Estimation of methane emitted by natural wetlands of Orissa: Based on case studies on three representative wetlands

Abstract

The rapid increase in the concentration of greenhouse gases in our atmosphere has led to significant changes in global climate. Methane is second to carbon dioxide in terms of its contribution to global warming. The wetlands serve as a major natural source of methane. Orissa State, located on the east coast of India, has a number of natural wetlands. Three representative wetlands: Chilka – the largest semi-saline lake of Asia, Anshupa – a land-locked fresh water lake and Gahirmatha – a tidal flood plain of Bhitara Kanika region that has sprawling mangrove vegetation (extension of the Sunderbans of the Gangetic delta) were chosen for intensive monitoring of water and sediment quality, along with methane flux over a period of three years during 1997–2000. The average seasonal methane fluxes were integrated to arrive at the annual flux from each wetland category. Finally, those results were extended to other natural wetlands of Orissa to arrive at the average annual methane flux of Orissa State. This is useful in calculating the total budget of greenhouse gases of India.

Keywords:

• Greenhouse gas budgeting
• Methane
• Natural wetlands
• Sediment and water quality

Acknowledgments

The authors are thankful to the Director, RRL, Bhubaneswar for the kind permission to publish the paper. They are grateful to the Department of Science and Technology, Govt. of India, New Delhi for providing financial assistance for the work. They are also grateful to the scientists of the National Physical Laboratory led by Dr. A.P Mitra for their financial, technical and moral support throughout the study period. Various young research scholars who visited the lake for sample collection and helped in analysis of different parameters also deserve thanks.