Nitrous oxide, a powerful greenhouse gas, is on the rise from ocean dead zones

The researchers are conducting studies on the global N2O emission from the dead zones of the oceans.

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The researchers are conducting studies on the global N2O emission from the dead zones of the oceans.

When organisms die, they sink through the water column, consuming oxygen in the sub-surface ocean as they decompose.
This leads to bands of oxygen-depleted water called oxygen minimum zones, or “dead zones.”
These harsh environments are uninhabitable for most organisms.
Although they occur naturally in some areas, dead zones often appear after fertiliser and sewage wash downstream into coastal areas, sparking algal blooms, which then die off and decompose.

It is more commonly known as “laughing gas”.
It is a potent greenhouse gas, 300 times more powerful than carbon dioxide.
Global emissions of N2O are increasing as a result of human activities that stimulate its production.
Aside from its effects as a greenhouse gas, N2O is also the predominant ozone-depleting substance emitted to the atmosphere.

The oceans currently account for around 25 per cent of global N2O emissions, and scientists are working to improve estimates of marine contributions.
Most research has focused on oxygen minimum zones, which are known as hotspots of N2O emissions.

Warming of the ocean due to climate change is driving the expansion of marine oxygen minimum zones globally.
This has led to speculation that N2O emissions from the oceans will continue to increase and further accelerate climate change.
Results indicate that even more N2O production may be expected where these low-oxygen waters are in contact with the seafloor.
The United Nations has declared 2021 as the start of a Decade of Ocean Science for Sustainable Development. Detailing the vital link between oceans and climate change has never been more timely than now.