Confined Water Bodies Research Articles

Efficacy of Molecular Identification Using DNA Barcoding Technique of Freshwater Edible Molluscs from Nagaland, India

Freshwater molluscs are widely utilized for food and medicine in many regions of the world. One such area in India is the northeast, where tribal and economically underdeveloped communities consume freshwater molluscs. Because they are an inexpensive source of protein and offer food security, livelihoods, and medicine, these molluscs are in great demand. In the present work, molecular identification and documentation of the edible gastropods of Nagaland is done. Throughout the twentieth century, identification was based on morphology and anatomy. However, the identification based on morphological structure is challenging due to the existence of cryptic species that shows similar morphology which can lead to erroneous identification of species. Freshwater molluscs shells are highly varied and exhibit convergence evolution and hence may not always accurately indicate systematic boundaries. Thus, DNA bar-coding is a potential method for taxonomic identification process that can mitigate this problem. It uses genetic markers such as cytochrome oxidase I (COI) gene, 16S rDNA and 18S rDNA. In the present study COI mitochondrial gene is used. A fragment of COI gene is sequenced and their DNA is compared to the existing sequences in the genomic library. The sequence is then submitted in NCBI to obtain accession number. A total of 7 species of edible freshwater molluscs belonging to two class bivalvia and gastropoda was collected from local fishery ponds, confined water bodies, rivers, streams, and were identified. The identified species with their accession number is as follows, Lamellidens marginalis (ON209524), Parreysia corrugata (OM074301), Indonaia subclatharata (OM075118), Indonaia caerulea (OM076974), Bellamaya bengalensis (OM056888), Paludomus sp (OM078498), Brotia costula (OM056887). The study provides substantial support for COI's effectiveness as a prime marker for DNA barcoding of Indian edible freshwater gastropods and bivalves.

Mode of formation of cryogenic cave carbonates: Experimental evidence from an Alpine ice cave

Coarsely crystalline carbonates that formed cryogenically in caves (CCCcoarse for short) are important paleoenvironmental archives that provide evidence of former perennial ice deposits in currently ice-free caves and allow the timing of the past freezing conditions close to 0 °C in the subsurface to be determined. Despite their significance, the mode of formation of these deposits has never been observed in statu nascendi.We conducted a series of freezing experiments in an Alpine ice cave to test the conceptual model of CCCcoarse formation in freezing pools of water in perennial ice deposits. Our results document a number of features associated with the freezing of such confined water bodies, including ice bulging, cracking and episodic expulsion of water. These observations help explain the degassing of carbon dioxide required to maintain carbonate precipitation in these semi-closed pockets of slowly freezing water. Our experiments yielded a range of morphological types of cryogenic calcite crystals and aggregates comparable to those reported from CCCcoarse from currently ice-free caves elsewhere. The experimentally grown crystals also exhibit the same depleted O isotope composition characteristic of natural carbonates interpreted as being formed subaqueously in a semi-closed pools subject to freezing. The main difference to naturally formed CCCcoarse is their smaller crystal size, reflecting the comparably short freezing time of our experiments of less than two weeks.This study confirms the conceptual model explaining the formation of CCCcoarse in localized pools in ice and calls for a revision of the currently existing classification scheme for cryogenic cave carbonates.

Effect of laser pulse repetition rate in the synthesis of nickel oxide nanoparticles in PVA solution on the adsorption efficiency against phosphate ions

Eutrophication of the receiving confined water bodies could be caused by the presence of phosphate traces in treated wastewater from municipalities and factory businesses. One of the promising methods for phosphate removal is adsorption, which could be used in conjunction with the phosphate ions in the wastewater sectors, to meet discharge requirements when the biological media performance is compromised by changes in operating conditions. For that, pulsed laser ablation in liquid media process was used to create nickel oxide nanoparticles and embed them with poly vinyl alcohol to create nanocomposite structures. Their effectiveness in removing phosphate from the water was then investigated under various aquatic environmental circumstances. Additionally, the novelty was appeared for the first time to vary their particle sizes using different laser ablation parameters, like repetition rate. To determine how surface characteristics affect the phosphate adsorption behavior, the surface structure of the materials was examined using X-ray diffraction, a N2-adsorption-desorption technique, UV–visible absorption spectroscopy, a transmission electron microscope, and Fourier transform-infrared spectroscopy. After that, in the adsorption investigation, adsorption isotherms, pH effects, and a desorbability study were all investigated during the adsorption test. The findings demonstrated that the prepared nanocomposite with a lower particle size of NiO NPs had higher adsorption efficiency than that with a larger particle size of NiO NPs because of the changes in surface structure of the materials. The results also demonstrated that the adsorbed amounts of phosphate tended to reduce with increasing pH for all samples. Thus, phosphate could be absorbed by the NiO/PVA nanocomposite structure in complicated solutions.

A preliminary evaluation of the utility of insects and algae for PMI estimation in confined, still-water environments

ABSTRACT The estimation of post-mortem interval (PMI) is of critical importance in forensic investigations. This requires thorough knowledge of the decomposition process, with decomposition of remains in terrestrial environments extensively investigated, and aquatic environments largely neglected. In terrestrial environments, entomology is well established as a method of PMI estimation, however in an aquatic environment there are no known predictable necrophages, limiting the use of insects. Common to decomposing aquatic remains, algae may serve as a useful alternative to insects for PMI estimation. This pilot study aimed to examine the use of algae for PMI estimation for remains in confined water bodies, and compare this with the practicality of utilizing entomology in aquatic situations. Pigs were either tethered to cement bricks or allowed to float in individual tubs of fresh water for a period of 1000 accumulated degree days (ADD), with algal species seen to bloom on the piglets successively throughout the trials. Insect appearance was inconsistent across replicates throughout decomposition, potentially as a consequence of seasonality. Overall, entomology was proven an unreliable method in aquatic situations. Algal succession may hold promise as a PMI estimation method in confined water bodies, but requires further investigation and evaluation.

Magnetically separable ZrO2@SiO2@Fe3O4 for selective phosphate removal from wastewater

Phosphorus (P), which is a non-renewable resource, has been extensively used in agricultural and industrial fields. However, the release of P into surface water through agricultural runoffs and wastewater can cause enrichment of P and eutrophication in confined water bodies. Hence, a novel technology that can remove phosphate (major species of P in water) from water bodies for eutrophication prevention and recover phosphate for minimising the loss of P resource is desired. Adsorption is a preferable approach for phosphate removal due to its simplicity of design, effectiveness even at low P concentrations, and potential for recovery. The use of zirconium-based adsorbents for phosphate removal from wastewater has received increasing attention. However, challenges remain to recover zirconium-based adsorbents. In this study, zirconium oxide-based superparamagnetic adsorbents (i.e. ZrO2@SiO2@Fe3O4) were developed for phosphate removal from wastewater. Magnetic separation efficiency, phosphate adsorption kinetics and isotherm, effects of coexisting anions and organic matters, and reusability are reported. The developed ZrO2@SiO2@Fe3O4 has an excellent magnetic separation efficiency of > 98%, fast adsorption kinetics, high adsorption capacity at low phosphate concentrations, and strong selectivity for phosphate even at a competitive anion (i.e. Cl-, NO3-, SO42- and HCO3-) to phosphate molar ratio of 100:1 and humic acid (HA) concentration of 100 mg C/L. Adsorption-desorption cyclic experiments demonstrated the good reusability of the ZrO2@SiO2@Fe3O4.

Arsenic and selenium in shore soils and bottom sediments of Samara city ponds

Arsenic and selenium are included in the group of chemical elements of the first hazard class, which confirms the need to analyze their content in natural environments of natural and man-made ecosystems during ecological and biogeochemical monitoring. By their chemical properties, arsenic and selenium are metalloids or semimetals. In very low concentrations, they are necessary for the normal functioning of the organisms, but with increasing concentrations in the habitat or food they show high toxicity. Particularly dangerous is the accumulation of arsenic and selenium in accumulative environments and landscapes, which include soils and confined water bodies. For the urban ecosystems of the Samara Region, earlier monitoring of the content of arsenic and selenium in the components of their accumulative landscapes was not carried out, which confirms the relevance and practical significance of the presented materials. The authors carried out ecological and geochemical studies of the accumulation of arsenic and selenium in coastal soils and bottom sediments of twenty ponds located in the Samara city within the coastal slope of the Saratov reservoir (Volga slope) and on the watershed between the Saratov reservoir and the Samara River. The results analysis showed a relatively low level of arsenic accumulation in the analyzed substrates of the studied ponds. Compared with the level of regional background for the Middle Volga, the studied accumulative aqual landscapes are noticeably enriched in selenium (2-15 times). The technogenic influx of arsenic and selenium into the accumulative landscapes of the Samara city may be associated with the activities of metalworking and machine-building enterprises, as well as thermal power plants. The materials presented in the paper concerning the content of arsenic and selenium in coastal soils and bottom sediments of urban ponds in the Samara city can be considered as pioneering for the region and subsequently used in the ecological and geochemical monitoring of regional urban ecosystems.

Convection in Lakes

Lakes and other confined water bodies are not exposed to tides, and their wind forcing is usually much weaker compared to ocean basins and estuaries. Hence, convective processes are often the dominant drivers for shaping mixing and stratification structures in inland waters. Due to the diverse environments of lakes—defined by local morphological, geochemical, and meteorological conditions, among others—a fascinating variety of convective processes can develop with remarkably unique signatures. Whereas the classical cooling-induced and shear-induced convections are well-known phenomena due to their dominant roles in ocean basins, other convective processes are specific to lakes and often overlooked, for example, sidearm, under-ice, and double-diffusive convection or thermobaric instability and bioconvection. Additionally, the peculiar properties of the density function at low salinities/temperatures leave distinctive traces. In this review, we present these various processes and connect observations with theories and model results.

Numerical modeling of the June 24, 2015, Hongyanzi landslide generated impulse waves in Three Gorges Reservoir, China

Subaerial landslides falling into confined water bodies often generate impulsive waves. Damaging landslide tsunamis in Three Gorges Reservoir, China, have struck several times in the last 15 years. On June 24, 2015, a 23 × 104 m3 slope failure occurred on the east bank of the Daning River opposite Wushan Town. The sliding mass intruded into the Three Gorges Reservoir and initiated a reservoir tsunami that resulted in two deaths and significant damage to shipping facilities. A post-event survey revealed the landslide geometry and wave run-up distribution, while an eyewitness video captured most of the landslide motion. Employing these firm constraints, we applied the Tsunami Squares method to simulate the 2015 Hongyanzi landslide and tsunami. The simulation revealed that the landslide experienced a progressive failure in the first few seconds and impacted the water with a maximum velocity of ~ 16 m/s. The initial wave propagated to the opposite shore in an arch shape, and the water surface reached a maximum amplitude of ~ 11 m near the landslide. Wave amplitude-time curves at four points on the river cross section show that the initial wave reached Wushan town in about 50 s with an average wave velocity of ~ 30 m/s. The maximum wave run-ups on the shoreline opposite the landslide are around 6 m and attenuate to less than 1 m beyond 2-km distance. The landslide simulation matches the observed geological profile and the eyewitness video, and the numerical results coincide with the observed wave run-up heights. Nearly 80% of landslide energy is lost due to frictional resistances, but the remaining fraction imparted to the tsunami carried catastrophic consequences to a large region. The numerical results emphasize the efficiency and accuracy of Tsunami Squares method for a “Quick Look” simulation of a potential landslide.

Removing organic and nitrogen content from a highly saline municipal wastewater reverse osmosis concentrate by UV/H2O2–BAC treatment

Reverse osmosis (RO) concentrate (ROC) streams generated from RO-based municipal wastewater reclamation processes pose potential health and environmental risks on their disposal to confined water bodies such as bays. A UV/H2O2 advanced oxidation process followed by a biological activated carbon (BAC) treatment was evaluated at lab-scale for the removal of organic and nutrient content from a highly saline ROC (TDS 16gL−1, EC 23.5mScm−1) for its safe disposal to the receiving environment. Over the 230-day operation of the UV/H2O2–BAC process, the colour and UV absorbance (254nm) of the ROC were reduced to well below those of the influent to the reclamation process. The concentrations of DOC and total nitrogen (TN) were reduced by approximately 60% at an empty bed contact time (EBCT) of 60min. The reduction in ammonia nitrogen by the BAC remained high under all conditions tested (>90%). Further investigation confirmed that the presence of residual peroxide in the UV/H2O2 treated ROC was beneficial for DOC removal, but markedly inhibited the activities of the nitrifying bacteria (i.e., nitrite oxidising bacteria) in the BAC system and hence compromised total nitrogen removal. This work demonstrated that the BAC treatment could be acclimated to the very high salinity environment, and could be used as a robust method for the removal of organic matter and nitrogen from the pre-oxidised ROC under optimised conditions.

인 제거를 위한 흡착제로서 란타늄-황토 복합체의 흡착특성

In this work, a composite formed by adding loess with lanthanium (La-Loess) was proposed for effective removal of phosphate found in confined water bodies such as lake and reservoir. It was found that the theoretical maximum amount of lanthanum that can be attached to Loess was 2.68 mg La/g Loess. The phosphate removal was enhanced as an added amount of La-Loess composite increased. Furthermore, there was a noticeable difference in phosphate removal between Loess and La-Loess as the latter required 1.5 to 10 times less Loess than the former. Both Isotherm equations of Freundlich and Langmuir can be used to explain the phosphate adsorption characteristics in using La-Loess composites. The phosphate removal was very effective in the pH range of 5~8, which means that the proposed adsorbent can be directly applied to natural water without adjusting pH. Also, the La-Loess composites were well settled within 30 min without causing turbidity in water. Consequently, the proposed La-Loess can be strongly recommended for phosphate removal in confined water bodies.

Ultimate removal of phosphate from wastewater using a new class of polymeric ion exchangers

The presence of trace concentrations of dissolved phosphate is often responsible for causing eutrophication problems in lakes, reservoirs, other confined water bodies and coastal waters. In this regard, both biological and physico–chemical treatment processes have been studied extensively to remove phosphate from contaminated water/wastewater. There, however, remains a major need to identify/develop a viable fixed-bed process which can essentially eliminate phosphate from contaminated water/wastewater. Previous investigators have shown the advantages as well as shortcomings of the fixed-bed process when strong-base anion exchangers, activated alumina and zirconium oxides are used as sorbents. The present study reports the results of a detailed investigation pertaining to selective phosphate removal by a new class of sorbent, referred to as polymeric ligand exchanger (PLE). Laboratory studies show strong evidence that the PLE is very selective toward phosphate, chemically stable, and also amenable to efficient regeneration. Anion exchange accompanied by Lewis acid–base interaction is the underlying reason for PLE's enhanced affinity toward phosphate. In several ways, this new ion exchanger (PLE) overcomes the shortcomings of previously used inorganic and polymeric sorbents.

Statistical and numerical analysis of tsunami wave heights in confined waters

Based on available data from tsunami occurrences in the Greek seas and in the Mediterranean, a statistical analysis has provided information on expected wave heights in the vicinity of the Rion-Antirrion Straits, for various probabilities of occurrence of a seismic event. The findings were compared with results obtained from a numerical model which solves the two-dimensional equations of continuity and linearized momentum. The comparison was satisfactory and indicates that the present model can simulate reliably tsunami waves, resulting from seismic events, in the off-shore regions of confined water bodies such as the Gulf of Corinth.

Frost heaving of bedrock in permafrost regions : Dyke, L D Bull Assoc Engng GeolV21, N4, Nov 1984, P389–405

Frost heaving of bedrock in permafrost areas is a widespread process that produces a variety of landforms and exhibits movements of possible concern to engineering endeavors. While the study of ice growth in soils is an actively researched subdiscipline of soil mechanics, the same process in rock escaped notice until major engineering projects were considered in areas outside the dominantly soil covered parts of the North American arctic. Geology and hydrology exert a fundamental control on the style of the rock heave process. Displacement of single blocks, panels, and domes has taken place where saturated zones in the active layer become confined by the downward-advancing freezing front. The attempted expulsion of water by continued freezing supplies the heaving force, much in the manner of the closed-system pingo. This mechanism is favoured where the water table lies close to the surface in the massive granites, gneisses, and quartzites of the Canadian Shield. The mechanism requires that ice-filled cracks be able to seal in high pore water pressures. Field measurements show that water pressures up to 400 kPa are attained within the confined water bodies, a pressure considerably in excess of that needed to offset the overburden pressure. Where drier conditions prevail and rocks less resistant to weathering are present, the accumulation of weathering products in cracks can provide a site for heaving. In this case, the forces are produced by the growth of segregated ice in soil-filled cracks. This mechanism is common in sandstones and limestones and contributes to the mechanical breakdown of outcrops. Laboratory experiments confirm that horizontal movements can be produced by vertically-downward freezing in vertical soil-filled cracks. This mechanism is widespread because saturated conditions are not necessary. Resurveying of markers at several locations from Churchill, Manitoba to the central Arctic Islands reveals yearly movements of up to 5 cm, horizontally and vertically. Recorded movements are most common at sites subject to the ice segregation mechanism. Vertical movements tend to be cyclical due to settlement during thaw. Features formed by the water expulsion mechanism presumably reach an equilibrium height and show little further movement.

Frost Heaving of Bedrock in Permafrost Regions

Frost heaving of bedrock in permafrost areas is a widespread process that produces a variety of landforms and exhibits movements of possible concern to engineering endeavors. While the study of ice growth in soils is an actively researched subdiscipline of soil mechanics, the same process in rock escaped notice until major engineering projects were considered in areas outside the dominantly soil covered parts of the North American arctic. Geology and hydrology exert a fundamental control on the style of the rock heave process. Displacement of single blocks, panels, and domes has taken place where saturated zones in the active layer become confined by the downward-advancing freezing front. The attempted expulsion of water by continued freezing supplies the heaving force, much in the manner of the closed-system pingo. This mechanism is favoured where the water table lies close to the surface in the massive granites, gneisses, and quartzites of the Canadian Shield. The mechanism requires that ice-filled cracks be able to seal in high pore water pressures. Field measurements show that water pressures up to 400 kPa are attained within the confined water bodies, a pressure considerably in excess of that needed to offset the overburden pressure. Where drier conditions prevail and rocks less resistant to weathering are present, the accumulation of weathering products in cracks can provide a site for heaving. In this case, the forces are produced by the growth of segregated ice in soil-filled cracks. This mechanism is common in sandstones and limestones and contributes to the mechanical breakdown of outcrops. Laboratory experiments confirm that horizontal movements can be produced by vertically-downward freezing in vertical soil-filled cracks. This mechanism is widespread because saturated conditions are not necessary. Resurveying of markers at several locations from Churchill, Manitoba to the central Arctic Islands reveals yearly movements of up to 5 cm, horizontally and vertically. Recorded movements are most common at sites subject to the ice segregation mechanism. Vertical movements tend to be cyclical due to settlement during thaw. Features formed by the water expulsion mechanism presumably reach an equilibrium height and show little further movement.