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19 pages, 15746 KiB  
Article
Description of a New Eyeless Cavefish Using Integrative Taxonomic Methods—Sinocyclocheilus wanlanensis (Cypriniformes, Cyprinidae), from Guizhou, China
by Yewei Liu, Tingru Mao, Hiranya Sudasinghe, Rongjiao Chen, Jian Yang and Madhava Meegaskumbura
Animals 2025, 15(15), 2216; https://doi.org/10.3390/ani15152216 - 28 Jul 2025
Viewed by 787
Abstract
China’s southwestern karst landscapes support remarkable cavefish diversity, especially within Sinocyclocheilus, the world’s largest cavefish genus. Using integrative taxonomic methods, we describe Sinocyclocheilus wanlanensis sp. nov., found in a subterranean river in Guizhou Province. This species lacks horn-like cranial structures; its eyes [...] Read more.
China’s southwestern karst landscapes support remarkable cavefish diversity, especially within Sinocyclocheilus, the world’s largest cavefish genus. Using integrative taxonomic methods, we describe Sinocyclocheilus wanlanensis sp. nov., found in a subterranean river in Guizhou Province. This species lacks horn-like cranial structures; its eyes are either reduced to a dark spot or absent. It possesses a pronounced nuchal hump and a forward-protruding, duckbill-shaped head. Morphometric analysis of 28 individuals from six species shows clear separation from related taxa. Nano-CT imaging reveals distinct vertebral and cranial features. Phylogenetic analyses of mitochondrial cytb and ND4 genes place S. wanlanensis within S. angularis group as sister to S. bicornutus, with p-distances of 1.7% (cytb) and 0.7% (ND4), consistent with sister-species patterns within the genus. Sinocyclocheilus wanlanensis is differentiated from S. bicornutus by its eyeless or degenerate-eye condition and lack of bifurcated horns. It differs from S. zhenfengensis, its morphologically closest species, in having degenerate or absent eyes, shorter maxillary barbels, and pelvic fins that reach the anus. The combination of morphological and molecular evidence supports its recognition as a distinct species. Accurate documentation of such endemic and narrowly distributed taxa is important for conservation and for understanding speciation in cave habitats. Full article
(This article belongs to the Section Aquatic Animals)
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16 pages, 5180 KiB  
Article
Establishing a Geological Knowledge Base for Braided River Deltas Using Google Earth
by Xiaoyu Yu, Mengjiao Dou and Shaohua Li
Appl. Sci. 2025, 15(11), 6186; https://doi.org/10.3390/app15116186 - 30 May 2025
Viewed by 362
Abstract
This study quantifies morphological features of global braided river deltas using Google Earth imagery, analyzing eight systems (e.g., Yukon–Kuskokwim, Poyang Lake, Lena River deltas). Methods include listwise deletion for missing data (retaining 87% of Poyang Lake delta samples) and sensitivity analysis (threshold changes [...] Read more.
This study quantifies morphological features of global braided river deltas using Google Earth imagery, analyzing eight systems (e.g., Yukon–Kuskokwim, Poyang Lake, Lena River deltas). Methods include listwise deletion for missing data (retaining 87% of Poyang Lake delta samples) and sensitivity analysis (threshold changes ≤2.4%). Nonparametric tests (Kruskal–Wallis, H = 12.73, p = 0.005) show significant differences in bifurcation angles across deltas, with the wave-dominated Po River (59.2°) having an 18% higher 80% threshold the than tide-dominated Poyang Lake (50.1°, p = 0.003). Key quantitative results include the following: 1.65% of bifurcation angles cluster at 30–60°, differing from fan deltas (p < 0.01); wavelength–amplitude relationships are nonlinear (R2 = 0.537–0.913), with positive slopes indicating a high sediment supply (e.g., Yukon–Kuskokwim) and negative slope channel avulsion (e.g., Poyang Lake); bifurcation spacing correlates with the sediment supply—54% of Poyang Lake spacings < 2000 m (dense networks) vs. 80% of Lena River spacings < 15,000 m (stable channels). The resulting dataset enables global, remote-sensing-based comparisons, providing thresholds for sedimentary modeling and reservoir prediction. Moderate missing data (≤13%) minimally affect results, though high-missingness cases need further analysis. This study replaces empirical rules with statistical validation, showing that morphometric differences reflect depositional dynamics, which are critical for reservoir heterogeneity assessments. Full article
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16 pages, 4926 KiB  
Article
Study on Characteristics of the Water Diversion Ratio and Impact of the Diversion Dyke at South and North Ports of the Minjiang River During Wet Season
by Cheng Chen, Weijia Yang, Zhihui Wang, Kailong Huangfu, Feng Cai, Haoyan Chen and Youlin Chen
Water 2025, 17(8), 1183; https://doi.org/10.3390/w17081183 - 15 Apr 2025
Viewed by 359
Abstract
The hydrodynamic processes in estuarine regions play a crucial role in the morphological and ecological stability of coastal zones. As a key hydrodynamic characteristic of bifurcated rivers, the water diversion ratio (WDR) influences flow distribution, sediment transport, and shoreline changes in estuaries. This [...] Read more.
The hydrodynamic processes in estuarine regions play a crucial role in the morphological and ecological stability of coastal zones. As a key hydrodynamic characteristic of bifurcated rivers, the water diversion ratio (WDR) influences flow distribution, sediment transport, and shoreline changes in estuaries. This study focuses on the lower Minjiang River and employs a MIKE 21-based two-dimensional hydrodynamic model to quantify the WDR variations between the South and North Ports on the scale of a tidal cycle during the wet season and to reveal the regulatory effects of diversion dyke length and angle. The results indicate that the WDR of the North Port exhibits significant variation with tidal stages. The WDR of the North Port increases with the length of the diversion dyke. The current 110 m-long dyke has little effect on regulating water flow between the North and South Ports, and its WDR remains unaffected by changes in angle. In contrast, a 450 m-long dyke is highly sensitive to angle variations. This study not only provides scientific support for channel regulation in the lower Minjiang River but also offers indirect insights into shoreline stability and ecological management under the combined influence of human activities and natural processes in estuarine environments. Full article
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11 pages, 1620 KiB  
Article
Ancistrohaptor forficata sp. n. (Monopisthocotyla, Dactylogyridae): A New Parasite of Triportheus signatus (Characiformes, Triportheidae) from the Salgado River, Brazil
by Maria Fernanda Barros Gouveia Diniz, Wallas Benevides Barbosa de Sousa, Priscilla de Oliveira Fadel Yamada and Fábio Hideki Yamada
Parasitologia 2025, 5(1), 3; https://doi.org/10.3390/parasitologia5010003 - 16 Jan 2025
Cited by 1 | Viewed by 824
Abstract
The genus Ancistrohaptor was proposed to accommodate monopisthocotylans flatworms parasitic on the gills of species of the genus Triportheus in Manaus, Amazonas state, Brazil. Its main characteristics are (a) an accessory piece of the male copulatory organ composed of two distinct parts; (b) [...] Read more.
The genus Ancistrohaptor was proposed to accommodate monopisthocotylans flatworms parasitic on the gills of species of the genus Triportheus in Manaus, Amazonas state, Brazil. Its main characteristics are (a) an accessory piece of the male copulatory organ composed of two distinct parts; (b) dextral or dextroventral vaginal openings; and (c) large ventral anchors with elongated shafts. A new species of Ancistrohaptor was found to parasitize the gills of Triportheus signatus collected from the Salgado River, Ceará State, Brazil. A new species of Monopisthocotyla was collected and described. Ancistrohaptor forficata sp. n. is primarily characterized by having a male copulatory organ with less than one turn, the presence of an articulated accessory piece with a concave rod-shaped termination, and a free accessory piece that is clamp shaped and bifurcated, as well as a dorsal bar with shading present in its medial part. This is the fourth species description of the genus Ancistrohaptor for fish of the genus Triportheus and the first record for T. signatus and the aquatic ecosystems of the Caatinga domain. Full article
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22 pages, 5881 KiB  
Article
Two New Species of Urocleidoides (Monopisthocotyla: Dactylogyridae) Parasitizing the Gills of Cyphocharax modestus (Characiformes: Curimatidae) Supported by Morphological and Molecular Data
by Priscilla de Oliveira Fadel Yamada, Melissa Miyuki Osaki-Pereira, Aline Angelina Acosta, Mariana Bertholdi Ebert and Reinaldo José da Silva
Diversity 2024, 16(12), 716; https://doi.org/10.3390/d16120716 - 23 Nov 2024
Cited by 3 | Viewed by 976
Abstract
The present study describes two new species of monopisthocotylans parasitizing the gills of Cyphocharax modestus (Characiformes: Curimatidae) from two localities of the Upper Paraná River basin, state of São Paulo, Brazil. Urocleidoides saghirus n. sp. and Urocleidoides taquariensis n. sp. differ from other [...] Read more.
The present study describes two new species of monopisthocotylans parasitizing the gills of Cyphocharax modestus (Characiformes: Curimatidae) from two localities of the Upper Paraná River basin, state of São Paulo, Brazil. Urocleidoides saghirus n. sp. and Urocleidoides taquariensis n. sp. differ from other congeners mainly in the morphology of the accessory piece: comprising two subunits (one scythe-shaped subunit, and one adjacent piece with a narrow base broadening towards the upper end, which is axe-shaped) in Urocleidoides saghirus n. sp., and a straight rod with a bifurcated proximal portion, a distal portion ending in a point, and two curved handles arising from the medial portion and uniting close to the distal portion in Urocleidoides taquariensis n. sp. The phylogenetic analyses revealed Urocleidoides to be non-monophyletic, indicating the need for a taxonomic review. This study provides the first molecular sequences for Urocleidoides spp. parasitizing Curimatidae, including the newly described species. These findings revealed distinct clades and suggested possible host specificity, underscoring the importance of additional research to better understand the phylogenetic relationships within the genus. Full article
(This article belongs to the Section Animal Diversity)
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21 pages, 8592 KiB  
Article
Numerical Simulation of Habitat Restoration for Floating Fish Eggs in the Upper Yangtze River Tributaries
by Pingyi Wang, Haofeng Zhang, Jian Li and Ye Tian
Sustainability 2024, 16(5), 1799; https://doi.org/10.3390/su16051799 - 22 Feb 2024
Cited by 2 | Viewed by 1310
Abstract
The upper reaches of the Yangtze River not only serve as a crucial waterway in China’s southwestern region but also function as a conservation area for rare fish species. Recognizing the tendency of current navigation channel improvement projects to overlook the impact on [...] Read more.
The upper reaches of the Yangtze River not only serve as a crucial waterway in China’s southwestern region but also function as a conservation area for rare fish species. Recognizing the tendency of current navigation channel improvement projects to overlook the impact on aquatic habitats and the limitations of existing habitat assessment systems, this study specifically focuses on the bifurcation section of the upper Yangtze River. To address these issues, a two-dimensional mathematical model is established to simulate and validate various improvement schemes. An analysis of the flow conditions necessary for fish migration and spawning in this section is conducted, determining optimal flow rates and water levels during spawning and migration periods. A suitability assessment system for spawning and migration is then established, utilizing the four major Chinese carps as representative fish species for evaluation. Through a comprehensive analysis of the results, rational improvement schemes are identified. The findings underscore the importance of considering elevation of dam crest during the construction of sub-dams to regulate the navigation channel, particularly regarding its impact on fish habitats during the dry season. In this plan, the weighted available area of the spawning ground increased by 189,251 m2, 165,860 m2, 89,527 m2, 66,542 m2, and 47,182 m2 under five conditions. Additionally, the evaluation indexes PPA, HFI, and CQI showed increases of 5.011%, 4.176%, and 2.901%, respectively. Moreover, this study refines fish habitats based on their reproductive and living habits, thereby enhancing existing habitat assessment models. Full article
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13 pages, 9942 KiB  
Article
Anomalies of Sponge Spicules: Exploring Links to Environmental Pollution
by Stefan Andjus, Bojana Tubić, Božica Vasiljević, Vera Nikolić and Momir Paunović
Water 2024, 16(2), 332; https://doi.org/10.3390/w16020332 - 19 Jan 2024
Cited by 1 | Viewed by 2592
Abstract
The aim of this study was to assess the frequency of spicule malformations in freshwater sponges in relation to selected environmental parameters of the streams and the presence of river pollutants. A total of 50 sponge samples were collected from ten rivers in [...] Read more.
The aim of this study was to assess the frequency of spicule malformations in freshwater sponges in relation to selected environmental parameters of the streams and the presence of river pollutants. A total of 50 sponge samples were collected from ten rivers in Serbia. Selected parameters of the water varied considerably at every site where sponges were found. After spicule preparation, the samples were subjected to morphological analysis by light and scanning electron microscopy, and the number of anomalies were recorded (spicules with bulbous enlargements, sharply bent, bifurcated, scissor- and cross-like, and t-shaped). The frequencies and types of malformations within the analyzed specimens varied from 1 to 100 per 1000 spicules, with an average number of 12 per 1000. The main types of anomalies were single- and double-bent spicules. The highest number of anomalies was found in a specimen of Eunapius fragilis collected at Markovac (Velika Morava River), and the lowest number was found in a specimen of Ephydatia fluviatilis from Kanjiža (Tisa River). The sites with the lowest and the highest numbers of anomalies showed statistically significant differences in concentrations of ammonia, orthophosphates, sodium, chloride, manganese, and lead. This study indicates that several pollutants potentially affect the occurrence of spicule anomalies. Full article
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28 pages, 10082 KiB  
Article
Spatiotemporal Pattern of Carbon Compensation Potential and Network Association in Urban Agglomerations in the Yellow River Basin
by Haihong Song, Yifan Li, Liyuan Gu, Jingnan Tang and Xin Zhang
ISPRS Int. J. Geo-Inf. 2023, 12(10), 435; https://doi.org/10.3390/ijgi12100435 - 23 Oct 2023
Cited by 5 | Viewed by 2192
Abstract
The Yellow River Basin is an important energy base and economic belt in China, but its water resources are scarce, its ecology is fragile, and the task of achieving the goal of carbon peak and carbon neutrality is arduous. Carbon compensation potential can [...] Read more.
The Yellow River Basin is an important energy base and economic belt in China, but its water resources are scarce, its ecology is fragile, and the task of achieving the goal of carbon peak and carbon neutrality is arduous. Carbon compensation potential can also be used to study the path to achieving carbon neutrality, which can clarify the potential of one region’s carbon sink surplus to be compensated to the other areas. Still, there needs to be more research on the carbon compensation potential of the Yellow River Basin. Therefore, this study calculated the carbon compensation potential using the β convergence test and parameter comparison method. With the help of spatial measurement tools such as GIS, GeoDa, Stata, and social network analysis methods, the spatiotemporal pattern and network structure of the carbon compensation potential in the Yellow River Basin were studied from the perspective of urban agglomeration. The results demonstrate the following: (1) The overall carbon compensation rate of the YRB showed a downward trend from 2005 to 2019, falling by 0.94, and the specific pattern was “high in the northwest and low in the southeast”. The spatial distribution is roughly spread along the east–west axis, and the distribution axis and the center of gravity keep shifting to the northwest. It also showed a weak divergence and a bifurcation trend. (2) The carbon compensation rate in the YRB passed the spatial correlation and β convergence tests, demonstrating the existence of spatial correlation and a “catch-up effect” among cities. (3) The overall distribution pattern of the carbon compensation potential in the YRB is a “low in the west and high in the east” pattern, and its value increased by 8.86% during the sampled period. (4) The network correlation of carbon compensation potential in the YRB has been significantly enhanced, with the downstream region being more connected than the upstream region. (5) The Shandong Peninsula Urban Agglomeration has the largest network center, followed by the Central Plains Urban Agglomeration, and the Ningxia along the Yellow River Urban Agglomeration has the fewest linked conduction paths. According to the research results, accurate and efficient planning and development suggestions are proposed for urban agglomeration in the Yellow River Basin. Full article
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21 pages, 15310 KiB  
Article
Numerical–Experimental Study of Scour in the Discharge of a Channel: Case of the Carrizal River Hydraulic Control Structure, Tabasco, Mexico
by Christian Caballero, Alejandro Mendoza, Moisés Berezowsky and Abel Jiménez
Water 2023, 15(15), 2788; https://doi.org/10.3390/w15152788 - 1 Aug 2023
Cited by 2 | Viewed by 1908
Abstract
Scour processes occur, among other causes, by the interaction of flow and sediment transport around structures built within a river. It is important to identify the location and quantify the magnitude of scour to avoid under or overestimation since the former puts the [...] Read more.
Scour processes occur, among other causes, by the interaction of flow and sediment transport around structures built within a river. It is important to identify the location and quantify the magnitude of scour to avoid under or overestimation since the former puts the structure at risk and the latter demands an excessive economic cost. The data obtained from a physical model with a scale of 1:60 (without distortion) was used to assess the accuracy of a 2D free-surface numerical model (2DH) in predicting maximum scour. The physical model corresponds to the hydraulic-regulating structure located at the entrance of the Carrizal River, tributary to the Mezcalapa River bifurcation, located in Tabasco, Mexico. The scour is produced by the effect of a jet generated by a discharge channel. The maximum experimental scour was compared to the results of a numerical model and the estimation of four empirical equations: Breusers, Farhoudi and Smith, Negm, and Dietz. Setting an acceptance threshold of 75% accuracy, only the Breusers method provided values close to the measured values, and the numerical model failed to reproduce the location and magnitude of maximum scour, yet when the 2DH model was calibrated for secondary flow effects in the hydraulics. This indicates that the application of 2D models for the estimation of scour caused by jets may not provide good results when secondary currents are developed. Full article
(This article belongs to the Topic Research on River Engineering)
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20 pages, 10508 KiB  
Article
Driving Forces and Influences of Flood Diversion on Discharge Fraction and Peak Water Levels at an H-Shaped Compound River Node in the Pearl River Delta, South China
by Yongjun Fang, Xianwei Wang, Jie Ren, Huan Liu and Ya Wang
Water 2023, 15(11), 1970; https://doi.org/10.3390/w15111970 - 23 May 2023
Cited by 5 | Viewed by 1974
Abstract
The SiXianJiao (SXJ) is the first-order exchange node of the West River and the North River and redistributes water (mass) to the downstream river network in the Pearl River Delta (PRD), South China. The lateral SXJ waterway plays a critical role in flow [...] Read more.
The SiXianJiao (SXJ) is the first-order exchange node of the West River and the North River and redistributes water (mass) to the downstream river network in the Pearl River Delta (PRD), South China. The lateral SXJ waterway plays a critical role in flow (mass) diversion between the West River and the North River, forming a unique H-shaped compound river node. Previous studies mainly focused on Y-shaped bifurcation and confluence nodes, and there is a lack of research on deltaic H-shaped river nodes. This study established the Delft3D model to investigate the driving forces and influences of flood diversion at the SXJ node. The results showed that the H-shaped SXJ river node was usually in hydraulic equilibrium but was often disturbed by large water level differences between the two rivers, due to unbalanced and asynchronous upstream flood waves. The large water level differences drove mutual flood diversion through the lateral SXJ waterway, which synchronized the downstream discharge and reduced the peak water levels (flood hazards), resulting in similar water levels or hydraulic equilibrium in the two rivers. There exists a critical flow fraction—about 75.9% (West River)—at which the incoming flow from both rivers presents similar water levels at the SXJ node, resulting in little flood diversion. Above the threshold, the flood water will divert from the West River to the North River with a maximum rate of −11,900 m3/s, accounting for 20% of the West River, reducing the peak water level up to 1.48 m at Makou. Below the threshold, the flood water will divert from the North River to the West River with a maximum rate of 11,990 m3/s, accounting for 55% of the North River, reducing the peak water level up to 6.63 m at Sanshui. Meanwhile, the discharge fraction at downstream Makou (Sanshui) maintained a near-constant value during individual floods and fluctuated around 76.6% (23.4%). This critical discharge fraction and the analytical approach are of significance in flood-risk management and hydraulic engineering design in the PRD. The concept model of the H-shaped compound river node clearly elucidates the flood diversion mechanism via the lateral SXJ waterway and may work for other similar river nodes as well. Full article
(This article belongs to the Special Issue A Safer Future—Prediction of Water-Related Disasters)
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16 pages, 8003 KiB  
Article
Methodology for Identification of the Key Levee Parameters for Limit-State Analyses Based on Sequential Bifurcation
by Nicola Rossi, Mario Bačić, Lovorka Librić and Meho Saša Kovačević
Sustainability 2023, 15(6), 4754; https://doi.org/10.3390/su15064754 - 7 Mar 2023
Viewed by 1384
Abstract
Levees are linear structures that are continuously reconstructed throughout the years and whose construction and behavior depends on local soil conditions, as well as requirements regarding impermeability and mechanical resistance. This results in various levee cross sections, even within the same levee. In [...] Read more.
Levees are linear structures that are continuously reconstructed throughout the years and whose construction and behavior depends on local soil conditions, as well as requirements regarding impermeability and mechanical resistance. This results in various levee cross sections, even within the same levee. In situations of extreme water events, when timely actions are required, this variability poses a problem for decision-making based on observed behavior, which is highly dependent on the specific section parameters. Creating models for each problematic section becomes impractical, and because of that, in this study, 91 different cross sections from 16 levees are considered to identify the key levee parameters with the largest effects on three observed mechanisms: deformations, exit hydraulic gradients, and factors of safety. The implemented factor screening methodology is based on the sequential bifurcation method (SB) and numerical analyses. The SB method successively investigates groups of factors and uses their cumulative effects to identify the important groups and to discard the unimportant based on a previously selected parameter Δ, until the groups are reduced to single factors that may be deemed important. It is found that approximately 30% of all the factors used to describe the most complex sections are considered important by at least one of the investigated mechanisms. Full article
(This article belongs to the Special Issue Geotechnical Engineering towards Sustainability)
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19 pages, 5368 KiB  
Article
Hydraulic Geometry and Theory of Equilibrium Water Depth of Branching River
by Yun Gao, Yufeng Lv, Ying Li, Yun Pan and Enshang Yang
Water 2023, 15(3), 430; https://doi.org/10.3390/w15030430 - 20 Jan 2023
Cited by 1 | Viewed by 2874
Abstract
Based on the flow continuity formula, resistance formula, sediment transport capacity formula and width-depth ratio relationship, the hydraulic geometry relationship and theory of equilibrium water depth for a branching river are established and are suitable for arbitrary section shape. The ratio of cross-sectional [...] Read more.
Based on the flow continuity formula, resistance formula, sediment transport capacity formula and width-depth ratio relationship, the hydraulic geometry relationship and theory of equilibrium water depth for a branching river are established and are suitable for arbitrary section shape. The ratio of cross-sectional area of a distributary channel and the main stream is a power function of its bifurcation ratio with an exponent of 6/7. This was applied to a 12.5 m deep-water channel of the Yangtze River (the North Passage, Fujiangsha Waterway and Shiyezhou Waterway). The reliability of the equilibrium water depth was verified and the construction effect of the channel regulation project was predicted. The results show that the regulation project has achieved certain results on the whole, but some waterways still cannot meet the requirement of 12.5 m navigation depth. It is necessary to adjust the layout of the regulation project and focus on increasing the bifurcation ratio and reducing the flow resistance so as to increase the maximum equilibrium water depth. Full article
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26 pages, 51355 KiB  
Review
The Geological Structure and Tectonic Complexity of Northern Thessaly That Hosted the March 2021 Seismic Crisis
by Sotiris Sboras, Spyros Pavlides, Adamantios Kilias, Dimitris Galanakis, Athanasios Chatziioannou and Alexandros Chatzipetros
Geotechnics 2022, 2(4), 935-960; https://doi.org/10.3390/geotechnics2040044 - 4 Nov 2022
Cited by 6 | Viewed by 3098
Abstract
Knowing the rich presence of active faults in northern Thessaly and the lack of any significant seismic activity since at least the mid-1940s, the 2021 seismic sequence did not surprise us. What did surprise us was the fact that (i) despite the great [...] Read more.
Knowing the rich presence of active faults in northern Thessaly and the lack of any significant seismic activity since at least the mid-1940s, the 2021 seismic sequence did not surprise us. What did surprise us was the fact that (i) despite the great knowledge of the neotectonic faults in the area, the causative faults were unknown, or almost unknown; (ii) the direction of the 2021 faulting was different than the expected, and given that the focal mechanisms showed almost pure normal dip-slip motion, the extensional main axis was also different than the one we thought we knew for this area; and (iii) besides the co-seismic ruptures that occurred within the Domeniko-Amouri basin and along the Titarissios River valley, there is evidence of rupturing in the alpine basement of Zarkos mountains. After thoroughly reviewing both the alpine and neotectonic structural setting and all the available literature concerning the seismotectonic data and interpretations of the 2021 sequence, including investigations of our own, we end up in a complex tectonic setting with older alpine structures now operating as inherited faults, and we also suggest the possible occurrence of a roughly N-dipping, low-angle, detachment-type fault. This fault runs below Mt Zarkos, reaching at least the Elassona Basin, with splay faults bifurcating upwards from the main fault zone. Following this complexity, rupture of the first mainshock must have chosen a split route reaching the surface through the gneiss rocks of Zarkos and almost (?) reaching the basinal sediments of the local tectonic depressions. This seismic sequence is a perfect case study to shed some light on the tectonic and rupture processes in the context of both geodynamics and seismic hazard assessment. Full article
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17 pages, 4486 KiB  
Article
Morphological Characteristics and Hydrological Connectivity Evaluation of Tidal Creeks in Coastal Wetlands
by Xu Chen, Mingliang Zhang and Hengzhi Jiang
Land 2022, 11(10), 1707; https://doi.org/10.3390/land11101707 - 1 Oct 2022
Cited by 4 | Viewed by 2887
Abstract
Tidal creeks play a critical role in delivering water, suspended sediments, and nutrients to coastal wetlands, so it is important to understand the characteristics of the tidal creek system to guide the development and sustainable utilization of coastal wetlands. Using the coastal wetlands [...] Read more.
Tidal creeks play a critical role in delivering water, suspended sediments, and nutrients to coastal wetlands, so it is important to understand the characteristics of the tidal creek system to guide the development and sustainable utilization of coastal wetlands. Using the coastal wetlands of the Liao River Estuary (LRE) as a study area, this study accurately divided the tidal flat based on the principle of tidal correction, extracted the linear features of tidal creeks using high-resolution remote sensing (RS) data, and then classified the tidal creeks on a tidal flat using the tidal creek ordering algorithm. Our study aimed to quantify the morphological characteristics of tidal creeks and qualitatively evaluate the parameters of the tidal creek network in the study area. The study results show obvious spatial heterogeneity in the order and the average length of tidal creeks in the coastal wetlands of the LRE. With the increase in the order of tidal creeks, the average length of tidal creeks increased exponentially and the number of tidal creeks decreased exponentially in the study area. The total density of tidal creeks was related to the beach surface elevation gradient, and the density and frequency of tidal creeks reduced substantially with an increase in the order of tidal creeks. The sinuosity ratio of tidal creeks declined sharply with a fall in the beach surface elevation gradient. The average bifurcation ratio of tidal creeks in the upper intertidal zone was higher than that in other zones, indicating that the tidal creeks in the upper intertidal zone were erratic. In addition, the hydrological connectivity of the tidal creek network in the upper intertidal zone and the development of the tidal creek system in the supratidal zone were the highest in the LRE. The study results help understand the spatial variations in tidal creek morphology under the influence of tidal hydrodynamics. Full article
(This article belongs to the Special Issue Monitoring and Simulation of Wetland Ecological Processes)
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18 pages, 2457 KiB  
Article
Living Status and Perspective of the Silver Carp (Hypophthalmichthys molitrix) in the Lower Reach of the Yangtze River: Insights from Population Distribution, Age Structure, and Habitat Preference Analyses
by Di-an Fang, Haibo Sun, Yunxin Peng, Zhen Kuang, Yanfeng Zhou and Dongpo Xu
Fishes 2022, 7(5), 254; https://doi.org/10.3390/fishes7050254 - 24 Sep 2022
Cited by 5 | Viewed by 2433
Abstract
Using systemic, periodic surveys from 2015 to 2019, population distribution, speculated age and habitat preference were analyzed to assess the living status for the Silver Carp (Hypophthalmichthys molitrix) in the lower Yangtze River. Small Silver Carps became more temporarily abundant in [...] Read more.
Using systemic, periodic surveys from 2015 to 2019, population distribution, speculated age and habitat preference were analyzed to assess the living status for the Silver Carp (Hypophthalmichthys molitrix) in the lower Yangtze River. Small Silver Carps became more temporarily abundant in spring and autumn, and the catch per unit effort (CPUE) fluctuated yearly. Spatially, going from Anqing (AQ) to Changshu (CS), Silver Carps in the 200 mm standard length(SL) group became less abundant, whereas those in the 400–600 mm and >600 mm SL groups steadily increased. According to the Von Bertalanffy growth equation, the Silver Carp exhibits isometric growth, and the inflection point of SL and body weight (BW) were 564.01mm and 2948.31g, respectively, with a growth characteristic index (φ) of 5.0655. The fish dominant age range was 0+ to 5 years, reflecting the young age composition of the fish. Furthermore, the habitat survey findings revealed that the Silver Carp has the different preference on habitat selection in different life history. Juvenile Silver Carps were comparatively staying in the lower Yangtze River, where there exists a relatively stable bifurcated river. Adult fishes were mostly found in the CS and Nantong(NT) section where the river is wide and the food is rich. When compared with the historical survey data, it was found that the Silver Carp live in the AQ through NT section. The living status and perspective of the Silver Carp in the lower reach of the Yangtze River were clarified, and future work should be more concerned with the strengthening of conservation and the restoration of adequate habitat. Full article
(This article belongs to the Section Biology and Ecology)
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