The Pacific Ocean and Oceania

The Pacific is the largest, deepest and oldest of the oceans; it covers about half of the World Ocean area and about one third of the Earth’s surface (the textbook says 180 million km², modern counts about 165–169 million km²). Five continents border it; it stretches about 15 000 km from north to south and more than about 19 000 km from west to east. In 1513 V. Balboa saw it from the Isthmus of Panama and called it the “South Sea”, and F. Magellan named it “Pacific” in 1520–1521; later J. Cook, V. Bering and A. Chirikov (1741), Kruzenshtern and others explored it. The Pacific floor is an independent lithosphere plate and is very mobile (about 7–10 cm a year); around it lies the “Ring of Fire” — a zone of strong earthquakes and active volcanoes. The deepest trenches are here: the Mariana (about 10 935 m), Tonga (about 10 882 m) and Kermadec. Water temperature is 28–29 °C at the equator and falls toward north and south; salinity is highest in the tropics (about 36 ‰). Typhoons occur in the western tropical part. The ocean is the richest in organisms, and more than half of the world’s fish catch comes from it; salmon, shrimp and krill are caught. A large share of the world’s population lives on its shores.