Water Physical Characteristics Research Articles

Study the Concentration of PAHS in Al-Rumayth River Water-Iraq

This study’s goals were to look into PAH concentrations and compositions as well as chemical and physical water characteristics. In Al –Rumaytha river. This study was conducted out during from November 2021 to October 2022. According to the results, sixteen PAHs compounds were found in the water, including According to the results, water contained sixteen different PAHs components including Acenaphthene and Acenaphthylene ranged between (47.1-91.5, 24.9-55.7) ppm, The values Anthracene, Naphthalene, phenanthene and fluorine results ranged (14.9-48.9 ppm,18.9 -68.7ppm,8.9-41.7 ppm,8.5-41 ppm) respectively, the minimum and maximum concentrations of Benzo[A]anthracen, Benzo[B]fluoranthene, Benzo [K] fluorantyene, Benz [G,H] perylen, Benz [A] Pryene, Chrysene, Dibenzo [A,H] Anthracene, Anthracene, Fluoranthene, Indeno and Pryene was 4.1-20.6 ppm, 20.1-69.7ppm, 30.1-97.4 ppm,4.1-36.9 ppm,0.29-1.6ppm 10.5-40.8 ppm, 8.9-36.9 ppm, 6.5-33.4 ppm,2.5-10.2 ppm,1.3-10.4 ppm. The results show that the Al-Rumaytha River is PAH-polluted, with human activities having the greatest negative effects on the river’s water quality and health.

Cascade damming impacts on microbial mediated nitrogen cycling in rivers

Rivers display essential role in nitrogen (N) cycling in terrestrial and aquatic ecosystems, but now they are suffering from damming worldwide, especially from cascade damming. Despite of the importance of microorganisms in biogeochemical nutrient cycling, little attention has been paid to microbial functional biogeography under damming disturbances. Here, the Geochip microarray was applied to investigate the microbial mediated N cycling across the single-dammed Yarlung Tsangpo-Brahmaputra River and the cascade-dammed Lancang-Mekong River in southwest China. Our results showed that the N cycling processes (nitrogen fixation, ammonification, denitrification, nitrification and anammox) were stimulated in reservoirs in both rivers and the enhancement was inversely coupled with hydraulic retention time, but the recovery of N-cycling gene abundance in downstream of dam was intervened by cascade damming. Moreover, N-cycling gene composition was significantly altered in the single-dammed river, while no remarkable change was found in the cascade-dammed reaches. However, different from the unvaried gene composition, cascade damming intervened the recovery of N-cycling gene flow connectivity and resulted in the continuous decrease of connectivity in cascade damming reaches. In addition, in the single-dammed river, nutrients were the important drivers for variation in gene abundance, while they did not influence gene composition. Meanwhile, the abundance and composition of N-cycling genes in the cascade-dammed river were both significantly correlated to geographical parameters and water physical characteristics. Therefore, our study has vital implications for anticipating microbial functional response and biogeochemical feedback to ongoing cascade damming, contributing to the protection of river ecosystems under river regulation.

Conservation Management Model of Subayang River in the Kampar Regency, Province of Riau based on Local Wisdom using Belida Fish (Chitala sp.) as Bioindicator

This research was conducted on the Subayang River in Kampar Regency, Riau Province, Indonesia, from January to December 2019. This research aims to determine the physical and chemical water characteristics of the Subayang River and the trend of the Belida fish (Chitalla sp.) population for constructing a river conservation management model based on local wisdom. To investigate the water's physical characteristics, a water sample was acquired from the Subayang river on three stations (upstream, middle stream, and downstream). The water sample was collected on each station iteratively at three different points at the river stream's left, middle, and right sides. The trend of Belida fish population data was gathered from interviews with the fishermen. Moreover, interviews with the traditional figure of the society around the Subayang river were also conducted. Then, the conservation model of the Subayang river was constructed by analyzing the interview and the population of Belida fish results using a system dynamic model. The investigation of the water’s physical and chemical properties shows that the Subayang river has a suitable environment for the growth of Belida fish. However, the Belida fish population trend in the last four years tends to decrease. The existence of "lubuk larangan" and "pantang larang adat", are local wisdom that gives a positive affection towards the Belida fish population. Those traditional rules can restrict citizens from doing illegal fishing which hardly affects the Belida fish population.

Composition, Distribution, and Fisheries Biology of Penaeid Shrimp from the Strong Wavy Waters of Southern Java, Indonesia

Penaeidae is a family of shrimp that has a high economic value, leading to intensive exploitation in many areas. This research was conducted to ascertain the composition, distribution, and fisheries biology of Penaeid shrimps in the strong wavy water of southern Java Island, Indonesia. The research locations were the water of Eastern, Central, and Western Java. Shrimp samples were obtained using various ways. The carapace length (CL) of the shrimps were measured using plastic callipers and recorded to the nearest 1 mm. The results showed that eight species of shrimps were caught in the water of southern Java, with Penaeus merguiensis, P. semisulcatus, and P. monodon being the most common. The species P. merguiensis was found in each sampling location, while P. latisulcatus and Metapenaeus palmensis were only present at Drini Beach (Central Java). The results also showed that P. japonicus and M. lysianassa were only found at Ranca Buaya Beach (West Java). The species P. merguiensis and P. monodon were the two most commercially important species. The distributions of the shrimps were related to the water physical characteristics associated with the shrimp habitat namely SST, bathymetry, and tides. Fishery biology analysis found that the length at first impregnation of P. merguiensis at Damas and Sidem Water (East Java) was 25.9 cm CL. Furthermore, the LBSPR analyses revealed that the spawning capacity of P. merguiensis and M. ensis in the same waters were still very high under the current level of exploitation. Therefore, the magnitude of fishing has not endangered the sustainability of the two shrimps.

Effect of Coal Water Slurry Gasification Slag on Soil Water Physical Characteristics and Properties in Saline-Alkali Soil Improvement

To explore the effect of coal water slurry (CWS) gasification slag on the soil water physical characteristics of saline-alkali soil in the Yellow River Basin of Inner Mongolia, CWS gasification coarse slag (GCS) and gasification fine slag (GFS) were used as improvement materials and mixed with saline-alkali soil in different proportions. The influence mechanism of GCS and GFS on saline-alkali soil water holding capacity was investigated by measuring particle size composition, water holding capacity, and the change in the soil water characteristic curve after mixing. The results showed that adding gasification slag improved the particle size composition of saline-alkali soil, with sand content increased by -3.79%~217.31% and clay and silt content decreased by 5.77%~56.50% and -0.38%~41.53%, respectively. Soil bulk density decreased significantly ( P < 0.05 ), with a decrease range of 15.17%~45.1%. The soil texture changed from silty loam to sandy loam, and the water retention performance improved, affecting the soil saturated water content, capillary water holding capacity, and field water holding capacity ( P < 0.05 ), with increases ranging from 20.75%~86.15%, 7.84%~27.81%, and -1.89%~34.56%, respectively. After adding GCS and GFS, the VG model fit the soil water characteristic curve of saline-alkali soil well, indicating that the addition of gasification slag enhanced soil water retention significantly. In conclusion, CWS gasification slag effectively improved the water physical properties of saline-alkali soil and significantly enhanced the water retention and water holding capabilities.

Hydrography and food distribution during a tidal cycle above a cold-water coral mound

Cold-water corals (CWCs) are important ecosystem engineers in the deep sea that provide habitat for numerous species and can form large coral mounds. These mounds influence surrounding currents and induce distinct hydrodynamic features, such as internal waves and episodic downwelling events that accelerate transport of organic matter towards the mounds, supplying the corals with food. To date, research on organic matter distribution at coral mounds has focussed either on seasonal timescales or has provided single point snapshots. Data on food distribution at the timescale of a diurnal tidal cycle is currently limited. Here, we integrate physical, biogeochemical, and biological data throughout the water column and along a transect on the south-eastern slope of Rockall Bank, Northeast Atlantic Ocean. This transect consisted of 24-h sampling stations at four locations: Bank, Upper slope, Lower slope, and the Oreo coral mound. We investigated how the organic matter distribution in the water column along the transect is affected by tidal activity. Repeated CTD casts indicated that the water column above Oreo mound was more dynamic than above other stations in multiple ways. First, the bottom water showed high variability in physical parameters and nutrient concentrations, possibly due to the interaction of the tide with the mound topography. Second, in the surface water a diurnal tidal wave replenished nutrients in the photic zone, supporting new primary production. Third, above the coral mound an internal wave (200 m amplitude) was recorded at 400 m depth after the turning of the barotropic tide. After this wave passed, high quality organic matter was recorded in bottom waters on the mound coinciding with shallow water physical characteristics such as high oxygen concentration and high temperature. Trophic markers in the benthic community suggest feeding on a variety of food sources, including phytodetritus and zooplankton. We suggest that there are three transport mechanisms that supply food to the CWC ecosystem. First, small phytodetritus particles are transported downwards to the seafloor by advection from internal waves, supplying high quality organic matter to the CWC reef community. Second, the shoaling of deeper nutrient-rich water into the surface water layer above the coral mound could stimulate diatom growth, which form fast-sinking aggregates. Third, evidence from lipid analysis indicates that zooplankton faecal pellets also enhance supply of organic matter to the reef communities. This study is the first to report organic matter quality and composition over a tidal cycle at a coral mound and provides evidence that fresh high-quality organic matter is transported towards a coral reef during a tidal cycle.

Analysis of entropy production in a bi-convective magnetized and radiative hybrid nanofluid flow using temperature-sensitive base fluid (water) properties

The heat transport characteristics, flow features, and entropy-production of bi-convection buoyancy induced, radiation-assisted hydro-magnetic hybrid nanofluid flow with thermal sink/source effects are inspected in this study. The physical characteristics of hybrid nanofluids (water-hosted) are inherited from the base liquid (water) and none has considered the physical characteristics of base liquid (water) in the study of temperature-sensorial hybrid nanofluid investigations, though the water physical characteristics are not constants in temperature variations. So, the temperature-sensorial attributes of base liquid (water) are taken into account for this hybrid nanofluid (Cu+{Al}_{2}{O}_{3}+text{water}) flow analysis. The mathematical forms of the flow configuration (i.e., the set of coupled, nonlinear PDE form of governing equations) are solved by utilizing the subsequent tasks: (i) congenial transformation; (ii) quasilinearization; (iii) methods of finite differences to form block matrix system, and (iv) Varga’s iterative algorithm. The preciseness of the whole numerical procedure is ensured by restricting the computation to follow strict convergence conditions. Finally, the numerically extracted results representing the impacts of various salient parameters on different profiles (F, G, H), gradients, and entropy production are exhibited in physical figures for better perception. A few noticeable results are highlighted as: velocity graph shows contrast behaviour under assisting and opposing buoyancy; temperature (G(xi ,eta )) is dropping for heightening heat source (Q) surface friction remarkably declines with the outlying magnetic field (St); thermal transport confronts drastic abatement under radiation ({R}_{1}), and St; the characteristics Reynolds and Brinkman numbers promote entropy. Furthermore, the bounding surface acts as a strong source of {S}_{G}-production. Summarizations are listed at the end to quantify percentage variations.

Assessment of the relationship between clay soils consistency and kinematic parameters of elastic waves

Assessment of the water-physical characteristics of soils by indirect geophysical indicators is simpler. Indirect indicators provide an opportunity to characterize various volumes of the researched environment. The article presents the results of determining the kinematic parameters of elastic waves of clay soils at different values of the liquidity index. In the transition from soils of very stiff consistency to soils with stiff and firm-stiff consistency, a correlation is observed between the ratio of the secondary, primary wave velocities, and the values of the liquidity index of clay soils.

Distribution and The Habitat Characteristics of Anopheles vagus (Diptera: Culicidae) Larvae at Paddy Fields in The Vicinity of Dramaga IPB University Campus Dramaga Bogor West Java

Dramaga sub-district is an area that has rice fields close to buffalo stalls and a population of wild Macaca fascicularis as natural hosts for several species of Plasmodium. This causes the Dramaga sub-district to become a potential vector habitat for malaria, including Anopheles vagus. This study aims to analyze distribution of An. vagus larval stage in 4 villages (Cikarawang, Babakan, Margajaya, and Ciherang) in Dramaga subdistrict which have paddy field areas. Larvae were collected using a dipper, and each collection sites of the larvae habitat were marked using Global Positioning System. The physical characteristics of the water habitat measured were temperature, pH, total dissolved solids and the electrical conductivity of the water. Pearson's correlation test was used to analyze the relationship between the number of larvae An. vagus with each of the parameters water physical characteristics. The results of this study obtained 309 An. vagus larvae from the 27 collection points. Larvae of An. vagus was found in 3 villages (i.e. Cikarawang, Babakan and Ciherang), but was not found in Margajaya village. The habitat characteristics of An. vagus in paddy fields showed a water temperature of 26.6-31.7oC, pH 6.40-8.10, the total dissolved solid 36-285 ppm, and the electrical conductivity 72-262 μm/cm. The Pearsons correlation test results did not show a significant difference between the number of An. vagus larvae and each parameter (r= -0.26, 0.13, -0.15 and -0.16, respectively). The presence of An. vagus in this area could be considered in malaria vector control programs.

Long-term Variation Characteristics of Zooplankton Community Structure in Meiliang Bay, Lake Taihu

Zooplankton, as an important part of the water food chain, plays an important role in lake ecosystems. It is an important monitoring indicator for water bodies. However, due to the lack of long-term monitoring data of zooplankton community structure, there is a lack of understanding about its long-term characteristics. Based on monthly monitoring data from 1997 to 2017 of Meiliang Bay in Lake Taihu, the long-term trends of zooplankton community structure and its relation to the environment were examined. The results showed that the abundance and biomass of zooplankton in Meiliang Bay significantly decreased from 1997 to 2017 (P<0.05). In particular, the abundance and biomass of rotifer and copepod slowly declined, and the abundance of cladocerans fluctuated but its biomass presented a significant decreasing trend (P<0.05). The cladocerous biomass contributed the most to the zooplankton biomass in Meiliang Bay. The dominance of smaller cladocerans and copepods increased with decreasing rotifer density, significantly decreasing the average body size of zooplankton (P<0.05). This study indicated that zooplankton were becoming smaller, potentially weakening the top-down control on phytoplankton. In addition, zooplankton abundance and biomass showed an upward trend in spring and decreased in autumn and winter, and reached maximum values of 1406.70 ind.·L-1 and 25.64 mg·L-1, respectively, in September. In the summer, their changes were the opposite. Pearson correlation analysis showed that zooplankton community structure was significantly related to water physical characteristics (alkalinity, electrical conductivity, water depth, suspended substance, and water temperature), chlorophyll a, and nitrogen (P<0.05). This indicated that the eutrophication of Meiliang Bay in Lake Taihu had a significant impact on the community structure of zooplankton.

Обґрунтування режимів водорегулювання при вирощуванні високопродуктивних кормових культур на осушуваних землях

The purpose. To justify technological parameters of water regulation on the basis of probe of features of water requirement of Echinochloa frumentacea, amaranth and field beans at their cultivation on sewed lands, formation of demands of these crops to water regime in rooted layer of soil. Methods. Experimental determination of meteorological indexes, water-physical characteristics of soil, water requirement of forage crops and their productivity. Results. Indexes of total water requirement of Echinochloa frumentacea from 0–50 cm soil layer on peat-moor area «Chemerne» (Sarne exploratory station) made 374,2 mm, amaranth — 266,4 and field beans — 270,6 mm, on drainage-humidifying system «Romen» — 221,0; 231,4 and 232,2 mm accordingly. The greatest intensity of water requirement of Echinochloa frumentacea and amaranth was determined during healthy growth and development, at field beans — at the period of formation of seeds. Bioclimatic quotients of Echinochloa frumentacea, amaranth and field beans were specified at their cultivation in conditions of Western Polissia and Forest-steppe of Ukraine. Averages for vegetative period of their value for Echinochloa frumentacea, amaranth and field beans made accordingly 0,63; 0,61 and 0,58 on peat-moor area «Chemerne», and 0,36; 0,42 and 0,39 on drainage-humidifying system «Romen». Importation of phosphoric-potash fertilizers into dose P60K120 increased productivity of forage crops on 13,4%, and at full fertilizer — on 20,5%. Optimum times of sowing on sewed lands of Western Polissia of Ukraine: for field beans — II ten-day period of April, Echinochloa frumentacea and amaranth — I ten-day period of May. Conclusions. Results of probes are the basis for determination of optimum reclamative regimes for Echinochloa frumentacea, amaranth and field beans according to phases of their vegetation and in view of features of water requirement. Premises for development of technique of cultivation of these forage crops on the reclaimed lands of humid zone of Ukraine are created.

Typical hydrothermal conditions of the Right-bank Forest-step zone and their influence on corn productivity

Corn is a highly productive crop of universal purpose, which is grown for food – 20–25 %, forage – 60–65 and technical purposes – 15–20 %. Increasing its yield is possible due to the improvement of the elements of the technology of cultivation taking into account biological characteristics. The growth and development of corn, the production of high yields, as well as the improvement of the quality of the main products are determined by factors of anthropogenic origin and weather conditions. Hydrothermal conditions of Ukraine have already begun to change significantly during the last decades, which resulted in a shift in the climatic seasons, changes in the vegetation period duration (depending on the zone and the biological features of the crops it can either decrease or expand), the decrease in the duration of a stable snow cover, changes in water resources of local drainage. The period 2005–2016 was analyzed for the reliable estimation of the typicality of weather conditions and their influence on the corn productivity under the following basic cultivation methods: ploughing at the depth of 28–30 cm (control), flat-cut tilling at the depth of 28–30 сm, chisel ploughing at the depth of 43–45 cm and disking at the depth of 10–12 cm. The dynamics of precipitation in the northern part of the Right Bank Forest Steppe during the corn vegetation period for the last 2005–2016 testifies to the noticeable tendency of increasing the amount of precipitation in May-June and their sharp decrease in July-August. It was determined that the conditions for eight years – 2006–2008, 2011–2014 and 2016 were optimal for their hydrothermal indices for the production of corn yields at the level of 5.83–9.47 t/ha. The hydrothermal coefficient for vegetation was 1.13–1.76. Weather conditions were unfavorable in 2005, 2009–2010, and 2015 with the amount of precipitation for vegetation of 120–288 mm, which is below the long-term amount by 120 mm, or 36 %. The peculiarity of these years was 37–61 % lower precipitation level in June–July with the grain yield of 3.12–6.51 t/ha. The mathematical-statistical analysis allows to characterize features and typicality of weather conditions of 2005–2016 and to estimate the influence of hydrothermal years and separate months on corn crops productivity. It has been established that there is the following correlation between weather conditions in July and the yield of corn: high correlation for disk soil cultivation (r=0.75–0.86), the average – for ploughing and chyzel loosening (r=0.49–0.53). Thus, the formation of a deep layer of soil with the best water–physical characteristics and fertility in these cultivation modes reduced the dependence of the elements of yield formation from the adverse weather conditions and provided a higher yield of corn by 6.0–8.0 %. Key words: hydrothermal conditions, hydrothermal coefficient (HTC), vegetation period, corn yield.

Tест-система визначення вмісту мангану у ґрунтах долини ріки Cамари дніпровської

Наведено характеристику фізико-хімічного тест-методу, який дає можливістьпросто та недорого виконати якісний, напівкількісний та кількісний аналіз ґрунтівна вміст мангану.

Seasonally physical characteristics of ROFI zone (Region of Freshwater Influence) in Pelabuhan Ratu Bay

Coastal waters have many oceanographic phenomena are still being studied. One such phenomenon is how the influence of freshwater to the water mass in coastal waters. This study aims to calculate freshwater fraction, volume transport of freshwater and water mass stability. Physical water characteristics were measured by CTD (Conductivity, Temperature and Depth) deployed in 15 locations for temperature, salinity and density. The results of freshwater fraction analysis show that the west season had a greater on water fraction than the east season with value ranging from 0.40 % - 0.70 % with the amount 18.07 %, while the east season had a value of 0.02 % - 0.28 % with the amount is 7.30 %. The transport of freshwater volume in west season is 1.429.244 m3s-1 while in the east season it is 1.066 m3s-1. Water mass stability of water column in the research location has static stability with its average N2 in west and east monsoon are 0.008 cycl/s and 0.7 × 103 cycl/s, respectively. Those analyses above infer that freshwater input hugely influences physical water mass of ROFI zone in research location.

Emissivity peculiarities of the inland salt marshes in the south of Western Siberia

ABSTRACTThe presence of water-dissoluble salts in soils leads to a wide variation in soil microwave radiation that makes precise determination of water-physical characteristics of soil using satellite data hardly possible. To assess the effect of soil salinization, the emissivity of salt-affected soils in the Kulunda plain located in the south of Western Siberia was studied. Steppe site and an inland salt marsh (ISM) formed at the bottom of depressions of dried-up salt lakes were the main objects of the research. Both sites are situated in the same natural-climatic conditions and have similar relief. The spatial distribution of the underlying surface brightness temperature was obtained from L1C product of Soil Moisture and Ocean Salinity (SMOS) mission. The diurnal temperature variations of ISM were measured in the course of a daily ground-based experiment to determine the temperature gradients. During the laboratory experiment, we defined the dielectric properties of soil and calculated its emissivity. The comprehensive studies are evidence of great diurnal variation in ISM microwave radiation. The joint use of satellite and laboratory data allows us to specify the contribution of salt-affected soils into total microwave radiation of the underlying surface. The brightness temperature obtained from SMOS and the one calculated from the laboratory dependencies of ISM emissivity on temperature and moisture are in fairly well correlation.

Surf zone fauna of Ecuadorian sandy beaches: Spatial and temporal patterns

Sandy beaches and their surf zones are the most common open shoreline habitat; however, surf zone fauna in the tropics is one of the least studied communities in the world. In the current study, we tested the hypothesis that Ecuadorian surf zone hyperbenthos (invertebrates and vertebrates 1–5mm in length) and epibenthos (fish and macrocrustaceans>5mm in length) vary among beaches and seasons. Therefore, the fauna was described and related to environmental variables. In addition, indicator taxa were identified. The hyperbenthos was divided into holo- and mero-hyperbenthos depending on whether taxa were present during their entire life or only early life stages, respectively. Samples were collected at eight different beaches during the wet, dry and intermediate or transitional season during the low spring tide, from 1999 to 2000, using a hyperbenthic sledge and epibenthic trawl. A total of 447 hyperbenthic and 30 epibenthic taxa were collected, most of which were crustaceans and fish, respectively (52 and 60% of taxa). The mysid, Metamysidopsis sp., was the most abundant member of the hyperbenthos (average±SD: 14,425±40,039 ind. 100m−2, present in 92% of samples collected), and the swimming blue crab, Areneus mexicanus, was the most encountered species among the epibenthos (1±1 ind. 100m−2, 97% of samples collected). All faunal groups varied among beaches, while the holo-hyperbenthos and less strongly the epibenthos varied among seasons. Variability in the three faunas among beaches, distance from the continental slope and the Guayas estuarine system, and beach water physical characteristics were all strongly correlated suggesting adjacent habitats can influence surf zone biological communities and water physical characteristics. Seasonal effects were related to changes in water physical characteristics among seasons potentially reflecting changes in oceanic currents. These results suggest that, similarly to other beaches around the world, Ecuadorian surf zone fauna is abundant, diverse, and vary among beaches and, for some faunal groups, among seasons, potentially due to the influence of adjacent habitats and seasonal changes in oceanic currents.

Modeling Chlorophyll &lt;formula formulatype="inline"&gt; &lt;tex Notation="TeX"&gt;$a$&lt;/tex&gt; &lt;/formula&gt; Concentration Affected by Artificial Upwelling in Qiandao Lake

Artificial upwelling of ocean water has been increasingly used to enhance primary marine productivity. This approach brings nutrient-rich deep water to the surface and alters the physical characteristics of water and thus the distribution of the nutrient over an effective period. Various water physical characteristics may affect chlorophyll $a$ concentration, a key indicator for assessing primary marine productivity. Therefore, it is important to study the correlation between chlorophyll $a$ concentration and various water physical characteristics in the artificial upwelling, which has never been examined in literature. In this paper, several water quality parameters, which have potential correlation with chlorophyll $a$ concentration, are selected and multiple linear regression (MLR) and multivariate quadratic regression (MQR) are employed to test the correlation. Then, two novel neural network approaches, i.e., genetic-algorithm-based neural network (GA-NN) and particle-swarm-optimization-based neural network (PSO-NN) are proposed to model the correlation, which are further compared with regular backpropagation neural network (BP-NN), MLR, and MQR. The experimental data are collected from Qiandao Lake, China. The modeling results show that chlorophyll $a$ concentration has a strong correlation with salinity, temperature, dissolved oxygen (DO), and pH in the process of artificial upwelling, and GA-NN and PSO-NN can provide reliable prediction of the correlation.

Analysis of the presence of perfluoroalkyl substances in water, sediment and biota of the Jucar River (E Spain). Sources, partitioning and relationships with water physical characteristics

The presence, sources and partitioning of 21 perfluoroalkyl substances (PFASs: C4–C14, C16, C18 carboxylate, C4, C6–C10 sulfonates and C8 sulfonamide) were assessed in water, sediment, and biota of the Jucar River basin (E Spain). Considering the three matrices, perfluoropentanoate (PFPeA) and perfluorooctane sulfonate (PFOS) were the most frequent compounds, being remarkable the high occurrence of short-chain PFASs (C≤8), which are intended to replace the long-chain ones in several industrial and commercial applications. In general, all samples were contaminated with at least one PFAS, with the exception of three fish samples. Mean concentrations detected in sediments (0.22–11.5ng g−1) and biota (0.63–274µgkg−1) samples were higher than those measured in water (0.04–83.1ngL−1), which might suggest (bio) accumulation.The occurrence of PFAS is related to urban and industrial discharges (Cuenca city in the upper part of basin, and car's factory, and effluents of the sewage treatment plant (STP) of Alzira, in the lower part). Increasing pollution gradients were found. On the other hand, higher contamination levels were observed after regulation dams of the catchment pointing out their importance in the re-distribution of these contaminants. None of the hazard quotients (HQ) calculated indicate potential risk for the different tropic levels considered (algae, Daphnia sp. and fish). PFAS concentrations found in this study can be considered in acceptable levels if compared to existing Regulatory Legislation and, consequently, they do not pose an immediate human health risk.

Influence of habitat heterogeneity on the foraging ecology of first feeding yellow perch larvae, Perca flavescens, in western Lake Erie

The diet of first-feeding fish larvae can influence their future growth and survival. The foraging ecology of yellow perch (YP) larvae was studied in western Lake Erie, a region characterized by habitat heterogeneity associated with the Maumee River Plume (MRP) and a high prevalence of invasive species. To determine the influence of the MRP on YP diet, water physical characteristics, zooplankton prey community, and larval YP diet and foraging selectivity were compared between MRP and non-MRP waters, 2006–2008. Water temperature was higher, while water clarity was lower in the MRP when compared to non-MRP waters. The zooplankton prey community (groups constituting >1% of YP prey items) did not differ between MRP and non-MRP waters, being composed of small cladocerans, cyclopoid and calanoid copepods and non-native dreissenid mussel veligers. Ration increased with YP total length (TL), with no differences found between MRP and non-MRP waters. Diet composition also varied with larval YP length, with the smallest larvae preying more heavily on dreissenid veligers than larger fish, and no differences between MRP and non-MRP waters. Most sizes of larvae positively selected for cyclopoid copepods in MRP and non-MRP waters, while selection for other prey was neutral or negative. Our study reveals a similar zooplankton community and larval foraging ecology between MRP and non-MRP waters during spring season, despite habitat physical differences, and points to mechanisms unassociated with larval foraging (i.e., predation) as a reason for higher recruitment of YP residing inside versus outside of the MRP as larvae.

WATERFLOODING FRONT MOVING TASK IN DUAL PERIODICAL AREA: PISTON-LIKE DISPLACEMENT CASE

Water-oil contact moving task has a high significance in a waterflooding the- ory: it’s possible to improve oil recovering characteristics due to prediction of flow features for both liquids - oil and water displaced it. There is the simplest mathematical pattern for conjoint oil-water flow presenting: it is called ”versi- color” liquids model and it suggests making oil and water physically identical to simplify solving process for water-oil contact moving task. However, another pattern was used in research described in this paper: it is called pistonlike dis- placement model and it supposes that oil and water physical characteristics, for example, viscosities, may be different. As for the oil-keeping reservoir pattern used in this research it was presented as homogeneous and infinity, with fixed thickness: furthermore its surface was covered by dual periodical lattice included production and injection wells in its cells.