本期主題
作者：
The ocean is one of Earth’s most valuable natural resources. It provides food in the form of fish and shellfish—about 200 billion pounds are caught each year. It’s used for transportation—both travel and shipping. It provides a treasured source of recreation for humans. It is mined for minerals （salt， sand， gravel， and some 1）manganese， copper， 2）nickel， iron， and 3）cobalt can be found in the deep sea） and drilled for 4）crude oil.
The ocean plays a critical role in removing carbon from the atmosphere and providing oxygen. It regulates Earth’s climate. The ocean is an increasingly important source of 5）biomedical organisms with enormous potential for fighting disease. These are just a few examples of the importance of the ocean to life on land. Explore them in greater detail to understand why we must keep the ocean healthy for future generations.
6）Hydrothermal 7）Vents
Most of us are familiar with “Old Faithful” in Yellowstone National Park. This famous geyser erupts several times a day. It spouts a column of water heated by 8）volcanic rock deep within the Earth’s 9）crust.
A hydrothermal vent is a geyser on the seafloor. It continuously 10）spews super-hot， mineral-rich water that helps support a diverse community of organisms. Although most of the deep sea is 11）sparsely populated， vent sites 12）teem with a fascinating array of life.
13）Tubeworms and huge 14）clams are the most distinctive inhabitants of Pacific Ocean vent sites， while eyeless shrimp are found only at vents in the Atlantic Ocean.
There are many reasons why scientists want to learn more about hydrothermal vents. These underwater geysers are believed to play an important role in the ocean’s temperature， chemistry， and circulation patterns. Scientists also are fascinated by the unusual life that inhabits vent sites. These creatures that live in darkness， from bacteria to tubeworms， may light the way to the development of new drugs， industrial processes， and other products useful to us all.
Ocean 15）Turbines
Covering more than 70 percent of the Earth’s surface， the ocean is the world’s largest 16）untapped， renewable energy resource. It produces both mechanical energy from its tides and waves and thermal energy from the sun’s heat. As new technologies are developed， ocean resources will be able to meet many of the world’s energy needs. Experts estimate that 0.2 percent of the ocean’s untapped energy could power the entire world.