'Dead Zone' - 60,000 sq Threat To Fisheries In The Indian Ocean

A huge, mysterious 'dead zone' - 60,000 sq kilometers devoid of oxygen and life - has been found in the Indian Ocean to the northeast of Australia.<br /> <br />

A huge, mysterious 'dead zone' - 60,000 sq kilometers devoid of oxygen and life - has been found in the Indian Ocean to the northeast of Australia.

Such zones have already been uncovered off the shores of North and South America, western Africa as well as the Arabian Sea.

But this is the first time one continues to be discovered encroaching into South-East Asia.

Dead zones are usually related to a deficiency of oxygen and concentrations stripping the critical nutrient nitrogen from the water.

In the case of the Bay of Bengal, no such nitrogen decline has yet been detected.

And touches of oxygen have been uncovered - at levels 10,000 times lower than normal air-saturated surface waters.

While this is less than is needed to support most life, in addition, it impedes nitrogen-picking microbes.

Once the last hints of oxygen evaporate, the Bay of Bengal could become 'a leading global player' in taking nitrogen from our oceans.

This may have a serious effect on marine nutrient balances, and then the density of marine life.

It's feared raising rates of fertiliser feeding into the Bay of Bengal from high intensity population centers will result in the last of this oxygen being absorbed.

"Time will tell, but the Bay of Bengal is at a 'tipping point', and we now need models to illuminate how human activities will affect the nitrogen cycle in the Bay of Bengal, and also globally," Dr Bristow says.