Antarctica is keeping the ocean alive…for now

Water in the ocean is constantly in motion. Scientists can identify distinct “water masses” in the ocean from different sources, and keep track of them by measuring dissolved salts, human pollutants, and the different isotopes of hydrogen and oxygen in the water molecules themselves. This is how oceanographers have mapped the world’s currents, like the Gulf Stream that brings warm water north from the equator and keeps Europe warmer than Siberia. Of all the water masses in the ocean, one is particularly responsible for keeping the ocean currents flowing. It’s the deepest and densest water in the ocean, and it only forms in a few specific sites off the coast of Antarctica. And it might collapse in the next few decades. Image by “Fred the Oyster” This water, called “Antarctic Bottom Water” or AABW, is so dense thanks to its high concentration of salt and extremely cold temperatures. It’s formed on the surface of the ocean in the waters around Antarctica itself. As seawater hits the cold…