Water Fluctuations Research Articles

Aquatic insects (Ephemeroptera, Plecoptera, Trichoptera and Diptera: Tipuloidea) from the upper Neretva in Bosnia-Herzegovina

Within the upper Neretva catchment in Bosnia several hydropower plants are projected. Between 28.6. and 1.7.2022 a baseline survey was initiated to screen the area regarding the diversity of aquatic insects and its linked conservation value. In total, 59 Trichoptera species, ten Plecoptera species, 19 Ephemeroptera and 16 Diptera (Tipuloidea) species were collected, of which Baeoura sp. is new to science. 35 species are endemics of the Balkans, most species are rheobiontic and need high water current. The most abundant taxa are species of the trichopteran genus Agapetus (A. slavorum and A. ochripes) – surface grazers sensitive to water fluctuations and therefore vulnerable to hydropower-induced water level changes. With estimated 40,000 attracted specimens per night, light traps were extraordinarily successful. The extremely high diversity, as well as the enormous abundance of aquatic insects, underline the importance of the upper Neretva as an unimpacted riverine system embedded in dense natural and near-natural forest.

Outflow of a supersonic overexpanded air jet into a water

Numerical simulation of the underwater outflow of a supersonic overexpanded air jet is considered. The calculations are carried out in an unsteady three-dimensional formulation with a hybrid approach using Reynolds-averaged Navier–Stokes equations for nozzle flow and large eddy-simulation for jet flow. The calculation of the interaction of a gas with a liquid is performed with a volume of fluid, which takes into account the surface tension and compressibility of water. The structural features of turbulence when a supersonic air jet exhausted into water are analyzed. An unsteady formation of a supersonic jet and a gas cavity in a water is obtained, the shock-wave structure of the flow is visualized and the level of pressure fluctuations in water is reported. A comparison of the flow pattern when an air jet exhausted into air and water is made on a qualitative level. The results of numerical simulation of the jet velocity field are used to analyze the Kelvin–Helmholtz and Rayleigh–Taylor instability mechanisms and to reveal the dominant instability mechanism in different jet propagation regions. The results obtained are compared with experimental high-speed photographic recording data and numerical calculations At a qualitative level in literature.

Earthquake prediction based on the analysis of water level fluctuations in the control well

This study examines the methodology and results of earthquake forecasting based on the assumption that the earthquake preparation process can be linked to the development of rupture mechanisms. The analysis focuses on water fluctuations in a control monitoring well, which provides valuable information about the earthquake’s preparation period well in advance. Studies on the territory of the Kryvyi Rih iron ore basin (Kryvbas) confirmed that the underground waters in a deep well (815 m deep) depend on the processes of the current lithosphere deformations evidenced by the changing elastic-deformation state of the crust in tectonic areas. The Kryvyi Rih-Kremenchuk crust-mantle fault produces a system of different-scale faults in the crystalline basement which determine the hydrodynamics of the Kryvbas underground filtration. The earthquake preparation process exhibits clear indicators of the rupture process, characterized by a periodic component of water fluctuations superimposed on the main level-changing process during the preparatory phase. The frequency of the periodic component increases as the date of the earthquake approaches. With this approach, an earthquake with a magnitude of 4.1 inKryvbas was successfully predicted one and a half year before the event, based on monitoring water level fluctuations for 120 days between February and June 2016. The efficacy of forecasting local earthquakes was evaluated using the retro-forecast of earthquakes in Kryvbas on July 29, 2017. The methodology was validated through testing, confirming the initial assumptions. This technique was tested to predict the exacerbation of the seismic situation in the iron ore mining area caused by powerful blasting activities.

Water Security Problems of Lake Tana and Its Possible Management Options: A Review

Lake Tana is the largest lake in Ethiopia and accounts for 50% of the country's freshwater resources. It provides a unique habitat for biodiversity and plays an economic role via tourism, electricity, agriculture, fishery, and, most importantly, it provides drinking water to the local inhabitants. Because of its immense water resource potential for socioeconomic development, Lake Tana has been identified as a major economic corridor in the country. Given the importance of the lake to the region and nation’s economy, human health, and livelihoods, assessing the water security problems of the lake in terms of water scarcity and quality is critical for its sustainable management. Doing so, studies on water level fluctuation and water scarcity, and physicochemical and related hydrological and biological features of the lake, which have been reported in the literature over more than a decade, were reviewed, and the studies showed that water level fluctuation was observed and resulted in water scarcity problems for surrounding communities. In addition to water scarcity and water fluctuation problems, the lake's trophic status has also gradually changed from oligotrophic to mesotrophic and eutrophic. In addition, faecal pollution, heavy metal pollution, and toxicogenic cyanobacteria are detected in the lake, especially on the shores and its tributary river mouths. Moreover, Lake Tana is infested by the ecologically dangerous and worst invasive weed, the so-called water hyacinth, with rapid area coverage and has resulted in dominant other important floras and posing a significant negative impact on water quality, biodiversity, fishing, water supply, water transportation, and other economic activities. There are options recommended to manage the lake. In this regard, different lake ecosystem management options like delineation of buffer zones, integrated watershed management, awareness creation about the lake and its associated wetlands, development of waste management practices, eradicating/reducing water hyacinth, and enforcement of environmental related policies and Strategies are recommended for sustainable management of Lake Tana.

Deformation Pattern and Failure Mechanism of Railway Embankment Caused by Lake Water Fluctuation Using Earth Observation and On-Site Monitoring Techniques

The prediction of railway embankment failure is still a global challenge for the railway industry due to the complexity of embankment failure mechanisms. In this work, the pre-failure deformation and the settlement from abnormal deformation to the final failure were investigated based on earth observation and on-site monitoring with a focus on the deformation stage and failure mechanism of railway embankments. Some new viewpoints are suggested: (1) the differential settlement of ~19 mm revealed via InSAR at the failure region of the embankment may have been caused by internal erosion after rapid drawdown. The cumulative settlement was found to increase with the decline of the lake water level. (2) The railway embankment experienced three phases of primary, secondary, and accelerated creep phases, similar to the evolution of most landslide or dam failures. However, the train loading and seepage force may have aggravated the secondary consolidation, promoting the embankment to enter the accelerated creep phase quickly. The deformation pattern was presented as an exponential curve trend. (3) The formation mechanism of embankment collapse can be summarized as “seepage failure-creep-shear slip-collapse” failure under repeated train loading and rapid drawdown. This work provides some clues for early warnings and for the development of maintenance plans.

Analysis of Coir Fiber/Wood Paint as Composite Anti-Weathering Coatings on Traditional Fishing Boats

The low resistance of wood as a frame material for traditional fishing boats against splashing sea water, humidity, and high-temperature fluctuations was studied in this study by adding coconut coir fiber to wood paint, where this mixture will become an anti-weathering composite material. To make compatibility between the fibers from coir which are water-absorbing (hydrophilic) and alkyd paints which are water-repellent (hydrophobic), the author gives special treatment to the coco fibers through an acetone pre-treatment process and hot alkali (hot alkali treatment) by soaking fiber in 10% high-temperature sodium hydroxide NaOH solution. Soaking in this solution is able to modify fibers that have a rough surface and reduce hydrogen bonding thereby improving the interfacial bond between the fiber and the filler in the composite. The results obtained were that the addition of fiber with a weight fraction of 3.40% to the alkyd paint matrix made the composite the most optimal anti-weathering coating.

Aiming at low nitrogen leaching diets based on nitrogen fertilizer regulatory policy: A regional bio-economic assessment of the Zayandeh-Rud river basin-Iran

Negative environmental impacts of nitrogen (N) intensive diets have triggered global debates on sustainable nitrogen management. Solutions such as dietary transitions, cropland reallocation and N Regulatory Policy (NRP) have been proposed to mitigate the adverse environmental impacts of N use in food production. However, there is still insufficient understanding of how NRPs could be designed to minimize negative environmental impact across diverse agro-ecological zones without sacrificing human dietary requirements. To increase this understanding, we evaluated the consequences of three NRP scenarios (low, moderate, and high N fertilizer rates) on the amount of livestock and non-livestock diet components as well as the associated N leaching and farmers' Gross Margin (GM) by optimizing the allocation of cropland between food and feed crops. We developed a bio-economic Interval Fuzzy Multi-Objective Programming (bio-economic IFMOP) model for the Zayandeh-Rud river basin, Iran, and a procedure that accounts for annual average availability of calories per capita, calorie sources from livestock and non-livestock components of three dietary preferences, and inequality in calorie distribution. The interaction among soil, climate and weather variability and NRPs across nine sub-regions of the case study region was handled by crop yield simulation using the DSSAT software. The solution of farmers' GM, derived from the optimization problem across possibilities of water fluctuations, was assessed to determine the uncertainty in GM. We also introduced an N leaching per Block of Distributed Calories (BDC) criterion based on solutions of supplied calories and associated N leaching. The upper bound of the moderate NRP scenario resulted in the smallest N leaching per BDC. This corresponded to ∼0.34, ∼0.34, ∼3.77 and 19.00 million BDC of meat, dairy, wheat and potato, respectively. Also, the upper bound of this scenario satisfied the lowest instability in farmers’ GM against water fluctuation compared with low and high NRP scenarios. The affordable volume of N leaching per BDC varied across sub-regions between [1.53,3.49], [1.52,3.33], [0.76,0.99] and [0.05,0.08] kg for meat, dairy, wheat and potato, respectively. Our results highlighted both optimistic and pessimistic prospects of producing low N leaching diets. The approach of this study could also be applied to other regions and countries.

Water-holding characteristics of litter and soil and the influencing factors after individual rainfall

To clarify the water-holding characteristics of forest litter and soil, different densities (0, 300, 600, 900 g·m-2) of Pinus tabuliformis litter were covered on the typical soil surface of loess cinnamon and calcareous cinnamon in north China. Based on an artificial simulated rainfall experiment, we observed the variation of litter and soil water content with time, and analyzed the variation process and influencing factors of litter and soil water content after rainfall. The results showed that water content of P. tabuliformis litter decreased significantly with the increases of duration after the rainfall, and that the range of litter water contents under all treatments was 22.9%-71.0%. There was a decreasing exponential function between the decline rate and time. Litter water content was only affected by litter density. The higher the litter density, the greater the decreasing rate of litter water content. Soil water content fluctuated and decreased with the increases of duration after the rainfall, with a variation of 1.5%-8.5%. Soil water-holding capacity was affected by litter density, soil type, and slope position. Litter could effectively reduce the fluctuation of soil water. The higher litter density, the smaller the coefficient of variation of soil water content, the greater the effect of litter on soil water fluctuation, and the better the soil water-holding capacity. The water-holding capacity on loess cinnamon soil was significantly higher than that of calcareous cinnamon soil. Soil water-holding capacity on the downslope was significantly higher than that on the upslope and middle slope, without any difference between upslope and middle slope.

Implementasi Alat Pemantau Debit dan Ketinggian Air Sungai Berbasis Internet of Things Untuk Penanggulangan Banjir

The increasing frequency and intensity of floods in Cirebon City demands innovative solutions to reduce the impact of damage and risks to society and infrastructure. requires the latest approaches to risk management and prevention. This research focuses on the implementation of an Internet of Things (IoT)-based river discharge and water level monitoring tool designed to improve flood detection and prevention capabilities in Cirebon City. The main problems faced include accurate measurements, real-time monitoring, and rapid response to river water fluctuations. By combining the latest sensors and IoT technology, this tool is able to provide accurate data about water discharge and river levels continuously. The first stage in developing the Internet of Things (IoT) is identification and study of flooding problems in Cirebon City and analysis of the need for a monitoring system for flood prevention. Second, design a monitoring tool concept that meets the needs and specifications and determine the type of sensors, hardware and IoT technology that will be used. Third, choose a sensor to measure river discharge and water level. Fourth, build a monitoring tool prototype based on conceptual design. Fifth, Testing and Validation. The results of this research are based on river tests in the city of Cirebon, there are 4 rivers that frequently flood and the results of the test are that the Kalijaga River has a height of 20cm in the Safe level category, the Kedung Pane River has a height of 15cm in the Safe Level Category, the Kesunean River has a height of 10cm in the Safe Level Category and the Sukalila River has a height of 17cm in the Safe level category this is influenced by dry weather. Then the data collected from monitoring tools can be used to analyze flood patterns, trigger factors and impacts. Then, from this data, a flood classification analysis can be carried out based on the level of river water discharge, so that it can be classified as light, medium or heavy floods based on the amount of water flowing.

Hydrological characteristics of Mahakam cascade lake as a reference for the sustainability management

Mahakam cascade lakes consist of Lake Semayang, Melintang, and Jempang is a floodplain lake. Mahakam cascade lakes include the 15 national priority lakes which are the most urgent situation. This lake is characterized by dynamic water level fluctuation, resulting in high fishery productivity. The lake’s hydrological characteristic is the main component in controlling the lake ecosystem, therefore it is crucial to evaluate the influenced factors. The objective of this research is to describe the lake’s hydrological characteristics, including inlet-outlet discharge, sedimentation, water level pattern, and land cover change in the catchment area. Further, provide a reference for the conservation of lake ecosystems. We performed a field campaign to measure river discharge and collect water samples for sediment-load laboratory analysis. We analyzed daily water level data recorded from 1989 to 2010. We obtained the time series land cover from Landsat data and performed GIS spatial analysis. Our results revealed that first, the Rebak Rinding River has the biggest contribution to lake sedimentation (3,859 tons/day, 77% of the total sediments entering the lake). Second, the water level tended to increase during the medium and extreme flood seasons. Contrary, a relatively small decrease in the water level during the medium-receding season. Third, the catchment area is 51,573 km2 (66 times larger than the lake water bodies). From 2000 to 2019, the forest decreased by 2,063 km2. As a consequence, increased erosion-sensitive area by 2,695 km2. We emphasized preserving the catchment area is vital to reduce the sedimentation rate and water fluctuation. We recommend the Rebak Rinding sub-catchment as the priority area for controlling deforestation, and erosion on the plantation, mining, and agricultural area.

FIELD AND MODEL RESEARCH OF THE GROUNDWATER FLOWS IN THE AREA OF THE PAKS-2 NPP CONSTRUCTION, HUNGARY

The construction of the nuclear power plant (NPP) requires conducting a large number of engineering and hydrogeological surveys, as well as assessment of the design decisions’ safety. A deep excavation pit at the Paks II NPP construction site requires execution of the cut-off wall due to extremely high groundwater saturation of the alluvial deposits. However, lithological anisotropy and the presence of dislocation zones did not allow identifying the appropriate depth for the cut-off wall construction. Unfortunately, engineering geological boreholes with a 20-meter distance between them and surface and borehole geophysical surveys could not identify the hydrogeological units. Thus, to conceptualize the hydrogeological settings, an analysis of the groundwater head distribution and the large-scale pumping tests were conducted. The interpretation of the geological data and the distinguishing of the hydrogeological units were carried out iteratively using the hydrogeological numerical model. The flow model could represent the hydraulic head distribution, the response of the lithologically heterogeneous layers to the water fluctuations in the Danube river, and the pumping tests carried out at the different depths. The results of the hydrogeological modeling revealed the aquitard to be continuous throughout the territory; however, its top’s depth changes from 30–35 to 90 m within the construction site of the Paks II NPP. This complex geometry of the aquitard is controlled by the plicated dislocation zone, which cuts the construction site in half and is revealed as the right wall of the graben.Correct hydrogeological stratification enabled us to ensure waterproof activities such as the cut-off wall construction using the hydrogeological model when excavating a deep pit for the Paks II NPP. This also minimizes the hydrodynamic impact on the closely located NPP Paks in operation.

Structural Fluctuation, Relaxation, and Folding of Protein: An Approach Based on the Combined Generalized Langevin and RISM/3D-RISM Theories

In 2012, Kim and Hirata derived two generalized Langevin equations (GLEs) for a biomolecule in water, one for the structural fluctuation of the biomolecule and the other for the density fluctuation of water, by projecting all the mechanical variables in phase space onto the two dynamic variables: the structural fluctuation defined by the displacement of atoms from their equilibrium positions, and the solvent density fluctuation. The equation has an expression similar to the classical Langevin equation (CLE) for a harmonic oscillator, possessing terms corresponding to the restoring force proportional to the structural fluctuation, as well as the frictional and random forces. However, there is a distinct difference between the two expressions that touches on the essential physics of the structural fluctuation, that is, the force constant, or Hessian, in the restoring force. In the CLE, this is given by the second derivative of the potential energy among atoms in a protein. So, the quadratic nature or the harmonicity is only valid at the minimum of the potential surface. On the contrary, the linearity of the restoring force in the GLE originates from the projection of the water’s degrees of freedom onto the protein’s degrees of freedom. Taking this into consideration, Kim and Hirata proposed an ansatz for the Hessian matrix. The ansatz is used to equate the Hessian matrix with the second derivative of the free-energy surface or the potential of the mean force of a protein in water, defined by the sum of the potential energy among atoms in a protein and the solvation free energy. Since the free energy can be calculated from the molecular mechanics and the RISM/3D-RISM theory, one can perform an analysis similar to the normal mode analysis (NMA) just by diagonalizing the Hessian matrix of the free energy. This method is referred to as the Generalized Langevin Mode Analysis (GLMA). This theory may be realized to explore a variety of biophysical processes, including protein folding, spectroscopy, and chemical reactions. The present article is devoted to reviewing the development of this theory, and to providing perspective in exploring life phenomena.

Improving the performance of recycled concrete by biodeposition of biogenic silica as a surface coating

This study addresses the challenges of sustainability and the implementation of a circular economy in the construction and maintenance of concrete structures used in clean-water applications. Specifically, it examines the use of an innovative surface treatment based on a biofilm comprising diatom biosilica deposition as a waterproofing agent and surface pore sealant to improve the longevity of recycled concrete. To this end biofilm-treated and untreated (control) samples of a concrete mix containing 50% recycled aggregates were subject to four performance tests directed at assessing the durability of concrete structures under environmental conditions: resistance to carbonation, freeze–thaw durability, resistance to water penetration, and electrical resistivity as an indicator of the corrosion resistance of concrete. In addition, the protective biofilm was characterised using SEM. Results suggest that the biogenic silica surface treatment significantly improves the durability of recycled concrete, in particular, for treated compared to untreated samples there was a 56 % reduction of the carbonation front, 26% lower mass loss in freeze–thaw cycles, 57% reduction in the water penetration front under pressure, and 44% higher electrical resistivity. Together these findings confirm that the biofilm used in this study constitutes an effective treatment to improve the properties of recycled concrete and ensure its durability, particularly when used in the construction of structures in contact with constant water fluctuations.

The provenance of microorganisms adapted to extreme salinity, extreme temperature, and toxic metals within the Montney shale formation.

Introduction Shale oil reservoirs are hypothesized to be sterile due to the extremely high temperature, pressure and salinity within these formations (Evans et al. 2018). High concentrations of toxic metals also pose challenges that demand specific microbial adaptions (Boyd and Barkay 2012, White and Gadd 1998, Ben Fekih et al. 2018). While some microorganisms are introduced into and are selected for within shale formations during hydraulic fracturing, the possibility that certain microorganisms are pre-existing inhabitants of these formations is less clear. Here, we followed the microbial diversity of input and output fluids injected into a Montney formation shale reservoir to assess the distribution and transport of microbial populations during hydraulic fracturing. Enrichment cultures distinguished various metabolisms in the microbial populations found in different sample types, and adaptations allowing them to colonize such niches. Material and methods Fracturing fluid, drilling muds (3302 m, 3350 m and 3400 m depths), shale cuttings (rinsed from the drillings muds), shale core plugs and produced water samples (12-month period) were sampled from a Montney shale oil reservoir. Microbial community compositions were analyzed by amplicon sequencing. Metal content was analyzed by inductively coupled plasma-mass spectrophotometry. High salinity enrichments at 90°C of the drilling muds or rinsed shale samples were set up in triplicate and amended with glucose and guar gum (a mannose/galactose-based polymer used during hydraulic fracturing). Sugars were measured through spectrophotometric assays. Metagenomic analyses were performed to assess microbial gene content. Results/Discussion Provenance of microorganisms from the Montney shale formation Provenance of microorganisms from the Montney shale formation Input fluids (fracturing fluid, drilling muds) were revealed to be the likely source of most of the microbial diversity. However, some microorganisms were only detected in the subsurface samples. ASVs affiliated with Aurantimonas, Caminicella, BRH-c8a (Family Desulfallas) and Geotoga exhibited occurrence patterns consistent with being derived from subsurface shale formations. Geotoga has only ever been reported from oil reservoirs (Semenova et al. 2020). Analysis of produced water revealed ASVs from these groups increasing in abundance during hydraulic fracturing operations, suggesting selective pressure from oil reservoir conditions (e.g., toxic metal presence, input of saline water, temperature and pressure fluctuations). Incubations set up from drilling muds showed a preference for glucose while incubations of the rinsed shale cuttings showed a microbial preference for guar gum (i.e., mannose production; Fig. 0), reinforcing the presence of different populations being derived from surface and subsurface samples. Adaptations for life in Montney shale Adaptations for life in Montney shale When considering adaptations of microorganisms for environmental conditions found in oil reservoirs, it is relevant to note the presence of toxic metals such as arsenic, cadmium and mercury. Levels of all three metals were found to vary over time within the 28-day shale microbial enrichments and 12-month produced water time course analyses (Suppl. material 1). Metagenomics revealed various genes for the internalization and metabolism of all three metals within the shale microbiome (i.e., arsenate reductases, arsenite transporters, metallothioneins, mercuric reductases). In conclusion, the results of this study suggest that shale reservoirs thus might not be sterile environments, and host microorganisms are able to contend with major perturbations.

Tides and Low Horizon in Calculating the Beginning of the Qamariyah Month

The lowness of the horizon is the plane that passes through the center point of the earth and is perpendicular to the vertical line. In general, during determination of the beginning of the month of Qamariyah, there is rarely a correction to the low horizon with the majority of these activities carried out on the beach. Tidal force is the fluctuation of sea water due to the attraction of celestial bodies. With the hypothesis that when the sea is in a state of high tide, the horizon is also higher and when the sea is at low tide the horizon is in a lower position. This study is intended to answer the problem of how the influence of tides on the low horizon? This research is a library research with primary data in the form of tidal data from Buku Tabel Pasang Surut Kepulauan Indonesia 2022 yang diterbitkan oleh Hidro-Oseanigrafi TNI AL. In this article, we will examine sea tides and their effect on the low horizon. With the result of tides the sea water does not affect the lowness of the horizon.

Assessing water security and footprint in hypersaline Lake Urmia

The quantitative assessment of water security including its distribution helps plan and manage adequate amounts of quality water to sustain livelihoods. This research introduces a hydrological modeling framework designed to evaluate the spatial and temporal fluctuations of blue water and green water, aiming to quantify the water security status of Lake Urmia in Iran. This lake, recognized as the second largest hypersaline lake globally, has experienced a significant decline in its water storage in recent years. This model, based on water consumption and population size was used to investigate water security and footprint while quantifying the spatial and temporal changes in the availability of blue water and green water. As the results demonstrate, the monthly and annual coefficient of variation for blue water (41.1 % and 27.6%, respectively) was greater than for green water (32.3% and 21.7%, respectively), hence green water flow showed more homogeneous than blue water flow distribution among different sub-basins. At the same time, the coefficient of variation for the spatial distribution differs between various components of the water footprint. Agricultural use requires the most water in this basin, with a blue water scarcity of 0.27. The blue water vulnerability value for total water consumption indicates a lower risk of a water crisis under low-flow conditions. In addition, the freshwater provision indicator in each sub-basin varies between the middle (0.64) and lower (0.80) parts. Thus, in these parts, water can be consumed with less negative impact on the environment. In conclusion, the environmental situation of Lake Urmia and its water security has clearly decreased over the last decade which requires urgent management action (e.g., changing irrigation pattern) to mitigate an environmental crisis. This research offers precise and quantifiable references related to water resources and water security, and can enhance targeted water footprint management within the study area. Our hydrological modeling framework provides the basis to inform water management in various similar watersheds across the globe.

Reproductive Characteristics and Germ Cell Status of Indian Major Carp, <i>Labeo rohita</i> Reared in Elevated Water Temperature Regime

Rearing water temperature and fluctuations in it has a profound effect on survival and gonadal development of fish. Reproduction in fish, compared with other physiological processes, only occurs in a bounded temperature range; therefore, small changes in water temperature could significantly affect this process. Here we analysed the effects of different rearing water temperatures (28 °C, 30 °C, 32 °C, 34 °C and 36 °C) and a cytotoxic drug (busulfan) on germ cell status and maturation in Indian major carp, Labeo rohita. The effectiveness of the treatment was assessed by gonadosomatic index, histology and dye uptake of GC. Thermo-chemical treatments were given either: as elevated water temperature alone (0.69±0.09) or in combination with busulfan that showed a low GSI value (0.49±0.26) as compared to control (0.88±0.009). Gonadal morphology visibly shrunk after the thermochemical treatments. Similarly, the gonadal histology confirmed that the GC depletion took place when the rohu were reared at elevated temperature along with the application of a cytotoxic drug busulfan (40 mg/kg). According to the deteriorating reproductive responses of the fish by temperature fluctuations, it is plausible that changes may affect aquaculture production and affecting future populations of fish, so new strategies for amelioration should be anticipated.

Response of denitrification microbiome to the nitrogen flux in three Gorges reservoir (TGR) sediments during two seasonal water fluctuation events

Three Gorges Reservoir (TGR) water fluctuation creates high water level (HWL) and low water level (LWL) condition in TGR aquatic ecosystem. HWL fluies significant nutrients, mainly introducing carbon and nitrogen into the ecosystem. The nitrogen input is a concern for water quality management of TGR since the possible eutrophication caused by nitrogen spike. Sediment denitrification is widely recognized as the dominant nitrogen removal process in freshwater ecosystem. Therefore, the response of TGR sediments microbiome to the input nitrogen flucatution is crucial for both nitrogen balance and the eutrophication status of the ecosystem. Using high throughout sequencing of 16S rRNA gene and the predicted denitrification enzyme, and qualitative PCR of denitrification functional genes, we investigated how TGR sediments denitrification microbiome respond to the input nitrogen flux during two seasonal water fluctuation events. Concomitant to expected input carbon and nitrogen, we observed distinct microbial community structure and denitrification microbiota in HWL and LWL, and also in seasonal sampling events. Sediments pH, total nitrogen and nitrate were the significant impact factors in shaping the microbial community structure. Important denitrification microbiota (e.g., Saprospiraceae, Gemmatimonadaceae, Pseudomonas) are the main taxa of the microbial community and also showed water level and seasonal variation. The relative abundance of denitrification enzyme (nar, nir, nor, nos) and function genes (nirS, nirK, nosZ) were higher in LWL than HWL. Denitrification enzyme were significantly (p < 0.05) correlated with the nitrate concentration. In addition, the relative abundance of denitrification enzyme and function genes increased during the transition from 2014 HWL to 2015 LWL. Results suggested that TGR sediments denitrification is nitrate concentration dependent. The denitrification microbiome is initially inhibited due to high nitrate input, then they developed denitrification ability in response to high nitrate concentration.

Studi Perubahan Garis Pantai dengan Metode DSAS (Digital Shoreline Analysis System) Sebagai Upaya Identifikasi Erosi di Pantai Utara Pulau Tarakan

The beach is an area on the edge of the sea which experiences the influence of sea water fluctuations. Between the coast and the mainland separated by an imaginary line called the coastline. One of the problems on the coast is the decline of the coastline (Abrasion) and the progress of the costline (Accretion). Beaches that must be protected from the phenomenon of Abrasion and Accretion needs to be identified first to find out how far the changes have occurred in the coastline. The beach which is the object of this study is the beach on the north side of Tarakan Island. Identification was carried out by applying the DSAS Method (Digital Shoreline Analysis System) with change analysis using the LRR Method (Linear Regression Rate) and RMSE Method (Root Mean Square Error) while the mold delineation coastline based on Landsat satellite imagery in 1988, 1990, 2010, 2016, 2022, and 2023. The results of studies conducted in this study indicate that there has been a decline in the coastline with an average rate of change of 2,16 Meter/year and is predicted to increase backward an average of 0,74 Meter/year in 2033 for sandy beach areas. While in other areas there is progress of the coastline which is estimated to have a rate increase of an average of 2,40 Meter/year for Mangrove vegetation areas and an average of 0,19 Meter/year for community residential areas in 2033.

Effects of drought hardening on the carbohydrate dynamics of Quercus acutissima seedlings under successional drought.

As precipitation patterns are predicted to become increasingly erratic, the functional maintenance of warm-temperate forests constitutes a key challenge for forest managers. In this study, 2-year-old Quercus acutissima seedlings were selected to elucidate the mechanisms whereby they respond to soil water fluctuations and the drought hardening effects on plant carbohydrate dynamics. Seedlings were trained under different soil water conditions for 2 months: drought (D), well-watered (W), 1-month drought and then 1-month well-watered (D-W), and 1-month well-watered and then 1-month drought (W-D). The functional traits involved in water- and carbon-use strategies were explored at the end of the hardening period. Compared with seedlings in group W, seedlings in groups D, D-W, and W-D had increased potential for carbon uptake (i.e., light saturated point, maximum ribulose-1,5-bisphosphate (RuBP) saturated rate, and electron transport rate) and water uptake (i.e., fine root-to-coarse root ratio) and downregulated growth and mitochondrial respiration to decrease carbon consumption. After water fluctuation hardening, we performed a successional dry-down experiment for 1 month to detect carbohydrate dynamics and explore the acclimation caused by prior hardening. Our results revealed that there were more soluble sugars allocated in the leaves and more starch allocated in the stems and roots of seedlings hardened in the D, W-D, and D-W treatments than that of seedlings hardened in the W treatment. No significant changes in total non-structural carbohydrates were found. In addition, we found near-zero (seedlings trained by D and D-W treatments) or negative (seedlings trained by W-D treatment) growth of structural biomass at the end of the dry-down experiment, which was significantly lower than that of W-hardened seedlings. This suggests that there was a shift in allocation patterns between carbon storage and growth under recurrent soil drought, which can be strengthened by drought memory. We conclude that Q. acutissima seedlings adjusted water- and carbon-use strategies in response to water fluctuations, whereas stress memory can enhance their overall performance in reoccurring drought. Therefore, taking advantage of stress memory is a promising management strategy in forest nurseries, and drought-trained seedlings might be more suitable for afforestation practices in sites characterized by fluctuating soil water content, considering the ongoing global climatic changes.