The Western Arctic Ocean is acidifying four times faster than other oceans as ice melts at record speeds. Melting ice has increased how fast Arctic waters are absorbing carbon dioxide, making them more acidic faster.
The change could disrupt entire marine ecosystems.
Ocean acidification occurs when seawater absorbs carbon dioxide from the atmosphere. With atmospheric CO2 increasing since the industrial revolution, oceans have become 30 per cent more acidic on average, with widespread consequences for marine ecosystems.
In most ocean basins, the rate of ocean acidification has closely followed increasing atmospheric CO2 levels.
From the data collected on 47 different expeditions to the Arctic between 1994 and 2020, and considering both pH levels as well as the saturation of the mineral aragonite, which affects whether organisms like coral and oysters can build shells, researchers noticed that lower levels of both measures correspond to more acidification.
They found pH decreased about four times faster in the western Arctic on average than in other oceans during the same period. Aragonite saturation decreased three times faster than in other oceans. The area of ocean with low pH and low aragonite grew from almost nothing in 1990 to about 7 per cent of the entire Arctic Ocean in 2020. Arctic ecosystems are especially sensitive, though the effects of acidification versus other changes like warming aren’t yet clear.
According to researchers, melting ice is behind the exceptionally rapid rate of acidification. Seawater newly exposed to air gobbles up CO2. Meltwater also dilutes compounds that serve to buffer absorbed CO2 and decreases the amount of mixing between the surface and the deep ocean. The disappearing sea ice is behind the higher rate of acidification, but other factors could also be involved.
Aruna Gaitonde Editor in Chief of the Asian Bureau, Rough&Polished
