An
attempt has been made to study the water quality in respect of physico-chemical
and microbiological characteristics and role of Phumdis in the Loktak Lake.
Surface water samples were collected on monthly basis from 15 stations
representing 5 zones, namely northern, western, eastern, middle and southern.
Water quality was poor in the northern and southern zones of the lake as they
have low dissolved oxygen, low pH, high CO2 and high BOD. Water
quality was healthier at the open water area than the Phumdi area. The total
nitrogen content of the macrophyte species of Phumdis was observed as follows: Salvinia
natans (1.8%) > Zizania latifolia
(1.6%) > Capillipedium sp. (1.3) > Brachiaria
mutica (1.2%) > Cyperus brevifolius
(1.2%) > Echinochloa stagnina
(1.0%) > Phragmites karka (1.0%)
> Hedychium coranarium (0.94%). The
present findings suggest that Phumdis are efficient in absorbing nutrients from
the lake water. However, they are deteriorating water quality as they reduce the
light penetration and accumulate organic matter in the lake ecosystem. Main
reasons for rapid proliferation of the Phumdis are identified as heavy inflow of
nutrients in the lake, transplantation of Phumdis for Phum fishing by the
fisherman, construction of Ithai barrage for power generation and the wind
action. Strategies for controlling proliferation of Phumdis and improvement of
water quality of the lake are discussed.
Address:
Lake Monitoring Laboratory, Loktak Development Authority
Ningthoukhong 795 126, Manipur, India
Phone: 0385-410630 Fax: 0385-410631
E-mail: Idawisa@dte.vsnl.net.in
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