Oceania is one of eight terrestrial biogeographic realms, which constitute the major ecological regions of the planet. Related to these concepts are Near Oceania, that part of western Island Melanesia which has been inhabited for tens of millennia, and Remote Oceania which is more recently settled. Although the majority of the Oceanian islands lie in the South Pacific, a few of them are not restricted to the Pacific Ocean – Kangaroo Island and Ashmore and Cartier Islands, for instance, are situated in the Southern Ocean and Indian Ocean, respectively, and Tasmania's west coast faces the Southern Ocean. The coral reefs of the South Pacific are low-lying structures that have built up on basaltic lava flows under the ocean's surface. One of the most dramatic is the Great Barrier Reef off northeastern Australia with chains of reef patches. A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Examples include Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of French Polynesia.
Oceania is one of eight terrestrial biogeographic realms, which constitute the major ecological regions of the planet. Related to these concepts are Near Oceania, that part of western Island Melanesia which has been inhabited for tens of millennia, and Remote Oceania which is more recently settled. Although the majority of the Oceanian islands lie in the South Pacific, a few of them are not restricted to the Pacific Ocean – Kangaroo Island and Ashmore and Cartier Islands, for instance, are situated in the Southern Ocean and Indian Ocean, respectively, and Tasmania's west coast faces the Southern Ocean. The coral reefs of the South Pacific are low-lying structures that have built up on basaltic lava flows under the ocean's surface. One of the most dramatic is the Great Barrier Reef off northeastern Australia with chains of reef patches. A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Examples include Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of French Polynesia.