rivers suck up carbon

In the turbid, frigid waters roaring from the glaciers of Canada’s high Arctic, researchers have made a surprising discovery: for decades, the northern rivers secretly pulled carbon dioxide from the atmosphere at a rate faster than the Amazon rainforest.
The findings, published in the Proceedings of the National Academy of Sciences, flip the conventional understanding of rivers, which are largely viewed as sources of carbon emissions.

I sense that this is important, but it is above my intellectual pay grade or energy level.