Pre-monsoon Period Research Articles

Recurrent dinoflagellate blooms in the South-eastern Arabian Sea - A preliminary assessment with focus on Ornithocercus magnificus blooms along the nearshore waters off Dakshina Kannada, South-west coast of India

Frequent bloom incidences of the dinoflagellate Ornithocercus magnificus Stein, 1883 along the surface waters off South-eastern Arabian Seas (SEAS) have been reported since 2015 and specifically during the years 2015, 2019 and 2020. All these blooming incidences coincided with the strong El Nino phases in the Indian Ocean. The present study addressed the bloom (1.65 x 106 cells l-1) of this species in the nearshore waters (7 m depth) off Dakshina Kannada (Surathkal and Chitrapur) on 11.02.2016 which occurred during pre-monsoon period and corresponding to the super El Nino year 2015/2016. A detailed evaluation of the physico-chemical characteristics and phytoplankton abundance as well as community structure was made, concurrent to the three phases viz., pre-bloom, bloom and post-bloom periods in this region. The study revealed that the bloom occurred in high saline (35.0±0.91 PSU), well oxygenated (7.414±0.823 mg l-1) and nitrogen limited waters (oligotrophic conditions) and had a positive correlation with oceanic nino index (ONI; rs= 0.790, p<0.001). Some of the O. magnificus (3%) harboured ectosymbionts probably cyanobacteria in their cingulum in response to the beginning of a stratified oligotrophic condition in this region. The water quality was fair during the bloom period with no conspicuous discolouration of the surface waters. The present study also attempted to evaluate the influence of the increasing frequency of the O. magnificus blooms on the oilsardine fishery along the SEAS. Keywords: Cyanobacteria, Dinoflagellate, Ectosymbionts, Nitrogen limited waters, Pre-monsoon season, SEAS, Sea surface temperature (SST), Oilsardine

Influence of elevation and rainfall on leaf growth, bean characteristics and yield components of arabica and robusta coffee under changing climatic conditions in Karnataka state, India

The study was undertaken to analyze the behaviour of coffee under changing climatic conditions in different coffee liaison zones of Karnataka State, India, during 2017-2020. Sample estates were identified based on elevation and rainfall patterns in different zones of the Chikkamagaluru and Hassan districts. The leaf growth parameters, bean characteristics and yield components were recorded in all the sample estates. Correlation studies indicated a significant positive relationship between the elevation, rainfall with specific leaf area (r = +0.912) and productivity (r = 0.475) during the pre-monsoon period. The monthly summer rainfall during March and April showed a significant correlation with yield in robusta (r = 0.511) and arabica (r = 0.451), indicating that blossom shower during this period significantly influenced the productivity of coffee. The studies between elevation, the quantum of rainfall and bean defect parameters indicated a significant (p<0.05) positive correlation. A positive relationship was also found between elevation and peaberry production in both robusta (r = 0.716) and arabica coffee (r= 0.456), respectively. However, there was also a significant relationship between rainfall (2020) and Jollu percentage (r = 0.386) in robusta coffee, indicating that higher elevation and rainfall-induced more peaberry content and Jollu percentage under changing climatic conditions. The overall result indicated that changes in climatic conditions such as excess rainfall and continuous soil moisture led to more vegetative growth than reproductive growth. This also produced more bean abnormalities which in turn affected the yield and quality of the coffee.

Bio-efficacy of new fungicide, Tebuconazole- 430SC against coffee leaf rust disease, Hemileia vastatrix Berk and Broome

Coffee is an important plantation crop cultivated worldwide and used as stimulating drink. Coffee leaf rust (CLR) disease is one of the devastating disease affecting foliage of Coffee, limiting Coffee production worldwide. It is caused by an obligate parasite Hemileia vastatrix, which reduce photosynthetic area in turn results in heavy defoliation and die-back of branches. In India CLR management is accomplished with one contact fungicide spray (Bordeaux mixture @ 0.5%) and effective systemic fungicide spray during pre and post monsoon periods respectively. However, to find an alternative to the recommended fungicide the studies were conducted to know the efficacy of new fungicide Tebuconazole 430 SC against CLR. The results revealed that, in the laboratory conditions, complete inhibition of the uredospore germination was observed in Tebuconazole 430 SC @ 0.5 ml/L and 0.75 ml/L and Hexaconazole 5 EC @ 2 ml/L. However, in lower concentration Tebuconazole 430 SC @0.25 ml/L there was 98.97 per cent inhibition and in Copper Oxychloride 50 WP @ 5.5 g/L 87.49 per cent inhibition was observed over control. Field trials indicated that, at all the locations, Tebuconazole 430SC @ 0.75ml/L was found very effective which recorded maximum disease reduction followed by Tebuconazole 430SC @ 0.5ml/L which was found on-par with the currently recommended fungicide Hexaconazole 5 EC @ 2 ml/L and minimum disease reduction was observed in Copper oxychloride 50 WP @ 5.5g/L.

Geogenic enrichment of fluoride in groundwater of hard rock aquifer in fluorosis prevalent area of Balangir district, Odisha, India

Hydrogeochemical characterization of groundwater has been carried out in a hard rock aquifer from Balangir district, a fluorosis-affected area of Odisha, India with the aim of understanding the sources and processes controlling fluoride (F−) enrichment. A total of 37 groundwater (tube wells) and 7 surface water (pond) samples were collected during the pre-monsoon period. Groundwaters are mostly categorized as moderate to very hard water types with alkaline nature. The enhanced Na+ and HCO3− concentration in groundwater is mostly a result of silicate weathering. The F− concentration in groundwater ranged from 0.4 to 4.29 mg/l, with 38% of samples exceeded the drinking water limit (1.5 mg/l; as prescribed by the World Health Organization, 2011), in contrast to very low F− (<0.9 mg/l) in surface water. High F− concentrations in underlying granitic bedrocks (up to 700 mg/kg), which spatially corresponds to F− rich groundwater, suggest that lithological composition is the main control of F−. Fluoride-rich waters are mostly Na–HCO3 type, followed by mixed Na–Ca–HCO3 (Cl) type with Na+/Ca2+ ratio >1. The significant positive correlations of F− with Na+, HCO3−, and pH indicate that the weathering of sodium-rich silicate minerals and increase of pH mobilizes F− ion. Geochemical modeling indicates that the activity of F− in groundwater increased by precipitation of calcite, dolomite, and aragonite. Fluoride risk assessment indicates that 38% of groundwater samples can cause a high prevalence of dental fluorosis with children being at greater risk than adults. Henceforth, it is advisable to treat this contaminated groundwater before consumption or provide alternative drinking water to avoid further fluorosis risks in the concerned area.

Effect of Seasonal Variations in Hematology, Biochemical, Immunity Constituents in Mugil cephalus, Chano chanos, and Arius arius on Southeast Coast of Tamil Nadu, India

The assessment of the effect of seasonal variations on health, hematology, and serum biochemical components of three marine teleost fishes, Mugil cephalus, Chanos chanos, and Arius arius from Kovalam, East Coast Road, Southeast coast of Tamil Nadu, India. The objectives of the study pointed out the effect of seasonal variation on fish health and immunity. During summer and pre-monsoon, a total of 20 samples were collected from each sample, and hematological, biochemical, immunity parameters, and fish health were considered. M. cephalus (L-23.86±1.03; W-171.22±35.42) C. chanos, (L-22.36±1.17; W-163.03±33.32) and A. arius (L-22.62±1.08; W-168.72±35.04) have different length and weight. The WBC, RBC, Hb, and HCT were higher during summer in M. cephalus, C. chanos, and A. arius likewise, these parameters were lower in the pre-monsoon period (P&lt;0.05). The MCV, MCH, MCHC, and ESR of all three species were higher in the pre-monsoon whereas in the summer they decreased. Likewise, leukocytes such as neutrophils, monocytes, lymphocytes, eosinophils, and thrombocytes show minimum levels in the pre-monsoon and attain maximum levels in the summer. Most importantly, in the summer, serum components protein and glucose were higher, while cholesterol and urea were lower, and vice versa. Although IgM and IgG levels (P&lt;0.05) were higher in the summer and declined in the pre-monsoon season. In the lysozyme assay, respiratory burst activity (NBT) (P&lt;0.05) reveals a higher concentration in the pre-monsoon and was lower in the summer. A total of thirteen hematological parameters, six biochemical, and two immunological parameters, and lysozyme and NBT activities showed a significant relationship with fish health throughout the seasonal changes. Based on the findings, M. cephalus shows maximum variations in length, weight, hematology, biochemical, and immunity levels, whereas C. chanos showed minimum variations. Hence the report indicates the seasons mainly impact the physiological status of the fish species.

Geoenvironment and weathering of silicate minerals in sediments of the Brahmaputra river, India: Implications for heavy metal pollution assessment

We carried out detailed compositional studies on fifteen sediment samples from the Brahmaputra River that were collected in the pre-monsoon period, to obtain the inherent contamination factor. The present study demonstrates that the degrees of metal contamination in the sediments of the Brahmaputra river. Typical metals Fe, Al, Ti, Pb, Zn, Cu, Ni, Co, Mn and Cr, have been evaluated using several parameters like, enrichment factor (EF), contamination factor (CF), geo-accumulation index (Igeo) and pollution load index (PLI). The relative distributions of the contamination are found to be: Al > Fe > Ca > Mg > Ti > Mn > Cr > Cu > Zn > Ni > Pb > Co. The suspended sediments have been found to be moderately contaminated by the elements Cu, Pb, Cr, Mn and Ni. The nature of weathering is estimated using plagioclase index of alteration (PIA), chemical index of alteration (CIA), chemical index of weathering (CIW) and index of compositional variation (ICV). The studied suspended sediment samples indicate an intermediate silicate weathering of adjoins area.

“Reproductive Ecology of Narrow mouthed frog Microhyla ornata”

: Reproductive ecology of Narrow mouthed frog Microhyla ornata was studied at selected breeding sites around Dharwad, Karnataka India during the wet periods between May 2017 and December 2018. The breeding activity varied depending upon the amount of rainfall. It was higher during monsoon when there was higher rainfall, whereas, when rainfall was scanty less activity was observed. Males begin the calling activity in the evening after the sunset at 1098min reaching its peak at around 1200min and extend till the early morning of the next day. Gravid females arrive at the breeding site one to one and half hour after the calling was initiated in the early pre-monsoon and monsoon period and amplexus took place soon after the arrival of females within one hour during peak calling days. Size assorted matting was observed in M. ornata and showed significant positive correlation. The female body size was positive correlation with clutch size. However, there was no significant correlation between female body size and egg size. Breeding activity of M. ornata spanning for seven months suggest that, this species is a prolonged breeder. The eggs and larvae of M. ornata were under constant threat by the predatory larva of the aquatic insects like Dragonfly and Water beetle. Few clutches during non rainy period faced the risk of desiccation. The breeding sites of many anurans are affected by urbanization and habitat fragmentation. There is a need to adopt the strategy to conserve the habitats to protect the species.

Impact of differential surface water mixing on seasonal arsenic mobilization in shallow aquifers of Nadia district; western Bengal Basin, India

Arsenic (As) mobilization in groundwater is linked to the dissimilatory reductive dissolution of As(V) coated Fe(III)-oxy-hydroxides from the aquifer sediment coupled with the degradation of available dissolved organic carbon (DOC) due to the presence of anaerobic microbes under anoxic conditions. Understanding the seasonal pattern of As mobilization in the shallow groundwater of the Bengal Basin remains a challenging task due to the heterogeneous character of the shallow aquifers and the involvement of multiple factors. To resolve this issue, in the present study, we showcased a comprehensive effort to advance understanding of the seasonal As mobilization process in the shallow groundwater, utilizing multiple geochemical tracers (i.e., the abundance of dissolved total As, Fe, Mn, NO3–, SO42-, DOC, Cl-, and δ18O, δ2H, δ13C-DOC isotopic tracers) between post-monsoon and pre-monsoon periods over multiple years from Nadia district, West Bengal, India. We quantified and explained the seasonal variation of dissolved total As concentrations in the groundwaters with the nature of the aquifer lithology (i.e., grey sand aquifer or ‘GSA’ and brown sand aquifer or ‘BSA’). The present study reported elevated dissolved total As concentrations in the shallow groundwater samples during dry pre-monsoon (‘PRM’) periods compared to post-monsoon (‘POM’) time. However, the magnitude of such seasonal changes in groundwater As concentrations (denoted as ΔAs = AsPRM-AsPOM) varied between years depending on the extent of rainfall, surface water infiltration, mixing, and groundwater withdrawal. Our current findings are different from the past studies that reported elevated As concentrations in the shallow groundwater during the monsoon and post-monsoon periods compared to the dry pre-monsoon periods. However, the limitations of the past findings are that most of the previous studies were carried out between seasonal intervals over a single annual cycle without reinvestigating the seasonal trends over different years under variable hydrological conditions. We proposed that the excess groundwater withdrawal during the dry pre-monsoon period drive draw-down and, therefore, trigger infiltration of surface-derived deep pond water into the shallow aquifer. Such surface water infiltration introduces fresh labile organic matter into the shallow aquifer, promoting high As mobilization during the dry pre-monsoon period. A viable alternative approach of ‘squeezing’ of aquifer intercalated clay-peat sedimentary lenses and mixing of organic-rich pore water in the adjoining groundwater can also enhance high As mobilization during the dry time, as examined in this study. This process is triggered by the excessive groundwater withdrawal practices and drawdown encountered during dry time, driving the aquifer intercalated clay-pockets compaction.

Groundwater Quality Assessment Using GIS for Agricultural Propose in Molakalmur Taluk, Karnataka

Objectives: To assess the carbonate concentration in relation to calcium and magnesium concentrations and to determine TDS and sodium concentration in relation to other cations. The study’s overall goal is to examine the suitability of groundwater for irrigation/agricultural purposes in Molakalmur Taluk of Chitradurga District, Karnataka, India. Methods: The current study was carried out to analyze the water quality and spatial distribution of physicochemical parameters of groundwater in study area. A total of 92 groundwater samples were collected during the pre-monsoon period; ArcGIS 9.2 was used to create a spatial distribution map based on a geographic information system. The concentrations of various ions like Ca+2, K+1, Cl-1, Mg+2, HCO3 -1, Na+1, CO3 -2, and SO4 -2 were evaluated as per BIS 3025 (2014) and compared to various irrigation standards like Sodium Adsorption Ratio (SAR), Percentage of Sodium (%Na), Magnesium Adsorption Ratio (MAR), Kelley’s Ratio/Kelly’s Index (KI), Permeability Index (PI) Electrical Conductivity (EC), Total Hardness (TH), Total Salt Concentration, Chloride in irrigation water and integrated standards such as USSL and Wilcox diagram. Findings: During the pre-monsoon period, the majority of the samples in the study area fell into the hard to very hard water category. According to Evaluated water quality indices like SAR, MAR, PI, KI, SSP, Cl and total salt concentration around 5 to 15 percent water samples are not good for agricultural purpose and as per the integrated parameters like USSL and Wilcox the percentage samples that are unsuitable for irrigation is going up to 30 percentage due to presence of higher Electrical conductivity. Novelty: In the study region, there is no perennial river and the main ion chemistry of Molakalmur Taluk’s groundwater has never been investigated before. The present work attempts to study the suitability of water for agricultural purpose. The findings of the study will aid in the collecting of crucial data on groundwater quality in Molakalmur Taluk. The findings of the study could also help groundwater managers and urban planners to restore and improve groundwater quality. Keywords: Physicochemical parameters; Irrigational water quality; Salinity hazard; Alkalinity hazard; Geographic Information System

Long‐term trends in aerosol optical properties and their relationship with cloud properties over southern India and Sri Lanka

AbstractAsia is one of the continents where aerosol levels are comparatively higher across the world. India and Sri Lanka are some of the regions in the South Asian continent where pollution is increasing rapidly due to the rise in industrialization. The present study investigated the interactions between atmospheric aerosol and cloud microphysical properties and their spatial, temporal, and seasonal variation at local and regional scales during 2000–2020 using remotely sensed data sets in south India and Sri Lanka. High values (&gt;0.5) of annual mean aerosol optical depth (AOD) were detected over southern India. On the other hand, lower values (0.2) were detected over Sri Lanka. In terms of seasonality, a high level of AOD was registered in both southern India and Sri Lanka during the premonsoon and monsoon periods. The angstrom exponent (AE412‐470) revealed the dominance of fine‐mode particles during winter and the postmonsoon, generally from biomass burning and industrial activities. The long‐term analysis exhibited an increasing trend of atmospheric aerosol concentration over southern India and Sri Lanka. Interestingly, there was a decrease in AOD during the year 2020; the reduction in anthropogenic activities in the region was attributed to the COVID‐19 lockdown, hence less accumulation of pollutants in the atmosphere. AOD showed a positive correlation with cloud effective radius over the western areas along with the Indian Ocean, north, southeast, and southern end of India, while negatively correlated with high AOD areas such as northeast of the study domain. The AOD and cloud optical depth were positively correlated over continental areas, while negative correlations were notable over the Indian Ocean around Sri Lanka, implying heterogeneities of aerosol's effect on cloud microphysical properties over the study area. Finally, the results from wind circulation and backward air mass trajectories reveal higher concentrations of fine‐mode particles associated with the continent, whereas coarse‐mode particles originate from the oceans.

Seasonal Variation in Microphysical Characteristics of Precipitation at the Entrance of Water Vapor Channel in Yarlung Zangbo Grand Canyon

Mêdog is located at the entrance of the water vapor channel in the Yarlung Zangbo Grand Canyon (YGC). This area has the largest annual accumulated rainfall totals and precipitation frequency on the Tibetan Plateau (TP). This paper investigates the seasonal variation in raindrop size distribution (DSD) characteristics in Mêdog based on disdrometer observations from 1 July 2019 to 30 June 2020. The DSD characteristics are examined under six rain rate classes and two rainfall types (stratiform and convective) in the winter, premonsoon, monsoon and postmonsoon periods. The highest (lowest) concentration of small raindrops is observed in monsoon (winter) precipitation, whereas large raindrops predominate in premonsoon precipitation. For stratiform rainfall, the mean mass-weighted mean diameter (Dm) exhibits overlooked differences in the four periods, while the mean normalized intercept parameter (Nw) is significantly higher in the monsoon period than in the other three periods. The convective rainfall in the monsoon and postmonsoon periods is characterized by a high concentration of limited-size drops and can be classified as maritime-like. This is probably attributed to abundant warm and humid airflow transported by the Indian Ocean monsoon into Mêdog. The westerly winds prevail over the TP during the premonsoon period, and thereby the premonsoon convective rainfall in Mêdog has a larger mean Dm and a lower mean Nw. In addition, the relationships of radar reflectivity Z and rain rate R for different precipitation types in different periods are also derived. A better understanding of the seasonal variation in the microphysical characteristics of precipitation in Mêdog is important for improving the microphysical parameterization scheme and the precipitation forecast of models on the TP.

Seasonal Waterlogging Variation in the Sylhet City Corporation Area, Bangladesh- an Integrated Geospatial Approach

Waterlogging is considered a severe environmental hazard in the Sylhet city corporation (SCC) area of northeast Bangladesh adversely affects the local socio-economic development. The integrated geospatial approach presents a worthy alternative to the conventional mapping of waterlogged surface areas. The remote sensing-based water index technique was used for delineating pre-monsoon and post-monsoon waterlogged areas of SCC in 2020 and 2021. Seasonal deviations of the waterlogging were determined by overlaying the waterlogged sites emanated from the pre-monsoon and post-monsoon periods under the GIS environment. Results show that waterlogged areas for pre-monsoon and post-monsoon seasons in 2020 are 2.25 sq. km and 4.12 sq. km, respectively, whereas 2.22 sq. km and 3.90 sq. km in 2021. Hence, the seasonal variations in waterlogged areas in 2020 and 2021 are 1.87 sq. km and 1.68 sq. km, respectively. This analysis also demonstrates that waterlogging in SCC is utterly driven by the high seasonal variations that mainly depend on the amount of rainfall besides the local flood-prone geologic settings and climate change.

Comparative Analysis of Aerosol Optical Properties over High Altitude Region of Western Ghats in Southern India

Observations of aerosols and Black Carbon (BC) were carried out at Ooty, high altitude region in Western Ghats using Multi wavelength solar radiometer (MWR) and Aethalometer. For the years 2018 and 2021, the Optical Characteristics of Aerosols and Clouds (OPAC) model was used to estimate monthly, seasonal, and spectral variations of aerosol optical properties such as Aerosol Optical Depth (AOD), Single Scattering Albedo (SSA), and Asymmetry Parameter (ASY). The dominance of fine anthropogenic aerosols was shown by higher AOD during the pre-monsoon period. The maximum and minimum seasonal variation of AOD occurred during pre-monsoon (1.1 ± 0.02) and winter (0.21 ± 0.001) respectively. The significant spectral variation of AOD occurred during March to May as it decreases with the increase in wavelength .The SSA increases as the wavelength increases, ranged between 0.83 ± 0.02 and 0.77 ± 0.01.The variability of SSA is significant during January and February which is a characteristic of coarse type aerosols. Asymmetry Parameter with the monthly mean of 0.75 ± 0.01 indicated the forward scattering of aerosols and there is no significant difference in them over the years.

People Deaths and Injuries Caused by Lightning in Himalayan Region, Nepal

Several natural disasters such as lightning, flood, fire, epidemics, and landslides frequently occur in the Himalayan region, of Nepal. The altitude of this region ranges from 59 m to “8848.86 m”—the height of Mount Everest—along with a distance of just 160 km. As a result, there is a considerable (i.e., nearly 95°C) variation in temperature in the region. Moreover, Nepal has a heterogeneous topography. All these features influence various natural disasters including lightning activity. This paper is aimed at analyzing the variations of lightning within and across the years from January 2011 to December 2021—a total of 11 years. For this, the data were taken from the Disaster Risk Reduction (DRR) portal of the Ministry of Home Affairs (MOHA). The analysis showed that there were no lightning events in November, and the lightning density was higher in the premonsoon period of study in this region. It also showed that the number of injured people is about thrice the death of the people due to the lightning. The null occurrence of lightning in November in the Himalayan region is a contribution novel to this field.

Interactions Between a Marine Heatwave and Tropical Cyclone Amphan in the Bay of Bengal in 2020

Interactions are diagnosed between a marine heatwave (MHW) event and tropical super cyclone Amphan in the Bay of Bengal. In May 2020, an MHW developed in the Bay of Bengal driven by coupled ocean-atmosphere processes which included shoaling of the mixed layer depth due to reduced wind speed, increased net surface shortwave radiation flux into the ocean, increased upper ocean stratification, and increased sub-surface warming. Ocean temperature, rather than salinity, dominated the stratification that contributed to the MHW development and the subsurface ocean warming that also increased tropical cyclone heat potential. The presence of this strong MHW with sea surface temperature anomalies &amp;gt;2.5°C in the western Bay of Bengal coincided with the cyclone track and facilitated the rapid intensification of tropical cyclone Amphan to a super cyclone in just 24 h. This rapid intensification of a short-lived tropical cyclone, with a lifespan of 5 days over the ocean, is unprecedented in the Bay of Bengal during the pre-monsoon period (March-May). As the cyclone approached landfall in northern India, the wind-induced mixing deepened the mixed layer, cooled the ocean's surface, and reduced sub-surface warming in the bay, resulting in the demise of the MHW. This study provides new perspectives on the interactions between MHWs and tropical cyclones that could aid in improving the current understanding of compound extreme events that have severe socio-economic consequences in affected countries.

Water quality characterization and pollution source apportionment in the Himalayan river flowing through Jammu City, India, using multivariate statistical approach and geospatial techniques.

The present study evaluates and characterizes the water quality of River Tawi in Jammu city of Union Territory of J&K, using water quality index, multivariate statistical methods, and geospatial techniques. Water quality parameters were measured at fourteen selected sites along a 12 km (approx.) stretch of river (passing through the city) over two seasons (pre-monsoon and post-monsoon) using standard methods. Water quality index (WQI) results demonstrated spatial and temporal variations and the pollution level of the river increased from upstream to downstream sites. Calculated WQI revealed 35.71% of the water samples in the unfit for drinking category, 28.57% in good and poor category each, and 7.14% samples in very poor drinking water category during the study period. Comparison of analysis results with the drinking water standards prescribed by the World Health Organization and Bureau of Indian standards recorded elevated ranges of parameters like turbidity, BOD, total alkalinity, nitrate, and faecal coliform beyond the permissible limits. Hierarchical cluster analysis has transformed the sites into two clusters during pre-monsoon and three clusters during post-monsoon season indicating more water quality variation during post-monsoon season. Principal component analysis resulted in two PCs for the water quality, explaining 80.827% and 73.672% of the variance for pre-monsoon and post-monsoon periods. The prepared WQI maps confirmed and depicted deterioration of river water quality towards the midstream and downstream sites of the river basin. Entry of major sewage drains from the city particularly at the midstream sites and dumping of solid waste and agricultural runoff towards the downstream sites of the river constituted the main anthropogenic sources that decreased the river water quality. The study establishes first step towards spatial zoning of River Tawi based on pollution level which would help in improving the river water quality through proper basin management. The study also recommends installation of sewage treatment plants particularly at the midstream and downstream sites.

Classification of groundwater using multivariate statistical methods: a case study from a part of Haryana, northwestern India.

This article aimed to estimate the local underground water associations, which will, in turn, be applied to discuss the location of each underground water cluster in the flow system. Additionally, this investigation intended to evaluate underground water's aptness from aquifers of the study area for domestic agricultural activities and the prime sources of alteration in the water chemistry. Geographically, the region does not have the privilege of the river (except the Yamuna in the eastern part) running through it and thus, has to rely heavily on groundwater. Therefore, it is necessary to study the groundwater characteristics in this region. This investigation manifested two sub-surface water associations (groups) showing two prime underground water types in the study area: the calcium-magnesium-bicarbonate water-types, groups (clusters) 1 member; and the sodium-bicarbonate-chloride water-types consisting of Group 2 members during post-monsoon and pre-monsoon periods. Group 1 is typical of underground water in recharge regions of the underground water flow system. It is the cleanest underground water type in part except for a few groundwater samples. The highest mean salinity was vested in group 2, the signature of underground waters in discharge regions of the underground water flow system. This investigation observes that three principal elements controlled the hydro-chemistry of underground water in the study area: chemical fertilizers from farms, carbonate mineral weathering, calcite, fluorite, silicate minerals, and exchange of cations in the region. All the underground water groups had high sodium (Na) concentrations and will cause the Na-hazard when applied for agricultural activities. Most samples of groups 1 and 2 were within the class II and I area of Doneen's plot during both periods and were therefore acceptable for agricultural activities in the investigation region.

DEVELOPMENT OF A GOOGLE EARTH ENGINE BASED APPLICATION TO MONITOR THE SEASONAL WATER SPREAD AREA OF RIVER GANGA

Abstract. The National River Ganga, home to the National aquatic animal, Gangetic dolphin along with species of critically endangered otters, gharial crocodile, turtles, waterbirds and numerous aquatic and semi aquatic life forms is of conservation importance to safeguard the biodiversity it harbors. Meanwhile, River Ganga is also the source of highly productive agricultural yield that satiates the nation’s food demands. The last few years have echoed demands for ‘e-flow’ regulations to be formalized and regularized to maintain healthy river conditions with adequate amount of water retained in the rivers while meeting the populations demand for water supply. Though e flow estimations are a complex science in itself, the simplest way is visualization. In this context, there needs to be a transparent mechanism to picturise and depict the ground conditions of the river stretches. Remote sensing provides ‘eyes in the sky’. The river receives water in the form of precipitation, snow melt and ground water recharge and the hydrological flux is evident in the surface water. Thus delineating the water spread area can provide a crude estimate of the water in the river. The Google Earth Engine platform provides a collection of satellite imageries, server side data processing and algorithms. The Landsat and Sentinel data catalogue offers good coverage of the river and its basin. Though sentinel data provides high ground resolution of 10m, Landsat provides multi temporal historic coverage at a good 30 m resolution, that works well for the main stem river. From the various available data processing methods, spectral decomposition technique of Modified Normalised Differential Water Index MNDWI was found to be most effective in delineating surface water. Data was filtered for the three major seasons of Pre monsoon, Monsoon and Post monsoon periods and MNDWI for the same was visualized. While Middle Ganga region through Uttar Pradesh shows seasonal flooding during the monsoon period, the Lower Ganga after the confluence of major tributaries of Son, Ghaghra, Gandak and Kosi flows in full bank width in the Post monsoon period. During the pre monsoon period many stretches of Ganga particularly the Upper middle stretch showed thin shallow channel and intermittent deep pools disconnected by dry sand beds. These regions result in disruption in the river flow and are priority sites to implement e flow regulations. Another key factor is the regulation of flow in the river from barrages. Sudden release of water can cause flooding resulting in disturbance to the life cycle of species that are tuned to the natural annual hydrological pulse of the river. This is because different aquatic species have different river width and depth requirements. Thus monitoring the seasonal variations in the water spread area helps to note the longitudinal and lateral connectivity of the river which is a prime characteristic for the health of a river. This study intended to create an application that offers to visualize the seasonal water spread in the Ganga river for the past years that can assist decision makers to monitor the river and make informed regulatory measures.

Hydrogeochemical characterization, multi-exposure deterministic and probabilistic health hazard evaluation in groundwater in parts of Northern India

This work attempts to identify the latent factors controlling the hydrogeochemistry and assess the groundwater quality and associated health risks in the intermontane valley of Nalagarh in the sub-Himalayan zone in northern India. Analytical results of 64 groundwater samples, 32 each collected during pre monsoon and post monsoon seasons show contrasting results for their major chemical constituents. During pre monsoon period, only 3% of the samples exceed their permissible limits for pH, EC, TH and Mg2+, while during post monsoon period, different parameters, such as TH, Mg2+ and K+, exceed their limits by 9, 16, and 3%, respectively. Gibbs and Piper diagrams reveal that groundwater chemistry is mainly controlled by water-sediment (alluvial) interaction. Geochemical signatures and saturation index (SI) further indicate that the weathering and dissolution of silicate, calcite and dolomite minerals mainly contributed to dominance of Ca2+, Mg2+ and HCO3 - ions in the aquifers. Monte Carlo simulation ascertains non-carcinogenic health risks due to NO3 − and F− in different sub-population groups. Deterministic and probabilistic estimates of these parameters via ingestion and dermal routes confirm their percentage hazard toxicity in the order infants (58.38; 39.62%) >children (15.62; 15.85%) >teens (6.25; 2.73%) >adults (6.25; 1.90%) for pre monsoon. The hazard toxicity for deterministic study implies only on infants (9.38%), whereas, the probabilistic simulation extracted the health risk on infants (6.57%), and children (0.58%) during post monsoon. Minor populations with their lower body weights are more vulnerable to groundwater pollution due to greater consumption of liquid diet. Therefore, treated groundwater is strongly recommended to mitigate health morbidities linked with the non-cancerous risks.

Seasonal Germ Cell Proliferation and Maturation Patterns in Indian Major Carp, Labeo Rohita (Hamilton, 1822) and Tilapia, Oreochromis Niloticus (Linnaeus, 1758)

The present work assessed the seasonal changes in germ cells (GC) and the maturation of rohu, Labeo rohita and tilapia, Oreochromis niloticus. Here, we showed two species representing two diverse types of spawning behavior, having two distinct GC proliferation and spawning patterns. During July, a single peak spawning season for rohu was recorded with the highest GSI (female: 19.5±1.29 and male 4.2±0.24), which is the peak monsoon time in Eastern India. However, two peak spawning seasons were marked in tilapia during the pre-monsoon (April) and post-monsoon (October) period with GSI values of male: 0.9±0.21, female: 3.9±1.32 and male: 1.1±0.3, female: 4.4±1.1 respectively. Gonadal histology in synchrony with GSI provides insights into the effects of various seasonal climate changes on the reproductive status of fish. Further, GC ultra-structure revealed various development stages in rohu and tilapia in different seasons using a scanning electron microscope. Here, comparative models were proposed for GC proliferation and maturation during different parts of the year in rohu and tilapia that may be used to plan breeding programs and hatchery management of these two species.