Two lakes in the lower Siwalik Himalayas, five in the Kashmir valley and two situated in the high mountains of the Kashmir Himalayas were investigated for their physico-chemical and biological features. The lakes, differing significantly in their morphology and in thermal behaviour, rank from the subtropical monomictic to the dimictic type. The lakes at high altitudes (> 3000 m) have very low electric conductivity which increases with the decrease in altitude. The most dominant ions in water are calcium and bicarbonate. The macrophytic vegetation of the lakes does not show any definite relationship either with altitude or with physico-chemical milieu. In the lakes with low fertility the phytoplankton is dominated by diatoms and Chlorophyceae but in eutrophic lakes Cyanophyceae predominate. The zooplankton population of the lakes is mainly comprised of rotifera. On the basis of general limnological features and the rates of phytoplankton production most of the lakes may be categorized either as eutrophic or in the process of rapid evolution. Only one lake is oligotrophic.

Present study has been done on two high altitude Himalayan ponds situated near the Badrinath temp le, Uttarakhand (India). During the investigation physico-chemical and bio logical 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 fro m 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 wh ich are responsible for the growth of more p lanktonic species at higher altitudes.

Phosphorus (P) release rates from bottom sediments are high (20.6 mg/m(2)/day) in Dal Lake (India), a polymictic hyper-eutrophic lake. These gross release rates occur over a period of 72 days during summer only. Likewise, a net internal load of 11.3 tons was obtained from mass balance estimates. Significant proportion i.e. approximately 80% of 287.3 tons/yr of nitrate nitrogen (NO(3)-N) load is either eliminated by denitrification or gets entrapped for a short period in high macrophyte biomass of 3.2 kg/m(2) f.w., which eventually get decomposed and nitrogen (N) is released back. These processes result in low lake water NO(3)-N concentrations which potentially influence sediment phosphorus (P) release. Especially, nitrate nitrogen (NO(3)-N) <500 microg/L in the lake waters were associated with high P concentrations. Phosphorus was also observed to increase significantly in relation to temperature and pH, and it seems likely that release of phosphorus and ammonical nitrogen (NH(4)-N) depend on decomposition of rich reserves of organic matter (893 tons d.w. in superficial 10-cm bottom sediment layer). Lake P concentrations were significantly predicted by a multivariate regression model developed for the lake. This study describes significance of various lake water variables in relation to P-release from bottom sediments.

Phytoplankton species composition and seasonal changes were investigated in the Bhoj wetland Bhopal. Taxonomic composition, diversity, and abundance of phytoplankton were studied at nine stations from March 2008 to February 2010, in relation to various physico-chemical factors. Total phytoplankton species composition in the Bhoj wetland was represented by 360 species. Among phytoplankton, diversity belonged to seven groups. Chlorophyceae was the dominant group (48%) followed by Bacillariophyceae (26%), Cyanophyceae (15%), and Euglenophyceae (9%), while Pyrophyceae, Chrysophyceae, and Xanthophyceae contributed 2% of the population. Phytoplankton on the basis of seasonal studies recorded 1651 units l(-1) during summer season which was contributed mainly by Chlorophyceae (39.3%), with Spirogyra sp. (14.2%) and Closteriopsis sp. (9.1%) contributing maximum to the total group in the first year, while during the second year of summer period, a total of 2095 units l(-1) was recorded which was contributed mainly by group Pyrophyceae (51%) with the main dominant species represented by Ceratium hirundinella (98.46%). The highest Shannon-Wiener diversity index (H') value (4.27) was recorded. Simpson values are approaching 1, signifying that sites have high relative diversity due to its supporting surrounding components. The trend of variation in evenness values was more or less the same as Shannon diversity index. Thus, the highest diversity indices recoded at all the stations in the present study justify the diverse nature of species inhabiting the different ecological niches in the ecosystem. The very high phosphate and nitrate concentrations in the wetland are indicators of pollution which may be due to the discharge of agricultural and sewage wastes enriched with nutrients as well as the human activities there. Our recommendation is to avoid as far as possible the discharge of sewage and agriculture wastes into the Bhoj wetland. The effects of various physicochemical water quality parameters on the seasonal distribution and succession of the above mentioned phytoplankton population as well as the interaction and eutrophication are discussed.

Extensive watershed development has resulted in excessive total phosphorus (TP) loads to Dal Lake, a high altitude Himalayan lake known for its tourism and economic potential. External and internal TP loads of 5 and ~1 g m -2 yr -1 , respectively, were estimated for the lake. These loading rates are high in relation to the lake's critical tolerance range of 0.1-0.2 g m -2 yr -1 , and, over time, have resulted in severe eutrophication in view of extremely high macrophyte biomass (average = 3.2 kg m -2 -fresh weight) and bottom sediment enrichment (79 tons of TP reserves which contribute 88% of the annual TP budget). This study emphasizes the importance of external TP load reduction as a primary management objective to counteract internal TP loading and P storage within bottom sediments resulting from historic anthropogenic loads. IntroductionTotal phosphorus (TP) loading resulting from watershed development has long been recognized as an important factor affecting lake trophic status (VOLLENWEIDER, 1968;DILLON and KIRCHNER, 1975;CANFIELD, 1983). The effect of excessive TP loading to shallow lakes is especially pronounced as it can lead to high macrophyte production, which on senescence contributes significant amounts of nutrients to both sediments and overlying waters (NICHOLS and KEENEY, 1973;CARPENTER, 1980;CARIGNAN and KALFF, 1982). Lake enrichment resulting from the mobilization of TP from watersheds is often, over time, followed by internal TP loading from bottom sediments (AHLGREN et al., 1988;NÜRNBERG, 1984;NÜRNBERG and LAZERTE 2004;FRENCH and PETTICREW, 2007).Earlier studies have described TP loading to Dal Lake, a high-altitude Himalayan (India) lake (e.g. ENEX, 1978; KAUL, 1989, 1990;WANGANEO and WANGANEO, 1994). KAUL (1989, 1990) estimated a TP loading rate to the lake of 7.5 g m -2 yr -1 and reported high transparency (0.7-5.2 m Secchi depth). VASS and ZUTSHI (1983) reported low phytoplankton primary productivity (115 g C m -2 yr -1 ) in the lake, similarly, WANGA-NEO (1984) described Dal as low productive lake in terms of phytoplankton productivity (219 g C m -2 yr -1 ), a finding recently confirmed by SOLIM and WANGANEO (2007). It is believed that Dal Lake maintains high transparency and low phytoplankton biomass, despite having high TP loading rates, due to biogenic calcite precipitation induced by photosynthesis in dense macrophyte stands KAUL, 1989, 1990; SOLIM and WANGANEO, . While phytoplankton biomass in Dal Lake is generally low, unabated TP loading and seasonal macrophyte decomposition has resulted in benthic eutrophication such that average macrophyte biomass in the lake is about 3.2 kg m -2 fresh weight (f.w.) (SOLIM and WANGANEO, 2007).Several factors have contributed to the eutrophication of Dal Lake, including: (1) deforestation and urbanization of various sub-catchments, (2) entry of municipal sewage, (3) residential and commercial developments in riparian areas, (4) diffuse runoff from denuded and urbanized residential areas, and (5) recycling of high autochthonous buildup of...