High Temperatures and Sea Ice Disintegration Leads to Acidification Hot Spots off Greenland

Nature Communications Earth & Environment, April 12

Some of the last remnants of thicker multi-year sea ice occur along the north Greenland coast. Increasing break-up and accumulation of this ice near the mouth of outlet fjords dams the flow of fresher surface water, coming off melting outlet glaciers within the fjords. This fresher water absorbs more carbon, with greater acidification rates and more corrosive conditions for shell-building organisms. In August 2019, near-surface ocean temperatures in Sherard Osborn Fjord reached a record-busting 4°C, about 3°C higher than any previously recorded in ocean waters off northern Greenland; and the mouth of the fjord became jammed with disintegrating pack ice. Low near-surface salinity (eg, more freshwater) in the dammed fjord then resulted in highly carbonate-corrosive waters from greater absorption of CO2. Neighboring ice-free Petermann Fjord however was not impacted in terms of temperature, salinity or chemistry. The break-up of multi-year ice off Greenland’s north coast may therefore dramatically impact the sensitivity of adjacent fjords to rising CO2 levels, with higher levels of acidification and corrosive conditions.

https://tc.copernicus.org/articles/15/1501/2021/

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