Hydrophysical Characteristics Research Articles

Correctness investigation for the suspension transport problem in coastal systems

This article is devoted to the confirmation the need for using a set of 3D dynamics models describing the various hydrophysical characteristics of the studied object to solve practical problems associated with the assessment of the ecological state of the water reservoirs. The present paper is devoted to the study of the three-dimensional model of transport and sedimentation of suspended matter in the coastal zone. The model takes into account such parameters as water movement, diffusionconvection, complicated bottom and shoreline geometry, lifting, transport and sedimentation of slurry. The existence and uniqueness of the solution of the corresponding indicated model of the initial-boundary value problem haas been envestigateded for two typical bottom boundary condirions. Also solution stability of the boundary-value problem in depend of functions: initial condition, boundary conditions and the righthand side in the norm L2 for any moment of time 0 < T < +∞, and also in the time-integral norm L2 has been proved. The model may be basis for the construction of hydrophysics models used to describe processes in the extraction of minerals from the seabed, in the dissemination of suspensions in shelf regions.

Soil hydro-physical characteristics and water retention function of typical shrubbery stands in the Yellow River Delta of China

The shell ridge worldwide that presents a combination of old and new shell ridges is located in the Yellow River Delta of China. The water storage and retention capacities of the shell sand soil are key factors for the growth and development of vegetation and act as important indicators in evaluations of vegetation-related soil and water conservation. We investigated the hydrological and physical characteristics of the soil and the interactions of these characteristics for the following dominant shrubbery stands on the shell ridge: Tamarix chinensis Lour, Periploca sepium Bunge and Ziziphus jujuba var. Spinosa. The different shrubbery stands presented significantly different physical shell sand parameters, such as water storage capacity, permeability and water-holding capacity. Compared with the bare soil, the shrubbery-covered shell sand soils showed significantly reduced bulk densities; increased porosities, water storage capacities, infiltration rates and water-holding capacities; and reduced particle sizes. The shrubbery increased the amount of soil water-stable aggregates and reduced the amount of soil air-dried aggregates, and the fractal dimension of the soil water-stable aggregates was significantly higher than that of the air-dried aggregates. T. chinensis shrub growth yielded a better soil aggregate structure compared with that of Z. jujuba, whereas the P. sepium shrub yielded the poorest structure. The soil porosity and the mean weight diameter of the soil aggregates were the major factors that affected the water retention capability of the shell sand. The best water retention capability was observed with the T. chinensis shrub stand followed by the Z. jujuba and P. sepium stands, whereas the bare soil exhibited the poorest results. Our results indicate that T. chinensis seedlings are the best choice for planting to improve soil porosity and soil aggregates on the shell ridges of the Yellow River Delta.

Amendment with sugarcane pith improves the hydrophysical characteristics of saline‐sodic soil

SummaryThe application of organic materials is an environmental practice in soil restoration, but the use of sugarcane pith, a by‐product of the paper industry, as an amendment in soil reclamation has not been tested so far. The objective of this study was to quantify the effects of the application of sugarcane pith on various hydrophysical properties of saline‐sodic soil. A 4‐month incubation pot trial under stagnant water and leaching conditions was carried out. Application of 5, 10 and 20 t ha−1pith led to a decrease in bulk density by 19, 41 and 42%, respectively, and a corresponding increase in drainable porosity. Likewise, soil structure expressed in terms of aggregate stability was enhanced substantially from 0.5 to 0.9. Water‐saturated hydraulic conductivity (Ks) and available water content were also positively affected by the amendments with pith; these changes were attributed to its spongy nature and the increase in organic matter with its decomposition. The doubling ofKsto 1.4 cm hour−1with the application of 20 t ha−1pith was considered crucial because it resulted in larger rates of leaching of salt. The fast decomposition of pith released Ca2+, Mg2+and K+ions, which accelerated the leaching of Na+. We recommend that saline‐sodic soil of the type that we investigated in this study should be amended with sugarcane pith powder up to a rate of 10 t ha−1. Future work should investigate the effects of pith amendments in field trials on a wide range of types of saline‐sodic soil.HighlightsIs fresh sugarcane pith effective as an amendment for saline‐sodic soil?Sugarcane pith could play a vital role in the management and reclamation of saline‐sodic soil.Application of 10–20 t ha−1sugarcane pith positively affected soil physicochemical properties.Sugarcane pith applied to saline‐sodic soil improves the hydrophysical characteristics.

English

Long molecular chain of polymers with active groups, combined with its complexity and flexibility to different environmental conditions provides an interaction of these groups with the mineral soil clays, thereby qualifying the polymers as soil flocculants effective. This study is aimed at evaluating the pore size distribution and hydro-physical properties of soils with cohesive horizons of the coastal plains of Pernambuco State, Brazil, with the application of anionic polyacrylamide (PAM). Thus, three horizons, one cohesive (Bt1) and two non cohesive (E and Bw/Bt) Ultisol were evaluated and, to compare the cohesive horizons, a BA horizon of Oxisol was selected. PAM aqueous solutions (12.5, 50.0 and 100.0 mg kg-1) and distilled water (control = 0 mg kg-1) were applied in undeformed samples by capillary. Pore volume was evaluated by diameter (macro, meso and micropores), total porosity, saturated hydraulic conductivity (Ksat), soil penetration resistance (PR) and soil-water characteristic retention curve. Polymer solutions reduced Ksat, macroporosity and total porosity of cohesive horizons (micropores dominated). More concentrated solutions increased PR of the Bt1 horizon. The excess negative charges in the system are the main factor for the negative effects of PAM on clay horizons. We hope that less electronegative PAMs may improve the hydro-physical characteristics of cohesive horizons. Key words: Polyacrylamide, coastal tablelands, soil penetration resistance, negative charges, water retention, macroporosity.

Water isotopic-geochemical composition in the Trekhtsvetnoe meromictic lake on the White Sea coast

The isotopic features of Lake Trekhtsvetnoe in the White Sea coast area were studied in 2012–2015 in both winter and summer. Lake Trekhtsvetnoe is a water body, separating from the sea, with constant vertical stratification throughout the observation period. Its isotopic, hydrophysical, and biological characteristics have been studied. By the isotopic profile of lake water body, three zones can be identified in the lake: (1) 0–1 m: mixolimnion zone with δ18O varying from–12 to–11.1‰; (2) 1.0–3.0 m: zone with transitional properties with δ18O varying from–11.1 to–5.5‰; (3) 3.0–7.6 m: monimolimnion zone with highest values of δ18O—from–5.5 to–4.7‰.

Operational system for diagnosis and forecast of hydrophysical characteristics of the Black Sea

The automatic system of operational forecasting of the Black Sea state which functions at the Marine Hydrophysical Institute is presented. Principles of the system construction are considered; the marine environment models used for forecasting, the data streams required for the system functioning, and tools for validating and visualizing the results of sea-state calculations are described. Some examples of investigating a number of processes and phenomena in the Black Sea are given.

Hydrophysical characteristics of selected soils from arctic and temperate zones

Abstract Hydrophysical characteristics of arctic and temperate zones soils were determined. The soils from the temperate zone showed a greater capability of water retention than those from the arctic zone. In both investigated depths (surface and subsurface layers), the highest water content was observed for the Sądecki Regosol, and the lowest one for Turbic Cryosol formed in the cell forms from Spitsbergen at all soil water potentials. The differences between water content for these soils at the same soil water potentials varied between 20 and 25% vol. in the surface layer, and from 19 to 22% vol. in the subsurface, respectively. The lowest differences (2.7-5.0% vol.) in water content were noticed between the Wyspowy Regosol and Turbic Cryosol (Skeletic) derived in the sorted circles. In both depths, higher values of water conductivity were observed for Regosols than for Cryosols at high soil water potentials, from -0.1 till -7 kJ m-3. These differences were especially high at -0.1 kJ m-3 and they were three or four times higher for soils from the temperate zone than from the arctic ones. For lower water potentials, the differences in water conductivity do not exceed one order in the surface layer and two orders in the subsurface.

Morphometry and metal concentrations in water and bottom sediments of mountain lakes in Ergaki Natural Park, Western Sayan Mountains

The concentrations of nutrients in water and the total concentrations of metals were determined in water and bottom sediments of four lakes in Ergaki Ridge, which differ in their geographic, morphometric, and hydrophysical characteristics. By the concentration of all examined metals in water and bottom sediments, the lakes can be divided into two groups. The first group includes lakes Oiskoe and Svetloe, which feature large size and depth, while the second group includes small and shallow lakes Raduzhnoe and Karovoe. The concentrations of metals are compared with data obtained for different lakes of other mountain regions and with standards established for their concentrations in water and sediments. The concentrations of Zn and Cu in the sediments of Lake Svetloe were found to exceed the threshold, introduced by international standards, below which no impact on biota is recorded.

Hydro-depositary and hydro-transmitting properties of soddy-podzolic soils in the course of simulating the water transfer by physically-grounded models

The results of field experiments conducted on the medium loamy agro soddy-podzolic soil showed that due to the hydraulic head of water at the soil surface the moisture movement occurs predominantly through migration ways that deteriorate the hydro-depositary properties of soils. The moisture movement was studied by a special method performed in two soil monoliths identical in size (42 cm in diameter and 60 cm high). The monolith walls were covered by a film, foamed and buried with the view of avoiding the lateral water loss. Both monoliths were simultaneously saturated with water: one of them was under a constant head of water in 5 cm, the other monolith was watered by fine-dispersed sprinkler without the formation of the water layer at the soil surface. The study was aimed at modeling the water movement under conditions of small headed infiltration and without the head of water as well as comparing the calculated and experimental data with the view of assessing the most adequate experimental provision of the model - the major hydrophysical characteristics obtained by empiric methods in the experiment or those calculated on the basis of hydrological constants and soil properties (pedo-transmitting functions). It seemed reasonable to establish that the experimental provision of the model can be shown in the following order: the use of regional pedo-transmitting functions provides better results as compared to the major hydrophysical characteristics, the latter being obtained by the method of tensiometers and capillarometers is better than the pedo-transmitting characteristics used the particle-size distribution as a predictor in Agrotool program (ROSETTA database) as well as those obtained by Voronin’s “secants”.

Role of morphological structure and layering ofSphagnumandTomenthypnummosses on moss productivity and evaporation rates

Goetz, J. D. and Price, J. S. 2015. Role of morphological structure and layering of Sphagnum and Tomenthypnum mosses on moss productivity and evaporation rates. Can. J. Soil Sci. 95: 109–124. Morphological structures of peatland mosses control moss water relations and the rate of water loss by drainage and evaporation, thus influencing their physiological functions. While many of these mechanisms are understood for Sphagnum mosses, there is a limited understanding of how these processes operate in Tomenthypnum nitens, a dominant brown moss species in northern rich fens. This study contrasts how different hydrophysical characteristics of Tomenthypnum and Sphagnum species affect capillary water flow that supports evaporation and productivity. Laboratory investigations indicate that volumetric water content (θ), gross ecosystem productivity, and evaporation decreased with water table depth for both mosses, with Sphagnum capitula retaining 10–20% more water (θ range of 0.18–0.32 cm3cm−3) than Tomenthypnum (0.07−0.16 cm3cm−3). Despite lower θ and a smaller fraction of pores between 66 and 661 µm to retain water within the Tomenthypnum structure (10%) compared with Sphagnum (27%), both mosses had similar fractions of water conducting pore spaces and were able to maintain capillary rise throughout the experiment. While there was a larger difference in the bulk density and porosity of the Tomenthypnum moss compared with its underlying peat than there was in the Sphagnum profile, a layer of partially decomposed moss of intermediate properties was sufficient to provide a connection between the moss and peat under low water table conditions. In trying to characterize the soil-water pressure (ψ) in near-surface mosses of Tomenthypnum based on measurements of vapour pressure, we found disequilibrium conditions that severely underestimated ψ (i.e., very large negative pressures). It is this disequilibrium that drives evaporation and draws up capillary water to the moss surface for peatland–atmosphere carbon and water transfers.

Effects of local hydrophysical conditions on the spatial variability of phytoplankton in the White Sea

The species composition and biomass of phytoplankton, chlorophyll a concentration (Chl), and hydrophysical characteristics of water masses have been studied in Onega and Kandalaksha bays (Chupa Inlet and Knyazhaya Inlet) of the White Sea at 16 stations June 17–26, 2012. Structural analysis of the phytoplankton community according to the Bray-Curtis similarity index has revealed two groups of stations. The first group united stations in stratified waters in Kandalaksha Bay; all stations located in Onega Bay formed another group. In turn, the stations in Onega Bay were separated into two subgroups corresponding to mixed (MWs) and stratified (SWs) waters. The total phytoplankton biomass and the biomass of diatoms and small unidentified flagellates were higher in Onega Bay. The biomass of dinoflagellates and cryptophytes, as well as Chl, did not differ significantly in Kandalaksha and Onega bays. In Onega Bay, the total phytoplankton biomass, Chl, and contribution of dinoflagellates to the total biomass were higher in SWs than in MWs. The contribution of diatoms was higher in SWs. The study addresses the role of the frontal zones in shaping the structure and distribution of the phytoplankton community.

On the role of rock fragments and initial soil water content in the potential subsurface runoff formation

Abstract Stony soils are composed of fractions (rock fragments and fine soil) with different hydrophysical characteristics. Although they are abundant in many catchments, their properties are still not well understood. This article presents basic characteristics (texture, stoniness, saturated hydraulic conductivity, and soil water retention) of stony soils from a mountain catchment located in the highest part of the Carpathian Mountains and summarizes results of water flow modeling through a hypothetical stony soil profile. Numerical simulations indicate the highest vertical outflow from the bottom of the profile in soils without rock fragments under ponding infiltration condition. Simulation of a more realistic case in a mountain catchment, i.e. infiltration of intensive rainfall, shows that when rainfall intensity is lower than the saturated hydraulic conductivity of the stony soil, the highest outflow is predicted in a soil with the highest stoniness and high initial water content of soil matrix. Relatively low available retention capacity in a stony soil profile and consequently higher unsaturated hydraulic conductivity leads to faster movement of the infiltration front during rainfall.

Modelling aquatic communities: Trophic interactions and the body mass-and-age structure of fish populations give rise to long-period variations in fish population size

AbstractWe present a mathematical model of an aquatic community, which includes zooplankton and fish reproduction, and age-weight-structured trophic relationships. We show that interactions between separate components of the aquatic community can give rise to long-period oscillations in fish population size. The period of these oscillations is on the order of decades.We show that predatory fish can be an element, which gives rise to the long-period oscillations. With this model we also show that an increase in the zooplankton growth rate may entail a sequence of bifurcations in the fish population dynamics: steady states → regular oscillations → quasicycles → dynamic chaos. Since aquatic, and in particular, lake ecosystems are spatially heterogeneous, they are often considered as consisting of separate habitats, which are distinguished by their hydrophysical and ecological characteristics. We show that interhabitat fish migration can lead to dramatic changes in the fish population dynamics. In particular, the fish migration can destabilize both stationary states and chaotic regimes giving rise to regular and quasiregular oscillations in the fish population size.

База данных метеорологических и гидрофизических характеристик для бессточного водного объекта

База данных метеорологических и гидрофизических характеристик для бессточного водного объекта

Contrasting summer phytoplankton communities in stratified and mixed waters of the white sea

The species composition and biomass of the phytoplankton, as well as the hydrophysical characteristics of the water masses have been analyzed in different regions of the White Sea at 37 stations during the period from June 20 to July 3, 2008. Three communities with different structures have been identified, each associated with water masses with specific structures and dynamics. The community dominated by Skeletonema costatum has been growing in Dvina Bay in stratified waters with the highest temperature and the lowest salinity compared with the other areas of the sea. The community dominated by Thalassiosira nordenskioeldii has been associated with mixed waters of Onega Bay and adjacent areas of the Basin with low temperatures and high salinity. The community dominated by dinoflagellates has been growing in different areas of the sea: both in stratified and mixed waters. The average phytoplankton biomass in the surface water layer and the total biomass under 1 m2 in the studied areas have been 134 ± 157 mg C/m3 (n = 37) and 1157 ± 874 mg C/m2 (n = 18), respectively.

Snow accumulation and ablation in disturbed mountain spruce forest in West Tatra Mts

AbstractIn the presented paper we deal with the impact of the mature spruce stand on the accumulation and melting of snow cover at Červenec research area located in the Western Tatras at an elevation of 1420 m a.s.l. The work analyses the data obtained from the monitoring of snow cover during the period 2009–2014 (6 seasons). Since the season 2012/2013 the measurements have been also performed in a dead part of the stand and in a meadow. The results proved significant impact of the spruce stand on hydro-physical characteristics of snow cover — snow water equivalent, snow density, as well as on their change due to the dieback of the stand. The data measured at individual locations (open space in the forest, open meadow area, living and dead forest) were tested with the paired t-test for the significance of average differences. Average snow water equivalent in the living forest, dead forest and meadow was 42%, 47% and 83% of the reference value measured at the open space in the forest, respectively. The process of snow accumulation and melting was fastest at the open space, followed by the dead forest. In the living forest, the processes were the slowest.

Impact of an agricultural chronosequence in recharge areas of aquifers in the Brazilian savannah

Current study was conducted, in 2010, on the Boa Vista Farm at the Rio Claro watershed of the southwestern region of Goias, state, Brazil. The region features micro-reliefs with marshy fields and predominantly Haplic Plinthosols. Most areas were incorporated into the agricultural production systems without evaluating the impact on their hydro-physical characteristics. Current analysis evaluates the transformation impact of marshy lands into agricultural areas through an investigation of empirical methods of water infiltration into the soil. Three chronosequenced areas for agricultural use and a preservation area were selected. Water infiltration in the soil was analyzed by field data and by calculations following Kostiakov, Horton and Lewis-Kostiakov. Models overestimated infiltration rates at the beginning of the process and compared to those from field data. The model proposed by Horton was highly similar to rate of basic infiltration speed harvested from field data. Structural quality was reduced through infiltration velocity in the area with human interference with grown under no-tillage system. Key words: Haplic plinthosol, mounds, hillocks, cylinder infiltrometers, no-tillage system.

Soil hydrophysical characteristics in the Nitra river basin (Slovakia): Their monitoring, analysis, online publishing

The paper is focused on the purpose made, or local monitoring of areal unit of the Nitra river basin (Slovakia, Central EU with total area 4501 km 2 ) in order to obtain the inputs on soil, moisture and hydrophysical characteristics of the given area. In this study, there was evaluated the share of individual soil texture classes in the Nitra river basin on the basis of map records and its comparison with the soil samples taken from the 111 selected sites. Soil samples were taken from two depths of soil profile (15-20 cm, 40-45 cm). The sites were chosen according to the percentage representation of individual soil texture classes. Based on the identification of sampling points localization and following analysis of granularity ratio, it can be concluded that the grain composition from the soil samplings does not correspond fully with the map records. Subsequently, drainage branches of moisture retention curves were measured for all sites Obtained hydrophysical data were enabled on the web-portal. With the use of OpenGeo Suite software, version 4.0.2 and its components Geoserver and Geoexplorer, the data on soil characteristics were published online at: http://fzki.uniag.sk/02FacultyStructure/02Departments/KBH/02Research/Hydrophysics.Thus, information about the soil characteristics in the basin is available to specialists.

On the nature of short-period oscillations of the main Black Sea pycnocline, submesoscale eddies, and response of the marine environment to the catastrophic shower of 2012

Field studies performed at the Shirshov Institute of Oceanology, Russian Academy of Sciences (SIO RAS), Black Sea hydrophysical polygon in 2012 are illustrated. The variations in the vertical distribution of the hydrophysical characteristics (water temperature, salinity, and density, as well as current velocity) in the upper 200-m layer of the Black Sea above the continental slope in the cold season, obtained using an Aqualog autonomous profiler on a moored buoy station, have been analyzed. It has been established that the position of the permanent pycno-halocline and the hydrosulphuric zone upper boundary intensively oscillate with a characteristic period of 5–10 days. These oscillations cause short-period variations in the thickness of the oxigenated layer by 20–40 m, which reaches one-third of the total thickness of the layer. Measurements performed with autonomous stations (bottom ADCP, thermochain) at the experimental subsatellite polygon in the Gelendzhik coastal zone, as well as meteorological, ship, and satellite data obtained during the catastrophic rains and flooding on July 6–7, 2012, and afterward, have been simultaneously analyzed. It has been established that a catastrophic flow of turbid fresh water into the sea caused the formation of a belt of freshened (by 1.0–2.7 psu) less dense water with a high suspension concentration on the shelf and the upper continental slope. This water formed a quasi-geostrophic northwestward along-shore current, the velocity of which reached 40–50 cm/s. Therefore, the freshened and turbid water mostly escaped from the Gelendzhik region northwestward for two days after the flood, and the remaining water became free of suspension owing to its settlement during approximately the same period. The fields of the current velocity and suspension concentration in a submesoscale cyclonic eddy, identified on the satellite image, were measured at the hydrophysical polygon. It has been established that a high (when compared to the background values) suspension concentration in the surface-water layer in an eddy is related to intense upwelling at the eddy center and the rising of suspension (apparently phytoplankton) from the thermocline layer, where the suspension concentration is maximal.

Mitochondrial DNA polymorphism (CO1) of three dominant copepod species in the South Atlantic

The Southern Ocean is characterized by the complex system of oceanic fronts that maintain the latitudinal zonality of biotopes. These fronts are boundaries of water masses with different hydrophysical characteristics. We explore the genetic differentiation of the dominant zooplankton species in regards to the complex hydrophysical zonality of the Southern Ocean. The barcoding region of mitochondrial CO1 gene was sequenced for three copepod species, Calanus simillimus, Rhincalanus gigas, and Metridia lucens. These species are the most abundant in the Southern Ocean and form the basis of the zooplankton community. Genetic differentiation was found neither for Calanus simillimus nor for Rhincalanus gigas. The mitochondrial haplotypes of Metridia lucens cluster in two genetically distant groups (Subantarctic and Antarctic) found together only in the Polar Front Zone.