The Land Under the Sea
Ten thousand years ago, as the last ice age ended, sea levels around the world were far lower than they are today. Much of the land under both the North Sea to the east of Britain and the English Channel which now separates France and Britain was part of a huge region of forests and grassy plains. Then the climate gradually became warmer and the water trapped in large masses of ice was released.
Now the development of advanced sonar (声呐) technology, known as bathymetry, is making it possible to study this flooded landscape in extraordinary detail. A special echo (回声) sounder is fixed to the bottom of a survey ship and it makes wide sweeps across the seabed. While previous technology has only been able to produce two-dimensional images, bathymetry can now use computers, satellite-positioning equipment and special software to create accurate and remarkably detailed maps. For the first time, an ancient riverbed jumps out of the three-dimensional image. The site of pre-historic settlements can now be pinpointed.
According to expert Linda Andrews, this technological development is of huge significance. “We now have the ability to map the seabed as accurately as we can map dry land,” she says.
Once bathymetric techniques have identified sites where people might have built their homes and villages, divers can be sent down to investigate further. Robot submarines (潜艇) can also be used, and researchers hope they will find stone tools and wood from houses as proof of human activity. The idea shared by many people in Britain of their country as a natural island kingdom will be challenged by the findings: Britain has been inhabited for about 500,000 years and much of this time it has been linked on and off to continental Europe. It remains to be seen how far this new awareness is taken on board, however.
In fact, the use of bathymetry will not be limited to the study of lost landscapes and ancient settlements. It will also be vital in finding ships that have been destroyed in accidents. In addition, commercial applications are a real possibility. Aggregates (骨材) for the construction industry are becoming increasingly expensive, and bathymetry can be used to identify suitable sites for digging for this material. Mapping the seabed will also identify places where rare plants and shellfish are living. Digging at such sites should be prevented, either to work for a profit or to make deeper waterways for massive container ships.
8. How does bathymetry work?
A.It has an echo sounder placed on the seabed. |
B.It makes use of a number of different devices. |
C.It produces two-dimensional images of the sea floor. |
D.It bases its calculations on the location of construction sites. |
9. What does the underlined word “pinpointed” in Paragraph 2 probably mean?
A.Occupied. | B.Adjusted. |
C.Rebuilt. | D.Discovered. |
10. The author believes a better understanding of the settlements on the seabed may ________.
A.attract investment in the research under the sea |
B.inspire people to take an interest in modern technology |
C.adapt the attitudes of the British to their country’s history |
D.receive confirmation of rebuilding ancient man-made objects |
11. We can learn that the use of bathymetry will help to ________.
A.identify new species of plants and animals |
B.provide the precise location of sunken ships |
C.evaluate the cost of seeking certain resources |
D.promote the development of deeper waterways |