E.M. MANOJ
KALPETTA
Illegal dumping of solid waste, coupled with the algal bloom in many parts of the Kabani river, a major tributary of Cauvery river, is posing a serious threat to the aquatic ecosystem of the water body.
The wild growth of algae on the river, especially in the Panamaram area, is a major concern of the public and environmental activists since many a drinking water project is located on the banks of the river.
A recent study, organised by a team of researchers led by V.F. Sanu, Assistant Professor, Department of Zoology, Mary Matha Arts and Science College, Mananthavady, revealed that the phenomenon called algal bloom occurs when large quantities of organic waste and fertilizers, used in the agriculture sector, enter water bodies.
Algae are microorganisms that grow naturally in water bodies, but they have the characteristics of both plants and animals. However, they multiply uncontrollably and change the colour, smell, and taste of the water when they are exposed to huge quantities of organic matter and chemical fertilizers, Dr. Sanu said.
“The invasive growth of blue-green algae is harmful to humans, aquatic life, and livestock, but such an invasive growth is not visible here,” Dr. Sanu said. The proliferation of the green algae ‘Dictyosphaeriyum’ species is a major reason for the colour change in many parts of the water body, he said. Another species of green algae ‘Chlorococcum’, a land origin species, is also multiplying in the river.
The oxygen level in the water has decreased significantly due to the growth of the green algae, he said. The dissolved oxygen observed in the water body is below 3.5 milligrams per litre. For a healthy aquatic ecosystem, it should be at least 4 to 5 milligrams per litre. Further proliferation of the bloom may lead to a condition known as ‘anoxia’, where the availability of dissolved oxygen will be nil or very little in freshwater systems. Such a condition would lead to the mass death of aquatic organisms.
Though there is no immediate issue of concern to the public at present, the current condition of the river is deplorable due to the presence of a large amount of waste, Dr. Sanu said. If there is a noticeable discolouration of the river as well as odours or sludge, the public should refrain from using the water until it has receded and the water level has returned to normal.
One of the reasons for the present condition of the river was the large amount of dry soil that reached the river during the low rainfall. It is a warning given by Nature concerning the deeds of pollution made by man, he said.
