Limnological Study on two High Altitude Himalayan Ponds, Badrinath, Uttarakhand

Present study has been done on two high altitude Himalayan ponds situated near the Badrinath temple, Uttarakhand (India). During the investigation physico-chemical and biological analysis (Phytoplankton & Zooplankton) were carried out at two selected sites one in each pond. A total 131species of phytoplankton and 51 species of zooplankton were encountered from both the ponds. Among phytoplankton, class Cyanophyceae was the most dominant whereas, among zooplankton Rotifera was the dominant class during the study period. Most of the phytoplankton and zooplankton species recorded from both the water bodies are indicators of higher trophic status. Physico-chemical features of ponds showed the nutrient rich water of both the ponds. Presence of various planktonic species and higher trophic status of both the ponds at high altitude showed the impact of high anthropogenic pressure as well as favourable environmental factors like temperature. Also, the impact of global warming on micro flora and fauna present in water bodies situated at high altitude has been discussed. Present study is preliminary work on these two ponds which will provide the baseline data for the further studies. Some further studies required to establish the importance of various environmental factors which are responsible for the growth of more planktonic species at higher altitudes.


Introduction
The aquatic habitats situated in mountains are some of the most sensitive indicators of environmental change [1]. Their high elevation leads to increased exposure to ultraviolet radiation as well as a shortened growing season that aggravates plankton populations due to both temperature and light limitations [2].
In order to assess the various limnological characteristics of the ponds, their physico-chemical and planktonological analysis was carried out. Study of plan ktonic population in relation to water chemistry provides the basic informat ion of entire ecology of the pond.
Plankton are considered indicators of the different trophic status of a water body because of their specific qualitative features and their capacity to reproduce in large number under environmental conditions that are favourable to them [3] and they used for pollution surveillance [4,[5][6].
Plan kton are impo rtant part o f aquat ic life and good ind icato r of ch anges in water qu ality because th ey are strongly affected by environmental conditions and responds quickly to changes in env iron mental quality. Apart fro m primary production, phytoplankton play an important role as food for herbivorous animals and act as biological indicators of water quality in pollution studies while, zooplankton occupy a vital role in the trophic structure of an aquatic ecosystem and p lay a key ro le in the energy transfer. Hence qualitative and quantitative assessments of plankton are of great importance.
The ponds are infested with macrophytic vegetation. The ponds receive glacial melt water besides runoff fro m the surrounding areas. These ponds are subject to high anthropogenic pressure by both local and tourists. The aim of this paper is to determine the overall role of anthropogenic pressure on these glacial fed ponds.

Material and Methods
Physico-chemical analysis of water samples was carried out following the standard methods as given in [7][8]. Water samples were direct ly collected fro m the surface of the pond for physico-chemical analysis and for the qualitative enumeration of planktonic population surface water samples were collected fro m d ifferent locations mainly fro m central part of the ponds. Plankton samples were filtered with the help of plankton net made of bolting silk of mesh size 20µ and concentrated samples were preserved with 1ml of Lugol's solution simultaneously in 100ml vials. The concentrated samples were examined under the inverted microscope and identification of p lankton was done using the following taxono mic references [9][10][11][12][13][14][15][16][17][18][19][20][21].
The inter-relat ionships between the different planktonic communit ies present in both the ponds were calculated by Jaccard's similarity index [22] Where, CCi = Jaccard coefficient of co mmunity similarity S 1 = Nu mber of species present in community 1 S 2 = Nu mber of species present in community 2 C = Nu mber of species common in both the communit ies

Study Area
Both the selected ponds are situated at high altitude Himalayan region near Indo-Tibet boarder in Chamo li district of Uttarakhand. The place is popularly known as Badrinath (an important holly place of India). The Badrinath town is situated in the cold climatic condition of Garhwal hills, on the banks of the Alaknanda River at an elevation of 415 meters. The town lies between the Nar and Narayana mountain ranges and in the shadow of Nilkantha peak, most of the period it was covered by snow. The location and important features of both the ponds have been mentioned in Table 1 and Figure 1.

Results and Discussion
The physico-chemical environ ment mainly controls the biological d iversity [23,[24][25]. Physico-chemical features of the ponds are given in table 2 and planktonic flora and fauna are enlisted in tables 3 and 4 respectively.
During the present study air temperature of 22 º C and water temperature of 18 º C was observed at both the sampling sites. This optimu m water temperature in both the ponds supports high biological population. The water colour of both the ponds was observed to be dark green due to the good growth of various algal species. The low transparency values of 36 cm and 40 cm was recorded in pond 1 and pond 2 respectively due to the dominance of green algae (table 2). Low t ransparency also indicates the eutrophic nature of pond waters [26][27]. The low transparency value in some of the high altitude Kashmir Himalayan water bodies has been attributed to the incoming silt fro m the catch ment [28][29]. Alkaline pH of 8.1 units (pond 1) and 7.9 un its (pond 2) indicating productive nature of pond waters. Free CO 2 recorded a value of 4.6 mg/l to 5.2 mg/ l in pond 1 and pond 2 respectively. Phenolphthalein alkalinity was absent in both the ponds. Total alkalinity of 116 mg/l and 120 mg/ l was recorded for pond 1 and pond 2 respectively. Water bodies having total alkalinity above 50 mg/ l can be considered productive in nature [30] (table 2). TDS value of 470 ppm and 510 ppm fo r pond 1 and 2 respectively, indicate regular interference fro m respective catchment area. The high specific conductivity values of 660 µS/cm and 650 µS/cm signify high amount of anthropogenic pressure .
Water bodies having conductivity values greater than 500 μS/cm are considered as eutrophic in nature [32]. Chloride content of 212 mg/l and 232 mg/l respectively again signify the impact of anthropogenic pressure (table 2). A value of 8.4 mg/l and 8.8 mg/ l of Dissolved oxygen in surface waters of both the ponds suggested good growth of autotrophs.    Total hardness values of 130 mg/l and 168 mg/ l was observed in pond 1 and pond 2 respectively. On the basis of hardness values water of both the ponds is of hard water type. Calciu m hardness of 44mg/l and 56 mg/ l and Magnesium contents 20.8 mg/l and 27 mg/l recorded for pond 1 and pond 2 respectively suggest that both the ponds are Calciu m rich. The water bodies rich in Calciu m and Magnesium ions have thick population of algae [33]. In the present study 0.056 mg/ l (pond 1) and 0.049 mg/ l (pond 2) of Orthophosphate; and 0.38 mg/ l (pond 1) and 0.43 mg/l (pond 2) of Nit rate values were recorded (table 2). These values of Orthophosphate and Nitrate indicated the healthy mesotrophic status of pond waters [34].
Besides physico-chemical features, observations on changes in planktonic diversity are generally considered a necessity in evaluating the impact of environ mental changes on an aquatic system, especially phytoplankton that show changes with the changes in the environmental factors [35].
Plankton are very significant tool for observing the continuous changes in the environ mental conditions at higher altitudes. They are the most sensitive micro organisms that respond quickly to any change in the ecological condition. Hence, they can be used as ecological indicators. They are able to grow at higher altitudes as compared to other macro flora and fauna.
During the present period of investigation, a total of 118 and 116 phytoplankton species have been recorded from pond 1 and pond 2 respectively (table 3).
In the pond 2, Chlorophyceae contributed 44 species (38%) of the total phytoplankton population followed by Bacillariophyceae 34 species (29%); Cyanophyceae 29 species (25%) and Euglenophyceae 7 species (6%) respectively. Class Dinophyceae and Xanthophyceae contributed 1specie (1%) each towards the total phytoplankton respectively (table 5 & figure 2)  (table 5). During the investigation it was observed that both the ponds were infested with macrophytic vegetation besides algal bloo ms in the surface waters. Maximu m p lanktonic d iversity was observed nearby macrophytic vegetation in the Himalayan water bodies [36]. The species recorded from the Badrinath ponds reflected higher anthropogenic impact supporting good growth of planktonic flora and fauna.
Generally, Bacillariophyceae are found as do minant group in temperate water bodies because diatoms are able to grow under the conditions of weak light and low temperature which are less suitable for the other phytoplankton groups [35][36][37]. But, during the present investigation Chlorophyceae was recorded as do minant among all the phytoplankton groups on account of relatively high temperature and nutrient condition.
Among Jaccard's similarity index showed that the species belongs to Dinophyceae and Xanthophyceae are 100% similar at both the sites while the species belonged to Bacillariophyceae showed 89% similarity fo llo wed by Chlorophyceae 84%, Cyanophyceae 78% and Euglenophyceae 67% between both the ponds. Among zooplankton Copepoda showed 100% similarity followed by 82% of Protozoa and 67% each of Rotifera, Cladocera and Ostracoda between both the ponds (table 6). The overall qualitative class wise species contribution of phytoplankton and zooplankton of both ponds have been shown in figure 4. The maximu m contribution was made by Chlorophyceae and min imu m by Dinophyceae among phytoplankton while Rotifera contributed maximu m and Ostracoda min imu m among zooplankton population.
The presence of more d iversity of p lanktonic flora and fauna at high altitudes showed the favourable environ mental conditions for their growth. Both the ponds are situated at base of high mountains and during the high precipitation the nutrient rich runoff settled in the ponds and increased the trophic levels and creates the favourable conditions for the growth of p lanktonic population. The changes in physico-chemical parameters led to increase in d iversity of planktonic flora and fauna in h igh alt itude Himalayan water bodies [57]. Besides the anthropogenic pressure, impact of global climate changes also supports the microscopic life to grow in aquatic systems situated at higher altitude.

Conclusions
The biological as well as physico-chemical result of both the ponds indicate the significant role of anthropogenic activity for growth of p lanktonic diversity and their distribution. Generally, water bodies situated at higher altitudes are oligotrophic and do not support the diverse groups of planktonic flora and fauna. But species recorded during present investigation are the classic indicators of a shift fro m oligotrophic (Low productivity) conditions to eutrophic (High productivity) conditions of both the ponds. However, the variation in some planktonic species in these ponds suggest the need of fu rther studies to establish the importance of various environmental factors, their seasonal fluctuations that produce a collective effect on the nature and distribution of freshwater microscopic life at higher altitudes. Present study is first hand work on these two small ponds which will provide the baseline data for the further studies.