The mixing of very deep warm and cold waters marks the intersection of the Atlantic, Pacific, and Southern Oceans at the southern terminus of the planet. This creates a biologically productive and simultaneously harsh environment. The Antarctic Peninsula juts 1,200 miles (1,931 kilometers) into the heart of this ocean junction; it is bordered on the west by the Bellingshausen Sea, on the north by the Drake Passage, and on the east by the Weddell Sea. The peninsula is 200 miles (322 kilometers) wide where it connects with the Antarctic mainland but ranges between 20 and 100 miles (32 and 161 kilometers) wide as it stretches northward into the Southern Ocean.