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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.
- Twenty miles southeast of Hawaii is the Loihi seamount, an active underwater volcano that is predicted to rise above the ocean surface in the next 50,000 years. That means it could become the ninth main Hawaiian island.
- Due to its remote location in the Pacific, Mauna Kea is free from the artificial light that is common in highly populated areas. Combined with its elevation of 4,205 meters (13,796 feet, 2.6 miles), the summit of Mauna Kea is the ideal location for the international astronomical observatory and the 13 international telescopes located there.
- Unlike the hot spot that formed Mauna Kea, Mount Everest formed as the result of a convergent tectonic boundary. As two continental plates came together, the crust buckled and pushed upward, creating the Himalayan mountain range. As the Indian and Eurasian plates continue to collide, the elevation of Mount Everest increases by 1-3 centimeters each year.
- National Geographic: Deep Sea Ecosystems—Extreme Living
- National Geographic: Undersea Geology
- National Geographic: Types of Volcanic Eruptions
Term Part of Speech Definition Encyclopedic Entry adaptation Noun
a modification of an organism or its parts that makes it more fit for existence. An adaptation is passed from generation to generation.
Encyclopedic Entry: adaptation archipelago Noun
a group of closely scattered islands in a large body of water.
Encyclopedic Entry: archipelago atoll Noun
a coral reef or string of coral islands that surrounds a lagoon.
Encyclopedic Entry: atoll biodiversity Noun
all the different kinds of living organisms within a given area.
Encyclopedic Entry: biodiversity endemic Adjective
native to a specific geographic space.
study of the physical history of the Earth, its composition, its structure, and the processes that form and change it.
environment where an organism lives throughout the year or for shorter periods of time.
Encyclopedic Entry: habitat hot spot Noun
intensely hot region deep within the Earth that rises to just underneath the surface. Some hot spots produce volcanoes.
Encyclopedic Entry: hot spot oceanography Noun
study of the ocean.
Encyclopedic Entry: oceanography plate tectonics Noun
movement and interaction of the Earth's plates.
an opening in the Earth's crust, through which lava, ash, and gases erupt, and also the cone built by eruptions.
Encyclopedic Entry: volcano
This material is based in part upon work supported by the National Science Foundation under Grant No. DRL-1114251. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.