The illustration above is from the supplement to the September 2012 issue of National Geographic magazine. Download the file and open to view in full.
Hawaii is the youngest and largest of a chain of islands making up the Hawaiian archipelago. The archipelago is composed of eight main islands and several smaller islands and atolls, which were once active volcanoes that have since sunk and eroded over millions of years. The Hawaiian archipelago forms because of the presence of a hot spot more than 1,448 kilometers (900 miles) deep in the Earth’s crust. As the Pacific tectonic plate moves northwest over the hot spot—at a rate of about 7.6 centimeters (3 inches) per year—magma from the hot spot breaks through the plate’s crust to form volcanic land masses. As the Pacific plate moves from the southeast to the northwest, the older islands get farther from the hot spot and begin a process of sinking and eroding. Niihau, the most northwesterly of the main Hawaiian Islands, is about 6 million years old. Hawaii, the youngest of the main islands, remains close to the hot spot, and at less than 1 million years old, it is still forming as the hot spot feeds lava to its active Kilauea volcano.
Mauna Kea, one of six volcanoes that have formed the island of Hawaii, is the tallest mountain on Earth at 9,966 meters (32,696 feet, 6.2 miles). This is 1,116 meters (3,661 feet, 0.7 miles) taller than Mount Everest and roughly the same height in the atmosphere where commercial airplanes fly. With 4,205 meters (13,796 feet, 2.6 miles) above sea level, more than half of Mauna Kea’s height falls below the surface of the ocean, with its base reaching 5,761 meters (18,900 feet, 3.6 miles) deep. Mauna Kea is dormant, having last erupted 4,600 years ago. Kohala is the island’s oldest volcano and is now extinct. Hualalai last erupted in 1801, and Mauna Loa last erupted in 1984. Kilauea has been erupting actively since 1983.
The geologic landscape of Hawaii’s islands has changed greatly over time, which has also impacted its ecologic landscape. As Hawaii’s volcanic islands rise and fall, organisms must adapt to a series of transitional habitats both above and below the ocean surface. In terms of the habitats and species that are part of Mauna Kea—from its mountain peak to its ocean deep—the colossal mountain is not only tall, but high in biodiversity as well. Mauna Kea’s variety of terrestrial habitats includes stone deserts, shrublands, alpine woodlands, and tropical forests. These varied habitats are home to several endemic species that are only found on Hawaii or the Hawaiian archipelago. The ocean habitats that characterize Mauna Kea are equally varied and full of life. The greatest quantity of marine life is found between the surface and a depth of 1,189 meters (3,900 feet, 0.7 miles) in the sunlight zone and twilight realm. Below 3,900 feet are the midnight zone and abyss, which are dark, cold, under high pressures, and lacking in food. Species in these extreme environments have developed unique adaptations to regulate their temperatures, protect themselves, help them locate food, communicate, and find mates.