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21 pages, 13177 KiB  
Article
Links Between the Coastal Climate, Landscape Hydrology, and Beach Dynamics near Cape Vidal, South Africa
by Mark R. Jury
Coasts 2025, 5(3), 25; https://doi.org/10.3390/coasts5030025 - 18 Jul 2025
Viewed by 271
Abstract
Coastal climate processes that affect landscape hydrology and beach dynamics are studied using local and remote data sets near Cape Vidal (28.12° S, 32.55° E). The sporadic intra-seasonal pulsing of coastal runoff, vegetation, and winds is analyzed to understand sediment inputs and transport [...] Read more.
Coastal climate processes that affect landscape hydrology and beach dynamics are studied using local and remote data sets near Cape Vidal (28.12° S, 32.55° E). The sporadic intra-seasonal pulsing of coastal runoff, vegetation, and winds is analyzed to understand sediment inputs and transport by near-shore wind-waves and currents. River-borne sediments, eroded coral substrates, and reworked beach sand are mobilized by frequent storms. Surf-zone currents ~0.4 m/s instill the northward transport of ~6 105 kg/yr/m. An analysis of the mean annual cycle over the period of 1997–2024 indicates a crest of rainfall over the Umfolozi catchment during summer (Oct–Mar), whereas coastal suspended sediment, based on satellite red-band reflectivity, rises in winter (Apr–Sep) due to a deeper mixed layer and larger northward wave heights. Sediment input to the beaches near Cape Vidal exhibit a 3–6-year cycle of southeasterly waves and rainy weather associated with cool La Nina tropical sea temperatures. Beachfront sand dunes are wind-swept and release sediment at ~103 m3/yr/m, which builds tall back-dunes and helps replenish the shoreline, especially during anticyclonic dry spells. A wind event in Nov 2018 is analyzed to quantify aeolian transport, and a flood in Jan–Feb 2025 is studied for river plumes that meet with stormy seas. Management efforts to limit development and recreational access have contributed to a sustainable coastal environment despite rising tides and inland temperatures. Full article
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17 pages, 4730 KiB  
Article
Comparative Quantitative Proteomic Analysis of High and Low Toxin-Producing Karenia brevis Strains Reveals Differences in Polyketide Synthase Abundance and Redox Status of the Proteome
by Kathleen S. Rein, Ricardo Colon, Carlos R. Romagosa, Nicholas R. Ohnikian, Kirstie T. Francis and Samuel R. Rein
Mar. Drugs 2025, 23(7), 291; https://doi.org/10.3390/md23070291 - 17 Jul 2025
Viewed by 535
Abstract
To identify differentially abundant polyketide synthases (PKSs) and to characterize the biochemical consequences of brevetoxin biosynthesis, bottom-up, TMT-based quantitative proteomics and redox proteomics were conducted to compare two strains of the Florida red tide dinoflagellate Karenia brevis, which differ significantly in their [...] Read more.
To identify differentially abundant polyketide synthases (PKSs) and to characterize the biochemical consequences of brevetoxin biosynthesis, bottom-up, TMT-based quantitative proteomics and redox proteomics were conducted to compare two strains of the Florida red tide dinoflagellate Karenia brevis, which differ significantly in their brevetoxin content. Forty-eight PKS enzymes potentially linked to brevetoxin production were identified, with thirty-eight showing up to 16-fold higher abundance in the high-toxin strain. A pronounced shift toward a more oxidized redox state was observed in this strain’s proteome. Notably, 25 antioxidant-related proteins were significantly elevated, including alternative oxidase (AOX), which increased by 17-fold. These results elucidate the cellular consequences of toxin biosynthesis in K. brevis, offer new leads for the study of brevetoxin biosynthesis, and suggest a novel red tide mitigation approach targeting high toxin-producing strains. Full article
(This article belongs to the Section Marine Toxins)
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18 pages, 2901 KiB  
Article
Red Tide Detection Method Based on a Time Series Fusion Network Model: A Case Study of GOCI Data in the East China Sea
by Tianhong Ding, Zhiqiang Xu, Yunjie Wang, Qinglian Hou, Xiangyong Liu and Fengshuang Ma
Sensors 2025, 25(11), 3455; https://doi.org/10.3390/s25113455 - 30 May 2025
Viewed by 374
Abstract
In China’s coastal regions, severe seawater eutrophication has led to frequent occurrences of red tides, causing significant damage to marine fisheries and aquatic resources. Therefore, red tide detection and prediction are of great research importance. Although current deep learning-based red tide detection methods [...] Read more.
In China’s coastal regions, severe seawater eutrophication has led to frequent occurrences of red tides, causing significant damage to marine fisheries and aquatic resources. Therefore, red tide detection and prediction are of great research importance. Although current deep learning-based red tide detection methods perform well in detecting single-day red tides, they struggle with continuous multi-day detection due to insufficient mining of temporal features and difficulties in accurately capturing dynamic variations, limiting further improvements in detection accuracy. To address these issues, this study proposes a time-series fusion network model (CSF-RTDNet) for red tide detection using time-continuous GOCI data from the East China Sea. By integrating multi-temporal GOCI data, the model comprehensively captures spatiotemporal characteristics of red tides, enhancing dynamic process modeling. The CSF-RTDNet method improves feature discrimination by introducing NDVI to enhance red tide characteristics and increase separability between red tides and seawater. Additionally, an ECA channel attention mechanism is employed to fully exploit spectral features across different bands for deeper feature extraction. A novel feature extraction module, ASPC-DSC, combines atrous spatial pyramid convolution with depthwise separable convolution to effectively fuse multi-scale contextual features while improving computational efficiency. Furthermore, ConvLSTM is introduced to integrate temporal and spatial features, effectively addressing the insufficient mining of sequential characteristics in multi-day red tide detection. Experimental results demonstrate that CSF-RTDNet achieves robust detection of red tides with complex boundaries and continuous temporal patterns, attaining an accuracy of 95.89%, precision of 93.03%, recall of 96.34%, and a Kappa coefficient of 0.95. This method significantly enhances red tide detection accuracy and provides valuable technical support for marine environmental monitoring. Full article
(This article belongs to the Section Sensor Networks)
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18 pages, 11135 KiB  
Article
Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate Akashiwo sanguinea
by Jiling Pan, Ting Fang, Shuang Xie, Ning Xu and Ping Zhong
Mar. Drugs 2025, 23(4), 153; https://doi.org/10.3390/md23040153 - 31 Mar 2025
Viewed by 625
Abstract
The mixotrophic dinoflagellate Akashiwo sanguinea is known to have acute toxic effects on multiple marine organisms, while the composition and chemical properties of its toxins remain unclear. In this study, we established a method for separation and purification of A. sanguinea toxins using chromatographic [...] Read more.
The mixotrophic dinoflagellate Akashiwo sanguinea is known to have acute toxic effects on multiple marine organisms, while the composition and chemical properties of its toxins remain unclear. In this study, we established a method for separation and purification of A. sanguinea toxins using chromatographic techniques. The acetone extract of A. sanguinea exhibited higher hemolytic activity and shorter incubation time compared to methanol and ethyl acetate extracts. Five fractions were obtained by solid-phase extraction (SPE), of which SPE3 (acetone/water ratio 3:2) and SPE4 (acetone/water ratio 4:1) exhibited the highest hemolytic activities and allelopathic effects. Further purification on SPE3 and SPE4 using reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with a diode array detector (DAD) resulted in 11 subfractions, among which Fr4-5 displayed the strongest hemolytic activity. Nearly all active subfractions exhibited higher hemolytic activities incubated under light than those in the dark (p < 0.05), suggesting that A. sanguinea can produce both photosensitive and non-photosensitive toxins, with the former being the primary contributors to its hemolytic activity. Molecular characterization by UV-Vis, FTIR, and HRMS/MS analysis revealed that the structural features of Fr4-5 were highly consistent with porphyrin analogs and could be derived from chlorophyll c-related precursors. These findings highlight that the photosensitive toxins in A. sanguinea may serve dual roles in stress adaptation and ecological competition, potentially contributing to the formation of the blooms. Full article
(This article belongs to the Special Issue Marine Algal Chemical Ecology 2024)
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25 pages, 7521 KiB  
Article
Simulation of 3D Summer Circulation in the Red Sea
by Fawaz Madah and Mohammed Alsaafani
J. Mar. Sci. Eng. 2025, 13(3), 470; https://doi.org/10.3390/jmse13030470 - 28 Feb 2025
Viewed by 594
Abstract
A high-resolution numerical model called Delft3D (5 km resolution) forced with realistic high-frequency atmospheric conditions was set up to describe the circulation pattern in the Red Sea basin. The validation of the model was performed considering several tide gauge data, the SST of [...] Read more.
A high-resolution numerical model called Delft3D (5 km resolution) forced with realistic high-frequency atmospheric conditions was set up to describe the circulation pattern in the Red Sea basin. The validation of the model was performed considering several tide gauge data, the SST of AVHRR/Pathfinder, and the available literature. The model outcomes show that the general circulation pattern in the Red Sea is dominated by energetic anticyclonic eddies consistent with observations in terms of both size and magnitude. We conducted two scenarios of numerical experiments considering thermohaline and wind forcing to investigate the main driving mechanism of the circulation patterns. When simulated using full forcing (wind and thermohaline), the wind forcing experiment mostly reproduces the circulation patterns. On the other hand, thermohaline forcing generates weaker circulation patterns with cyclonic eddy dominance. The model effectively replicates the reversal of the three-layer exchange flow system at the Bab el Mandeb Strait, which is enhanced by both wind and thermohaline forcing. The simulation indicates that subsurface inflow deflects along the eastern coastline of the southern part of the Red Sea. Full article
(This article belongs to the Section Ocean and Global Climate)
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19 pages, 7401 KiB  
Article
A New Algorithm Based on the Phytoplankton Absorption Coefficient for Red Tide Monitoring in the East China Sea via a Geostationary Ocean Color Imager (GOCI)
by Xiaohui Xu, Yaqin Huang, Jian Chen and Zhi Zeng
Remote Sens. 2025, 17(5), 750; https://doi.org/10.3390/rs17050750 - 21 Feb 2025
Viewed by 610
Abstract
Rapid and accurate dynamic monitoring and quantitative analysis of red tide disasters are of significant practical importance to national economic development. Remote sensing technology is an effective means for monitoring red tides. This paper utilizes GOCI satellite data and employs a quasi-analytical algorithm [...] Read more.
Rapid and accurate dynamic monitoring and quantitative analysis of red tide disasters are of significant practical importance to national economic development. Remote sensing technology is an effective means for monitoring red tides. This paper utilizes GOCI satellite data and employs a quasi-analytical algorithm (QAA) to retrieve the spectral curves of phytoplankton absorption coefficients. On the basis of a detailed analysis of the differences in the spectral curves of the phytoplankton absorption coefficients between red tide and non-red tide waters, we establish a red tide identification algorithm for the East China Sea on the basis of phytoplankton absorption coefficients. The algorithm is applied to multiple red tide events in the East China Sea. The results indicate that this algorithm can effectively determine the occurrence locations of red tides and extract relevant information about them. Full article
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16 pages, 5786 KiB  
Article
The Development of Rapid Test Strips for Alexandrum tamarense
by Zhang Kang, Jiahang Mu, Junhua Fang, Changgong Zhang and Kefu Zhou
Chemosensors 2025, 13(2), 53; https://doi.org/10.3390/chemosensors13020053 - 5 Feb 2025
Viewed by 851
Abstract
Among algae that synthesize paralytic shellfish toxins (PSTs), Alexandrium tamarense is a widely distributed and highly dangerous species with significant impacts on the marine environment and human health. Therefore, establishing fast and reliable monitoring technology for Alexandrium tamarense is crucial. Developing effective detection [...] Read more.
Among algae that synthesize paralytic shellfish toxins (PSTs), Alexandrium tamarense is a widely distributed and highly dangerous species with significant impacts on the marine environment and human health. Therefore, establishing fast and reliable monitoring technology for Alexandrium tamarense is crucial. Developing effective detection and early warning systems for toxic red tides is of paramount importance. Conventional detection methods, such as microscopy and molecular biology, are complex and time-consuming, requiring specialized personnel and equipment, which makes them unsuitable for on-site rapid testing. In this study, we successfully developed polyclonal and monoclonal antibodies targeting Alexandrium tamarense using colloidal gold immunochromatography technology. Based on these antibodies, we created colloidal gold test strips capable of detecting Alexandrium tamarense in water samples. These test strips enable rapid detection of the target algae in aquatic environments and semi-quantitative estimation of algal concentrations using a colorimetric card. They can quickly determine whether the concentration of red tide algae has reached a critical level, allowing for timely preventive measures. This innovation holds significant practical value and broad application potential. Full article
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11 pages, 5901 KiB  
Article
Quantitative Real-Time Polymerase Chain Reaction (PCR) Assay for Rapid Monitoring of the Harmful Algal Bloom Species Cochlodinium polykrikoides
by Min-Jeong Kim, Hyun-Jung Kim, Joon Sang Park, Donhyug Kang, Sungho Cho, Hansoo Kim, Seung Ho Baek, Jordan Jun Chul Park, Jeonghoon Han, Kang Eun Kim and Seung Won Jung
J. Mar. Sci. Eng. 2025, 13(2), 277; https://doi.org/10.3390/jmse13020277 - 31 Jan 2025
Viewed by 764
Abstract
Harmful blooms of the dinoflagellate Cochlodinium polykrikoides (Margalefidinium polykrikoides) had detrimental aquacultural and economic effects globally, and to reduce the damage caused by these blooms, early biomonitoring and quantitative analysis of C. polykrikoides are of the utmost importance. Here, for the [...] Read more.
Harmful blooms of the dinoflagellate Cochlodinium polykrikoides (Margalefidinium polykrikoides) had detrimental aquacultural and economic effects globally, and to reduce the damage caused by these blooms, early biomonitoring and quantitative analysis of C. polykrikoides are of the utmost importance. Here, for the detection of C. polykrikoides using quantitative real-time polymerase chain reactions, we developed specific primers targeting the large subunit ribosomal DNA (LSU rDNA) and evaluated their applicability in the field during the occurrence of a C. polykrikoides bloom. The specific primers not only accurately detected C. polykirkoides but also had a detection performance comparable with that obtained using microscopic observations. Accordingly, we developed a system that can be used in the field and applied when red tides occur, with accurate results being obtained more than five times more rapidly than those obtained based on microscopic analysis. Collectively, our findings indicate that the C. polykrikoides bloom detection system developed in this study can be applied to rapidly detect and accurately quantify C. polykrikoides in environmental samples. Data obtained using this system could be used as a basis for developing prompt monitoring and warning systems for the early detection of C. polykrikoides blooms in the field. Full article
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25 pages, 4995 KiB  
Article
Dynamics of Lingulodinium polyedra Development in the Bulgarian Part of Black Sea (1992–2022)
by Daniela Klisarova, Dimitar Gerdzhikov, Petya Dragomirova, Nina Nikolova, Martin Gera and Petya Veleva
Diversity 2025, 17(2), 105; https://doi.org/10.3390/d17020105 - 30 Jan 2025
Viewed by 992
Abstract
Long-term data on the phytoplankton of the Bulgarian Black Sea (BBS) coast describe three states for the ecosystem: a “pristine” reference phase (1954–1970 years); an intensive anthropogenic eutrophication (1970–1992 years) phase; and a post-eutrophication phase after the early 1990s of the 20th century. [...] Read more.
Long-term data on the phytoplankton of the Bulgarian Black Sea (BBS) coast describe three states for the ecosystem: a “pristine” reference phase (1954–1970 years); an intensive anthropogenic eutrophication (1970–1992 years) phase; and a post-eutrophication phase after the early 1990s of the 20th century. The eutrophication period is characterised by ecosystem degradation and intense phytoplankton blooms, some of which were formed by the potentially toxic species Lingulodinium polyedra. This warm-water species is a red tide former that is associated with fish and shellfish mortality events. In the 1980s, L. polyedra reached the highest biomass of 84.4 g·m−3 in Varna Bay, BBS. The aim of this study (1992–2022) was to provide an overview of the development of L. polyedra in the phytoplankton biocenosis in the Bulgarian part of the Black Sea, taking into account the influence of anthropogenic stress and the climatic variables NAO and SST on the development of the species population. An analysis of the distribution of the dinoflagellate L. polyedra is based on a total of 5126 phytoplankton samples collected during the period between 1992 and 2022 under projects led by the Institute of Fish Resources, Varna. The samples were analyzed using standard methods validated for the Black Sea, and phytoplankton abundance and biomass were determined. The species are most abundant in summer in the coastal marine areas exposed to anthropogenic influence. During the analyzed period, a decrease in the abundance and biomass of L. polyedra in Bulgarian Black Sea waters were observed. It was found that the influence of climatic factors such as NAO and SST on the species population is from weak to moderate, and the correlation with NAO cycles is better expressed. Full article
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15 pages, 3232 KiB  
Article
Analysis on Bacterial Community of Noctiluca scintillans Algal Blooms Near Pingtan Island, China
by Yunguang Liu, Yutong Zhang, Haiyan Yao, Zewen Zheng, Wenbo Zhao and Gang Lin
Biology 2025, 14(1), 101; https://doi.org/10.3390/biology14010101 - 20 Jan 2025
Cited by 2 | Viewed by 1169
Abstract
Noctiluca scintillans, known as a global red tide species, is a common red tide species found in Pingtan Island. To examine the bacterial community structure in different environments during the red tide period of N. scintillans on Pingtan Island, samples were collected [...] Read more.
Noctiluca scintillans, known as a global red tide species, is a common red tide species found in Pingtan Island. To examine the bacterial community structure in different environments during the red tide period of N. scintillans on Pingtan Island, samples were collected from the Algal Bloom Area (ABA), Transition Area (TA), and Non-Algal Bloom Area (NBA) on 6 April 2022, and the environmental physicochemical factors and bacterial community were determined. The outbreak of N. scintillans red tide significantly impacted the water quality and bacterial community structure in the affected sea area. The water quality in the ABA has deteriorated markedly, with the contents of COD, NH4+-N, and PO43− in the ABA being significantly higher than those in the TA and NBA, while the pH is significantly lower than that in the TA and NBA. The richness, diversity, and evenness of the bacterial community in the ABA are all lower than those of the TA and NBA. For instance, the Shannon index values of the three sampling points are 4.41, 5.41, and 6.37, respectively. At the phylum level, the dominant bacterial phyla in the ABA are Proteobacteria, Firmicutes, and Cyanobacteria; in the TA, they are Proteobacteria, Bacteroidetes, and Firmicutes; and in the NBA, they are Proteobacteria, Bacteroidetes, and Cyanobacteria. At the genus level, the dominant bacterial genera in the ABA are Vibrio, Carnobacterium, Candidatus_Megaira, Planktomarina, and Pseudoalteromonas; in the TA, they are Vibrio, Planktomarina, Lentibacter, Glaciecola, and Jannaschia; and in the NBA, they are Planktomarina, Amylibacter, NS5_marine_group, Aurantivirga, and marine_metagenome. In the ABA, the combined proportion of Vibrio and Carnobacterium exceeds 50%, with Vibrio_splendidus accounting for 93% of the total Vibrio population. These research results can provide a scientific basis for clarifying the environmental characteristics and bacterial composition during the large-scale N. scintillans red tide in Pingtan Island. Full article
(This article belongs to the Special Issue Biology, Ecology and Management of Harmful Algae)
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16 pages, 1650 KiB  
Article
Multi-Step Forecasting of Chlorophyll Concentration with Multi-Attention Collaborative Network
by Yingying Jin, Feng Zhang, Xia Wang, Lei Wang, Kuo Chen, Liangyu Chen, Yutao Qin and Ping Wu
J. Mar. Sci. Eng. 2025, 13(1), 151; https://doi.org/10.3390/jmse13010151 - 16 Jan 2025
Viewed by 804
Abstract
In a marine environment, the concentration of chlorophyll is an important indicator of quality, which is also considered an indicator used to predict the marine ecological environment, which is further considered an important means of predicting red tide disasters. Although existing methods for [...] Read more.
In a marine environment, the concentration of chlorophyll is an important indicator of quality, which is also considered an indicator used to predict the marine ecological environment, which is further considered an important means of predicting red tide disasters. Although existing methods for predicting chlorophyll concentration have achieved encouraging performance, there are still two limitations: (i) they primarily focus on the correlation between variables while ignoring negative noise from non-predictive variables and (ii) they are unable to distinguish the impact of chlorophyll from that of non-predictive variables on chlorophyll concentration at future time points. In order to overcome these obstacles, we propose a Multi-Attention Collaborative Network (MACN)-based triangle-structured prediction system. In particular, the MACN consists of two branch networks, with one named NP-net, focusing on non-predictive variables, and the other named T-net, applied to the target variable. NP-net incorporates variable-distillation attention to eliminate the negative effects of irrelevant variables, and its outputs are used as auxiliary information for T-net. T-net works on the target variable, and both its encoder and decoder are related to NP-net to use the output of NP-net for assistance in learning and prediction. Two actual datasets are used in the experiments, which show that the MACN performs better than various kinds of state-of-the-art techniques. Full article
(This article belongs to the Section Marine Environmental Science)
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16 pages, 12816 KiB  
Article
Influence of Nutrient Desorbed from Sediments and Density Variations Driven by Organic Matter on Flow Patterns in Closed Water Bodies
by Jinichi Koue
Water 2025, 17(1), 100; https://doi.org/10.3390/w17010100 - 2 Jan 2025
Cited by 1 | Viewed by 998
Abstract
In enclosed water bodies, water quality deterioration has emerged as a critical environmental issue. Eutrophication contributes to phenomena such as red tides and blue tides, raising concerns about foul odors and adverse impacts on surrounding aquatic ecosystems. Despite efforts to reduce nutrient loading [...] Read more.
In enclosed water bodies, water quality deterioration has emerged as a critical environmental issue. Eutrophication contributes to phenomena such as red tides and blue tides, raising concerns about foul odors and adverse impacts on surrounding aquatic ecosystems. Despite efforts to reduce nutrient loading through water quality management measures, reports of stagnant or a worsening water quality persist. One key factor is the accumulation of nutrients in deep layers. Nutrient-rich fluids form density currents along the lakebed, transporting nutrients and organic matter to deeper regions. This study investigates the hydrodynamic properties of a nutrient release from the lakebed in Lake Biwa using hydrodynamic and ecosystem models. The results reveal that a nutrient release triggers plume formation along sloping lakebed surfaces, facilitating the transport of nutrients and dissolved organic matter. Additionally, water circulation driven by density currents and nutrient concentrations along the slopes generate compensatory flows, leading to dynamic variability in Lake Biwa’s hydrodynamics. Full article
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14 pages, 3475 KiB  
Article
Near-Inertial Oscillations of Thermocline in the Shelf Area off Vladivostok, the Sea of Japan, from a Set of Thermostrings
by Olga Trusenkova, Igor Yaroshchuk, Alexandra Kosheleva, Aleksandr Samchenko, Alexander Pivovarov and Vyacheslav Dubina
J. Mar. Sci. Eng. 2024, 12(12), 2263; https://doi.org/10.3390/jmse12122263 - 9 Dec 2024
Viewed by 883
Abstract
The shelf area off Vladivostok in the Sea of Japan is known by the intense internal wave activity investigated for many years. The present contribution to these studies is based on data collected on 3–14 October 2022, from four moorings aligned across isobaths [...] Read more.
The shelf area off Vladivostok in the Sea of Japan is known by the intense internal wave activity investigated for many years. The present contribution to these studies is based on data collected on 3–14 October 2022, from four moorings aligned across isobaths and equipped with thermostrings. Multivariate analysis is performed in the depth–time domain, while timescales and directions and speeds of temperature anomaly movement are estimated from wavelet transform. Approximately 50% of the variance results from vertical stratification changes, i.e., thermocline deepening or shoaling, and temperature anomalies on different timescales moved towards the shoaling seafloor. For the first time, near-inertial (NI) oscillations are detected throughout the record and turn out to be the most intense among the 6 to 70 h timescales, moving with the speeds of 0.41–0.55 m/s, although previous attention was paid to the semidiurnal internal tide. A frequency decrease, i.e., red shift, of the NI oscillations is detected towards shallower water, with the frequency eventually becoming subinertial, and is explained by anticyclonic relative vorticity at the eastern side of the mushroom-like structure detected from thermal satellite imagery. The semidiurnal and two-day oscillations were detected, moving with the speeds of 0.95–1.11 and 0.15–1.17 m/s, respectively. The two-day timescale, never reported before, is considered as a difference one caused by nonlinearity. These results are interpreted as the propagation of an internal wave generated at the steep slope offshore to the inner shelf. Full article
(This article belongs to the Section Physical Oceanography)
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24 pages, 6941 KiB  
Article
Discriminating Seagrasses from Green Macroalgae in European Intertidal Areas Using High-Resolution Multispectral Drone Imagery
by Simon Oiry, Bede Ffinian Rowe Davies, Ana I. Sousa, Philippe Rosa, Maria Laura Zoffoli, Guillaume Brunier, Pierre Gernez and Laurent Barillé
Remote Sens. 2024, 16(23), 4383; https://doi.org/10.3390/rs16234383 - 23 Nov 2024
Cited by 1 | Viewed by 1782
Abstract
Coastal areas support seagrass meadows, which offer crucial ecosystem services, including erosion control and carbon sequestration. However, these areas are increasingly impacted by human activities, leading to habitat fragmentation and seagrass decline. In situ surveys, traditionally performed to monitor these ecosystems, face limitations [...] Read more.
Coastal areas support seagrass meadows, which offer crucial ecosystem services, including erosion control and carbon sequestration. However, these areas are increasingly impacted by human activities, leading to habitat fragmentation and seagrass decline. In situ surveys, traditionally performed to monitor these ecosystems, face limitations on temporal and spatial coverage, particularly in intertidal zones, prompting the addition of satellite data within monitoring programs. Yet, satellite remote sensing can be limited by too coarse spatial and/or spectral resolutions, making it difficult to discriminate seagrass from other macrophytes in highly heterogeneous meadows. Drone (unmanned aerial vehicle—UAV) images at a very high spatial resolution offer a promising solution to address challenges related to spatial heterogeneity and the intrapixel mixture. This study focuses on using drone acquisitions with a ten spectral band sensor similar to that onboard Sentinel-2 for mapping intertidal macrophytes at low tide (i.e., during a period of emersion) and effectively discriminating between seagrass and green macroalgae. Nine drone flights were conducted at two different altitudes (12 m and 120 m) across heterogeneous intertidal European habitats in France and Portugal, providing multispectral reflectance observation at very high spatial resolution (8 mm and 80 mm, respectively). Taking advantage of their extremely high spatial resolution, the low altitude flights were used to train a Neural Network classifier to discriminate five taxonomic classes of intertidal vegetation: Magnoliopsida (Seagrass), Chlorophyceae (Green macroalgae), Phaeophyceae (Brown algae), Rhodophyceae (Red macroalgae), and benthic Bacillariophyceae (Benthic diatoms), and validated using concomitant field measurements. Classification of drone imagery resulted in an overall accuracy of 94% across all sites and images, covering a total area of 467,000 m2. The model exhibited an accuracy of 96.4% in identifying seagrass. In particular, seagrass and green algae can be discriminated. The very high spatial resolution of the drone data made it possible to assess the influence of spatial resolution on the classification outputs, showing a limited loss in seagrass detection up to about 10 m. Altogether, our findings suggest that the MultiSpectral Instrument (MSI) onboard Sentinel-2 offers a relevant trade-off between its spatial and spectral resolution, thus offering promising perspectives for satellite remote sensing of intertidal biodiversity over larger scales. Full article
(This article belongs to the Section Ecological Remote Sensing)
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16 pages, 2711 KiB  
Case Report
Endocrine Perspective of Cutaneous Lichen Amyloidosis: RET-C634 Pathogenic Variant in Multiple Endocrine Neoplasia Type 2
by Alexandru-Florin Florescu, Oana-Claudia Sima, Claudiu Nistor, Mihai-Lucian Ciobica, Mihai Costachescu, Mihaela Stanciu, Denisa Tanasescu, Florina Ligia Popa and Mara Carsote
Clin. Pract. 2024, 14(6), 2284-2299; https://doi.org/10.3390/clinpract14060179 - 29 Oct 2024
Cited by 1 | Viewed by 1502
Abstract
Background: Medullary thyroid carcinoma (MTC), the third most frequent histological type of thyroid malignancy, may be found isolated or as part of multiple endocrine neoplasia type 2 (MEN2). One particular subtype of this autosomal dominant-transmitted syndrome includes an association with cutaneous lichen amyloidosis, [...] Read more.
Background: Medullary thyroid carcinoma (MTC), the third most frequent histological type of thyroid malignancy, may be found isolated or as part of multiple endocrine neoplasia type 2 (MEN2). One particular subtype of this autosomal dominant-transmitted syndrome includes an association with cutaneous lichen amyloidosis, although, generally, a tide genotype–phenotype correlation is described in patients who carry RET proto-oncogene pathogenic variants. Methods: Our objective was to provide an endocrine perspective of a case series diagnosed with RET-positive familial MTC associated with cutaneous primary lichen amyloidosis amid the confirmation of MEN2. Six members of the same family had cutaneous lesion with different features (from hyperpigmented, velvety to red/pink appearance) and four of them harbored a RET pathogenic variant at 634 codon (exon 11): c.1900T>G, p.634G (TGC634CGC). Results: All six patients were females with the lesion at the interscapular region. Except for two women, four of these subjects were investigated and had MTC (three of them with postoperatory confirmation). The youngest affected individual was 6 years old. The three adult females were confirmed with RET pathogenic variant during their 30s, while the girl underwent the familial screening as a newborn. None of them had primary hyperparathyroidism until the present time, except for one subject, and two out of the three adults also had bilateral pheochromocytoma. Notably, all patients were rather asymptomatic from the endocrine perspective at the moment when endocrine tumor/cancer was confirmed, and the skin was progressively affected a few years before the actual MEN2 confirmation. Conclusions: This case series highlights the following key message: awareness of the dermatologic findings in MTC/MEN2 patients is essential since lesions such as cutaneous lichen amyloidosis might represent the skin signature of the endocrine condition even before the actual endocrine manifestations. These data add to the limited published reports with respect to this particular presentation, noting the fact that RET-C634 is the most frequent pathogenic variant in MEN2-associated lichen amyloidosis; females are more often affected; the interscapular region is the preferred site; the age of diagnosis might be within the third decade of life, while we reported one of the youngest patients with the lesion. The same RET pathogenic variant is not associated with the same dermatologic features as shown in the vignette. The same RET mutation does not mean that all family members will present the same skin anomaly. Full article
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