IS’HAQ BHAT
Unusual change in surface water color of famed Dal Lake might be attractive to the landscape photographers to compose breathtaking frames particularly during gold light hours. Perhaps green, red and brown alga fascinate photographer, as unusual combination of these colors gives one liberty to play with the camera sensors to create wonders.
But nowadays these breathtaking colorful pictures of Dal Lake are beyond the imagination of environmentalists’ as they easily understand the quotation and consequences of this changing color pattern, pleading to save the dying lake.
Brown alga patch scattered across the lake are beyond the beauty, they (Environmentalists’) call it eutrophication. It is harmful algal bloom, a major environmental problem like obesity in humans.
These blooms are usually scummy or look like paint on the surface of the water, the red, brown or green algae and cyanobacteria are examples of harmful algal blooms that can have severe impacts on human health as well as aquatic ecosystems.
Some algal blooms are the result of an excess of nutrients (particularly phosphorus and nitrogen) into waters and higher concentrations of these nutrients in water cause increased growth of algae and green plants.
The brown colour of these algae results from the dominance of the xanthophyll pigment fucoxanthin, which masks the other pigments, Chlorophyll a and c, beta-carotene and other xanthophylls.
The most common nutrients causing eutrophication are nitrogen and phosphorus. The main source of nitrogen pollutants is run-off from agricultural land, whereas most phosphorus pollution comes from households and industry, including phosphorus-based agents.
Oxygen depletion, or hypoxia, is a common effect of eutrophication in water. The direct effects of hypoxia include fish kills, especially the death of fish that need high levels of dissolved oxygen. In extreme cases hypoxic conditions promote the growth of bacteria that produce toxins deadly to birds and animals.
Human activities also contribute excess amounts of nitrogen and phosphorus into water. Therefore, human causes of eutrophication include the use of agricultural fertilizers. Other causes include sewage and aquaculture, which is the growing or farming of fish and aquatic plants.
One of the negative impacts of eutrophication and increased algal growth is a loss of available oxygen, known as anoxia. These anoxic conditions can kill fish and other aquatic organisms such as amphibians. Eutrophication reduces the clarity of water and underwater light.
Eutrophic lakes are very fertile from all the nutrients carried into the lake from the surrounding landscape. These nutrients (Phosphorus and Nitrogen) support high densities of algae, fish and other aquatic organisms. This decomposition uses up oxygen, causing the bottom of the lake to become anoxic in the summer.
Lake Eutrophication is an economic, recreational, and aesthetic problem that affects every lake. Eutrophication is the natural process of lake aging, and progresses irrespective of man's activities. Pollution, however, can hasten the natural rate of aging and shorten the life expectancy of a body of water.
The best, easiest, and most efficient way to prevent eutrophication is by preventing excess nutrients from reaching water bodies. This can be done in a number of ways, the simplest of which is just being aware of the chemicals, fertilizers and other pollutants being drained into the water body.
In a healthy lake the nutrients occur in small amounts. But in large quantities, they can cause a major water pollution problem. Too many nutrients stimulate the rapid growth of plants and algae, clogging waterways and sometimes creating blooms of toxic algae.
Nitrates are necessary nutrients for algae and phytoplankton growth. Discharge of nitrates to surface water bodies greatly accelerates the natural process of eutrophication, causing algal blooms which ultimately lead to depleted oxygen levels and generally poor water quality.
Eutrophication is a serious environmental problem since it results in a deterioration of water quality and is one of the major impediments to achieving the quality objectives established by the Water Framework Directive (2000/60/EC) at the European level.
Continuous disposal of waste has severely depleted the Dal Lake’s water quality. Oxygen density in the water has come down from 10.2 mg/litre to 6.8 mg/litre.
Dissolved solids such as phosphorus and nitrogen have increased, taking their levels from 30.2 mg/litre to 200 mg/litre. In certain parts of the lake, algae growth has made the water green, brown or red.
A natural lake, Dal has existed for centuries and flourished during the Mughal rule, especially during the reign of Jahangir who constructed gardens that provided best views of the lake. The views of Dal, over the last 30 years reveal the toll pollution is taking. Though Central and State authorities have invested to restore Lake’s glory, pollution continues to be a constant threat to its existence.
The Dal Lake has been damaged extensively due to the part played by the local population. Nearly 7,500 people live in the houseboats that populate the Dal’s surface. More than 50,000 people populate the small islands nearby and household waste from them is inevitably dumped into the Dal.
Over Rs 1,100 crore has been spent on improving the lake’s state since the 1980s. But as has been the case with several river and lake conservation projects expenditure did not necessarily translate to results.
The Dal Development Project was launched by the Central government in 1986 and constituted of a team from the Ministry of Urban Development to look into the Dal pollution matter, but could do little to stem further pollution of the lake.
It is not too late yet to take serious measure to save the lake from dying a slow death, when it is possible high in the mountains of Guatemala where people can’t afford to put food on the table.
Guatemala is one of the poorest countries in the Western hemisphere. It is also home to the deepest, and arguably prettiest, lake in Central America: Lake Atitlán. However, the lake’s water quality has been rapidly declining. The lake’s traditionally clear blue waters are becoming a darker shade of green as the lake becomes more eutrophic.
“Education is key,” said Sudeep Chandra, an associate professor of natural resources and environmental science with the University of Nevada, Reno, said in a newspaper interview “People value this amazing resource. They know how important it is. They just don’t know how to conserve it.”
With a grant from the U.S. Agency for International Development, Chandra is training Guatemalan students and citizens to monitor the water quality of Lake Atitlán. Working with scientists from both the U.S. and Guatemala, Chandra is also working to understand why water quality is degrading and what can be done to stop it.
Chandra and his team have developed a series of short courses and field training programs to teach students and community members about the lake and basic limnology. Working in both Spanish and English, students rise with the sun and head out to sample the lake each day. The students learn about limiting nutrients, phytoplankton, pathogens, water clarity, and the importance of waste water treatment.
