No hiding place for Amazon refugia idea.For climate researchers, pollen grains are nothing to sneeze at This article is about the Garfield and Friends episode. For the Rocko's Modern Life episode, see Nothing to Sneeze At / Old Fogey Froggy. Nothing to Sneeze At is an episode of Garfield and Friends. . These pesky little particles can pack vast amounts of information about ancient worlds that have long since vanished. By studying prehistoric pollen from a lake in the Amazon, a team of researchers has overturned a long-held assumption about the peak of the last ice age, 18,000 years ago. "The expectation was that the Amazon was dry during the last glacial maximum The Last Glacial Maximum (LGM) refers to the time of maximum extent of the ice sheets during the last glaciation (the Würm or Wisconsin glaciation), approximately 20,000 years ago. This extreme persisted for several thousand years. ," explains Paul A. Colinvaux of the Smithsonian Tropical Research Institute The Smithsonian Tropical Research Institute (STRI) in Panama, the only bureau of the Smithsonian Institution based outside of the United States, is dedicated to understanding biological diversity. in Balboa, Panama Balboa is a district of Panama City, located at the Pacific entrance to the Panama Canal. History The town of Balboa, founded by the United States during the construction of the Panama Canal, was named after Vasco Núñez de Balboa, the Spanish conquistador credited . Many researchers had assumed that the rain forest shrank then, forming small isolated patches called refugia In the most basic biological sense refugia (singular: refugium) are locations of isolated or relict populations of once widespread animal or plant species. This isolation (allopatry) can be due to climatic changes or human activities such as deforestation and over-hunting. that were separated by grasslands. To test that theory, Colinvaux searched the Amazon basin “Amazonian” redirects here. For other uses, see Amazonian (disambiguation). The Amazon Basin is the part of South America drained by the Amazon River and its tributaries. to find an ancient lake containing pollen from the last ice age. "It's taken me 10 years of agony," he says. The scientist and his colleagues hit pay dirt when they drilled into the sedi- ments at the bottom of Lake Pata, just north of the equator. Carbon dating of the sediment layers reveals that they go back more than 40,000 years. In the Lake Pata sediments, pollen from grasses is extremely rare, even during the peak of the last ice age. This finding suggests that dry grasslands did not take over the Amazon at that time. Instead, the rain forest held its grip, the scientists report in the Oct. 4 Science. Judging from the pollens present during the last ice age, Colinvaux calculates that the Amazon was 5#161#C to 6#161#C cooler then. This finding helps shore up evidence that at least the land area in the tropics tropics, also called tropical zone or torrid zone, all the land and water of the earth situated between the Tropic of Cancer at lat. 23 1-2°N and the Tropic of Capricorn at lat. 23 1-2°S. cooled markedly during the ice age. These data stand in sharp contrast to evidence from ocean sedi- ments, which indicate that little tropical cooling occurred during the ice age. Supporters of the refugia idea contend that Colinvaux's evidence from one lake cannot address what happened to the entire Amazon. To fill in the gaps, he is planning to bore holes in many parts of the rain forest. "We're going to get the truth out of the Amazon somehow," he says. |
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