Huge dead zone discovered in Bay of Bengal

  • The Bay of Bengal hosts a ‘dead zone’ of an estimated 60,000 square kilometres – an area that contains little or no oxygen and supports microbial processes that remove vast amounts of nitrogen from the ocean, scientists including those from India have found.
  • Dead zones are well known off the western coasts of North and South America, off the coast of Namibia and off the west coast of India in the Arabian Sea.
  • “The Bay of Bengal has long stood as an enigma because standard techniques suggest no oxygen in the waters, but, despite this, there has been no indication of nitrogen loss as in other ‘dead zones’ of the global ocean.
  • The researchers also discovered that the Bay of Bengal hosts microbial communities that can remove nitrogen, as in other well-known dead zones and even some evidence that they do remove nitrogen, but at really slow rates. “Remove the last amounts of oxygen, and the Bay of Bengal could become a major global player in nitrogen removal from the oceans.
  • Removing more nitrogen from the oceans could affect the marine nitrogen balance and rates of marine productivity.
  • Globally, warming of the atmosphere through climate change is predicted to lead to an expansion of ‘dead zones’ in the ocean.
  • It is currently unclear whether climate change would lead to the removal of these last traces of oxygen from the Bay of Bengal waters.
  • However, the Bay of Bengal is also surrounded by a heavy population density, and expected increases in fertiliser input to the Bay may increase its productivity, contributing to oxygen depletion at depth.

Dead Zone is an area in water body that contains little or no oxygen (or they are hypoxic) in bottom and near-bottom water.

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