Arctic ocean acidification may cause more harmful greenhouse gases

Geneva: The gradual acidification of the subarctic region of the Pacific ocean, is causing a significant increase in the production of nitrous oxide, an ozone-depleting greenhouse gas, according to a study.

The researchers, including those from the Swiss Federal Institute of Technology Lausanne (EPFL) in Switzerland, studied the production of nitrous oxide near the Hokkaido and the Kuril Islands -- disputed territories between Japan and Russia in the northern Pacific ocean.

The rising levels of carbon dioxide in the atmosphere due to human activities increases the acidity of the ocean, according to the researchers.

The study, published in the journal Nature Climate Change, revealed that if pH -- which has a scale from zero (most acidic) to 14 (most alkaline) -- keeps falling at the current rate of 0.0051 units per year, the nitrous oxide produced in this Pacific region may rise by 185 per cent to 491 per cent by 2100.

The researchers added that the greenhouse effect of nitrous oxide, forming in these regions, is 298 times greater than that of carbon dioxide

As part of the study, they collected samples at five different sites off the coast of Japan, from the subarctic region to the subtropical region.

When they lowered the samples' pH levels, it triggered a natural process in which microbes in the water converted ammonium into nitrate and nitrous oxide.

"Our study provides additional proof that rising carbon dioxide emissions are disrupting natural biogeochemical cycles, which are highly sensitive to changes in the environment. However, our conclusions are valid only for the part of the Pacific that we examined," said study senior author Florian Breider from EPFL

Breider said additional research is needed to ascertain whether the same process is occurring in other parts of the world

Developing models of this process, taking all environmental variables into account, may help scientists obtain critical information for predicting future climate, Breider said.