1. A team of scientists recently published one of the most comprehensive efforts yet to understand just how much carbon great whales absorb from the ocean,and the value that presents in the fight against climate change.
"Whales are large-bodied animals,and they live for a long time.Many of them migrate over vast distances," said study leader Heibi Pearson,a marine biologist at the University of Alaska Southeast. "And so they have the potential to have these huge impacts on the ecosystem,including the carbon cycle."
In their most direct impact,whale bodies hold an enormous amount of carbon that would otherwise be in the ocean or atmosphere.Twelve great whale species hold an estimated 2 million tons of carbon in their bodies,the authors found.
And that's just the living members of the whale family.Another 62,000 tons of carbon is kept under the sea every year in the form of whale falls.When a whale dies in open water and sinks into the deep,a lifetime of collected carbon goes with it.It can take up to 1,000 years for water and elements at the bottom of the sea to cycle back up to the surface,which means that carbon is effectively
sequestered for that long.
In addition,whales' waste facilitates the growth of organisms at the base of the marine food chain,promoting the growth of carbon-consuming life throughout the ecosystem.
However,whale populations still haven't recovered from the destructive effects of industrial whaling.Commercial hunting in the 19th and 20th centuries decreased the total mass of whales on the planet by 81%,according to the authors.
"Whales alone are not going to solve climate change,but thinking about whales as playing a role in the carbon cycle can help motivate whale conservation," said Andrew Pershing,a co-author of the study. "There are a lot of win-wins there,and I think that's very true of a lot of natural climate solutions."
(1)How do whales influence the climate change?
A.By storing carbon in their bodies.
B.By speeding the carbon cycle.
C.By absorbing carbon from the air.
D.By consuming carbon on their migration.
(2)What does the underlined word "sequestered" in paragraph 4 probably mean?
A.Employed.
B.Trapped.
C.Monitored.
D.Measured.
(3)What can we learn about whales from the text?
A.Their population has risen by 81%.
B.Their waste contributes to the ecosystem.
C.Whale hunting has been banned altogether.
D.Their death will break the marine food chain.
(4)What is implied in Andrew Pershing's words?
A.We can rely on whales to change climate.
B.Whale protection still has a long way to go.
C.We'll soon win the battle against climate change.
D.Whale protection is beneficial to solving climate issues.