Phycological studies in himalayan dal lake ecosystem: seasonal composition and role of physico-chemical parameters

A research study conducted on the Himalayan Dal Lake has shown that this lentic ecosystem is rich in microalgal flora. During the study, a total of 21 algal genera comprising of 39 species, 6 varieties were identified during the four seasons at six different sites of Dal Lake. Cyanophyceae with 16 genera, 29 species and 2 varieties were the largest class recorded, showed their peak abundance during summer and autumn seasons with the maximum standing crop at DLS-VI. Euglenophyceae includes 4 genera, 9 species and 4 varieties and show their appreciable numbers at DLS-VI during the autumn season. In case of Rhodophyceae only one genera and one species namely Glaucosphaera vacuolata was reported during the autumn season at DLS-IV and is a new record reported to the phycological studies of India. Blue green microalgae Microcystis aeruginosa was found abundantly at DLS-II indicating alarming toxic nature of water as this alga contains microcystins of neuro and hepato toxins. The water chemistry revealed the lake is undergoing tremendous cultural eutrophication, DLS-VI was the most polluted site of the lake with the highest chemical nutrient load observed in summer season exhibiting highest value of 3.95 ppm of nitrate and 1.80 ppm of phosphate.