Weddell Sea Bottom Water

Weddell Sea Bottom Water (WSBW) is the densest variety of Antarctic Bottom Water, formed in the Weddell Sea, the largest single source of abyssal water in the global ocean. Brine rejected by sea ice in coastal polynyas, plus cooling under the Filchner-Ronne Ice Shelf, makes high-salinity shelf water that mixes with Warm Deep Water and Ice Shelf Water and cascades down the slope, with temperatures near minus 0.7 degrees C. WSBW feeds the deep Weddell Gyre and exports northward as Antarctic Bottom Water, ventilating the South Atlantic abyss. Long records show it warming and contracting in recent decades.