processes, and responses to climate change. Traditionally, phytoplankton classification has heavily relied on chemical analysis methods based on phytoplankton pigments, such as High-Performance Liquid Chromatography (HPLC) analysis. This approach limits the classification resolution to the phylum level of phytoplankton, making it difficult to refine classification to the genus or species level. With the observation of the hyperspectral ocean satellite PACE (Plankton, Aerosol, Cloud, ocean Ecosystem mission) louched by NASA in February 2024, there is potential to achieve finer classification of phytoplankton based on differences in spectral characteristics. This study cultivates various phytoplankton species in the laboratory to observe their light absorption properties (e.g., specific absorption coefficients spectra under unit concentration), investigating the spectral differences between different phyla and among species within the Dinoflagellates and Diatoms. Based on the observed absorption and scattering properties of each phytoplankton species, we simulated the remote sensing reflectance of different species under various ocean color components, examining the potential of hyperspectral remote sensing discrimination of phytoplankton types, and analyzing the impact of Chlorophyll <em>a</em> (Chla), colored dissolved organic matter (CDOM), and non-algal particles (NAP) concentrations on the remote sensing discrimination. The results show significant differences in absorption spectra between different groups of phytoplankton (i.e., Diatoms, Dinoflagellates, Xanthophytes, Coccolithophores, Chlorophytes, Cyanobacteria, Cryptophytes). Among species within the Dinoflagellate group, there are also significant spectral differences, while species within the Diatom group exhibit relatively small variations in their spectral shapes. As Chla concentration increases, the potential for remote sensing discrimination of phytoplankton species also increases; conversely, lower Chla concentrations pose greater challenges for remote sensing disscrimiantion. Other ocean color components, such as increased CDOM or NAP concentrations, interfere with the spectral characteristics of phytoplankton in the blue-green spectral domain. Using hierarchical clustering for phytoplankton classification, the results indicate that Cyanobacteria and Chlorophytes can be well distinguished from other group at lower NAP concentrations, while Diatoms, Cryptophytes, and Xanthophytes are not easily distinguishable from each other. Differentiating between species within the same group using remote sensing data presents significant challenges. This study provides a comprehensive investigation into the optical characteristics of different phytoplankton types, laying a foundation for their remote sensing classification and deepening the understanding of the potential of hyperspectral remote sensin
不同类型的浮游植物在海洋生态系统、生物地球化学过程和气候变化响应中发挥着不同的作用。传统上，浮游植物分类主要依赖于基于浮游植物色素的化学分析方法，如高效液相色谱（HPLC）分析。这种方法将分类分辨率限制在浮游植物门一级，很难将分类细化到属或种一级。随着美国国家航空航天局（NASA）将于 2024 年 2 月发射高光谱海洋卫星 PACE（浮游生物、气溶胶、云层、海洋生态系统任务），有可能根据光谱特征的差异对浮游植物进行更精细的分类。本研究在实验室中培养各种浮游植物物种，观察它们的光吸收特性（如单位浓度下的比吸收系数光谱），研究不同门类之间以及甲藻和硅藻中不同物种之间的光谱差异。根据观测到的各浮游植物物种的吸收和散射特性，我们模拟了不同物种在不同海洋颜色成分下的遥感反射率，考察了高光谱遥感分辨浮游植物类型的潜力，并分析了叶绿素 a（Chla）、有色溶解有机物（CDOM）和非藻类颗粒（NAP）浓度对遥感分辨的影响。结果显示，不同浮游植物群（即硅藻、甲藻、黄绿藻、球藻、叶绿藻、蓝藻、隐藻）之间的吸收光谱存在明显差异。Dinoflagellate 组中的物种在光谱上也有显著差异，而 Diatom 组中的物种在光谱形状上的差异相对较小。随着 Chla 浓度的增加，遥感分辨浮游植物物种的潜力也在增加；反之，Chla 浓度越低，遥感分辨的挑战就越大。其他海洋颜色成分，如 CDOM 或 NAP 浓度的增加，会干扰浮游植物在蓝绿光谱域的光谱特性。利用分层聚类对浮游植物进行分类，结果表明，在 NAP 浓度较低的情况下，蓝藻和叶绿藻可以很好地与其他类群区分开来，而硅藻、隐藻和黄藻则不易区分。利用遥感数据区分同类中的物种是一项重大挑战。本研究对不同浮游植物类型的光学特征进行了全面调查，为其遥感分类奠定了基础，并加深了人们对高光谱遥感在浮游植物详细分类方面潜力的认识。
{"title":"Optical distinguishability of phytoplankton species and its implications for hyperspectral remote sensing discrimination potential","authors":"Yuan Zhang , Fang Shen , Haiyang Zhao , Xuerong Sun , Qing Zhu , Mengyu Li","doi":"10.1016/j.seares.2024.102540","DOIUrl":"10.1016/j.seares.2024.102540","url":null,"abstract":"<div><p>Different phytoplankton types play distinct roles in marine ecosystems, biogeochemical processes, and responses to climate change. Traditionally, phytoplankton classification has heavily relied on chemical analysis methods based on phytoplankton pigments, such as High-Performance Liquid Chromatography (HPLC) analysis. This approach limits the classification resolution to the phylum level of phytoplankton, making it difficult to refine classification to the genus or species level. With the observation of the hyperspectral ocean satellite PACE (Plankton, Aerosol, Cloud, ocean Ecosystem mission) louched by NASA in February 2024, there is potential to achieve finer classification of phytoplankton based on differences in spectral characteristics. This study cultivates various phytoplankton species in the laboratory to observe their light absorption properties (e.g., specific absorption coefficients spectra under unit concentration), investigating the spectral differences between different phyla and among species within the Dinoflagellates and Diatoms. Based on the observed absorption and scattering properties of each phytoplankton species, we simulated the remote sensing reflectance of different species under various ocean color components, examining the potential of hyperspectral remote sensing discrimination of phytoplankton types, and analyzing the impact of Chlorophyll <em>a</em> (Chla), colored dissolved organic matter (CDOM), and non-algal particles (NAP) concentrations on the remote sensing discrimination. The results show significant differences in absorption spectra between different groups of phytoplankton (i.e., Diatoms, Dinoflagellates, Xanthophytes, Coccolithophores, Chlorophytes, Cyanobacteria, Cryptophytes). Among species within the Dinoflagellate group, there are also significant spectral differences, while species within the Diatom group exhibit relatively small variations in their spectral shapes. As Chla concentration increases, the potential for remote sensing discrimination of phytoplankton species also increases; conversely, lower Chla concentrations pose greater challenges for remote sensing disscrimiantion. Other ocean color components, such as increased CDOM or NAP concentrations, interfere with the spectral characteristics of phytoplankton in the blue-green spectral domain. Using hierarchical clustering for phytoplankton classification, the results indicate that Cyanobacteria and Chlorophytes can be well distinguished from other group at lower NAP concentrations, while Diatoms, Cryptophytes, and Xanthophytes are not easily distinguishable from each other. Differentiating between species within the same group using remote sensing data presents significant challenges. This study provides a comprehensive investigation into the optical characteristics of different phytoplankton types, laying a foundation for their remote sensing classification and deepening the understanding of the potential of hyperspectral remote sensin","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102540"},"PeriodicalIF":2.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S138511012400073X/pdfft?md5=e2856ffb3f97ce21a55839a518589eaa&pid=1-s2.0-S138511012400073X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Internal waves are easily recognized features of remote sensing images. They occur below the sea surface and can be observed using optical and radar sensors due to their interactions with surface waves. Nonlinear internal waves, known as Internal Solitary Waves (ISW), maintain their coherence and visibility through nonlinear hydrodynamics and appear as long quasilinear stripes in images. Optical sensors can capture changes in sea surface roughness modulated by ISW when their location is close to specular reflection from the sun. Optical imagery with wide area coverage and high temporal resolution has the potential to track and analyze ISW dynamics. However, a comprehensive analysis of the mechanisms underlying ISW manifestation patterns in optical images is necessary. The GCOM-C/SGLI satellite, equipped with a visible-near infrared radiometer and an infrared scanner, provides a detailed view of ISW manifestations using various scanning techniques. By analyzing SGLI products that detect ISW patterns, this study investigated how these waves manifest on the sea surface. The comparison between Level-1B data and Level-2 Ocean products observed by the SGLI sensor reveals that ISW patterns significantly affect ocean color parameters and thermal channel data. The consistent ISW manifestation pattern detected in TOA radiance and ocean color products suggests that ISWs impact sea surface roughness. Additionally, the detection of ISW patterns in SST data is a notable finding, highlighting the potential influence of ISWs on air-sea interactions and the atmospheric boundary layer. Understanding these impacts is crucial for remote sensing applications, particularly for long-term internal wave monitoring and ensuring that smaller-scale internal wave signals do not interfere with large-scale satellite estimations of ocean color.
{"title":"Surface manifestation characteristics of internal solitary waves observed by GCOM-C/SGLI imagery","authors":"Chonnaniyah , Eko Siswanto , Abd. Rahman As-syakur , Takahiro Osawa","doi":"10.1016/j.seares.2024.102541","DOIUrl":"10.1016/j.seares.2024.102541","url":null,"abstract":"<div><p>Internal waves are easily recognized features of remote sensing images. They occur below the sea surface and can be observed using optical and radar sensors due to their interactions with surface waves. Nonlinear internal waves, known as Internal Solitary Waves (ISW), maintain their coherence and visibility through nonlinear hydrodynamics and appear as long quasilinear stripes in images. Optical sensors can capture changes in sea surface roughness modulated by ISW when their location is close to specular reflection from the sun. Optical imagery with wide area coverage and high temporal resolution has the potential to track and analyze ISW dynamics. However, a comprehensive analysis of the mechanisms underlying ISW manifestation patterns in optical images is necessary. The GCOM-C/SGLI satellite, equipped with a visible-near infrared radiometer and an infrared scanner, provides a detailed view of ISW manifestations using various scanning techniques. By analyzing SGLI products that detect ISW patterns, this study investigated how these waves manifest on the sea surface. The comparison between Level-1B data and Level-2 Ocean products observed by the SGLI sensor reveals that ISW patterns significantly affect ocean color parameters and thermal channel data. The consistent ISW manifestation pattern detected in TOA radiance and ocean color products suggests that ISWs impact sea surface roughness. Additionally, the detection of ISW patterns in SST data is a notable finding, highlighting the potential influence of ISWs on air-sea interactions and the atmospheric boundary layer. Understanding these impacts is crucial for remote sensing applications, particularly for long-term internal wave monitoring and ensuring that smaller-scale internal wave signals do not interfere with large-scale satellite estimations of ocean color.</p></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102541"},"PeriodicalIF":2.1,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1385110124000741/pdfft?md5=741457f247ddbefce26f58d47b644ebf&pid=1-s2.0-S1385110124000741-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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