题目内容

Ocean Acidification: 'Evil Twin' Threatens World's Oceans

The rise in human emissions of carbon dioxide is driving dangerous changes in the chemistry and ecosystems of the world's oceans, international marine(海洋的)scientists have warned. "Ocean conditions are already more extreme than those experienced by marine organisms and ecosystems for millions of years," says the latest issue of the journal Trends in Ecology and Evolution. "This emphasizes the urgent need to adopt policies that markedly reduce CO2 emissions."

Ocean acidification, which the researchers call the 'evil twin of global warming', is caused when the CO2 emitted by human activity, mainly burning fossil fuels, dissolves into the oceans. It is happening independently of, but in combination with, global warming. Evidence gathered by scientists over the last few years suggests that ocean acidification could represent an equal -- or perhaps even greater threat -- to the biology of our planet than global warming. More than 30% of the CO2 released from burning fossil fuels, cement production, deforestation and other human activities goes straight into the oceans, turning them gradually more acidic.

"The resulting acidification will impact many forms of sea life, especially organisms whose shells or skeletons are made from calcium carbonate(碳化钙), like corals and shellfish. It may interfere with the reproduction of plankton species which are a vital part of the food web on which fish and all other sea life depend," he adds.

The scientists say there is now persuasive evidence that mass extinctions in past Earth history, like the "Great Dying" of 251 million years ago and another wipeout 55 million years ago, were accompanied by ocean acidification, which may have delivered the deathblow to many species that were unable to cope with it. "These past periods can serve as great lessons of what we can expect in the future, if we continue to push the acidity the ocean even further" said lead author, Dr. Carles Pelejero, from ICREA and the Marine Science Institute of CSIC in Barcelona, Spain. "Given the impacts we see in the fossil record, there is no question about the need to immediately reduce the rate at which we are emitting carbon dioxide in the atmosphere," he said further.

"Today, the surface waters of the oceans have already acidified by an average of 0.1 pH units from pre-industrial levels, and we are seeing signs of its impact even in the deep oceans," said co-author Dr. Eva Calvo, from the Marine Science Institute of CSIC in Spain. "Future acidification depends on how much CO2 humans emit from here on -- but by the year 2100 various projections indicate that the oceans will have acidified by a further 0.3 to 0.4 pH units, which is more than many organisms like corals can stand," Prof. Hoegh-Guldberg says.

"This will create conditions not seen on Earth for at least 40 million years."

"These changes are taking place at rates as much as 100 times faster than they ever have over the last tens of millions of years" Prof. Hoegh-Guldberg says. Besides directly impacting on the fishing industry and its contribution to the human food supply at a time when global food demand is doubling, a major die-off in the oceans would affect birds and many land species and change the biology of Earth as a whole profoundly, Prof. Hoegh-Guldberg adds.

67. What is the biggest cause of the ocean acidification according to the report?

   A. the increase of carbon dioxide emission by human beings

   B. The worsening of global warming

   C. The disappearance of the world’s forests

   D. The decrease of marine life

68. In what way according to the report does ocean acidification affect the majority of marine life?

   A. It affects their reproduction          B. It destroys their food chain

   C. It affects the growth of their young    D. destroys their habitats

69. Which of the following statements is NOT true about ocean acidification?

   A. Ocean acidification has made ocean conditions most extreme in millions of years.

   B. Ocean acidification may do more damage than global warming to human and plant life in the long run.

   C. Ocean acidification is suspected of having caused mass extinctions of life in past Earth history.

   D. The effects of ocean acidification are not now but will be felt in the foreseeable future.

70. From the report we can clearly feel that the situation with ocean acidification __________.

   A. is quite optimistic                B. remains well under control

   C. looks more than urgent            D. is already out of control 

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 "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 CO2 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(小行星) 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-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.”

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

f 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

Most experts once believed storing carbon dioxide in the ocean would reduce________ .

   A. the CO2 absorbed by the ocean             B. the amount of greenhouse warming

   C. the acidity of the ocean                   D. the gradual release of CO2

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 CO2

“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 CO2 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(小行星) 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(珊瑚礁) and other organisms whose shells contain calcium carbonate(碳酸钙) 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 station 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 --- 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.”

The ocean is becoming more acidic due to __________.

       A.the higher level of CO2 in the air   B.the warming atmosphere

       C.the increasing use of oil fuels       D. the lower water pH value

According to Dr Caldeira, __________.

       A.more oil fuels will be used in the near future

       B.ocean absorption of carbon dioxide is a good thing

       C.the future situation of the amount of acidity is extremely serious

       D.scientists may predict climate changes with computer models

If the water’s acidity level keeps rising, __________.

       A.the waters’ pH value will become higher and higher

       B.some disastrous events will occur more often than before

       C.organisms living near the surface are more sensitive to pH changes

       D.ocean life whose structures contain calcium carbonate may be affected

Most experts once believed storing carbon dioxide in the ocean would reduce __________.

       A.the CO2 absorbed by the ocean      B.the amount of greenhouse warming

       C.the acidity of the ocean            D.the gradual release of CO2

The purpose of this passage is to __________.

       A.show people the findings of a research team 

       B.introduce Dr Caldeira and his team’s research

       C.warn people of the higher level of CO2 

       D.inform people of how acid the ocean is now


E
“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 CO2 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(小行星) 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(珊瑚礁) and other organisms whose shells contain calcium carbonate(碳酸钙) 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 station 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——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.”
57.The ocean is becoming more acidic due to_______.
A.the lower water PH value                                   B.the warming atmosphere
C.the higher level of CO2 in the air                 D.the increasing use of oil fuels
58.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
59.If the water's acidity level keeps rising,____________.
A.ocean life whose structures contain calcium carbonate may be affected
B.the water's 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
60.Most experts once believed storing carbon dioxide in the ocean would reduce_________
A.the CO2 absorbed by the ocean                    B. the amount of greenhouse warming
C.the acidity of the ocean                               D.the gradual release of CO2


“The world's oceans are slowly getting more acidic(酸的),” 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 CO2 into the atmosphere,” said Dr Caldeira. And we predict the amount of future acidity will be greater than anything we have seen over the last several hundred million years.
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(碳酸钙) 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 station 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——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.”
67. The ocean is becoming more acidic due to___________.
A. the lower water PH value                              B. the warming atmosphere
C. the higher level of CO2 in the air                   D. the increasing use of oil fuels
68. 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
69. If the water's acidity level keeps rising, ___________.
A. ocean life whose structures contain calcium carbonate may be affected
B. the water's 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
70. Most experts once believed storing carbon dioxide in the ocean would reduce___________.
A. the CO2 absorbed by the ocean               B. the amount of greenhouse warming
C. the acidity of the ocean                          D. the gradual release of CO2

Rising levels of carbon dioxide in the atmosphere are a major cause of climate change, and now a new study has confirmed that atmospheric CO2 is also affecting the ocean chemistry and potentially harming sea life.

Montana State University scientist Robert Dore has been researching the water in the Pacific Ocean for almost two decades. We've been going to the same spot in the Pacific Ocean, and we try and characterize long-term change in the open ocean environment. And one of the key things that we measure is CO2 levels. And we've been able to record this increasing quantity of atmospheric CO2 into the ocean.

Scientists expected that as atmospheric CO2 increased, more and more of the carbon dioxide would be absorbed into the ocean, affecting the chemical balance of the sea water, with a potentially harmful impact on shellfish and coral in particular.

"As carbon dioxide dissolves(溶解) in the water, or seawater in this case, it forms a weak acid, carbonic acid," Dore explains. "And therefore, as the concentration of CO2 in the atmosphere goes up and that exchanges with the surface seawater, it drives the PH down, and makes it more acidic."

The seawater Dore and his colleagues have analyzed confirms what the theory predicts.

The effect was particular striking at about 250 meters down, and again at 500 meters. Dore and his colleagues came up with two possible explanations. It could be that surface water picked up CO2 and then moved to those depths. Or there could be a biological explanation.

"It's important to realize that the oceans are really becoming acidic. And it can have negative(消极的) impacts on a whole variety of sea life from fish to coral. It's potentially catastrophic."

1.What can be the best title of the passage?

    A.Sea Life Facing Danger          

B.Scientist Researching Seawater

    C.Oceans Becoming More Acidic     

D.Climate Change Affecting Seawater

2.With the increase of atmospheric CO2         .

    A.more corals will appear in the sea

    B.the surface water is becoming warmer

    C.the chemical balance of the seawater is affected

    D.the PH of the ocean out here has been increasing

3.Which of the following shows the process of the impact of atmospheric CO2 on sea life?

    a.Sea life is endangered.

    b.CO2 goes into the surface water.

    c.The ocean chemistry is affected.

    d.CO2decreases the PH and makes the seawater more acidic.

e.CO2 levels in the atmosphere go up.

4.Scientist Robert Dore came to the conclusion based on        .

    A.his research and analysis

    B.the expectation of other scientists

    C.some former theory

    D.a major cause of climate change  

 

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