Describe the differences in environment between Oceania's low and high islands

Question

What will be an ideal response?

Answer 1

Much of Melanesia and Polynesia is part of the seismically active Pacific Rim of Fire. As a result, volcanic eruptions, major earthquakes, and tsunamis are common across the region. Most of Oceania's islands were created by two distinct processes: either volcanic eruptions or, alternatively, coral reef-building. Those with a volcanic heritage are referred to as high islands because most of them rise hundreds and even thousands of feet in elevation above sea level. The Hawaiian Islands are good illustrations, with a volcanic mountain of more than 13,000 feet (4000 meters) on the Big Island of Hawaii. Tonga, Samoa, Bora Bora, and Vanuatu provide other examples of high islands (Figure 14.9, page 656). Even larger and more geographically complex are the continental high islands as found in New Guinea, New Zealand, and the Solomon Islands. In contrast, low islandsare formed from coral reefs, making the islands not just lower, but also flatter and usually smaller than high islands. Further, because the soil on these islands originated as coral, it is generally less fertile than the soil of high islands and supports less varied plant life. Low islands often begin as barrier reefs around or over sunken volcanic high islands, resulting in an atoll (Figure 14.10, page 656). The world's largest atoll, Kwajalein in Micronesia's Marshall Islands, is 75 miles (120 km) long and 15 miles (25 km) wide. Low islands dominate the countries of Tuvalu, Kiribati, and the Marshall Islands.