Ground Level Water Research Articles

New insights into diffusive kinetic fractionation during liquid condensation under supersaturated environment: an alternative approach for isotope tagging of ground-level water vapour

ABSTRACT Stable water isotopes in ground-level vapour are key to estimating water exchange between geospheres. Their sampling, however, is limited to laser-absorption spectrometers and satellite observations, having inherent shortcomings. This study investigates diffusive kinetic fractionation during liquid condensation under supersaturated environment, providing a cost-effective, reliable way of sampling ground-level vapour isotopes (18O, 2H). Experiments were undertaken at three locations in India with ‘liquid’ samples collected from condensation of ambient air at 0°C. Simultaneously, pristine ‘vapour’ was sampled via cryogenic-trapping using liquid nitrogen–alcohol slush at –78°C. The ‘liquid’ condensed under supersaturation was progressively more depleted in 18O, and less enriched in 2H than expected under equilibrium fractionation, with an increasing degree of supersaturation expressed as saturation index (S i). This study revealed: (1) S i, molecular density, Rh, T together control the extent of isotopic kinetic fractionation. (2) The presence of diffusive concentration gradient inhibits the flow of heavier isotopes during liquid condensation. (3) The stochastic nature of the process cannot be explained using a physics-based model alone. The artificial neural network model is hence deployed to sample δ 18O (δ 2H) within –0.24 ± 1.79‰ (0.53 ± 11.23 ‰) of true value. (4) The approach can be extended to ground-validate isotope-enabled general circulation models and satellite observations.

Identification of Suitable Recharge Sites by Integrated Hydrogeophysical Approach for Augmenting Groundwater in Reodar Block, District Sirohi, Rajasthan

Abstract The dependence of human beings on groundwater and ever-increasing demands of growing population, agriculture and industries, has resulted in its over-exploitation. This has led to the decline of groundwater levels and its shortage especially in lean season. The study area, Reodar block of Sirohi district, Rajasthan, is an over-exploited block with the stage of groundwater extraction at 159% and has an average declining water level trend at the rate of 0.24 m/year. Artificial recharge was proposed in the study area through the construction of recharge shafts and injection wells, after delineating the weathered thickness in the submergence area of existing ponds and check dams of the study area by carrying out vertical electrical sounding (VES). In all, VES were conducted at 178 sites and recharge structures were constructed at 76 out of 109 scientifically selected sites with suitable weathered thickness and attempt was made to establish their impact on water levels through pre-monsoon water level monitoring. The comparison of pre-monsoon water level observations spanning over four decades reveals its spatio-temporal decline in the study area. The construction of these recharge structures has resulted in significant increase in area from 38% to 68%, under 0 to 20 m below ground level water level range. This study demonstrates the importance of resistivity surveys in scientifically selecting the suitable sites for construction of recharge structures and significance of long-term water level monitoring in assessing the groundwater scenario and impact assessment, in poorly characterized hydrogeological areas.

Study on potential aspect of an ornamental plant - Syngonium podophyllum (Schott) as a phytoremidiator on environmental pollution: A Short Review

Environmental pollution is a globally faced problem by which the humans are facing various issues directly or indirectly. This is a long-term consequence which are created by both developed countries and developing countries. The stability of the ecosystem has been declined every year and it is evident by the loss of vegetation, quality of the air, ground level water contamination and extinct and dumping excessive amount of harmful chemicals without proper degradation. Due to these factors, serious threats have been evolved all over the world faced by all living organisms. Now, people are greatly focusing on green remediation, to remove or treat the hazardous materials using plants. Remediation with the usage of plants and phytoplanktons plays an important role as they are user friendly, cost effective and can be implemented at faster rate. Among the plants used for the study, ornamental plants plays a major role in the removal of pollutants and cleaning up of the environment. Syngonium podophyllum (Schott), commonly called as arrowhead plant is an ornamental plant has the ability to remove benzene, toluene, formaldehyde and xylene gases and has been approved as air purifier by researchers at NASA. The whole plant is found to be poisonous to humans but have the capability to remove toxins from air by cleaning air. Hence, the review study is focused on the ability of plants to remove indoor pollutants harmful for mankind.

Dry-Season Fog Water Utilization by Epiphytes in a Subtropical Montane Cloud Forest of Southwest China

Fog water is generally considered to be an important water source for epiphytes in cloud forests because they cannot directly access ground-level water sources. However, the water use proportions of potential water sources and water use efficiency of epiphytes in the subtropical montane cloud forests (MCF) remain to be further explored. In this study, we investigated the water use pattern in the dry season and the intrinsic water use efficiency (WUEi) of four epiphyte groups (i.e., epiphytic lichens, epiphytic bryophytes, epiphytic ferns, and epiphytic seed plants) using stable isotope (δ2H, δ18O, and δ13C) techniques. Our results indicated that the water sources of epiphytes were significantly different among groups and species. The contribution proportions of fog water to epiphytic lichens, epiphytic bryophytes, epiphytic ferns, and epiphytic seed plants were 83.2%, 32.7%, 38.8% and 63.7%, respectively. Epiphytic lichens and epiphytic seed plants mainly depended on fog water whereas the epiphytic bryophytes and epiphytic ferns relied on both fog water and humus. This may be due to their differences in morphological and structural traits (e.g., thallus or leaves, rhizoid or roots). Additionally, the difference in WUEi was also significant among epiphyte groups and species, which could be related to their different water acquisition patterns. In conclusion, our study reveals the differentiation of water utilization in epiphytes and confirms the importance of fog water for epiphytes during the dry season.

New Insights into Diffusive Kinetic Fractionation During Liquid Condensation Under Supersaturated Environment: A Novel Approach for Isotope Tagging of Ground Level Water Vapor

New Insights into Diffusive Kinetic Fractionation During Liquid Condensation Under Supersaturated Environment: A Novel Approach for Isotope Tagging of Ground Level Water Vapor

Reproductive traits associated with species turnover of amphibians in Amazonia and its Andean slopes.

Assembly of ecological communities is important for the conservation of ecosystems, predicting perturbation impacts, and understanding the origin and loss of biodiversity. We tested how amphibian communities are assembled by neutral and niche‐based mechanisms, such as habitat filtering. Species richness, β‐diversities, and reproductive traits of amphibians were evaluated at local scale in seven habitats at different elevation and disturbance levels in Wisui Biological Station, Morona‐Santiago, Ecuador, on the foothills of the Cordillera del Kutukú; and at regional scale using 109 localities across evergreen forests of Amazonia and its Andean slopes (0–3,900 m a.s.l.). At local scale, species composition showed strong differences among habitats, explained mainly by turnover. Reproductive modes occurred differently across habitats (e.g., prevalence of direct developers at high elevation, where breeding in ground level water disappears). At regional scale, elevation was the most important factor explaining the changes in species richness, reproductive trait occurrences, and biotic dissimilarities. Species number in all groups decreased with elevation except for those with lotic tadpoles and terrestrial reproduction stages. Seasonality, annual precipitation, and relative humidity partially explained the occurrence of some reproductive traits. Biotic dissimilarities were also mostly caused by turnover rather than nestedness and were particularly high in montane and foothill sites. Within lowlands, geographic distance explained more variability than elevation. Habitat filtering was supported by the different occurrence of reproductive traits according to elevation, water availability, and breeding microhabitats at both scales, as well as other assembly mechanisms based in biotic interactions at local scale. Human‐generated land use changes in Amazonia and its Andean slopes reduce local amphibian biodiversity by alteration of primary forests and loss of their microhabitats and the interaction network that maintains their unique amphibian assemblages with different reproductive strategies.

Southwest (SW) Monsoon Dynamics Study in Indo-Gangetic Plains Using Isotopic Techniques

The atmospheric ground level water vapors (GLV) were collected during 2008-10 on daily basis by condensation method in Indo-Gangetic plains at sites: Roorkee (Uttarakhand) and Sagar (Madhya Pradesh). The two sites are located a few hundred kilometers away along the southwest monsoon track. Isotopic composition of GLV collected at both the sites is compared and it is found that the two isotopic spectra grossly correlate at most part of the spectrum indicating that although rainout process take place locally, its effect on the atmospheric water vapors can be observed over long distances. This opens up possibility of monsoon prediction through monitoring of atmospheric water vapor.

The unbearable lightness of technocratic efforts at dengue control

To identify key elements that should provide an added value and assure sustainable effects of the deployment of technical tools for Aedes aegypti control. An observational study was conducted between April 2001 and March 2002 in 30 blocks (1574 houses) in the central zone of Guantanamo city. A trial that combined two complementary technical interventions, the distribution of new ground level water tanks and the intensive use of insecticide, was nested in May 2001. Another 30 blocks (1535 houses) were selected as control area. We assessed community perceptions and household risk behaviour at baseline and after 9 months, and measured the trial's impact through entomological indices. Perceived self efficacy to solve A. aegypti infestation and prevent dengue was not modified. We found no changes in behaviour. In the study area the container indices decreased significantly from 0.7% before to 0.1% 1 month after the intervention. Six months later, they had increased to 2.7% and uncovered new water tanks constituted 75.9% of all breeding sites. Over the 9 months after the trial the average monthly house indices were similar in the study and control areas. A technical approach and lack of community involvement in the trial's implementation were the main causes of these short-lived results. Top-down deployment of technical tools without active involvement of the community has a temporary effect and does not lead to the behavioural changes necessary for sustainable A. aegypti control.

Measurements of atmospheric attenuation near 225 GHz: Correlation with surface water vapor density

The total attenuation through the earth's atmosphere for radio waves at frequencies near 225 GHz has been monitored for several weeks from a 1-km elevation site. The zenith attenuation at these frequencies was found to be correlated with the ground level water vapor content of the atmosphere; the correlation is consistent with the relation A (db)= 0.50 \rho ( g \dot m-3of water) predicted for clear sky conditions by theory, assuming a 2-km scale height for water in the atmosphere.