- Dead Zone is an area in water body that contains little or no oxygen (or they are hypoxic) in bottom and near-bottom water.
- Mostly they occur naturally but it can be caused by excessive nutrient pollution from human activities coupled with other factors.
- They are well-known off western coasts of North and South America, off coast of Namibia and off west coast of India in Arabian Sea.
- In recent times, warming of the atmosphere through climate change is predicted to lead expansion of ‘dead zones’ in the ocean.
- Why in news? Scientists have discovered a huge dead zone in Bay of Bengal.