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气溶胶减排或使亚洲高山湖泊生态退化
【发布时间:2017-03-06 】 【 】【打印】【关闭

  

  近日,《自然·气候变化》首次刊发兰州大学陈发虎院士团队关于亚洲高山湖泊生态系统历史影响的研究成果,该成果指出“人为排放气溶胶正在对亚洲高山湖泊生态系统产生深刻影响,减缓了亚洲高山湖泊的富营养化”。

  陈发虎团队根据黄土高原近2000年来的湖泊沉积物记录,首次揭示出在自然暖期(公元540年至760年和公元900年至1300年)的环境下,亚洲高山湖泊发生了显著的湖泊富营养化,富营养化藻类种属平均占比60%以上,营养物质磷平均含量在1100ppm以上。在当前50年来自然暖期环境下,人类活动排放的气溶胶阻止了亚洲夏季风增强,贫营养化的藻类种属平均占比75%以上,沉积物磷含量保持在850ppm以下,亚洲高山湖泊没有富营养化发生。“如果未来人类活动排放的气溶胶减少,形成地表温度下降和亚洲季风增强的状态,将导致高山湖泊富营养化状态。”陈发虎认为。

  课题组研究发现,人为排放气溶胶形成的全球变暖,事实上已经改变了自然状态下气候对生态系统的影响方式,而且这种人为影响明显超越了过去2000年的自然变率。研究表明,亚洲地区气溶胶减排将减弱对夏季风的影响,导致亚洲高山水生生态系统返回到自然变暖环境下的状态,从而加速亚洲高山湖泊发生富营养化,加剧高山湖泊生态系统退化,可能挑战这一地区日益紧张的淡水供应形势。“在目前全球气候变暖背景下,该项研究首次揭示了气溶胶污染对生态系统的可能潜在影响,为评估亚洲水生生态环境变化提供了科学依据。”陈发虎说。

Jianbao Liu; Kathleen M. Rühland; Jianhui Chen; et al

  Anthropogenic aerosol increases over the past few decades have weakened the Asian summer monsoon with potentially far-reaching socio-economic and ecological repercussions. However, it is unknown how these changes will affect freshwater ecosystems that are important to densely populated regions of Asia. High-resolution diatom records and other proxy data archived in lake sediment cores from the Chinese Loess Plateau allow the comparison of summer monsoon intensity, lake trophic status and aquatic ecosystem responses during warming periods over the past two millennia. Here we show that an abrupt shift towards eutrophic limnological conditions coincided with historical warming episodes, marked by increased wind intensity and summer monsoon rainfall leading to phosphorus-laden soil erosion and natural lake fertilization. In contrast, aerosol-affected Anthropocene warming catalysed a marked weakening in summer monsoon intensity leading to decreases in soil erosion and lake mixing. The recent warm period triggered a strikingly different aquatic ecosystem response with a limnological regime shift marked by turnover in diatom species composition now dominated by oligotrophic taxa, consistent with reductions in nutrient fertilization, reduced ice cover and increased thermal stratification. Anthropogenic aerosols have altered climate–monsoon dynamics that are unparalleled in the past ~2,000 years, ushering in a new ecological state.

  (来源:Nature Climate Change, 2017, 7: 190-194)

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