Studies on past-environment by ice core analyses using microbial activities in the snow and ice

应用16SrRNA基因分析、RT-PCR和DGGE微生物群落分析等DNA分析新技术，对生物冰芯分析方法进行了改进。我们采集了俄罗斯阿拉泰、欧洲阿尔卑斯山、智利安第斯山脉、阿拉斯加等地的冰芯样品，并对冰芯中的雪藻、细菌、真菌和花粉等生物成分进行了分析。在所有这些分析中，我们可以表明，我们可以使用冰芯中的雪藻和花粉作为年层的良好标记，这对准确测定中纬度冰芯的年龄是有用的。我们还检测了南极冰芯中的细菌DNA，以期作为研究过去环境的新的环境标志。我们发现南极冰芯保存了许多古老的空气中的细菌，而…冰期和间冰期的冰芯中所包含的更多的生物群落有所不同。这些结果表明，如果我们能够确定细菌的来源，南极冰芯中的空气细菌可能会成为新的环境标志。因此，我们还开始了对亚马逊热带雨林释放的空气中细菌的初步采样和分析。亚马逊热带雨林可能是南极冰芯中储存细菌的来源之一。为了对世界各地的冰川生态系统进行比较研究，我们收集了以下地区的冰川微生物样本：俄罗斯阿拉泰、阿拉斯加山脉、欧洲阿尔卑斯山、智利安第斯山脉和乌干达的鲁文佐里山脉。通过用新的方法对这些样品进行分析，我们可以获得许多对了解冰川生态系统和改进生物冰芯分析具有重要意义的结果。例如，我们可以在冰雪中发现10多个适应寒冷环境的新细菌物种。这些分析的结果还表明，冰川上的细菌群落随着海拔的变化而变化。这一结果表明，冰芯中的细菌和雪藻一样可以作为新的环境标志，因为它们的生物量和物种组成随着环境条件的变化而变化。

We improved the method of biological ice-core analysis applying the following new techniques of DNA analysis, such as species identification by 16SrRNA gene analysis, RT-PCR and microbial community analysis by DGGE method. These improvements enabled identification and quantification of bacteria and cyanobacteria in the ice-cores and snow and ice samples which had been difficult with old techniques.We collected ice-core samples in Russian Altai, European Alps, Chilean Andes, Alaska and analyzed biotic contents in these cores, such as snow algae, bacteria, fungi and pollens. In all these analyses, we could show that we can use the snow algae and pollens in the ice core as a good markers for annual layers useful for accurate dating of mid-latitude ice cores. We also examined bacterial DNA in the Antarctic ice cores for potential use as new environmental markers for the study on the past environment. We found that the Antarctic ice core preserved many ancient airborne bacteria and that bac … More terial community contained in the ice core differed between the samples of glacial age and interglacial age. The results suggest that air borne bacteria in the Antarctic ice cores could be new environmental markers if we can identify the source of the bacteria. So, we also started preliminary sampling and analysis of airborne bacteria released from Amazonian tropical rain forest, one of the possible source of bacteria stored in the Antarctic ice cores.To make comparative studies among glacier ecosystems of various part of the world, we collected microbiologial samples at the glaciers of the following regions: Russian Altai, Alaska mountain-range, European Alps, Chilean Andes and Rwenzori mountains of Uganda. By analyzing these samples with new methods, we could obtain many results important to understand glacier ecosystems and improve biological ice-core analysis. For example, we could find more than 10 new bacterial species adapted to cold environment in the snow and ice. The results of these analyses also showed that bacterial community on the glacier changed depending on the altitude. The result implies that we can use bacteria in the ice core as new environmental markers as well as snow algae because their their biomass and species composition change with environmental condition.[ Less