Ocean Warming blamed for low-oxygen dead zones in North Pacific

There was a long-standing debate about the cause of the expansion of ‘Oxygen Minimum Zones’ also known as ‘Dead Zones’ in the oceans. A recent study has linked the Dead Zones in North Pacific to past ocean warming. The study revealed a link between sudden ocean warming at the end of the last ice age and the advent of oxygen deficient or hypoxic condition leading to vast marine dead zones. The study conclusively links the warming of the surface and dead zones at great depths.

Candace Major, a program director in NSF’s Division of Ocean Sciences, said that it finally rests a long-standing debate about the existence of vast regions of oxygen deficient regions in the oceans known as dead zones.

The study also reveals that the response time between warming and dead zone expansion is very fast.

Large-scale warming events happened 14,700 years ago and again 11,500 years ago. The event happened rapidly and triggered rapid depletion of oxygen in the North Pacific.

The study has once again raised the fear that with the global temperatures rising, it will once again trigger an expansion of low-oxygen areas in the world.

In recent times, anomalous warmth has been detected in the North Eastern Pacific Ocean and the Bering Sea, which if sustained can lead to the large sections of ocean becoming deficient in oxygen and leading to the bigger formation of Dead Zones.

The latest study has established a distinct link between two historical incidences of abrupt ocean warming that brought to an end the last ice age. It leads to an increase of marine plankton sinking to the sea floor and lead to a sudden onset of hypoxia or oxygen deficit conditions.

The study was funded by the National Science Foundation and was published in the latest edition of journal Nature.

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