Meltwater from Antarctic Glaciers Is Slowing Deep-Ocean Currents
https://eos.org/articles/meltwater-from-antarctic-glaciers-is-slowing-deep-ocean-currents
Excerpt: Antarctic ice drives crucial deep-ocean currents that help regulate Earth’s climate. But the system is slowing down. ...When the sea freezes around Antarctica’s fringes in winter, the ice expels salt into the water below. Trillions of metric tons of this briny, supercooled, heavy water cascade down Antarctica’s continental slope, dropping into the deep ocean in submarine waterfalls. As these waters sink from the Antarctic shelf, they spread north through the Southern Ocean, driving abyssal circulation—the lower limb of the global ocean overturning circulation. They are the densest water masses in the world’s oceans and the engine room of a current system that conveys heat, dissolved gases, and nutrients around the world. ...But diminishing glaciers in West Antarctica—primarily the Amundsen Sea—are freshening the shelf waters in the Ross Sea and slowing the production of bottom water, according to research led by Kathy Gunn, a physical oceanographer at the Commonwealth Scientific and Industrial Research Organisation in Hobart, Tasmania....