[ti:New Discovery Suggests Antarctica Once Had Warm Rainforest] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.04]Today we know Antarctica as an extreme environment containing ice and snow. [00:08.88]But new research provides evidence that the area was very different in the past. [00:17.60]The evidence was found inside a piece of Earth sediment collected by researchers [00:24.48]from under the seafloor off the coast of Antarctica. [00:30.52]In the sediment, they found forest soil estimated to be about 90 million years old. [00:39.96]This would have been in the Cretaceous Period, when dinosaurs were the main land animals. [00:49.36]The sediment was removed by scientists on the research icebreaker [00:55.08]RV Polarstern in the Amundsen Sea near the Pine Island Glacier. [01:03.44]Johann Klages is a geologist with the Alfred Wegener Institute's [01:09.56]Helmholtz Center for Polar and Marine Research in Germany. [01:16.24]He was the lead writer of a study on the findings, published in the journal Nature. [01:24.84]He said the sediment was collected from a depth of about 30 meters below the ocean floor. [01:34.20]Klages said an examination showed that the material formed on land, not in the ocean. [01:43.84]The researchers estimate that the area – about 900 kilometers from the South Pole [01:51.68]– had average yearly temperatures of about 12 to 13 degrees Celsius. [01:59.80]During the warmest summer months, average temperatures likely reached between 20 to 25 degrees Celsius. [02:11.28]The average yearly temperature in that area is about 40 degrees below zero Celsius. [02:20.92]The examination process included the use of X-ray imaging technology. [02:28.88]Those results showed "a dense network of roots that spread through the entire soil layer," [02:37.16]the Helmholtz Center said in a statement. [02:41.68]The condition of the soil was in such good condition that the researchers could see individual cell structures. [02:52.24]The dark brownish-gray soil included fine dirt particles and hard clay, [02:59.24]as well as substances linked to at least 65 different kinds of plants, the study found. [03:09.20]"If you would go to a forest near you and drill a hole, it would probably look pretty similar," [03:16.92]Klages told the Reuters news agency. [03:21.32]He added that the plants included trees, ferns and flowering plants. [03:29.08]While no animal remains were found, Klages said there were likely dinosaurs, [03:35.64]flying reptiles and many insects in the environment. [03:42.24]The research represents new evidence of the major climate changes Earth [03:48.04]has experienced in the past - and is currently undergoing today. [03:54.80]The soil dates back to the planet's warmest period of the past 140 million years, [04:02.80]with sea levels about 170 meters higher than today. [04:09.48]The researchers said that the rainforest environment in Antarctica was especially surprising because each year, [04:19.16]the area experiences a four-month polar night when there is no sunlight to fuel plant life. [04:28.16]Klages said no ice sheets were present during the time, but seasonal snowfall was likely. [04:37.52]I'm Bryan Lynn. 更多听力请访问51VOA.COM