Tuesday May 30, 2023
PhysOrg —
Antarctica is a unique landscape, full of mystery and wonder. Its environments have a huge impact on the rest of the planet—on the climate, the ocean and on life itself.
About 250 trillion metric tons of salty, oxygen-rich, and dense water sinks near Antarctica each year. This is known as Antarctic Bottom Water (AABW). The process of sinking drives a global network of currents. Newly formed AABW fills up to 40% of the total volume of the world’s ocean. Much like the way a lung pumps oxygen into our blood, AABW transports oxygen—as well as carbon and nutrients—into the deep Indian, Pacific and Atlantic Oceans.
But a new study led by CSIRO researcher Dr. Kathy Gunn, shows this sinking of dense water has slowed. And, with this, deep ocean oxygen levels have also declined. The research is published in the journal Nature Climate Change.
“Our observations show the deep ocean circulation around Antarctica has slowed overall by about 30% since the 1990s. This slowdown locks in decades of impacts,” Kathy said.