Department Of Geology

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    Evaluation of seasonal dynamics of the surface water hydrochemistry using multivariate statistical techniques and aquatic macrophyte productivity in a mountainous lake, Northeast India
    (Springer Science and Business Media Deutschland GmbH, 2022-05-13T00:00:00) Singh, Konthoujam Khelchandra; Singh, Kshetrimayum Krishnakanta; Usha, Khuraijam; Das, Subhasish; Singh, Salam Shantikumar
    The present work elucidates the effective application of multivariate statistics in understanding the probable relations between surface water hydrochemistry and aquatic macrophyte productivity and their underlying seasonal dynamics in a remote mountainous lake of northeast India. The result of hierarchical cluster analysis revealed three distinct clusters corresponding to the pre-monsoon (35.42%), post-monsoon (52.08%), and monsoon (12.50%) seasons. The factor analysis yielded three principal components suggesting the sediment flux, farming discharge, domestic waste, bacterial oxidation of sulfur compounds, and dissolution of plant matters associated with dissolved feldspar minerals as the influential factors. The lake hydrochemistry also varied significantly, both spatially and temporally implying geogenic weathering processes from rock-soil-water interactions. Overall, sixteen aquatic macrophytes were identified, and their monthly and daily net primary productivity varied considerably in different seasons. Regression analysis highlighted the effect of temperature, total dissolved solids, electrical conductivity, and turbidity on the seasonal fluctuations in macrophyte productivity. Overall, the study provides insights into seasonal variation in the lake water chemistry and highlights the role of statistical tools in understanding the fragile aquatic ecosystems over cost-, labor-, and time-intensive inventory studies. � 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
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    Evaluation of spatial characteristics of groundwater hydrochemical constituents across different geomorphic units of the�Imphal Valley in Northeast India
    (Springer Science and Business Media Deutschland GmbH, 2021-07-05T00:00:00) Singh, Laishram Premananda; Kshetrimayum, K.S.
    The assessment of hydrochemical constituents across different geomorphic units of the Imphal valley of Northeastern India has been carried out. Geomorphologically, the valley is broadly demarcated as the�residual hill, piedmont zone, alluvial plain, and flood plain. The Scholler diagram and Box and Whisker plots suggest that the distribution of ions is characterized by dispersed concentrations owing to variation in the�lithologies in the�geomorphic units. The pH value ranges from 6.90 to 7.21 with a mean value of 7.04, indicating neutral water in the residual hill. In the piedmont zone, it ranges from slightly acidic (4.83) to neutral (7.40) with a mean of 6.58. In the alluvial and flood plains, the values range from 6.15 to 7.44, with a mean of 6.84 and 6.07 to 7.14 with an average of 6.73, respectively suggesting neutral water. TDS range shows slight reduction in the�alluvial plain and flood plain owing to effluent water supply from the�rivers whereas, oxidation�reduction potential (Eh) ranges from 8 to ?�19�mV with highest in the�residual hill, indicating reducing condition. Higher Ca2+ and Mg2+ in the�residual hill and piedmont zone are associated with the�cation-exchange process. Na+ and HCO3? are highest in the�alluvial and flood plains due to weathering of sodium-rich montmorillonite or dissolution of halite or nahcolite (NaHCO3) minerals from clay. The scatter plots indicate that the hydrogeochemical processes throughout the geomorphic units are mainly controlled by the�ion exchange, silicate weathering, carbonate weathering, and evaporate dissolution. The hydrochemical facies are characterized by (i) Na�K�Cl, (ii) Ca�Cl, and (iii) Na�K�Ca�Mg�Cl�SO4�HCO3. The residual hill and piedmont zones are dominated by Ca�Cl facies, implying recent meteoric water coupled with halite riched source of water. The alluvial plain is dominated by Na�K�Cl facies, while the flood plain is characterized by Na�K�Ca�Mg�Cl�SO4�HCO3 facies, suggesting the�mixed type resulted from the ion exchange process. These facies suggest that the groundwater belongs to the initial and intermediate stages of chemical evolution indicating fresh quality. � 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.