Researchers of the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany discovered the unexpectedly low oxygen environments several hundred kilometres off the coast of West Africa.

A paper, published in Biogeosciences, describes 100-mile-long eddies of swirling water spinning their way across the Atlantic for months at a time.

The group of researchers led by Dr Johannes Karstensen  have suggested that: ‘the eddies propagate westward, at about four to five kilometres per day, from their generation region off the west African coast into the open ocean.’

Dead zones are usually found in shallow bodies of water, such as lakes and shallow coastlines. However, the swirling movement of the eddies found in the Atlantic ensures that no water can escape, so the oxygen supply is quickly used up.

“The fast rotation of the eddies makes it very difficult to exchange oxygen across the boundary between the rotating current and the surrounding ocean.

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http://www.independent.co.uk/news/science/animal-life-at-risk-as-oxygenstarved-dead-zones-discovered-in-the-atlantic-ocean-10221983.html

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