River Area Research Articles

Anthropogenic Influence and Climate Change on Water and Nutrient Dynamics in the Kebir-Rhumel Basin, (Northeastern Algeria)

<p>This study investigates the Anthropogenic Influence and Climate Change: Water and Nutrient Dynamics in the Kebir-Rhumel Basin in Northeastern Algeria. Utilizing an advanced methodology and integrating 10 physicochemical variables, this research provides a novel insight into the environmental factors shaping the basin's ecosystem. By employing a PCA analysis, it highlights two distinct factors accounting for 80.90% of the total variance and identifies a strong positive correlation between various variables, particularly NH4+ and PO43-. Two contrasting river areas were noted: Oued Radjas and Oued Rhumel rivers, displaying evidence of anthropogenic activities, and Oued Kebir and Oued El-Kotone rivers, indicative of pristine conditions. Seasonal fluctuations were noted in atmospheric temperature, precipitation, humidity, and wind speed, as well as in physical parameters and nutrient concentrations of surface water, revealing new details about the potential impact of human activities on water quality and ecosystem health. The findings here are not only significant in understanding the dynamics of water quality but also crucial in devising effective management strategies. High EC and TDS values in the Oued Radjas River point to anthropogenic pollution, and high nitrogen nutrient concentrations in the Oued El-Kotonne River hint at potential eutrophication. The study underscores the importance of understanding the interplay between human activities and natural processes in managing water resources and ecosystems. This research contributes to the existing body of knowledge by shedding light on specific aspects of water quality in the region, paving the way for more focused investigations and policy interventions for sustainable development.</p>

Rainfall Runoff Modelling of Panchaganga River Using HEC-HMS Software and it's Analysis.

The present study of this project is intended on the formation of a working flood model of the river Panchaganga flood in the Kolhapur stretch which is in Maharashtra state in India. Using HEC-HMS the precipitation is used to estimate the run off along the watershed. The central aim of this project resides in the development of a calibrated working model of the 2019 floods. This model is later used to simulate the various possibilities of flood event. Rainfall Runoff Model which is a mathematical model which relates the rainfall and runoff with the use of catchment area or watershed area. Hydrological modeling can estimate for the runoff in the study area of the model by evaluating the precipitation and discharges inputs given to the HEC-HMS software. Hydrological models on the other hand estimates the surface runoff within the study area. In recent decades, India has experienced an increase in the frequency of flood disasters. Flood is a flow that overtops either hydraulic structure or river bank along a stream resulting in damage to the adjoining property or life. The primary reason behind this is the Climate change and Immense urbanization, which has resulting in alteration of basin characteristics. The development projects near riverbanks have the worst effects on a reach's ability to drain, which increases the likelihood of flood-like conditions. In this project an area of the Panchaganga river is to be taken and a flood mapping using HEC-HMS (Hydrological Modelling System) and GIS software is to be drawn. According to the drawn flood map there will be a suitable mitigation measure suggested and the effect of the suggested mitigation measure is to be modeled.

Brucella spp. in Wildlife of the Lombardy Region, Northern Italy.

Surveillance data collected in the period 2017-20 for Brucella spp. in wildlife of the Lombardy Region in northern Italy were used to describe the exposure of the wildlife species to Brucella spp. in wild boar (Sus scrofa), European brown hare (Lepus europaeus), fallow deer (Dama dama), red deer (Cervus elaphus), and roe deer (Capreolus capreolus). Among the tested species, wild boar (n=6,440) showed the highest percentage of seropositive samples (5.9%). Notably, wild boars of perifluvial area of the Po River showed higher percentages of positivity than those of the pre-Alpine district. In addition, during the hunting season in 2018, 95 organs (uterus or testes, spleen, and submandibular lymph nodes) from wild boar of the perifluvial area of the Po River were collected for bacteriological examination. Brucella suis was isolated in culture from 18.9% of tested lymph nodes. These serological and microbiological results highlight the presence of B. suis in wild boar and suggest the importance of wild boar as a reservoir for B. suis. Comparison of the spatial distribution of Brucella-seropositive wild boars with the location of backyard swine farms revealed a higher chance of contact between the two populations only in the areas where the lower percentage of seropositive samples was observed. Conversely, the high percentage of seropositive samples observed in the Po River area coupled with positive microbiological cultures suggest a greater risk of infection for the humans directly or indirectly involved in wild boar hunting activity. These results may serve as a basis to establish sound wildlife management and to adopt education campaigns aimed at reducing the risk of human infection in people involved in wild boar hunting related activities.

A method for detecting navigable areas in narrow rivers under complex reflection conditions

A method for detecting navigable areas in narrow rivers under complex reflection conditions

Aqueous VOCs in complex water environment of oil exploitation sites: Spatial distribution, migration flux, and risk assessment

Pollution of the aqueous environment by volatile organic compounds (VOCs) has caused increasing concerns. However, the occurrence and risks of aqueous VOCs in oil exploitation areas remain unclear. Herein, spatial distribution, migration flux, and environmental risks of VOCs in complex surface waters (including River, Estuary, Offshore and Aquaculture areas) were investigated at a typical coastal oil exploitation site. Among these surface waters, River was the most polluted area, and 1,2-Dichloropropane—which emerges from oil extraction activities—was the most prevalent VOC. Positive matrix factorization showed that VOCs pollution sources changed from oil exploitation to offshore disinfection activities along River, Estuary, Offshore and Aquaculture areas. Annual volatilization of VOCs to the atmosphere was predicted to be ∼34.42 tons, and rivers discharge ∼23.70 tons VOCs into the Bohai Sea annually. Ecological risk assessment indicated that Ethylbenzene and Bromochloromethane posed potential ecological risks to the aquatic environment, while olfactory assessment indicated that VOCs in surface waters did not pose an odor exposure risk. This study provides the first assessment of the pollution characteristics of aqueous VOCs in complex aqueous environments of oil exploitation sites, highlighting that oil exploitation activities can have nonnegligible impacts on VOCs pollution profiles.

Exploring the microbial community and biotechnological potential of the sponge Xestospongia sp. from an anchialine cave in the Yucatán Peninsula

Sponge-associated microorganisms are key influencers of nutrient biogeochemistry and important sources of bioactive natural products. This study provides the first insights into the taxonomic diversity of the microbial community associated with the sponge Xestospongia sp. from an anchialine cave in the coastal area of the underground river of the Yucatán Peninsula in Xcalak, Quintana Roo, Mexico, and the potential antimicrobial activity of its cultivable bacteria. High abundances of Sulfurospirillum and Desulfovibrio were detected with 16S rRNA amplicons, suggesting that the microbial community of Xestospongia sp. plays an important role in the geochemical sulfur cycle. Analysis with crude extracts of Nocardiopsis dasonvillei NCA-454 revealed antimicrobial activity against methicillin-sensitive Staphylococcus aureus ATCC 25913 (MSSA) and methicillin-​resistant ​S. aureus ATCC 43300 (MRSA). Studies of the microbiomes of sponges from the anchialine cave system in the Yucatán Peninsula can help elucidate the biogeochemical cycles of these poorly studied environments. Moreover, the microorganisms of these microbial communities represent an untapped source of secondary metabolites with biotechnological potential.

Serum metabolic changes link metal mixture exposures to vascular endothelial inflammation in residents living surrounding rivers near abandoned lead–zinc mines

Metal exposure is associated with vascular endothelial inflammation, an early pathological phenotype of atherosclerotic cardiovascular events. However, the underlying mechanism linking exposure, metabolic changes, and outcomes remains unclear. We aimed to investigate the metabolic changes underlying the associations of chronic exposure to metal mixtures with vascular endothelial inflammation. We recruited 960 adults aged 20–75 years from residential areas surrounding rivers near abandoned lead–zinc mine and classified them into river area and non-river area exposure groups. Urine levels of 25 metals, Framingham risk score (FRS), and serum concentrations of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), as biomarkers of vascular endothelial inflammation, were assessed. A “meet-in-the-middle” approach was applied to identify causal intermediate metabolites and metabolic pathways linking metal exposure to vascular endothelial inflammation in representative metabolic samples from 64 participants. Compared to the non-river area exposure group, the river area exposure group had significantly greater urine concentrations of chromium, copper, cadmium, and lead; lower urine concentrations of selenium; elevated FRS; and increased concentrations of ICAM-1 and VCAM-1. In total, 38 differentially abundant metabolites were identified between the river area and non-river area exposure groups. Among them, 25 metabolites were significantly associated with FRS, 8 metabolites with ICAM-1 expression, and 10 metabolites with VCAM-1 expression. Furthermore, fructose, ornithine, alpha-ketoglutaric acid, urea, and cytidine monophosphate, are potential mediators of the relationship between metal exposure and vascular endothelial inflammation. Additionally, the metabolic changes underlying these effects included changes in arginine and proline metabolism, pyrimidine metabolism, starch and sucrose metabolism, galactose metabolism, arginine biosynthesis, and alanine, aspartate, and glutamate metabolism, suggesting the disturbance of amino acid metabolism, the tricarboxylic acid cycle, nucleotide metabolism, and glycolysis. Overall, our results reveal biomechanisms that may link chronic exposure to multiple metals with vascular endothelial inflammation and elevated cardiovascular risk.

WITHDRAWN: The main threats facing the eel (Anguilla anguilla) and the sea lamprey (Petromyzon marinus) in Galicia (NW Spain) through Partial Least Squares Path Modelling

Migratory fish are very important species from an ecological and socioeconomic point of view, but they suffer the effects of many threats such as climate change, pollution, or overfishing, thus contributing to the decline of these species. To study the main factors influencing these species, Partial Least Squares Path Modelling (PLS-PM) methodology has been used to analyse and quantify the main threats facing two highly relevant migratory species: the eel (Anguilla anguilla) and the sea lamprey (Petromyzon marinus). Based on this statistical approach, two models have been developed for a total of 14 rivers located in the Autonomous Community of Galicia (NW Spain), one for the eel and the other for the lamprey. For the construction of the models, the influence of environmental factors, surface water quality and anthropogenic impacts on the population of these species has been studied. Two scenarios have also been simulated to assess how the application of corrective measures to reduce the anthropogenic impact implies important improvements to the eel and lamprey populations. The results of the models developed indicate that the variables analysed predict 69% of the eel "Population", with the weight of the measured variables (MV) 'Water treatment plants' having the most substantial weight (W=0.939) followed by the significant negative influence of 'Surface area of reservoirs and rivers' (W=-0.746). Similarly, in the lamprey model, an R2 of 0.58 has been obtained, where the negative influence of the MV "Agricultural nitrate discharge points" (-0.938) stands out substantially. In relation to the scenarios developed for both species, we highlight that the application of measures aimed at reducing anthropogenic pressure manages to mitigate the impact by 4.82% in the case of eel and by 1.37% in the case of lamprey. The set of models and scenarios proposed will make it possible to design preventive and corrective measures to mitigate the impacts affecting these populations, guaranteeing the integrated management of these species, and improving future decision-making, thus strengthening environmental governance.

동북아 역사상 마한문화의 위상과 익산

Iksan’s historical and cultural status and source in the history of Northeast Asia occupy a very important position. Iksan had already attracted attention as a center of Bronze Age culture based on the recovery of a large amount of archaeological relics in the 1970s. The ruins of Buyeo, Iksan and Jeonju(Wanju) within a 60km radius of Iksan were set as the ‘Iksan Cultural Area’. It is presumed that technological innovations were achieved in regions including Iksan by residents who came down from the political upheaval in Liaodong and the northwest region. Archaeologically, the founding period of Mahan is believed to be between the 3rd and 1st centuries B.C. in connection with the introduction of iron culture. In this case, the Mahan small states of Iksan is likely to be the Geonma states that appears in China's records of the 『Samkukji』. This small state’s name is connected to Jimomilji in the 「Gwanseumeungheomgi」 and Jimohyeon, Jimamaji, Geummajeo, Geumma in the geography of the 『Samguksagi』, showing regional historicity. Also, considering the spatial scope of Mahan as the southwestern part of the Korean Peninsula in Gyeonggi, Chungcheong, and Jeolla regions, Iksan small states is considered to encompass the Geum River and Mangyeong River areas such as Okgu, Impi, Hamyeol and Geumma. In the late 4th century, the Iksan region was subordinated to Baekje along with the western regions of Jeollabuk-do, including Gunsan, Jeonju(Wanju), Gimje, Buan, Jeongeup and Gochang, and was incorporated into the local system after the transfer of the capital to Ungjin. After the 5th century, the Ipjeom-ri and Ungpo-ri tombs and the Sanwol-ri ruins in Daeya-myeon in the Geum River area related to Iksan show that they came under the control of central political forces. Even in the 6th century, Iksan was an important area through the fact that even Baekje’s Geummajeo, Geumma-gun, and Geumma-san were continuously mentioned in the literature records. Even in the 7th century, the theory of Iksan as the capital and separate capitals means that it had the same weight and importance as Sabi, the capital of Baekje at the time.

Late Holocene vegetation dynamics: degree and regional patterns of the Dark Ages woodland regeneration (ad 300–700) in the Netherlands

AbstractDuring the Dark Ages, which include the Late Roman period (ad 270–450) and the Early Middle Ages (ad 450–1050), large-scale vegetation development in northwest Europe was characterised by widespread regeneration of woodlands. This regeneration phase represents a break from the extensive reduction in woodland from human activities in late Holocene vegetation history. In the Netherlands, possible causes for this reversal can be found in a decreased human impact on the landscape, a colder and possibly wetter climate, and geomorphological changes. This paper presents a synthesis from 38 pollen records from a range of sites across the Netherlands, from which regional differences in the degree of woodland regeneration and vegetation composition before and during the Dark Ages have been identified. Both original data as well as vegetation abundance modelled by REVEALS were used to assess the regrowth of the woodland cover. The observed trends were considered in terms of the landscape setting and population estimates in order to disentangle the relative importance of these forcing factors. The results indicate that landscape and human impact were the most important factors determining the vegetation structure and changes to it. The pollen data show that in the Netherlands, the clearance of woodland in the Roman period followed by its regrowth afterwards were greatest in the river area. This can be linked to a high population density there during the Roman period followed by a strong decrease of population in the Dark Ages and to increased flooding.

Evaluation of Reservoir Properties of Sylhet Limestone of Jaintia Group, North-Eastern Sylhet, Bangladesh

The Sylhet Limestone in the Bengal Basin, formed in the Eocene Epoch and known for its fossil content, is significant in understanding the reservoir characteristics. Despite exposure in Jaflong and Takerghat of the Bengal Basin, little research has been conducted on reservoir characteristics. This study aimed to comprehensively examine the Sylhet Limestone Formation, encompassing its crystalline upper and fossiliferous lower sections. It utilized field investigations and laboratory analyses to address the gaps of sporadic or insufficient earlier studies. A thorough examination of thin sections from the Sylhet Limestone, exposed in the Dauki River area, provides insights into the textural and mineralogical attributes and the presence of skeletal fossils within the limestone. Based on the analysis of thin sections, the limestones are categorized as Rudestones and Packstones. The porosity observed in the exposed rocks ranges from 5% to 12%, with most pores associated with interconnected fractures and joints. However, thin-section studies also indicate evidence of diagenetic recrystallization and calcite cementation. Hence, closely spaced, interconnected joints and fractures filled with diagenetic calcite might deteriorate the reservoir quality. Notably, this limestone exhibits fossilized specimens such as Nummulite, Discocyclina, Alveolina, Assilina, and Ostracoda, among others. The combination of the fossil assemblage, limestone texture, and composition strongly suggests that this limestone formation was deposited in a shallow marine environment with minimal sediment input under a warm and humid climate. The petrographic analysis of the limestones concludes that the upper portion of the formation is fine-grained while the lower part is coarse-grained. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(2), 2023, P 119-137

Analysis of Spatial and Temporal Changes in FVC and Their Driving Forces in the Inner Mongolia Section of the Yellow River Basin

To investigate the spatial and temporal changes in fractional vegetation coverage (FVC) and their driving forces in different regions of the Inner Mongolia section of the Yellow River Basin, this paper observed the spatial trends and stability of FVC in these regions based on the MOD13Q1 information regarding the 2000–2020 period as a data source. It used the dimidiate pixel model to invert FVC, and based on the centre of gravity migration model, the coefficient of variation and the Mann–Kendall and Sen’s slope estimator test, it studied the spatial variation trend and stability of FVC in the four relevant areas of the Inner Mongolia section; an attribution analysis using a geodetector was also conducted. The following results were found: (1) in terms of temporal FVC change in the relevant areas, from 2000 to 2020, the overall FVC showed an increasing trend, indicating an obvious hierarchy of change as per different seasonal scales (summer > growing season > fall > spring). There is a mutation point in FVC in different areas, and the FVC sequence is random. (2) Regarding spatial change, the overall FVC showed a trend of being high in the eastern regions and low in the western regions and low–high–low from the north to the south; the stability of the Hetao Irrigation District–Wuliangsuhai Area changed more significantly with the successive seasons, and the degraded areas of FVC were mainly distributed in the city centre of the Kundulun River–Daheihe River Area and in the Hetao Irrigation District in the summer. (3) In terms of driving factors, soil type had a relatively higher explanatory power regarding the Hetao Irrigation District–Wuliangsuhai Area, rainfall had a relatively higher explanatory power regarding the Morin River–Wuding River Area and the Kundulun River–Daheihe River Area, and land use had a relatively higher explanatory power regarding the Ten Kongtui–Heidaigou Area.

The deployment of spur dike group improves physical habitats in urban meandering rivers: Insight from a 2D habitat suitability model

Although channel meandering is currently a popular approach for river ecological restoration, the spiral flow formed in bends may lead to fragmentation of aquatic habitats due to the concave bank erosion and convex bank sedimentation. The aforementioned issue motivated this study, which aims to mitigate the adverse effects of curved flow on aquatic habitats within bends. We proposed a placement strategy of dike group within the curved channel to adjust the water–sediment structure of meandering rivers, thereby safeguarding against bank erosion and the fragmentation of river habitats. The effectiveness of this strategy has been validated by the development of numerical models based on 2D depth-averaged water–sediment equations, coupled with the IFIM method. These models investigate the mechanism of aquatic habitat enhancement achieved by deploying groups of submerged and non-submerged dikes on the convex and concave banks of the Fuhe River in Chengdu, China. The findings indicate that the implementation of dike groups resulted in an enhancement of approximately 30% in the weighted usable area (WUA) of the specific river. This improvement was accompanied by a 25% decrease in the ecological flow threshold (WUAmax). Furthermore, subsequent comprehensive comparative analyses under various conditions revealed that the fluctuations in enhancement effects were mitigated by flow increases. The degree of submergence parameter exhibits heightened sensitivity to enhancement effects, especially when the flow remains below the ecological threshold. The findings of this study can serve as a reference for the ecological restoration of river systems.

Results of petrographic analysis of stone assemblage from the Kosa Mesolithic sites (Northern Kama region)

In this paper, the results of petrographic analysis of stone materials from the Mesolithic sites of Kosa 1–3 in the northern Kama River area (Perm Region) are discussed. The sites of Kosa 1 and 2 are located on the second terraces of the Lolog and Kosa Rivers, and Kosa 3 — on the first terrace of the Kosa River. Kosa 1 and 2 are considered chronologically similar and belong to the Late Mesolithic period. The site of Kosa 3 is younger, and it marks the transition from the Mesolithic to the Neolithic. For the analysis, aimed at determining the ancient raw material strategies, selected were five stone artifacts from Kosa 1, five stone artifacts from Kosa 2, and eight samples from Kosa 3. Polarised microscopy was used for the petrographic study of stones in thin sections. This method allows the precise diagnosis of minerals and rocks based on their optical characteristics. The results indi-cate that flint and jasper were applied as main raw materials at all analysed sites. The choice of material for the stone industry at the sites was limited. Sandstone and siltstone were used for production of stone macro tools. The difference in raw source materials was determined for the Kosa 1 and Kosa 2 sites on one hand, and Kosa 3 on another — the main raw sources at the Mesolithic sites were flint and jasper, while at the Kosa 3 transitional site coloured pebbly flint was used. The comparison of the results with petrographic data from other Mesolithic sites of this region demonstrates similarity in the main principles of the strategy of raw source choices such as using flint and jasper. Furthermore, a larger variety of source raw materials has been determined for the sites of the Middle Kama River basin. The comparison with the results from the Late Stone Age sites also revealed a greater variety in the materials used in comparison with the Kosinsk sites (platy flints, cherts, tuffs, gabbro, and others). All raw materials were of local origin such as alluvial deposits of the Lolog and Kosa Rivers. The results of the petrographic analysis suggest the situational choice of materials for the manufacture of tools by the local population, with the main factor being their easy accessibility.

Traceability of gushing water in the MiddleRoute of the South-to-North Water Diversion (Beijing section) through the river area

To trace the origin of the gushing water in the riverine area of the Beijing section of The Middle Route of South-to-North Water Diversion Project, a dataset was established comprising water chemistry, three-dimensional fluorescence spectra, and stable isotopes for different water bodies. Results indicated significant differences in Electrical Conductivity (EC), Total Dissolved Solids (TDS), and Ca2+ concentration among the gushing water, river water, and the water from the Middle Route of South-to-North Water Diversion Project (MRSD). Analysis using parallel factor analysis (PARAFAC) and fluorescence index revealed that dissolved organic matter (DOM) in the MRSD mainly originated from endogenous sources, while the river water and gushing water showed influences from both endogenous and exogenous sources. Nitrate sources varied among the water bodies, with distinct contributions from domestic sewage and fertilizer sources. The evaporation lines of river water and gushing water exhibited similar intercepts and slopes, but their intercepts and slopes are much smaller than those of the MRSD, suggesting stronger kinetic evaporative fractionation. In conclusion, the gushing water in the riverine area of the MRSD was determined to originate from the river, providing a fast and efficient method for gushing water source identification.

Analisis Hujan Ekstrim Probable Maximum Precipitation (PMP) menggunakan metode Hersfield dan Perhitungan Debit Banjir

Extreme rain is rain with the lowest intensity of 50 mm/24 hours or 20 mm/hour. River is an elongated surface water flow and flows from a higher place (upstream) to a lower place (downstream). The area of KIuet is 1429.93 km and the area of Kluet River is 163.51 km2 and the length of the river is 68.26 km. The problem is that Kluet Utara River experiences high rainfall, resulting in overflows that flatten agricultural land and submerge residential areas. The purpose of the study was to calculate the planned return period rainfall, analyze the PMP (probable Maximum Precipitation) value and analyze the flood discharge to evaluate the PMF (Probable Maximum Flood) value and the return flood discharge. The benefits of this research are used to see the PMF value and return period rainfall to analyze the frequency of flooding KIuet Utara Watershed (DAS). The scope of the research was to calculate rainfall and flood discharge in KIuet Utara Watershed and secondary data which includes 10 years rainfall data obtained from BMKG (Meteorology, Climatology and Geophysics Agency) Indrapuri Aceh Besar and watershed maps obtained from PT. Mediatama Indoconsult. Processing of rainfall data on return period used Log Pearson III Method and PMP used Hersfield Method while calculating the planned flood discharge using Melchior Method. The results of the research is the rainfall value for the return period for the lowest rainfall in the 2 year return period is as high as 211,836 mm and the highest rainfall for the 1000 year return period is 566,239 mm, so that the flood discharge plan for the return period for the lowest flood discharge in the 2 year return period is equal to 2061,342 m3/s and the highest flood discharge at the 1000 year return period is 5510,490 m3/s. The PMP value was obtained at 2128,432 mm so that the PMF was obtained at 20714,772 m3/s. Log Pearson III and PMP methods can be used to calculate the rainfall in KIuet Utara and the results from the rainfall are used to calculate the planned flood discharge using Melchior Method.

The accumulation of microplastics in fish freshwater in the Mun river, Thailand

Background: Microplastic pollution mainly occurs from terrestrial sources, but research on plastic contamination in aquatic environments is limited. Freshwater fish are widely consumed throughout Southeast Asia. Microplastic contamination is becoming an important issue that leads to human health risks from consumption. Objectives: The study aimed to determine the accumulation of microplastics ingested by fish in freshwater in the Mun River. Methods: Freshwater fishes in the Mun River caught by local fishermen and the most dominant species consumed in the Mun River include Paralaubuca typus, Phalacronotus bleekeri, and Morulius chrysophekaion. Twenty-four samples from each species were collected. Microplastics in these species were analysed for abundance, size, shape, color, and type of polymer. Results: The results showed that the average amounts of microplastic contamination in the gastrointestinal tracts (GIT) and gills of Morulius chrysophekadion were 17.70±8.20 pieces/fish, Phalacronotus bleekeri were 11.83±8.74 pieces/fish, and Paralaubuca typus were 10.25±7.56 pieces/fish, respectively. The average number of microplastics found in the urban area was 26.50±4.21 pieces/fish; in the agricultural area, it was 9.77±4.10 pieces/fish; in the confluence of the Mun and Chi River areas, it was 9.50±3.51 pieces/fish; and the natural area had 7.27±4.15 pieces/fish, respectively. The average size of microplastics found in fish was 878.29±904.41μm. The most common polymer type microplastic was polyethylene (PE) where the most common shape was Fiber-shaped, and the most common colour was blue. Conclusion: The study findings indicate a prevalent form of microplastic accumulation in three fish species especially among Morulius chrysophekaion. And findings show that every fish species in the urban area have the most contamination. As a result, fish GIT and gills should be removed before consumption to reduce exposure to microplastics instead of consuming them.

Land cover and space use influence coyote carnivory: evidence from stable-isotope analysis

For many species, the relationship between space use and diet composition is complex, with individuals adopting varying space use strategies such as territoriality to facilitate resource acquisition. Coyotes (Canis latrans) exhibit two disparate types of space use; defending mutually exclusive territories (residents) or moving nomadically across landscapes (transients). Resident coyotes have increased access to familiar food resources, thus improved foraging opportunities to compensate for the energetic costs of defending territories. Conversely, transients do not defend territories and are able to redirect energetic costs of territorial defense towards extensive movements in search of mates and breeding opportunities. These differences in space use attributed to different behavioral strategies likely influence foraging and ultimately diet composition, but these relationships have not been well studied. We investigated diet composition of resident and transient coyotes in the southeastern United States by pairing individual space use patterns with analysis of stable carbon (δ13C) and nitrogen (δ15N) isotope values to assess diet. During 2016–2017, we monitored 41 coyotes (26 residents, 15 transients) with GPS radio-collars along the Savannah River area in the southeastern United States. We observed a canopy effect on δ13C values and little anthropogenic food in coyote diets, suggesting 13C enrichment is likely more influenced by reduced canopy cover than consumption of human foods. We also observed other land cover effects, such as agricultural cover and road density, on δ15N values as well as reduced space used by coyotes, suggesting that cover types and localized, resident-like space use can influence the degree of carnivory in coyotes. Finally, diets and niche space did not differ between resident and transient coyotes despite differences observed in the proportional contribution of potential food sources to their diets. Although our stable isotope mixing models detected differences between the diets of resident and transient coyotes, both relied mostly on mammalian prey (52.8%, SD = 15.9 for residents, 42.0%, SD = 15.6 for transients). Resident coyotes consumed more game birds (21.3%, SD = 11.6 vs 13.7%, SD = 8.8) and less fruit (10.5%, SD = 6.9 vs 21.3%, SD = 10.7) and insects (7.2%, SD = 4.7 vs 14.3%, SD = 8.5) than did transients. Our findings indicate that coyote populations fall on a feeding continuum of omnivory to carnivory in which variability in feeding strategies is influenced by land cover characteristics and space use behaviors.

Wind and rainfall erosion energy in large sediment generating and coarse sediment class areas of the middle Yellow river

Joint action by strong winds and high-intensive rainfall leads to serious soil erosion problems in large sediment generating and coarse sediment class areas of the middle Yellow River. Investigating the variation of trend and alternating wind and rainfall energy is an important prerequisite for controlling regional sediment transport problems. We calculated the wind and rainfall erosion energies by using the aerodynamic energy and rainfall kinetic energy formulas. The Mann-Kendall (MK) trend test and Theil-Sen approach were used to analyze the spatial-temporal variation and alternation of joint erosion energy during the last 40 years (1979–2018). The results show the following. 1) Wind erosion energy increased and rainfall erosion energy decreased. However, the former is larger than the latter. 2) The dominant erosive energy varies for different seasons. Wind erosive energy dominates in spring, and rainfall erosive energy dominates in summer. 3) There is a regular wind-rainfall-wind alternation of erosive energy. The wind-rainfall energies were alternately distributed in May–July and the rainfall-wind energies were alternately distributed in September–December. Furthermore, the dominant time of rainfall erosive energy decreased when wind erosive energy increased. The results can help decision makers to develop soil erosion control strategies to reduce soil erosion when it occurs in wind and water staggered areas.

Influence of atmospheric rivers on extreme precipitation in western Ukraine

Formulation of the problem. In recent years, interest in the atmospheric river (AR) phenomenon is growing, as more and more researchers associate it with extreme precipitation. Relatively few works are devoted to the assessment of the influence of atmospheric rivers on precipitation in Eastern Europe. The purpose of the article is to assess the occurrence of atmospheric river events during extreme precipitation in the western regions of Ukraine (Lviv and Volyn regions) and to analyze the geographical features of the spatial distribution of atmospheric river bends during extreme precipitation. Methods. We used the catalog of atmospheric rivers identified according to the methodology of D. Walliser and B. Guan to analyze the occurrence of atmospheric river events on the territory of the western part of Ukraine. Also, we used the sample of days with extreme precipitation (greater than 95th percentile for each meteorological station and each month) in the Lviv and Volyn oblasts of Ukraine to match it with AR episodes. It is shown that in most cases extreme precipitation events were accompanied by the atmospheric river phenomenon detected on the territory of Ukraine or the bordering territories. Results. The typical shape of atmospheric river bends during extreme precipitation most often is arc-shaped while the typical spatial coverage stretched from North Africa through the Mediterranean Sea and Turkey to the territory of Ukraine. Less often, the form of detected AR area had the form of a meridional bend extending from the eastern part of the Mediterranean Sea towards Ukraine. However, the analysis showed that the presence of atmospheric river phenomenon is not the exceptional reason for extreme precipitation. Part of the extreme precipitation events is associated with specific synoptic situations (precipitation caused by cold fronts or occluded fronts) whereas conditions for atmospheric river detection are not fulfilled (bend size, meridional flow component, flow intensity). Atmospheric river episodes were not observed at most of the days of general sample (on average 72.36%) within the study area based on the period of 1991-2020. At the same time, precipitation events in the absence of AR were recorded on average in 32.2% of days (relative to the total number of days). In the presence of AR, precipitation was not recorded in about a third of cases. In the sample of days in the absence of AR and in the presence of AR, the proportion of precipitation of different gradations is as follows: for 10-20 mm is 2.73% and 2.64% respectively; for 20-50 mm is 1.37% and 1.63%; more than 50 mm is 0 .19% against 0.16%. In the spring, there is a certain consistency with the negative daily value of the NAO index and the AR axis orientation from the southwest to the territory of Ukraine. Thus, within 5 days before the localization of AR on the territory of Ukraine, values of the NAO index <-0.5 are noted, but the index changes in the process of the pressure field change. Based on a limited sample of extreme precipitation (94 cases), we assessed the correspondence of the precipitation rate to the area of atmospheric rivers and their features of the spatial orientation. ARs extending from the southwest (north of Africa) and the south (western part of the Mediterranean Sea) are characterized by the greatest recurrence. No regularities were found either concerning the dependence of the precipitation rate on the orientation of the AR, or concerning the dependence of the number of stations with extreme precipitation on the orientation of the AR. No linear dependence was found for the area of atmospheric rivers within both the study region and the territory of Eastern and Southeastern Europe with daily precipitation in the western regions of Ukraine.