New Evidence of a Freshwater Arctic Ocean Covered by Thick Ice

Nature, February 3

During the two most recent ice ages, the Arctic Ocean was almost completely isolated from the rest of the world’s oceans by a thick ice shelf bordering the polar ice sheets covering the Arctic Ocean and parts of North America and northern Europe. This ice shelf cut off connections to the Atlantic and Pacific, leading to freshwater conditions in the Arctic basin for thousands of years. The thick ice shelf in regions of the Arctic and Nordic seas isolated the Arctic from salty inflows from the Atlantic Ocean; and low sea levels blocked the exchange of water with the Pacific Ocean through the Bering Strait. Freshwater from melting land ice and precipitation therefore entered, and eventually made fresh the isolated Arctic basin. The Arctic region is currently undergoing rapid climatic and environmental change, so knowledge of this past variability is crucial for predicting future ones.

https://www.nature.com/articles/s41586-021-03186-y

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