Dynamics of Atmospheres and Oceans最新文献

{"title":"A Demonstration of the Capability of Low-Cost Hyperspectral Imaging for the Characterisation of Coral Reefs","authors":"J. Teague, J. Day, Michael J. Allen, Thomas B. Scott, E. Hochberg, David A. Megson-Smith","doi":"10.3390/oceans4030020","DOIUrl":"https://doi.org/10.3390/oceans4030020","url":null,"abstract":"The use of hyperspectral imaging in marine applications is limited, largely due to the cost-prohibitive nature of the technology and the risk of submerging such expensive electronics. Here, we examine the use of low-cost (<5000 GBP) hyperspectral imaging as a potential addition to the marine monitoring toolbox. Using coral reefs in Bermuda as a case study and a trial for the technology, data was collected across two reef morphologies, representing fringing reefs and patch reefs. Hyperspectral data of various coral species, Montastraea cavernosa, Diploria labyrinthiformis, Pseudodiploria strigosa, and Plexaurella sp., were successfully captured and analyzed, indicating the practicality and suitability of underwater hyperspectral imaging for use in coral reef assessment. The spectral data was also used to demonstrate simple spectral classification to provide values of the percentage coverage of benthic habitat types. Finally, the raw image data was used to generate digital elevation models to measure the physical structure of corals, providing another data type able to be used in reef assessments. Future improvements were also suggested regarding how to improve the spectral data captured by the technique to account for the accurate application of correction algorithms.","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"7 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90003855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Harbor Porpoise Aggregations in the Salish Sea","authors":"David Anderson, Laurie Shuster, C. Elliser, Katrina MacIver, Erin Johns Gless, Johannes Krieger, A. Hall","doi":"10.3390/oceans4030019","DOIUrl":"https://doi.org/10.3390/oceans4030019","url":null,"abstract":"Harbor porpoises are typically seen in small groups of 1–3 individuals, with aggregations of 20+ individuals treated as rare events. Since the 1990s, the harbor porpoise population in the Salish Sea has seen a significant recovery, and an increased number of observed aggregations that exceed the more usual small group sizes has been observed in recent years. By combining the observational data of United States and Canadian research organizations, community scientists, and whale watch captains or naturalists, we demonstrate that harbor porpoise aggregations appear to be more common than previously known, with 160 aggregations documented in 2022 alone. Behavioral data also indicate that foraging behaviors are common and social behaviors, like mating, are seen more often during these encounters compared to small groups. Other behaviors that are considered to be rare or unknown were also observed during these encounters, including cooperative foraging and vessel approach. These aggregations are likely important foraging and social gatherings for harbor porpoises. This holistic approach integrating data from two countries and multiple sources provides a population level assessment that more effectively reflects the behavior of harbor porpoises in this region, which do not recognize the socio-political boundaries imposed upon the natural world.","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"63 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78729380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical Distribution, Community and Population Structures of the Planktonic Chaetognatha in the Western Subarctic Pacific: Insights on the Eukrohnia Species Group","authors":"Haochen Zhang, Y. Nakamura, A. Yamaguchi","doi":"10.3390/oceans4030018","DOIUrl":"https://doi.org/10.3390/oceans4030018","url":null,"abstract":"In the oceans, Chaetognatha can contribute significantly to the total zooplankton biomass (up to 10–30%). The genus Eukrohnia, the dominant Chaetognath genus in the western subarctic Pacific, includes E. hamata and E. bathypelagica. Although it has been pointed out that there is no genetic difference between the two species, no study has been made that treats them as the same species group. In this study, we investigated vertical distribution based on the eight vertical stratification samplings down to 1000 m depths conducted day/night at four seasons covering one year, community structure, and population structure of the three dominant Chaetognath species: Parasagitta elegans, E. hamata, and E. bathypelagica in the western subarctic Pacific. The population densities of each species at 0–1000 m water column were 0.04–0.36 ind. m−3 for P. elegans, 0.14–1.60 ind. m−3 for E. hamata, 0.24–1.54 ind. m−3 for E. bathypelagica, and 1.37–2.62 ind. m−3 for Eukrohnia juveniles. The vertical distributions were consistent both day and night, and no diel changes were observed for all species throughout the seasons. The vertical distribution of Chaetognaths evaluated by the distribution center was 61–169 m for P. elegans, 143–206 m for Eukrohnia juveniles, 134–279 m for E. hamata, and 253–612 m for E. bathypelagica. The body length of P. elegans ranged from 4 to 34 mm, and one to three cohorts were identified at each sampling occasion. While the presence of the eight stages has been reported for Eukrohnia, only one to five stages occurred, and specimens belonging to six to eight stages were not observed in the samples throughout the year. The body length of the whole Eukrohnia species ranged from 2 to 14 mm. The body length histograms of the Eukrohnia species group, including E. hamata and E. bathypelagica, and their juveniles showed the presence of two to four cohorts at each sampling date. Within the Eukrohnia species group, vertical changes in body length were present, which were characterized by the smaller specimens occurring at shallower depths, followed by an increase in body length with increasing depths. From the vertical distribution and population structure of the Eukrohnia species group (Eukrohnia juvenile + E. hamata + E. bathypelagica) in this study, there was no difficulty in treating them as one species. It may suggest that E. hamata and E. bathypelagica in the western subarctic Pacific could be treated as one species group. To clarify this point, a detailed genetic analysis of the Eukrohnia species group will be needed for future studies.","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"55 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84455067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal Changes in Vertical Distribution and Population Structure of the Dominant Hydrozoan Aglantha digitale in the Western Subarctic Pacific","authors":"Tianlun Gao, Mari Aizawa, A. Yamaguchi","doi":"10.3390/oceans4030017","DOIUrl":"https://doi.org/10.3390/oceans4030017","url":null,"abstract":"Hydrozoans are numerically dominant taxa in gelatinous zooplankton communities of the worldwide oceans and play an energy transfer role connecting primary producers and higher trophic level organisms. In the western subarctic Pacific, St. K2 has been established as a long-term time-series monitoring station. Various studies on zooplankton have been conducted, while hydrozoans have not been treated. This study presents the abundance, vertical distribution, and population structure of the dominant hydrozoan species (Aglantha digitale) at St. K2. Samples collected by vertical stratification samplings from eight layers of 0–1000 m both day and night during four seasons in one year. Hydrozoans occur throughout the year. The annual mean abundance of A. digitale was 198.4 ind. m−2 and composed of 91.9% of hydrozoans. The vertical distribution of A. digitale was concentrated for the epipelagic layer (0–200 m), both day and night of the most season. The bell height (BH) of A. digitale ranged between 2.4–18.9 mm. Most of the mature individuals, with gonad length larger than 10% of BH, occurred only in July. The BH of mature individuals ranged from 4.7 to 17.6 mm, with the BH of most mature individuals were larger than >10 mm. Through observation on BH at each sampling layer, small individuals with BH < 6 mm were distributed below 300 m depths throughout the seasons, expanding their vertical distribution to the deeper layers. Inter-region comparison of abundance, maturation body size, and generation length of A. digitale revealed that these parameters are varied with the region and depend on the marine ecosystem structures.","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"64 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91261755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel Interaction between a Rabbitfish and Black Corals","authors":"Erika Gress, T. Bridge, Justin Fyfe, G. Galbraith","doi":"10.3390/oceans4030016","DOIUrl":"https://doi.org/10.3390/oceans4030016","url":null,"abstract":"Herbivorous fishes play important functional roles in coral reef ecosystems, and their influence on mediating competitive dynamics between corals and macroalgae is well studied. Nonetheless, direct interactions between herbivorous fishes and corals may also be relevant, although these are less studied. Here, we describe a series of observations of schools of the herbivorous streaked rabbitfish (Siganus javus) nibbling on black corals (order Antipatharia) at the SS Yongala wreck, within the Great Barrier Reef Marine Park. We provide a hypothesis that may explain this behaviour, which, if confirmed, would represent a mechanism influencing the health of the corals. Moreover, this interaction extends the typical coral–algae competition for space paradigm and furthers knowledge of complex relationships between coral reef organisms.","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"45 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83497436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental Conditions Affect Striped Red Mullet (Mullus surmuletus) Artisanal Fisheries","authors":"F. Leitão","doi":"10.3390/oceans4030015","DOIUrl":"https://doi.org/10.3390/oceans4030015","url":null,"abstract":"The influence of environmental variables (oceanographic and climatic) on the catch rates of striped red mullet (Mullus surmuletus) by artisanal fishery was investigated using different time series models (Dynamic Factorial Analyses; Min-Max Factorial Analyses and Generalized Least Square models). Climatic and oceanographic survey data were collected at different areas of the Portuguese coast (Northwestern, Southwestern and South-Algarve) with distinct oceanographic regimes. Time series analyses reveal an effect of fishing effort in catch rates in Southwestern areas. Variability in M. surmuletus catch rates was associated to regional environmental multi-controls. Upwelling and westerly winds were the main drivers of catch rates variability across the three areas but the type of relationship varied among them. A consistent relationship between catch rates and environment factors was identified during the peak period of seasonal recruitment (spring to summer) in Southwest and South-Algarve coast, with Upwelling-summer and Sea surface temperature-spring affecting short term (lag 2 years) catch rates. In South-Algarve the increase in SST in summer, during peak of spawning, was correlated with the catch rate increase with a lag of two years. Environmental effect on catch rates reveals that fisheries management needs to accommodate the regional effect of environment variables on species biology to better define future assessment plans (catch limits).","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"36 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75232624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Microbial Community Analysis of Fur Seals and Aquaculture Salmon Gut Microbiomes in Tasmania","authors":"Erin D’Agnese, Ryan J. McLaughlin, M. Lea, E. Soto, W. Smith, J. Bowman","doi":"10.3390/oceans4020014","DOIUrl":"https://doi.org/10.3390/oceans4020014","url":null,"abstract":"In Tasmania, Australian fur seals (Arctocephalus pusillus doriferus) regularly interact with Atlantic salmon (Salmo salmar L.) aquaculture lease operations and opportunistically consume fish. The microbial communities of seals and aquaculture salmon were analyzed for potential indicators of microbial sharing and to determine the potential effects of interactions on wild seal microbiome composition. The high-throughput sequencing of the V1–V3 region of the 16S rRNA genes from the gut microbial communities of 221 fur seals was performed: 41 males caught at farms, 50 adult scats from haul-outs near farms, 24 necropsied seals, and controls from Bass Strait breeding colonies, encompassing 56 adult scats and 50 pup swabs. QIIME2 and R Studio were used for analysis. Foraging at or near salmon farms significantly shifted seal microbiome biodiversity. Taxonomic analysis showed a greater divergence in Bacteroidota representatives in male seals captured at farms compared to all other groups. Pathogens were identified that could be monitoring targets. Potential indicator amplicon sequence variants were found across a variety of taxa and could be used as minimally invasive indicators for interactions at this interface. The diversity and taxonomic shifts in the microbial communities of seals indicate a need to further study this interface for broader ecological implications.","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"06 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85972925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic algorithm and deep learning models compared for swell wave height prediction","authors":"Mourani Sinha ,&nbsp;Susmita Biswas ,&nbsp;Swadhin Banerjee","doi":"10.1016/j.dynatmoce.2023.101365","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2023.101365","url":null,"abstract":"<div><p>A comparative study has been conducted between genetic algorithm (GA) and deep learning models to predict swell wave heights in the Bay of Bengal (BOB) region. To simulate the required parameter SWAN (Simulating Waves Nearshore) model is integrated with daily 25 km wind from 2009 to 2018 for July and December separately representing the southwest and northeast monsoons respectively. For the BOB region empirical orthogonal function (EOF) analysis is applied on the swell parameter to study the spatial and temporal patterns. GA is applied on the principal component of swell wave heights to generate a forecast explicit equation and thus a basin scale EOF-GA model is established. Next a grid (20⁰ N, 90⁰E) is chosen in the head bay region and the outcomes of the standalone GA model and the deep learning models are compared to predict the time series data of swell wave heights (SWS). It is observed that the performances of the deep learning model is better during the calm conditions in December than the rough seas in July. Another grid (15⁰ N, 82⁰E) is chosen along the east coast through which the severe cyclonic storm PHETHAI (13–18 December 2018) passed and the model accuracies are tested. The EOF-GA model serves as an effective computationally cheap basin scale forecast model. Thus, both the genetic algorithm and deep learning models can be developed and utilized for normal and extreme wave prediction having wide application in the ocean engineering domains.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"102 ","pages":"Article 101365"},"PeriodicalIF":1.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49702030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The changes in dynamical tropopause associated with the Euro-Atlantic and West-Asia atmospheric blocking","authors":"Kamel Azarm,&nbsp;Ali R. Mohebalhojeh,&nbsp;Mohammad Mirzaei","doi":"10.1016/j.dynatmoce.2023.101361","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2023.101361","url":null,"abstract":"<div><p><span><span>In this study, the anomalies of dynamical tropopause associated with blocking events in wintertime of the period 1959–2020 are analyzed using the JRA-55 re-analysis data with focus on the </span>Southwest Asia. The identification and analysis of blocking properties is based on a wave breaking index. To this end, at first, the periods of occurrence of blocking are identified, and then the anomalies of the tropopause in the upstream and downstream of the relevant blocking locations in the two sectors of West Asia (Aral) and Euro–Atlantic are investigated. The analysis is carried out for the whole blocking events irrespective of their strength and blocking events with the large blocking index. Results show that the general characteristics obtained for blocking, such as location and frequency of occurrence, are in agreement with most previous studies. In addition, with the occurrence of blocking in the above-mentioned sectors, the characteristics of tropopause in the geographical area of blocking occurrence generally undergo well-defined changes. However, in the downstream of the respective </span>atmospheric blockings, corresponding to the Southwest Asia, the changes in the characteristics of tropopause are relatively small. Although the changes are small compared to those in blocking event area itself, but they are expected to have important implications for the evolution of synoptic systems. For both the two sectors, results for the population of events with large blocking index indicate a significant eastward displacement of the location of blocking relative to that of the whole population of blocking events.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"102 ","pages":"Article 101361"},"PeriodicalIF":1.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49728992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using EEMD mode decomposition in combination with machine learning models to improve the accuracy of monthly sea level predictions in the coastal area of China","authors":"Haoyu Jin ,&nbsp;Ruida Zhong ,&nbsp;Moyang Liu ,&nbsp;Changxin Ye ,&nbsp;Xiaohong Chen","doi":"10.1016/j.dynatmoce.2023.101370","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2023.101370","url":null,"abstract":"<div><p><span>In the context of climate change and human activities, the global sea level is facing a rising trend, which poses serious challenges to the ecological environment of coastal areas. In this study, we selected the monthly mean sea level (MSL) time series of 9 stations in the coastal areas of China as the research object. First, we analyzed the spatiotemporal distribution characteristics of the monthly MSL in the coastal areas of China. Secondly, we analyzed the ability of ensemble empirical mode decomposition (EEMD) to decompose the monthly MSL series. Finally, we choose three machine learning models, namely Back Propagation<span> (BP), K-Nearest Neighbor (KNN), and Long Short-Term Memory (LSTM) neural network models to compare model prediction effect between single machine learning models with machine learning models combined with EEMD. The results show that except for the YANTAI (YT) station, which showed an insignificant downward trend, the monthly MSL of other stations showed an upward trend, indicating that the coastal areas of China are facing the risk of sea level rise. EEMD can effectively reduce the complexity of the original monthly MSL time series, and different intrinsic mode functions (IMFs) reflect changes in monthly MSL at different frequencies. Comparing the single machine learning model and the machine learning model combined with EEMD, it is found that the simulation effect of the machine learning model combined with EEMD is better than that of the single model. The model with the best prediction effect on monthly MSL in the coastal areas of China is LSTM-EEMD, followed by KNN-EEMD. This study provides an important reference for systematically understanding </span></span>sea level changes and selecting an appropriate monthly MSL prediction model in the coastal areas of China.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"102 ","pages":"Article 101370"},"PeriodicalIF":1.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49702004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}