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Author Khadka, Udhab Raj ♦ Ramanathan, AL.
Source SpringerLink
Content type Text
Publisher Springer Berlin Heidelberg
File Format PDF
Copyright Year ©2012
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Earth sciences
Subject Keyword Seasonal variation ♦ Major ion ♦ Begnas Lake ♦ Pokhara Valley ♦ Nepal ♦ Earth Sciences
Abstract The Begnas Lake in the Pokhara Valley is one of the threatened habitats in Nepal. The major ion chemistry explains the status of most of the inorganic nutrients and their possible sources. However, the earlier studies mostly cover limnological investigations, and phytoplankton and zooplankton diversity. Thus, the present study has been conducted to investigate the geochemical processes and to examine the seasonal variation of chemical composition within Begnas Lake. The results showed that SO 4 2- , PO 4 3- , and NO 3 - increased compared with the previous values. The domination of Ca$^{2+}$, Mg$^{2+}$, and HCO 3 - explains the influence of carbonate weathering on the major ion concentration. In general, pH and dissolved oxygen decreased with the depth of water-column, while electric conductivity, total dissolved solids, HCO 3 - , Cl$^{-}$, H$_{4}$SiO$_{4}$, K$^{+}$, Mg$^{2+}$, Ca$^{2+}$, Mn$^{2+}$, and Fe increased. Among the cations, the predominance of Ca$^{2+}$ and Mg$^{2+}$ as characterized by high (>0.6) (Ca$^{2+}$ + Mg$^{2+}$)/(Tz$^{+}$) and (>0.8) (Ca$^{2+}$ + Mg$^{2+}$)/(Na$^{+}$ + K$^{+}$) equivalent ratios, also suggests prevalence of carbonate weathering. The low value of (Na$^{+}$ + K$^{+}$)/Tz$^{+}$ ratio shows deficiency of Na$^{+}$ and K$^{+}$, suggesting low contribution of cations via aluminosilicate weathering. The C-ratio suggests a proton source derived both from oxidation of sulfide and dissolution and dissociation of atmospheric CO$_{2}$ during different seasons. Though the major hydro-chemical parameters are within permissible limit, the increase in trophic state of the lake suggests that inherent biogeochemical processes make the limiting nutrients available, rendering eutrophic effect. Therefore, further comprehensive studies incorporating sediment–water interaction ought to be carried out to explain the ongoing phenomena and curb the eutrophication process in the lake.
ISSN 18667511
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2012-09-26
Publisher Place Berlin, Heidelberg
e-ISSN 18667538
Journal Arabian Journal of Geosciences
Volume Number 6
Issue Number 11
Page Count 16
Starting Page 4191
Ending Page 4206

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Source: SpringerLink