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虽然人类影响主宰着今天亚马孙流域的雨林火灾,但土壤或湖泊沉积物中埋藏的古老木炭碎片,却证实了火灾曾经在亚马孙流域林历史上起过很大作用。这种火灾也许已经影响了今天雨林的多样性和结构,并且如果有利于过去这种火灾的事件一再发生,就有可能对亚马孙流域森林的未来造成极大的后果。通过对小木炭碎片的显微镜观察,详细研究卡拉雅斯湖(Caraias)沉积物使我们查明了过去这些火灾事件。通过放射性碳测定年代,这些研究较好地确定了木炭碎片的年代,并且有可能把它们与过去的古环境和古气候联系起来。这些古数据表明,火灾事件伴随着最近7000年间频度不定的短暂干旱气候时段而发生。这种干旱气候事件可能与南美州热带不同地区观察到的过去气候条件有关。
Although human influence dominates today’s rainforest rains in the Amazon basin, ancient fragments of charcoal buried in soil or lake sediments confirm that fires once played a large part in the history of Amazonian forests. Such fires may have affected the diversity and structure of today’s rainforests and if events conducive to such past fires were repeated, there could be great consequences for the future of the Amazonian forests. A detailed examination of sediments from the Caraias through microscopic observations of small charcoal fragments allowed us to pinpoint these past fire events. By radiocarbon dating, these studies have better defined the age of charcoal fragments and have the potential to relate them to past paleoenvironments and paleoclimatologies. These old data show that the fire incident occurred with the occasional short-lived arid climate over the last 7,000 years. This arid climate event may be related to the past climatic conditions observed in different parts of tropical South America.