Three days a week, four women in white lab-coats ferry the Loktak Lake in a custom-motorboat, scooping flaskfuls of water for analysis. Via their instruments they record changes in the temperature, acidity, conductivity and dissolved-oxygen in the 300-sq km lake.
Rising urbanisation and land-use change over the years has seen the Loktak Lake, the largest in the northeast, become a dump-yard for the city’s municipal waste, ranging from plastic refuse to chemical runoff from farming. This worsens during years of floods.
Rajkumari Supriya, a researcher at the Institute of Bioresources and Sustainable Development (IBSD), said that she and her colleagues, all in their 20s, as part of their routine, first measure preliminary characteristic of the water on the boat and then follow it up with more analysis at their lab.
“Over there, we calculate the biochemical oxygen demand, chemical oxygen demand, chloride test and nitrogen levels,” she said while demonstrating some of the machinery.
Though the Loktak Lake is yet to see worrying levels of pollution, early signs suggest that there’s need to be wary. “Everyone talks about carbon dioxide levels, but nitrogen pollution is a major, silent threat,” said Dinabandhu Sahoo, director, IBSID and project head, “Already 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.
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.
The health of the lake also affects the Phumdis, or the unique ‘floating islands’, of the Loktak lake. These islands, made of a mix of vegetation and soil, coalesce to form a thick mat that, for centuries, has hosted huts and fishing settlements. “We are also studying the nutrient uptake of these vegetation and monitoring their health,” said Sahoo, a botanist at the Delhi University and now deputed by the Department of Biotechnology to coordinate research at the IBSD.
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,” Sahoo added, “We shouldn’t wait for the lake to hit the intensive care unit before thinking of ways to save it.”
