Increasing Temperature Values Research Articles

Tectonics and gravity field structure of Central Kazakhstan

Purpose. Identification of the nature of the manifestation of tectonic elements of different ages in Central Kazakhstan in gravitational fields based on the results of the calculation of regional, intra-crustal and local transformants. Methodology. Synthesis and analysis of the data on integrated interpretation and modeling of gravitational, geomagnetic, geothermal fields, the latest movements of the Earth’s crust and parameters of the seismic regime, tectonics and stratigraphy of rocks. Findings. Regional, intra-crustal and local heterogeneities in the lithosphere manifest themselves differently in blocks of Precambrian rocks, Early and Late Caledonides, Early and Late Hercynides. They may be associated with the processes of Paleozoic intracontinental rifting, with the rise of mantle matter and its emplacement into the Earth’s crust, followed by the manifestation of Late Paleozoic orogenesis, doubling of the thickness of the Earth’s crust, outpourings of magmatic formations. Originality. It is established that large gravitational minima are distinguished in areas with Hercynian folding, characterized by abnormally high amplitudes in the movement of the Earth’s crust. In the regions of the Caledonian folding, the values of gravity field anomalies of intermediate intensity and increased amplitudes of the latest movements of the Earth’s crust are manifested. Areas with Pre-Paleozoic folding have relative maxima of gravitational anomalies and minimum values of the latest movements of the Earth’s crust. Earthquake sources are concentrated in the consolidated crust at the junction of areas with different ages of basement consolidation, in gradient zones of geothermal, geomagnetic and gravitational anomalies. According to the variations of the intra-crustal transformant, it was found that a wide range of changes in the values of the gravitational field corresponds to areas with minimal temperature values, whereas in areas with increased temperature values, the range of changes in the values of gravity anomalies is reduced. The distribution of the local transformant of the gravitational field indicates the existence of highly variable anomalies, which reflects the high-frequency gravitational effect of near-surface objects of the Earth’s crust. Practical value. The distribution of inhomogeneities in the lithosphere with various density, geomagnetic and geothermal anomalies of geophysical fields, the nature of the seismic regime and the latest movements of the Earth’s crust predetermined the formation of geostructures with different types of mineralization, each of which is recommended to be searched and explored by a specific rational set of geophysical methods.

Dimensionality-Transformed Remote Sensing Data Application to Map Soil Salinization at Lowlands of the Syr Darya River

The problem of saving soil resources and their reclamation measures under current climate change conditions attracts the world community’s close attention. It is relevant in the Syr Darya River’s lowlands, where the secondary soil salinization processes have intensified. The demand for robust methods to assess soil salinity is high, and the primary purpose of this study was to develop a quantitative analysis method for soil salinity estimation. We found a correspondence between the sum of salts in a topsoil layer to the Landsat 8 data in the Tasseled cap transformation of the image values. After testing several methods, we built a prediction model. The K-nearest neighborhood (KNN) model with a coefficient of determination equal to 0.96 using selected predictors proved to be the most appropriate for soil salinity assessment. We also performed a quantitative assessment of soil salinity. A significant increase in a salt-affected area and the mean soil sum expressing an intensification of secondary soil salinization from 2018 to 2021 was found. The increasing temperature values, decreasing soil moisture, and agricultural use affect the extension of salt-affected ground areas in the study area. Thus, the soil moisture trend in the Qazaly irrigation zone is negative and declining, with the highest peaks in early spring. The maximum temperature has a mean value of 15.6 °C (minimum = −15.1 °C, maximum = 37.4 °C) with an increasing trend. These parameters are evidence of climate change that also affects soil salinization. PCA transformation of the Landsat-8 satellite images helped to remove redundant spectral information from multiband datasets and map soil salinity more precisely. This approach simultaneously extends mapping opportunities involving visible and invisible bands and results in a smaller dataset.

Entropic Uncertainty for Two Coupled Dipole Spins Using Quantum Memory under the Dzyaloshinskii-Moriya Interaction.

In the thermodynamic equilibrium of dipolar-coupled spin systems under the influence of a Dzyaloshinskii–Moriya (D–M) interaction along the z-axis, the current study explores the quantum-memory-assisted entropic uncertainty relation (QMA-EUR), entropy mixedness and the concurrence two-spin entanglement. Quantum entanglement is reduced at increased temperature values, but inflation uncertainty and mixedness are enhanced. The considered quantum effects are stabilized to their stationary values at high temperatures. The two-spin entanglement is entirely repressed if the D–M interaction is disregarded, and the entropic uncertainty and entropy mixedness reach their maximum values for equal coupling rates. Rather than the concurrence, the entropy mixedness can be a proper indicator of the nature of the entropic uncertainty. The effect of model parameters (D–M coupling and dipole–dipole spin) on the quantum dynamic effects in thermal environment temperature is explored. The results reveal that the model parameters cause significant variations in the predicted QMA-EUR.

Schottky barrier engineering in metal/semiconductor structures for high thermal stability

In this study, Co/eosin-y/p-Si/Al and Co/eosin-y/n-Si/Al heterojunctions with Schottky barrier were produced and electrical characteristics were investigated in the temperature range 100–460 K at intervals of 20 K. For each device, the barrier heights (φ b), ideality factors (n) and series resistance (Rs) values were calculated using different methods from the current–voltage curves. It was observed that the ideality factor and series resistance increased with decreasing temperature, while the height of the barrier decreased. One of the reasons for this change in parameters is the inhomogeneity of the Schottky barrier. The Rs values were found with the help of Cheung functions and Norde functions. The contact parameters obtained from the Cheung functions and those obtained from the Norde function were compared. It was observed that the barrier heights obtained from these methods increased linearly with increasing temperature values. The variation of temperature-dependent interfacial state density versus interfacial state energy was shown. The density of the interfacial state decreased, with increasing interfacial state energy at each temperature value. These characteristics indicate that Co/eosin-y/p-Si/Al and Co/eosin-y/n-Si/Al devices are good candidates for rectifying and thermal sensing applications.

Генезис вантгофіту, левеїту й кізериту в родовищах калійних солей Передкарпаття за даними експериментальних досліджень

The genesis of vanthoffite, loeweite and kieserite in the potassium salts deposits of Precarpathian region is characterized on the basis of mineralogical, geochemical and experimental studies. Vanthoffite and loeweite are rare minerals. Vanthoffite associates with astrakhanite and loeweite. It is proved due to experimental studies that dehydration of astrakhanite occurs at the stages of late diagenesis–katagenesis under conditions of increasing temperature. From the products of its decomposition, loeweite is formed first, and then vanthoffite. This is facilitated by an increase of pressure, under which minerals with a higher density are more stable (the density of vanthoffite (2.69 g/cm3 ) is much higher than that of loeweite (2.37) and astrakhanite (2.32)). Kieserite is found in sylvinite, kainite and kainite-langbeinite rocks in the amount of small impurities up to 10–33 %. It is unstable on the day surface: it absorbs water from the atmosphere and transforms into hexahydrite. Experimental studies have shown that kieserite does not precipitate in salt sedimentary basins, but is formed from epsomite (hexahydrite) due to its dehydration Петро Білоніжка 60 ISSN 2078-6220. Мінералогічний збірник. 2021. № 71 under conditions of increasing temperature and pressure at the stages of late diagenesis and katagenesis. Increasing temperature values (up to 200 °С), which existed in the potassium salts deposits of Precarpathian region during the thrust of the Skybova zone to the Precarpathian Foredeep Inner zone and the formation of folding in salt deposits, are sufficient for phase transformation of astrakhanite to loeweite and vanthoffite, and epsomite (hexahydrite) – to kieserite.

Effect of diverse Pechini sol-gel parameters on the size, morphology, structural and optical properties of the Tenorite (CuO) NPs: A facile approach for desired properties

Copper oxide (CuO) nanoparticles (NPs) have been successfully synthesized by the Pechini sol-gel approach. The effect of three fundamental synthesis parameters on the size, morphology, structural, and optical properties of the prepared products was systematically investigated. The prepared powders were evaluated by XRD, FTIR, DSC/TG, FE-SEM, TEM, and EDS analyses. Based on these experiments, the monoclinic phase structure of highly pure CuO NPs with space group C2/c was characterized. A wide range of crystallite size from 19.1 nm to 45.7 nm were obtained via diverse compositions and calcination temperatures. The preferred orientation (Texture) was found to be altered from (311) to (020). Structural quantities were calculated by Rietveld analysis. Microstructural observations demonstrated that the different morphologies of the CuO NPs (spherical, semi-spherical, and plate-like decorated by semi-spherical NPs) can be achieved by controlling the synthesis parameters. The optical properties of the prepared samples were studied by UV–vis spectroscopy. The estimated direct band gap was decreased from 4.17 eV to 3.01 eV by increasing temperature values. It was found that the size, morphology, texture, and consequently properties of the prepared CuO nanostructures can be controlled by changing the Pechini process parameters.

The First Principles Approach to The Structural, Elastic, Electronic, Vibrational and Thermal Properties of CsCl type-ErAu Alloy

Lanthanide-gold binary alloys are very attracting attention in applications of electrical measuring technology based on resistance. Such materials are considered suitable for electrical circuits due to the large temperature stability. In this study, the structural, elastic, electronic, vibrational and thermal properties of the CsCl-type crystal structure of the ErAu binary alloy with two atoms in the unit cell are investigated in the framework of the first principles approach. The lattice parameter is found as 3.603 Å. Obtained structural parameters are consistent with the available studies. Considering of electronic properties, the electronic band structures, total and partial density of states of the ErAu alloy are determined. From these calculations, it has been decided that ErAu alloy is metallic in nature. The elastic constants are calculated using the stress-strain method. The elastic constants are also obtained for different pressure values. Elastic properties of the system present that ErAu alloy is mechanically stable at different pressure values. Phonon frequencies are calculated and the structure is determined as dynamically stable. To present the thermal properties of ErAu alloy, the free energy, entropy and heat capacity of the system are also obtained under increasing temperature values.

Yarı-Heusler LiScPb Yarıiletkeni Üzerine Bir İlk İlkesel Araştırma

A first-principles study of structural, elastic, electronic, vibrational, thermodynamic and optical properties of a half-Heusler (HH) LiScPb semiconductor has been reported using the plane-wave pseudo-potential technique based on density functional theory (DFT). The elastic properties are represented using second-order elastic constants. The electronic band structure calculations are obtained with partial density of states. Optical properties of HH-LiScPb semiconductor are also investigated and related parameters such as refraction index, extinction coefficient, reflectivity and loss function are determined using dielectric functions in this study. Phonon calculations have been taken into account to evaluate the stability of half-Heusler (HH) LiScPb semiconductor. Also, the system's free energy, entropy and heat capacity were investigated under increasing temperature values.

Structure of Water in Zn2+ Aqueous Solutions from Ambient Conditions up to the Gigapascal Pressure Range: A XANES and Molecular Dynamics Study.

The structural modifications induced on a 0.5 M Zn2+ aqueous solution by increasing the pressure to 6.4 GPa were investigated using a combination of X-ray absorption near edge structure (XANES) spectroscopy and molecular dynamics (MD) simulations. The Zn K-edge XANES experimental spectra show two different trends depending on the pressure and temperature conditions of the system. On the one hand, when the pressure is increased to 1.0 GPa while keeping the temperature at 300 K, the highly structured nature of Zn2+ second hydration shell is preserved. On the other hand, when the Zn2+ aqueous solution is simultaneously pressurized and heated to follow the melting curve above 1.0 GPa, the Zn2+ second shell loses its high degree of structuring and becomes much more disordered and unstructured. These results are confirmed by the analysis of MD simulations of Zn2+ aqueous solutions under high pressure. By combining distance and angular distribution functions it is possible to highlight the loss of water structuring in the Zn2+ second coordination shell that takes place upon pressurization and heating. A progressive crowding of the Zn2+ second shell is observed with increasing pressure; the water structure becomes remarkably different from that found at ambient conditions, and for pressure values higher than 1.0 GPa the tetrahedral arrangements of water molecules is highly distorted. Moreover, MD simulations of Zn2+ aqueous solutions performed at 1.0 GPa and at increasing temperature values have shown that the loss of water structuring in the Zn2+ second coordination shell observed by simultaneously pressurizing and heating is due to a combined effect of pressure and temperature, both producing an increase of the Zn2+ second-shell disorder.

Rheological properties of dextrin-riboflavin solutions under thermal and UV radiation effects

The combination of saccharides and UV sensitive chemical molecules in the solution form has been in the interest of medicine for treating medical complications and imaging techniques due to their remarkable properties under UV radiation. Therefore, two samples of dextrin based riboflavin solutions containing 10wt% of dextrin content and 0.1wt% of UV sensitive riboflavin content were prepared at the room temperature. In order to understand how UV radiation affects the viscosity of prepared solutions at various temperatures, one of the prepared samples was protected from light while another sample was radiated to UV at a biologically harmless wavelength where the absorbance peaks are obtained by UV/visible spectroscopy. Dynamic viscosity measurements of UV-radiated and un-radiated solutions for different temperatures were performed with constant velocity where the most reliable torque is shown. It was understood that application of UV radiation increased the viscosity value of radiated sample at the room temperature, however; it did not alter the fluid types of test samples. Fluid type of all test solutions was found to be non-Newtonian dilatant fluids as the shear stress vs. shear rate curves of solutions reliably obeyed Ostwald-de-Waele equation. Flow type of all solutions was classified as shear thickening fluids (STF) since power law consistency coefficient (n) of Ostwald-de-Waele equation was found to be >1 (n>1). Based on this experimental outcome, the effect of UV radiation on shear thickening behavior of the solutions which include low viscous biocompatible solutions was studied for the first time. Thermal behavior of all test solutions was mathematically modeled via Arrhenius viscosity equation. The degree of STF increased and viscosity of dextrin based riboflavin solutions was found to be slightly greater than other test samples at increasing temperature values after UV radiation. As expected, viscosity values of all test samples decreased at elevated temperatures.

Study of Magnetic Properties of Fe-Doped CuO: Monte Carlo Simulations

Using Monte Carlo simulations, we are studying the magnetic properties of Fe-doped CuO thin films. The total magnetizations and the susceptibilities are studied as a function of the effect doping, external magnetic field, and exchange coupling. The critical temperature is discussed as a function of the effect of iron concentration. On the other hand, we investigate the effect of increasing temperatures on the coercive field for a constant value of exchange coupling and a fixed concentration. The coercive magnetic field is found to decrease with increasing temperature values until reaching its null value. The effect of increasing the exchange coupling amount on the saturation magnetic field H s is illustrated. A linear growth of the saturation magnetic field is found as a function of the exchange coupling interaction. To complete this study, we presented and discussed the magnetic hysteresis cycle loops.

Farmland shift due to climate warming and impacts on temporal-spatial distributions of water resources in a middle-high latitude agricultural watershed

Climate warming increases the active accumulated temperature (AAT) of crops and may change crop structures and patterns. Climate warming along with farmland responses has combined consequences for watershed hydrological indicators, which would be expected to exhibit different temporal-spatial patterns. In our study we investigate the combined impacts of increased temperature and shifted farmland on the hydrological features in middle-high latitude agricultural watersheds. The AAT responses in latitudinal and altitudinal directions were revealed by using an agro-climate model under different warming scenarios (△T=0.1°C is applied to the interval from 0.7°C to 1.5°C). Then, the spatial distributions of dryland shifting to paddy land were determined considering △AAT. For every 1°C increase in average annual temperature, the boundary for planting paddy fields will shift northward by approximately 160km and upward in the altitudinal direction by 180m. Increasing temperature values and the new crop distributions were imported into the SWAT model, which quantified the temporal (monthly and yearly) and spatial changes of runoff and actual evapotranspiration (ET). Annual runoff decreased at a rate of 9.5mm/°C, and annual ET increased at a rate of 7mm/°C under climate warming combined with shifted farmlands. Combined impacts increased runoff in February, March and September, and decreased runoff from April to July. ET increased from March to July and decreased in August and September. The comparison of spatial water resource responses indicated that lower altitude and lower latitude areas experienced larger changes in runoff and ET than was the case for higher altitude and higher latitude areas.

Biotemplated Luffa cylindrica for the oil spill clean-up from seawater

Biotemplated Luffa cylindrica (B-LC) is used to remove oil spills from Mediterranean seawater. The main objective of this work is to develop a biotemplated organic sorbent. L. cylindrica is coated with chitosan for efficient delivery of oil droplets throughout the lumens of fiber. Thus, L. cylindrica acted both as a natural sorbent and a chitosan carrier template. In second step, the optimum conditions for the efficient oil sorption of B-LC are determined. Besides seawater tests, DDI water tests are also performed in order to investigate the effect of background water chemistry. Both modified and raw L. cylindrica samples are studied for the determination of baseline sorption capacity. SEM and Fourier transform infrared spectroscopy analyses are performed for the characterization studies. Results showed that B-LC has a higher sorption capacity compared to the raw samples. It is understood that increasing temperature has an adverse effect on seawater oil sorption value. It is generally noticed that positive effect of increased contact time and agitation speed is hindered by the increasing temperature values. Effect of background water chemistry is negligible. A slight increase in sorption capacity for the B-LC in seawater is observed. Overall results suggested that the B-LC can effectively be used as an efficient natural sorbent in the oil spill clean-up process.

Predicting the habitat expansion of the invasive roach Rutilus rutilus (Actinopterygii, Cyprinidae), in Great Britain

The roach is influential ecologically and has a preference for water temperatures >12°C. In this study, we attempted to predict its habitat expansion in response to global warming, hypothesing its increase in Great Britain. Historical data for air temperature over different time scales (annual, seasonal, monthly and daily) and for the presence of roach in Great Britain were used to create four Ecological Niche Models. Mean seasonal air temperature (EncRoach-S) was the best predictor. Using EncRoach-S, two future climate scenarios were tested: a sensitivity test (i.e. incrementally increasing temperature values by 1°C), and using air temperature data from UKCIP 11-member ensemble of climate change projections for 2031–2040, 2061–2070 and 2091–2100. Both approaches predicted an increase in habitat suitability in Great Britain with rising air temperatures but the extent of change differed for England, Wales and Scotland. In England, the rate of expansion was initially slow but rapidly increased mid-century leading to 88% coverage by the century end. In Wales, there was a greater increase by the century end and a similar trend in Scotland. This study supports the conjecture that a rise in air temperature over the next few decades will lead to an increase in potential roach habitat.

Effects of Seasonal Changes on Pigment Composition ofAzolla filiculoidesLam.

Abstract Azolla is a floating fern, which contains the nitrogen-fixing cyanobacterium Anabaena azollae in the dorsal lobe cavity of the leaves. This study investigated the effects of seasonal changes on the pigment composition of Azolla filiculoides in a small pond located in Istanbul, Turkey. Sampling was conducted in March, April, May, October, November, December 2007. The average total chlorophyll and carotenoid content of the leaves was almost a half fold lower in March-April-May than in October-November-December. For late winter–spring, while the average chlorophyll a/b ratio of the leaves was 2.6, for autumn - early winter it was 5.5. In March, leaf dimensions reduced, whereas the anthocyanin accumulation in the leaves increased. In May, together with the increasing temperature values, while the leaf dimensions and biomass increased, the leaves returned to green. From October to November, both leaf dimensions and amount of anthocyanin in the leaves reduced. Results showed that the probable growth se...

Can the combination of decreased pH and increased temperature values induce oxidative stress in the clam Chamelea gallina and the mussel Mytilus galloprovincialis?

The combined effects of decreased pH and increased temperature values on antioxidant enzyme activities and lipid peroxidation were evaluated for the first time in the clam Chamelea gallina and the mussel Mytilus galloprovincialis, two bivalve species that are widespread along the northwestern coast of the Adriatic Sea. For 7days, bivalves were exposed to three pH values (8.1, 7.7 and 7.4) at two temperatures (22 and 28°C). Three independent experiments were carried out at salinity values of 28, 34 and 40psu. Superoxide dismutase, catalase and glutathione S-transferase activities as well as lipid peroxidation were measured in the gills and digestive gland of the bivalves. The results demonstrated that the experimental conditions significantly influenced the biochemical parameters of the bivalves, although the variation pattern varied depending on the species and tissues analysed.

Significant increasing of onset temperature of FM transition in LSMO thin films

La0.67Sr0.33MnO3 (LSMO) thin films with a significant increased onset temperature of ferromagnetic transition were prepared using an on-axis dc magnetron sputtering from a stoichiometric ceramic target onto one-side polished MgO (001). The highest temperature of insulator-metal transition was observed at TP=416K. Magnetization hysteresis curves taken at T=398K indicate the beginning of the ferromagnetic transition above 400K. The negative magnetoresistance reaches 15% at a temperature of 400K. We show that the LSMO thin films with increased temperature values of resistance peak TP and Curie temperature TC are characteristic by a proper microstructure with distorted orthorhombic unit cells. This microstructure is developed during the layer growth, it is not caused by the underlying substrate and it is linked with an appropriate pseudocubic out-of-plane lattice parameter ac⊥, splitted Bragg reflections in rocking curves and as well as in reciprocal space maps.

Optimal process conditions for the isomerization–cracking of long-chain n-paraffins to high octane isomerizate gasoline over Pt/SO 42––ZrO 2 catalysts

An assessment of the process conditions for the isomerization–cracking of long-chain n-paraffins over commercial Pt/SO 4 2––ZrO 2 catalysts was made. Pretreatment and reaction conditions were optimized with a focus on the maximization of the yield of short, high octane branched paraffins for the gasoline pool. While selectivity was an important issue attention was also paid to the reduction of the yield to gases (C 1–C 4). Therefore cracking had to be modulated to produce the correct molecular size adjustment without scission to too much smaller fragments. Skeletal isomerization was to be maximized. The activity in both acid-catalyzed reactions had to be tuned while keeping a stable activity level. The only pretreatment condition assessed was the calcination temperature (screened in the 600–800 °C range). Calcination at 600 °C produced the highest activity level while 700 °C was convenient from the point of view of selectivity. The optimum temperature coincided with the production of the highest concentration of Brönsted acid sites. Regarding the reaction conditions, increasing temperature values augmented the conversion but also increased the cracking. Therefore optimum values were found at a moderate temperature, 225 °C, given the high reactivity of the feed. Space velocity values were analyzed with attention to the liquid C 5+ yield, the selectivity to branched isomers and the stability of the catalysts. Best yields to branched naphtha products were obtained at WHSV = 18 h – 1 . The H 2/hydrocarbon molar ratio was a function of the catalyst coking rate. A value of 10 was enough to attain a stable conversion value. The values of liquid yield as a function of pressure displayed a volcano pattern that was rationalized in terms of a non-classical bifunctional mechanism of reaction. High pressure values increased the concentration of Brönsted acid sites and hence the activity while high pressures enhanced hydrocracking and decreased the liquid yield. The optimal pressure value was 20 atm.

Screening of optimal pretreatment and reaction conditions for the isomerization-cracking of long paraffins over Pt/WO 3–ZrO 2 catalysts

Pretreatment and reaction conditions for the isomerization-cracking of long paraffins over commercial Pt/WO 3–ZrO 2 catalysts were screened. Optimal conditions were seeked for the production of short, high octane branched paraffins for the gasoline pool. n-C 16 was used as a model molecule. The reaction over the acidic catalyst was used to adjust the size of the molecules to the boiling range of gasolines and to add branching in order to increase the octane number of the product. These adjustments had to be done while minimizing the production of light gases and getting a stable activity level. With respect to the pretreatment it was confirmed that the best calcination temperature of the tungstate oxoanion promoted hydroxides was 800 °C. Optimality was mostly related to the activity level. The optimum temperature coincides with the appearance of small WO 3 crystallites which are thought to be center for creation of Brönsted acid sites in the presence of platinum and hydrogen. Regarding the reaction conditions, increasing temperature values augmented the conversion but also increased the cracking. Therefore optimum values were found at moderate temperature given the high reactivity of the feed. Space velocity values were analyzed with attention to the liquid C 5+ yield, the selectivity to branched isomers and the stability of the catalysts. Best yields to branched naphtha products were obtained with Pt/WO 3–ZrO 2 at WHSV = 18 h −1. The catalyst coking rate was a function of the H 2/hydrocarbon ratio. A value of 6 was enough to attain a stable conversion value on Pt/WO 3–ZrO 2. The values of liquid yield as a function of pressure displayed a volcano pattern that was rationalized in terms of a non-classical bifunctional mechanism of reaction. High pressure values increased the concentration of Brönsted acid sites and hence the activity. Too high pressures enhanced hydrocracking and decreased the liquid yield. The results indicate that in general terms Pt/WO 3–ZrO 2 at moderate reaction conditions transforms a paraffinic heavy cut into a branched isomerizate that can be added to the gasoline pool to improve the quality properties. It was however found that under some conditions the octane gain is inversely proportional to the yield of light gases indicating that a high RON isomerizate can only be got at the expense of the liquid yield.

The Study of some Physical–Chemical Parameters of Water

Paper presented to the investigation conducted in two fish ponds on biological year March to October 2008. The study highlights the fluctuations physical - chemical: temperature, dissolved oxygen, organic substance, nutrients along with the dynamics of phytoplankton development season and ecological analysis of this group in relation to the variables analyzed, the factors that concur at degree impurification of water. Water temperature increases simultaneous with the air temperature, highest value recorded in the summer. Evolution of phytoplankton fallow an variables season in depending of physical-chemical parameters studied; the spring season is dominated by blue algae (16-18 species), their number decreasing with increasing values of temperature, number of blue algae were relatively constant throughout the year, the share increase is green algae species dominated in summer and autumn. Dissolved oxygen shows a gradual fall with submission to the summer months leading to an intensification of the processes of degradation of organic matter, influence such variations that occur at the pH, which increases and fluctuations of nutritive elements based on nitrogen N-NH4, N -NH3-N NO2-, NO3-N and phosphorus P-PO4, depending on which water falls into the category mesosaprobic. Meet excellent indicators of a class of water quality mesosaprobic: Synedra, Nitzschia, Melosira, Closteriopsi acicularis, Actinastrum hantzschi, Monoraphdyum grifitti, Scenedesmus opoliensis, Pediastrum duplex