Oceans cover about 70% of the Earth's surface. The oceans contain roughly 97% of the Earth's water supply. Life on Earth originated in the sea water. Pacific Ocean 64,186,000 square/miles - Atlantic Ocean 33,420,000 square/miles - Indian Ocean 28,350,000 squares/miles - Southern Ocean 7,848,300 sqares/miles - Arctic Ocean 5,106,000 squares/miles. Deepest depth is located in Mariana Trench of Pacific Ocean,about 36,200 feet. There are also many smaller seas ; seas are often partly enclosed by land. The largest seas are the South China Sea, the Caribbean Sea, and the Mediterranean Sea.