Loktak lake

News Summary
  • The model of a floating laboratory ties into a larger initiative by the Centre’s Department of Biotechnology (DBT) to monitor the health of aquatic systems in the northeast.
  • Last September, the DBT announced plans to have multiple floating boats cruising the 3,500-km Brahmaputra river and collecting water samples to track its health.
Need of Laboratory in Loktak lake
  • There have been rising urbanisation and land-use change over the years in and around the Loktak Lake.
  • The lake has become a dump-yard for the city’s municipal waste, ranging from plastic refuse to chemical runoff from farming.
  • The situation worsens during years of floods.
  • Though the Loktak Lake is yet to see worrying levels of pollution, early signs suggest that there is a need to be wary.
  • Preliminary characteristics of the water are first measured on the boat with more follow up analysis in the labs.
  • Biochemical oxygen demand, chemical oxygen demand, chloride test and nitrogen levels are measured on site.
  • Following are some of the major observations of the researchers:
    • Major Pollutant Instead of Carbon Dioxide, Nitrogen is a major pollutant in the lake.
    • pH of the lake: The pH of the lake, as per measurements so far, varies from 6.8-7.2 (ideally the pH of a healthy lake should be slightly below 7).
  • However, studies of ocean acidification have shown that even a 0.1 increase in pH can cause (harmful) decalcification.
Major Effects of pollution in Loktak lake
Calcium anomalies
  • There are signs of calcium anomalies in some of the mollusc and other aquatic life in the lake.
  • This is similar to the phenomenon of coral bleaching in oceans, where rising sea surface temperature cause organisms that live on corals to disengage, thereby killing the corals themselves.
Effect on Phumdis
  • The health of the lake also affects the Phumdis (the unique ‘floating islands’) of the Loktak lake.
  • These islands are made of a mix of vegetation and soil.
  • These coalesce to form a thick mat that, for centuries, have hosted huts and fishing settlements.
Loktak lake
  • It is the largest freshwater lake in North -East India and is famous for the phumdis (heterogeneous mass of vegetation, soil and organic matters at various stages of decomposition) floating over it.
  • Keibul Lamjao is an integral part of the lake and is the only floating national park in the world.
  • It is located near Moirang in Manipur.
  • The etymology of Loktak is Lok = “stream” and tak = “the end”.
  • The largest of all the phumdis covers an area of 40 km2 (15 sq mi) and is situated on the southeastern shore of the lake.
  • This ancient lake plays an important role in the economy of Manipur.
  • It serves as a source of water for hydropower generation, irrigation and drinking water supply.
  • The lake is also a source of livelihood for the rural fishermen who live in the surrounding areas and on phumdis and catch their fish by using various nets and indigenous traps.
  • Human activity has led to severe pressure on the lake ecosystem.
  • There are 55 rural and urban hamlets around the lake which have a population of about 100,000 people.
  • Considering the ecological status and its biodiversity values, the lake was initially designated as a wetland of international importance under the Ramsar Convention on 23 March 1990.
  • It was also listed under the Montreux Record on 16 June 1993.
  • Montreux Record is a record of Ramsar sites where changes in ecological character have occurred, are occurring or are likely to occur.
Previously asked related questions in UPSC prelims
Question 1:
Which of the following National Park is unique in being a swamp with floating vegetation that supports a rich biodiversity?
    1. Bhitarkanika National Park
    2. Keibul Lamjao National Park
    3. Keoladeo Ghana National Park
    4. Sultanpur National Park
Answer: b
Question 2:
Consider the following pairs:
  1. Nokrek Biosphere Reserve : Garo Hills
  2. Loktak Lake : Barail Range
  3. Namdapha National Park : Dafla Hills
Which of the above pairs is/are correctly matched?
    1. 1 only
    2. 2 and 3 only
    3. 1, 2 and 3
    4. None
Answer: a
Section : Environment & Ecology