River Branches Research Articles

Analysis of spatial structure and filling mechanism of a paleokarst channel against a background of denudation: A case study in the Tahe Oilfield, Tarim basin

Accurate delineations of the formation chronology and sedimentary characteristics of underground rivers are crucial for prospecting karst reservoirs. Based on drilling records, core samples, seismic data, and thin-section microscopy, qualitative and quantitative analyses of the fillings within the S65 karst channel, located within the erosional zone of the Tahe Oilfield Conventional seismic data, acoustic impedance inversion seismic data, mud inversion seismic data, and well drilling data were used to elucidate the lateral variations and combinations of fillings. Key coring wells were selected, and cores were calibrated using logging data on acoustic time difference (AC), density (DEN), deep-shallow dual lateral resistivity (RD-RS), natural gamma ray (GR), and shale content (Vsh). A range of quantitative benchmarks were thus established to distinguish between various types of fillings. Discrimination between breakdown breccia and calcite fillings was achieved using AC-DEN crossplots. The former exhibited elevated DEN values (2.64–2.72) coupled with moderate AC values (>49.5). Conversely, the latter displayed higher DEN values (2.66–2.76) and lower AC values (<49.5). Mechanical components and unfilled or low-filled components were identified using GR-RS or △R-Vsh crossplots, where △R signified the absolute difference between deep and shallow resistivity measurements, with a GR value of 20 API and a Vsh value of 5% within these plots representing the boundary between the two. The filling characteristics of the underground river fillings, and the mechanisms underlying the formation of these fillings were explained. A comparative analysis of the channels during different geological epochs revealed the following: (i) Sandstone and sandstone-cemented breakdown breccia that were primarily filled with a combination of mechanical and collapse fillings developed in the doline. Mudstone and calcite developed in the corridor region, whereas breakdown breccia developed at the intersections of fault lines. Uncemented breakdown breccia was frequently encountered in the branches of the underground river, with calcite developed on the blind side. (ii) The top channel of the S65 underground river formed during a period of rising sea levels in the Carboniferous. The poor lateral reservoir connectivity resulted from the extensive infiltration of mud. In contrast, the bottom channel, primarily consisting of Silurian sandstone and sandstone-cemented breakdown breccia, formed during the denudation phase of the early Hercynian. This bottom channel played a significant role in the substantial oil and gas production within the underground river system.

Evaluation of small hydropower turbines installed downstream of Nile River branches (Egypt)

The current study proposes a new strategy for using small hydroelectric turbines in downstream river branches with the least amount of construction and the lowest cost by comparing two different methods of installing the turbines, the first by installing the turbines at the river's bottom and the second by installing the turbines on floating boats. The methodology of this article is based on predicting the distribution of velocities through the watercourse using experimental data collected at various points in the river's depth, and then predicting the resulting electrical power for different sizes of turbines, as well as estimating the number of turbines for each row and the number of rows along the river. Therefore, Investigate the proposed systems. The proposed small hydropower system's economic viability and environmental impact are investigated in this article. According to the nature of the waterway, the best diameter of a turbine that can be used is 1.5 m based on water velocities and river depths. The proposed power plant generated 25.8 kW per single turbine row, with an estimated cost of produced power (0.035 USD/kWh) of approximately 20 turbines installed per row. Compared to other renewable energy sources, the proposed hydropower system is cost-effective and environmentally friendly, as generating electricity with the proposed small hydropower plant could reduce annual carbon dioxide emissions by 368 tones of CO2 per single turbine row.

Remote sensing inversion of water quality parameters in the Yellow River Delta

In recent years, with the rapid socio-economic development of the Yellow River Delta (YRD), the pressure on the supply of water resources has continued to rise. The development of oil-based industries has also led to a series of ecological and environmental problems, such as wetland degradation and water quality deterioration. As an increasing number of rivers are getting polluted, resulting in the deterioration of their water quality, monitoring, managing, and protecting water resources in the YRD is particularly important. In this study, water quality monitoring data and simultaneous Sentinel-2 image data from April 30, 2020, to October 26, 2021, were used to construct an experimental sample in the YRD. Water quality parameters (WQPs) concentrations were correlated with Sentinel-2 image element spectral reflectance and sensitive bands were selected. An empirical method based on the characteristic bands was used to invert a total of six water quality indicators, namely dissolved oxygen (DO), permanganate index (CODMn), ammonia nitrogen (NH3-H), total phosphorus (TP), total nitrogen (TN) and turbidity. The results show: (1) A total of five water quality inversion models for DO, TN, CODMn, TP and TN were effective in the areas of the Guangli River, the Tiaohe and the Branch River. The inversion accuracies of the five inversion models (R2of 0.6099, 0.9271, 0.9581, 0.8784 and 0.7387; RMSE of 1.2723, 0.3413, 0.9923, 0.0118 and 1.8476; RPD of 1.53, 2.08, 3.56, 2.76 and 1.53) indicated the feasibility of the water quality inversion method based on Sentinel-2 data using statistical theory for monitoring water quality concentration in the YRD. (2) The spatial distribution of water quality in the YRD was generally characterized by high water quality in the upper reaches and low water quality in the middle and lower reaches (except for some seasonal variations). Among them, the water quality of the upper reaches of the Guangli River was poor, with opposite trends in DO and TN concentrations. In the Tiaohe, CODMn and TP concentrations were not strongly correlated. However, CODMn and TP concentrations were high in the middle reaches where water quality was the worst. The TN concentrations in the Branch River decreased between 2020 and 2021, but the water quality is still in Category V. Therefore, continued attention and appropriate water quality management measures in the YRD are required. Further, by measuring water quality indicators at monitoring stations, regression-fitting equations for WQPs were established to obtain complementary multi-platform observations. Thus, the water quality conditions in the YRD region can be evaluated more accurately and quickly. The research results not only provide an important reference basis for the identification and monitoring of pollution sources, prevention and treatment of water environment pollution in the YRD, but also provide water security for socio-economic and ecological environment security.

DOWNSCALING CLIMATE PROJECTIONS TOWARDS COASTAL HYDRODYNAMICS MODELS

State-of-art modelling has shown a largely altered oceanographic environment as a consequence of climate change. The climate models implemented normally present low temporal and spatial resolutions as they aim at a general understanding on how large scale processes vary in a changing climate. Through downscaling projections towards coastal applications it is possible to reach higher resolutions and much more detailed information. If such an approach is performed using unstructured models instead of finite difference ones, it allows for an even better representation of complex morphologies. The latter enables studying more in depth the behavior of coastal environments, such as deltas, that heavily involve the oceanographic and hydrologic components. One of such areas is the Po Delta located in the Northern Adriatic Sea. With its complex system of lagoons and river branches (Maicu et al., 2018), downscaling is fundamental for representing the local processes driven by the interaction between the basin wide circulation and the freshwater inputs. In the context of the European Strategic Italy-Croatia AdriaClim Project (ID 10252001), hydrodynamic downscaling from regional scenario projections to high-resolution coastal applications is undergoing. The final local, high-resolution implementation is a finite element hydrodynamic model that uses the atmospheric forcing, and hydrologic and oceanographic boundaries from the projections.

Dynamical behavior of solutions of a reaction–diffusion model in river network

In this paper, we study the long-time behavior of solutions of a reaction–diffusion model in a one-dimensional river network, where the river network has two branches, and the water flow speeds in each branch are the same constant β. We show the existence of two critical values c0 and 2 with 0<c0<2, and prove that when −c0≤β<2, the population density in every branch of the river goes to 1 as time goes to infinity; when −2<β<−c0, then, as time goes to infinity, the population density in every river branch converges to a positive steady state strictly below 1; when |β|≥2, the species will be washed down the stream, and so locally the population density converges to 0. Our result indicates that only if the water-flow speed is suitably small (i.e., |β|<2), the species will survive in the long run.

The Comet Assay, a Sensitive Biomarker of Water Quality Improvement Following Adoption of Beneficial Agricultural Practices?

Numerous actions have been undertaken by farmers to attenuate the impact of agricultural activities on aquatic ecosystems. The identification of biomarkers that respond quickly to water quality improvement could facilitate the assessment of adopted alternative practices and help maintain mobilization among stakeholders. We evaluated the potential of the comet assay, a biomarker of genotoxic effects, using a freshwater mussel, Elliptio complanata, as a model animal. The frequency of DNA damage was assessed in hemocytes of mussels collected from a pristine habitat and caged for 8 weeks in the Pot au Beurre River, a tributary of the fluvial Lake St.-Pierre (Quebec, Canada) impacted by agricultural activities. We found that the level of DNA damage naturally induced in mussel hemocytes was low and showed very limited variations over time. Compared with these baseline levels and to laboratory controls, we observed a doubling in DNA alterations in mussels exposed to agricultural runoff in the third branch of the Pot au Beurre River. The genotoxic response was significantly lower in mussels caged in the first branch of the Pot au Beurre River, where longer stretches of shoreline have been restored as buffer strips. Glyphosate, mesotrione, imazethapyr, and metolachlor were the main discriminant pesticides between these two branches. Metolachlor was found in sufficient concentrations to induce DNA damage, but it is more likely that the observed genotoxicity was the result of a "cocktail effect," that is, the cumulative contribution of coexisting genotoxicants including the above-mentioned herbicides and ingredients in their formulation. Our findings suggest that the comet assay is a sensitive tool for the early detection of changes in water toxicity following the adoption of agricultural beneficial practices. Environ Toxicol Chem 2023;42:2201-2214. © 2023 Crown copyright and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland.

Measuring and Manipulating the Rhine River Branches: Interactions of Theory and Embodied Understanding in Eighteenth Century River Hydraulics.

Eighteenth century river hydraulics used both theory and measurement to address problems of flood safety, navigation and defense related to the rivers. In the late eighteenth century the Dutch overseer of the rivers, Christiaan Brunings, integrated hydraulic theory and meteorological practices, which enabled him to design a unique instrument for measuring river flow. The question is whether the unprecedented detail of measurements fits the putative empirical stance in the eighteenth century. The interactions between theory, instrument, measurement, and other knowledge practices are here assessed using experiences in similar measurement practices. I argue that Brunings had theoretical and embodied understanding of hydrodynamics, as he knew how to design an instrument for flow measurement of sufficient accuracy for his purpose in the sociopolitical context of river management.

Flow dynamics in rivers with riffle-pool morphology: a dataset from case studies and field experiments

Bars and pools, common for natural riverbeds, form sequential patterns due to interactions between river flow, alluvium and vegetation. While the morphodynamics of bar-pool units are relatively well understood, far less is known about associated riffle-pool hydrodynamics because of a lack of high-resolution data collected in rivers and problems attaining natural scaling in laboratory studies. Here we present a dataset on turbulent flow structure in riffle-pool sequences of a natural river. Two case studies and two field-based experiments were carried out in a side branch of the braided gravel-bed Tagliamento River in Italy. Our case studies deliver detailed information about the three-dimensional structure of mean and turbulent flows in natural riffle-pool/run and pool-riffle/glide transitions. Field-based experiments completed with the in-stream flume models of a riffle-pool transition and a shallow jet model provide a methodological bridge for linking simplified hydrodynamic theories of shallow jets to complex flow structure documented by our case studies. Therefore, this dataset enables examination of scaling effects and can be widely used for validation of numerical models.

Checklist of freshwater periphytic diatoms in the midstream of Brantas River, East Java, Indonesia

Abstract. Masithah ED, Islamy RA. 2023. Checklist of freshwater periphytic diatoms in the midstream of Brantas River, East Java, Indonesia. Biodiversitas 24: 3269-3281. Periphytic diatoms are a group of microalgae that live attached to the surface of the substrate such as rocks, aquatic plants, or other objects in the water. This group has potential as an indicator of environmental quality of water because its existence is influenced by water quality, such as nutrient levels and pollution levels. They are also useful in describing the ecological state, performances, and sustainability of ecosystems because of their ability to measure various environmental parameters and correlate them with diversity, evenness, and richness. This study provides a checklist of freshwater periphytic diatoms in the midstream of Brantas River, East Java, Indonesia. The sampling and identification according to published methods were carried out at the Laboratory of Aquaculture, Faculty of Fisheries and Marine, Universitas Airlangga, Surabaya. This study was undertaken once a week in a month (May 2022) between 9 a.m. and 1 p.m. (GMT + 7). Determination of sampling sites based on differences in land use. Sampling site 1 is located at the Kedungkandang Dam, sampling site 2 is located at the Waterfall Amprong tourist area, sampling site 3 is located at the river branch below the Kedungkandang bridge, and sampling site 4 is located in a residential and agricultural area. The total abundance of freshwater periphytic diatom ranges from 938,905 Ind/mm2 - 1,597,758 Ind/mm2. The lowest total abundance is at station 1 with a value of 938,905 Ind/mm2 and consists of 17 genera. The highest total abundance is at station 4 with a value of 1,597,758 Ind/mm2 and consists of 17 genera. In this study, 27 genera were found spread across 3 phylum.

The analysis Hydromorphometric Watershed Barsool Basin

The Barsool River watershed is one of the branches of the lower Zab River in the Pishdar district. It flows into the lower Zab River about 100 meters southwest of Kawiya village. It is located between the latitudes (o36 07" 14'-o36 12" 00’) of North and longitudes (o45 "09 '51-o45 "19 '22) of East. The main source of this river is located in the Kurdistan Region, in the Pishdar district. The source of water for this river is located in the valley of Beklo, Gira, Dega, Badinbal, and Darashman villages. The main goal of the study is to introduce the environmental characteristics of the study area and describe the specific map for each of them in order to analyze and determine how to use the water resources in the study area. At The beginning of the research was an analysis of the natural environment of the Barsool watershed and its impact on the water flow system, such as (geology, topography, water, air, and soil). This is based on an analysis of natural characteristics and their direct and indirect impacts on river flow. In the second part, the most important hydro morphometric measurements were conducted for the watershed, emphasizing the surface water resources that are reflected in the two branches of the river (Badin and Bajkaran) that form the Barsool River in Barsool village. Groundwater includes 19 springs in terms of morphometric characteristics (area, shape, topography, flow network, and flow rate) have been described. The results show that the natural characteristics of the study area play a major role in the richness of water resources and the rapid flow of streams, rivers, and the main river of the watershed.

Does The Existence of Sharia Microfinance Institutions Contribute to Agricultural Financing? (Study at BMT Khairul Amin Martapura)

Baitul Mal wa Tamwil (BMT) is a Microfinance institution that boosts the economy in the MSME sector. BMT is expected to reach the agricultural sector. In some cases, capital is still weak in the agricultural sector. The establishment of the BMT Khairul Amin Martapura Rangas River branch is expected to help the community, especially farmers, solve the capital problems. This research is field research using qualitative method approach. In addition to producing qualitative data results, this research uses a simple quantitative approach to strengthen the analysis results by explaining the data with numbers. There are six informants in the study. The results revealed that the existence and accessibility of BMT are pretty good. However, in the agricultural sector, it is still not good because the percentage of farmer customers is only 21.05%, and the financing disbursed is only 35.04%.

Employing the Flash Flood Potential Index (FFPI) with Physical Environmental Factors in Baling, Kedah through GIS Analysis

On July 4, 2022, Sungai Kupang, Baling, Kedah experienced a devastating flood that caused 3 fatalities, destroyed or damaged 17 houses, affected 3,546 residents, and resulted in losses estimated at RM25.91 million. The flood was triggered by heavy rainfall in the highland area, which caused multiple landslides to occur simultaneously. The landslides led to a debris flow phenomenon in four main river branches, ultimately resulting in a tragic debris and mud flood in the lowlands and downstream villages. The aim of this study is to analyze the location of flash flood occurrences in Baling and to estimate the likelihood of flash floods based on the identified land physical factors. This study also identifies the critical area of Baling basin that have high potential for a flash flood and evaluates the effectiveness and applicability of the FFPI model compared with historical flood events and remote sensing imagery which have occurred in the few watersheds area. The FFPI model, which was created for the first time in 2003, is used in this study to analyze the flash flood that occurred in Baling by considering slope, land cover, soil data, and vegetation. The FFPI technique is applied in five scenarios to determine the flash flood potential, and the value used is also based on the references. A value of 1 on the index denotes a minimal probability of flash floods, while a value of 10 indicates the highest probability. Based on the findings, the study area had a high possibility of having a flash flood at an index value of 7. The danger level of a severe flash flood is present throughout the research region in all scenarios when the value is more than 50%. The outcome is then utilized to do comparisons using historical information on flash floods and their hotspots area, as well as utilizing satellite imagery to determine the true scale of the flood. This is also important to reduce the impact of floods occurrence in the same place as well managing risk and to plan for disaster-mitigation operations.

Correction of nonstationary tidal prediction using deep-learning neural network models in tidal estuaries and rivers

An operational tidal prediction method based on a combination of nonstationary harmonic analysis and deep-learning neural network models is described. Nonstationary harmonic analysis (NSHA), which was based on classical harmonic analysis (CHA), has been developed for tidal forecasting in tidal rivers and estuaries. However, the prediction accuracy is poor when the discharge grows very large or changes abruptly. Therefore, in this study, we aimed to combine nonstationary harmonic analysis with a deep-learning neural network model to improve tidal forecasts in tidal rivers and estuaries. The long short-term memory (LSTM) neural network model, which works well for processing long-term time series data, was chosen to correct the errors from NSHA. In addition, the traditional feed-forward neural network (FFNN) model was also applied and compared with LSTM to determine and optimize the structure of the neural network. Through experiments, the results showed that a two-layer network with a fully connected layer on top of an LSTM layer that uses discharge in addition to the previous time series as input data exhibited the best performance in predicting the errors of the NS_TIDE model. After correction by the proposed model at three stations on the West River, a branch river of the Pearl River, the root mean square error (RMSE) at 24 h by the NS_TIDE model can be reduced from approximately 0.3 m to less than 0.1 m. More specifically, the results indicated a significant improvement for extremely high-level prediction, which is crucial for water conservancy administrations. Finally, optimization approaches of the neural network to prevent overfitting and improve efficiency are also discussed.

Genetic Algorithm Optimization Model for Central Marches Restoration Flows with Different Water Quality Scenarios

A Genetic Algorithm optimization model is used in this study to find the optimum flow values of the Tigris river branches near Ammara city, which their water is to be used for central marshes restoration after mixing in Maissan River. These tributaries are Al-Areed, AlBittera and Al-Majar Al-Kabeer Rivers. The aim of this model is to enhance the water quality in Maissan River, hence provide acceptable water quality for marsh restoration. The model is applied for different water quality change scenarios ,i.e. , 10%,20% increase in EC,TDS and BOD. The model output are the optimum flow values for the three rivers while, the input data are monthly flows(1994-2011),monthly water requirements and water quality parameters (EC, TDS, BOD, DO and pH).The objective function adopted in the optimization model is in a form the sum of difference in each of the 5 water quality parameters, resulting from themixing equation of the waters of the rivers, from the accepted limits of these parameters , weighted by a penalty factor assigned for each water quality parameter according to its importance. The adopted acceptable limits are 1500,1000, 6,4 and 7, while the penalty factors are 1,0.8,0.8,0.8,and 0.2 for EC,TDS,BOD,DO,and pH respectively. The constraints adopted on the decision variables which the monthly flows of the three rivers are those that provide the monthly demands downstream each river, and not exceed a maximum monthly flowlimits. The maximum flow limits adopted are for three flow cases, wet, average and dry years. For each flow case three scenarios for the monthly water quality parameters were adopted , the average values(scenario 1),the 10% increase in EC,TDS, and BOD (Scenario2),and the 20% increase in these three water quality parameters (Scenario 3). Hence nine cases are adopted and for each an optimum monthly flows are found for each river. The genetic optimization model adopt a variable number of population of 100 to 1000 in a step of100,0.8 and 0.2 cross over and mutation rates, and three iterations to reach the stable optimum solutions. The results indicates that the flow analysis shows a significant decrease in the flow values of the three rives after year 2000,hence, the flow values for the period of (1994-1999), are excluded and the only used values are those for (2000-2011). The estimated monthly demands exhibits low variation. The observed optimum monthly flow values decrease in general as the case flow changed from wet to normal and dry cases. The change in Scenarios from S1 to S2 and S3 , do not necessarily increase all the required optimum monthly flow values. The obtained minimum objective functions do not exhibits a certain trend with the change in the flow cases and/or the change in the scenarios.

Movements and spatial usage of harbour seals in the Elbe estuary in Germany

Harbour seals are top predators in the North Sea and regarded as sentinels for ecosystem health. A few hundred also occur in adjacent estuaries, such as the Elbe estuary, Germany. However, only little is known about how these animals use this dynamic tidally influenced habitat, which has been under high anthropogenic pressure for decades. In this context, nine harbour seals (Phoca vitulina) from the Elbe estuary were equipped with biotelemetry devices to track their movements over multiple months. Harbour seal movements were characterised by short trips (trip length outside pupping season for females: 9.0 ± 1.12 km, males: 7.0 ± 1.24 km) as well as small home ranges (median 50% home range for females: 16.3 km2, males: 36.1 km2) compared to harbour seals from marine regions. Within the estuary, the animals utilised the fairway, river branches and tributaries. During the pupping season in June and July, four seals showed strongly reduced trip lengths and durations, increased daily haul out durations as well as smaller home ranges. Even though a continuous exchange with harbour seals from the Wadden Sea likely occurs, most individuals in this study spent the entire deployment duration inside the estuary. This indicates that the Elbe estuary provides a suitable habitat for harbour seals, despite extensive anthropogenic usage, calling for further studies on the consequences of living in such an industrialised habitat.

Using geochemical models to delineate the relationship between the Pleistocene aquifer groundwater and the oxidation ponds at El-Sadat city, Egypt

This study aims to assess the risk of the wastewater plume from the oxidation ponds contaminating the underneath shallow groundwater aquifer. The study area is an industrial city comprised of three main zones: industrial, populated, and agricultural. The study area is bordered on the eastern side by a wastewater pond and the Rosseta Nile river branch. The geochemical investigation is based on the determination of groundwater salinity, major ions, nitrogen compounds (NH4−, NO2−, NO3−), phosphate (PO43−), heavy metals, and the isotopic content (δ18O and δ2H) as well as the geochemical groundwater modeling. The results show most groundwater samples (50%) in the study area are freshwater, 31% are marginal saline water, and 18% are brackish. Higher nitrogen and PO43− compound concentrations are found in the shallow groundwater close to the oxidation ponds and populated zone. The δ18O and δ2H in the Quaternary groundwater is relatively depleted; they range from −2.1 to 2.3‰ and −7 to 21‰, respectively. The integrations of the geochemistry and isotopes show that the Pleistocene aquifer receives considerable recharge percent (14–56%) from the Rosseta Nile river branch and has been polluted due to the seepage from the oxidation ponds (seepage percent range: 0.6–3.6%). The results suggest that excessive fertilizer usage in the agricultural zone, seepage from oxidation ponds into the subsurface aquifer, and the anthropological effects of population size and industrial zones all contribute to the decline in groundwater quality. The highly vulnerable groundwater sites extend from the northeastern areas close to the oxidation ponds and the southwestern areas close to the industrial and populated zones.

Occurrence Distribution and Risk Assessment of Organophosphate Esters in A Typical Area of the Estuary in the Yellow River Basin

As a type of emerging pollutant, organophosphate esters (OPEs) have the characteristics of toxicity, persistence, and bioaccumulation. Due to their wide use in production and life, OPEs pose potential risks to ecosystems when they enter the environment. In this study, the concentrations of 14 species of OPEs in surface water were determined using UPLC-MS/MS, and the spatial distribution of the OPEs in the surface water of the estuary of the Yellow River basin was further analyzed. The pollution sources were analyzed using correlation analysis and principal component analysis, and the ecological risk was evaluated. The results indicated that the concentration of Σ14OPEs in surface water ranged from 183.81 to 1674.52 ng·L-1, with an average concentration of 638.25 ng·L-1. Tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propanyl) phosphate (TCPP) were the main OPEs. The Xiaoqing River flowing through the urban area differed from the main stream of the Yellow River and other branches in terms of OPEs composition characteristics, which showed a greater impact from human activities. The distribution of Σ14OPEs showed an obvious regional pattern, with a trend of increasing and then decreasing along the direction of the Yellow River inlet. The results of source analysis revealed that human activities such as industrial wastewater discharge from different industries, transportation, and atmospheric deposition were the sources of OPEs in surface water. The ecological risk assessment results indicated that TCEP posed a high risk to aquatic organisms in the main stream of the Yellow River, Xiaoqing River, and Zhimai River, and tri-n-butyl phosphate (TnBP) and triphenyl phosphate (TPhP) posed a low risk at some sites.

Continuity and Discreteness of the Communities of Hydrobionts in the Lotic-Lentic Ecosystem of the Danube River Delta: Phytoplankton

The paper deals with the patterns of continuity and discreteness of the main abiotic parameters and phytoplankton in the transboundary lotic-lentic aquatic ecosystem, including the branches of the Danube River, the Danube - Sasyk canal, and the Sasyk Reservoir, in autumn and winter periods. Water temperature, dissolved oxygen content, and pH are characterized by spatial continuum, whereas water salinity - by discreteness (fresh water is registered in the branches and canal and brackish water - in the reservoir). Local discreteness conditioned by the difference in the structure of dominant complexes (polydominant complexes - in river branches and oligodominant complexes - in the canal and reservoir) is registered with a spatial continuum of phytoplankton, which manifests itself in a predominance of plankton forms of diatoms, green, and blue-green algae. Phytoplankton cell numbers and biomass are typical of mesotrophic (delta branches) and hypertrophic (the canal and reservoir) ecosystems, whereas oligodominant and polydominant complexes are responsible for high information diversity belonging to essential phytoplankton adaptation characteristics.

Strategi Kantor Pos dalam Meningkatkan Kualitas Pelayanan Perspektif Ekonomi Islam

This research is motivated by the application of service quality carried out by a company engaged in the service sector is to provide the best quality service for consumers with the aim of creating customer satisfaction. Of course, to implement good service quality there must be strategies carried out by the post office. The purpose of this study is to determine the Strategy of the Salak River Branch Post Office in Improving Service Quality. This research is qualitative research. The results showed that the strategy of the Salak River branch post office in improving the quality of service was not fully in accordance with the teachings of Islam. It can be seen from the strategies that have been carried out only on the right strategy and communication, but the implementation of the mandate strategy which should be a trustworthy strategy is also important to make people more interested in using post office services. Thus, it can be concluded from the results of the study that the strategy of the Sungai Salak branch post office in improving service quality is not fully in accordance with the teachings of Islam.

Watershed Ecological Compensation Mechanism for Mainstream and Branches Based on Stochastic Evolutionary Game: A Case of the Middle Yellow River

Establishment of a watershed ecological compensation mechanism between multiple subjects is an effective means to realize the collaborative governance of water pollution and maintain the security of water ecology. This paper breaks through the conventional upstream and downstream perspectives of watershed ecological compensation design research and combines them with uncertainty factors. The watershed ecological compensation mechanism for the mainstream and branches was established based on the evolutionary game and the random process. Then, taking the midstream of the Yellow River as an example, some constraint conditions and influencing factors were explored. Results show that: (1) The branch government (i.e., the Shanxi provincial government) is the key to establishing an ecological compensation mechanism between the river mainstream and branches. (2) The proportion of pollution transferred by other branches, the initial probability and the random factors are the main factors affecting the decision-making of branch governments (Shanxi and Shaanxi provincial governments). (3) The compensation and reward of the mainstream government to the branch government and the compensation of the branch government to the mainstream government are the main factors affecting the decision-making of mainstream and branch governments (Shanxi–Henan provincial governments, Shaanxi–Henan provincial governments). The study may provide scientific guidance for the construction of a watershed ecological compensation mechanism between mainstream and multiple branches.