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C "The world's oceans are slowly getting more acidic.”say scientists.The researchers from California report that the change is taking place in response to higher levels of carbon dioxide in the atmosphere. The lowering of the waters’pH value is not great at the moment but could cause a serious threat to current ocean life if it continues, they warn. Ken Caldeira and Michael Wickett, from the Lawrence Livermore National Laboratory, report their concerns in the journal Nature. Increasing use of oil fuels means more carbon dioxide is going into the air, and most of it will eventually be absorbed by seawater. Once in the water, it reacts to form carbonic acid. Scientists believe that the oceans have already become slightly more acidic over the last century. These researchers have tried to predict what will happen in the future by combining what we know about the history of the oceans with computer models of climate change."This level of acidity will get much more extreme in the future if we continue releasing COZ into the atmosphere," said Dr Caldeira. "And we predict the amount of future acidity will exceed(超过)anything we have seen over the last several hundred million years, let alone perhaps after rare disastrous events such as asteroid(小1j-%+.'_) impacts.” However, it is not absolutely clear what that means for ocean life.Most organisms live near the surface, where the greatest pH change would be expected to occur, but deep-ocean life forms may be more sensitive to pH changes.Coral reefs and other organisms whose shells contain calcium carbonate(小行星) may be particularly affected if the water's acidity levels keep going up, the team predict. They could find it much more difficult to build these structures in water with a lower pH. In recent years some people have suggested storing carbon dioxide from power stations in the deep ocean as a way of dealing with global warming.But Dr Caldeira said that such a strategy should now be re-considered. "Previously, most experts had looked at ocean absorption of carbon dioxide as a good thing一because in releasing CO2 into the atmosphere we warm the planet, and when CO2, is absorbed by the ocean, it reduces the amount of greenhouse warming.” 66 .The ocean is becoming more acidic due to_. A，the lower water pH value B.the warming atmosphere C .the higher level of COZ in the air D.the increasing use of oil fuels 67. According to Dr Caldeira,_. A .ocean absorption of carbon dioxide is a good thing B .more oil fuels will be used in the near future C .scientists may predict climate changes with computer models D .the future situation of the amount of acidity is extremely serious 68.If the water's acidity level keeps rising,_. A .ocean life whose structures contain calcium carbonate may be affected B .the waters’pH value will become higher and higher C .organisms living near the surface are more sensitive to pH changes D .some disastrous events will occur more often than before 69.Most experts once believed storing carbon dioxide in the ocean would reduce_. A .the COZ absorbed by the ocean B .the amount of greenhouse warming C .the acidity of the ocean D .the gradul release Of CO2 70.The purpose of this passage is to_. A .show people the findings of a research team B .inform people of how acid the ocean is now C .introduce Dr Caldeira and his team's research D .warn people of the higher level of COZ D As you move around your home, take a good look at the things you have. It is likely that your living room will have a television set and a video, and your kitchen a washing machine and a microwave oven. Your bedroom drawers will be filled with almost three times as many clothes as you need. You almost certainly own a car and possibly a home computer, holiday abroad at least once a year and eat out at least once a week. Now, perhaps, more than ever before, people are wondering what life is all about, and what it is for. Seeking material success is beginning to trouble large numbers of people around the world. They feel that the long hours work culture to make more money is eating up their lives, leaving them very little time or energy for family or pastimes. Many are turning to other ways of living and downshifting is one of them. Six percent of workers in Britain took the decision to downshift last year. One couple who downshifted is Daniel and Liz. They used to work in central London. He was a newspaper reporter and she used to work for an international bank. They would go to work by train every day from their large house in the suburbs, leaving their two children with a nanny. Most evenings Daniel wouldn’t get home until eight or nine o’clock and nearly twice a month he would have to fly to New York for meetings. They both earned a large amount of money but began to feel that life was passing them by. Nowadays, they run a farm in the mountains of Wales. “I always wanted to have a farm then,” says Daniel, “and we took almost a year to make the decision to downshift. It’s taken some getting used to, but it’s been worth it. We have to think twice now about spending money on car repairs and we no longer have any holidays. However, I think it’s made us stronger as a family, and the children are a lot happier. Liz, however, is not quite sure. “I used to enjoy my job, even though it was hard work and long hours. I’m not really a country girl, but I suppose I’m gradually getting used to looking after the animals. One thing I do like, though, is being able to see more of my children. My advice for other people wanting to do the same is not to think about it too much or you might not do it at all.” (责任编辑：admin) |