Physical and Chemical Limnology of 34 Lentic Waterbodies along a Tropical-to-Alpine Altitudinal Gradient in Nepal

Abstract

Physical and chemical factors were studied in 34 lentic waterbodies distributed along a steep altitudinal gradient ranging from tropical (77 m) to high alpine (up to 4,980 m) environments in Nepal. Bicarbonate and calcium were dominant among anions and cations, respectively, reflecting a strong influence of carbonate weathering and watershed area, rather than altitudinal climate. The relative patterns of dominant ions were similar among lakes in all altitudinal regions, although total concentrations increased with decreasing altitude. Total suspended solids were relatively high in the study lakes, as is also typical of rivers in the Ganges watershed. Suspended solids had a greater influence on water transparency than did algal biomass in the study lakes. In general, high-altitude waterbodies were oligotrophic, while those at low altitude were eutrophic. The productivity of high-altitude study lakes appeared to be limited by both available phosphorus and nitrogen, while lowland ones were nitrogen-limited.

Physico-chemical Characterization of Gosainkunda Lake

“…The data on pH of water are given in table 4. The average value of pH 7 was also reported by (Lacoul andFreedman 2005 &Shimkhada 2006). However, the alkaline pH has been reported in the Gokyo lake of Sagarmatha National Park by (Gurung et al 2011, Lacoul & Freedman, 2005and Tartari et al 1998b).…”

“…Similar trend of conductivity was reported in a previous study of the Gosainkunda lake (Shimkhada, 2006). Lowest values were found in highly (Lacoul and Freedman, 2005). High altitude lakes generally possess low conductivity due to low weathering rates (Catalan et al, 2006).…”

“…The first high altitude limnological study in Nepal was carried out by Löffler (1969), who provided the data on morphometry, temperature, chemistry and biology of 24 lakes at altitudes between 4500 and 5600 m in the Mount Everest region (Khumbu Valley). Although there have been several studies on high mountain lakes, very few studies focused on water chemistry (Loffler 1969, Aizaki et al 1987, Tartari et al 1998a & b, Lacoul & Freedman 2005. Studies in other lakes include Okino and Satosh 1986, Aizaki et al 1987, Liu & Sharma 1988, Tartari et al 1998.…”

“…These studies are based on water chemistry (Gosso et al 1993, and Lake Biota (Manca et al 1994, Manca & Mura 1997. After several years Lacoul and Freedman (2005) made the contribution, especially in the physical and chemical limnology of lentic water bodies of Nepal in different altitudinal gradient ranging from tropical to lowland (77 m) and high altitude alpine region (up to 4980 m).…”

Scientific Discourse of Lakes in Nepal

“…The research studies carried out in the lakes and ponds of Nepal have covered various aspects of limnology (Ferro 1978, Okino & Satoh 1986, Aizaki et al 1987, Nakanishi et al 1988, Jones et al 1989, McEachern 1994, Tartari et al 1998, Rai 2000, Lacoul & Freedman 2005, plankton, macrophytes, macroinvertebrates (Manca et al 1998, Bhatt et al 1999, Dhakal 2007, Lacoul & Freedman 2006, environmental change (Lami et al 1998, Sharma et al 2009, diatoms (Hickel 1973a, b;Lohman et al 1988, Jüttner et al 1996, Rothfritz et al 1997, Cantonati et al 2001, Jüttner et al 2003, 2004, Dahal & Jüttner 2004, Simkhada 2007. Studies on the composition of vegetation surrounding the lakes have been carried out by Baral (1992), Bhattarai (1997), , Rai (1998), , Siwakoti (2006) in order to understand the habitat type.…”