Scientists from the United States say they have found fish and other creatures living under icy waters in Antarctica. They made the announcement after completing three months of research at the Ross Ice Shelf, the world's largest floating ice sheet.
The researchers hoped to find clues to explain the force of the melting ice and its effect on sea level rise. Reed Scherer and Ross Powell are with Northern Illinois University in DeKalb, Illinois. They just finished up their research on our southernmost continent. Money for the project came from America's National Science Foundation.
" We chose a study site where, in the first year, we went into the subglacial(冰川下的) lake and tried to understand the environment in there, both ecologically and in terms of the ice dynamics about how the lake operates, and how the sediment(沉淀物) underneath the ice sheet operates, as well, because it's the water and the sediment underneath the ice that controls how fast the ice is flowing into the ocean." says Ross Powell, who led the investigation. The team included scientists, engineers, mechanics and technicians. They used tractors to pull electric generators, science laboratories, heavy machinery and other supplies across the ice from the main U.S. scientific base at McMurdo Station to the researcher's camp.The camp was near a subglacial lake, where an earlier study took place.
Ross Powell says the latest study may provide evidence that can help predict the effect of climate change on rising sea levels.
"What we have found is that these are very sensitive areas to the stability of how dynamic the ice is and how fast the ice may react to increases of melting both from the ocean and the atmosphere."
Among the new instruments built for the project was a powerful hot water drill. The researchers used the drill to dig down some 740 meters. They collected water, sediment and other material from the grounding zone.
Working around the clock before the deep hole refroze, they sent a video camera down to the 400-square-meter undersea area.
Reed Scherer says the video images they saw in the Command Center were a total surprise.
"It's a very mobile environment. The bottom is changing constantly. And so the things that we saw were all very mobile organisms, things that swim and some things that crawl. And obviously they are getting enough nutrition that they can thrive. Some of the little crustacean-like creatures called amphipods that we saw swam quite quickly and were quite active."
This is the farthest south that fish have ever been seen. How did the creatures get here? What do they feed on? And what effect will the retreating(退去的) ice have on them?
Ross Powell says the ice and sediment cores taken from the grounding zone can offer clues.
"We know that the ice is melting there at the moment and so by opening up the cores once they get back, we hope to be able to understand what the ice was doing in the past, relative to what it is doing now. And because it is melting so fast or seems to be melting fast at the moment, we anticipate that there will be some differences that we'll see in the history of the ice sheet from the sediment cores, once we open them up." But Ross Powell says the work raises more questions than it answers.
61.Scientists conducted the three-month research at the Ross Ice Shelf with the intention of ____________.
A.predicting how climate change influences rising sea levels.
B.finding out whether there are life forms existing deep under Antarctic ice.
C.providing the speed of ice flowing into the ocean is controlled by water.
D.discovering an explanation of the effect the melting ice has on sea level rise.
62.What made the researchers surprised when they saw the video images?
A.Researchers saw fish in the farthest south for the first time.
B.A video camera was able to work well under deep icy waters.
C.Sediment cores present differences in the history of the ice sheet.
D.The drill should dig down 740 meters to collect things.
63.From sediment cores taken from the grounding zone, scientists will probably know __________
A.what the ice will do in the near future.
B.the ice in the grounding zone is melting at the moment.
C. some differences rarely exist in the history of the ice sheet.
D.something about the creatures under icy water in Antarctica.
64.What can be inferred from the passage?
A. Scientists will conduct a follow –up study on the frozen continent.
B. No creatures once appeared or lived in icy water in Antarctica.
C. America’s National Science Foundation is in complete charge of the research.
D. Researchers have found how the sediment underneath the ice sheet operates.