Practice 2　　Until recently, scientists knew little about lif

Practice 2　　Until recently, scientists knew little about life in the deep sea, nor had they reason to believe that it was being threatened. Now, with the benefit of technology that allows for deeper exploration, researchers have uncovered a remarkable array of species inhabiting the ocean floor at depths of more than 660 feet, or about 200 meters. At the same time, however, technology has also enabled fishermen to reach far deeper than ever before, into areas where bottom trawls can destroy in minutes what has taken nature hundreds and in some cases thousands of years to build.　　Many of the world's coral species, for example, are found at depths of more than 200 meters. It is also estimated that roughly half of the world's highest seamounts - areas that rise from the ocean floor and are particularly rich in marine life - are also found in the deep ocean.　　These deep sea ecosystems provide shelter, spawning and breeding areas for fish and other creatures, as well as protection from strong currents and predators. Moreover, they are believed to harbor some of the most extensive reservoirs of life on earth, with estimates ranging from 500,000 to 100 million species inhabiting these largely unexplored and highly fragile ecosystems.