Impact on the biological diversity in polar lakes affected by global environmental changes.

为了解2002-2005年全球环境变化对极地湖泊生物特征的影响，对东南极锡奥瓦站邻近地区的水样、湖底植被、沉积物岩心样品和湖泊研究项目提供的环境数据进行了调查，根据水温、盐度、溶解氧等将南极东部锡奥瓦站邻近地区的湖泊划分为4种类型(类型1-4)。类型1：冰川融水直接流入湖泊，类型2：融水通过溪流流入湖泊，类型3：来自雪床的融水流入湖泊，类型4：湖水源自海水。这些湖泊类型也与生物特征相对应。对西奥瓦站湖底水生苔藓植被和沉积物中的有机碳(TOC)、总氮(TN)、碳氢化合物、脂肪酸和甾醇等有机成分进行了研究，以阐明其与古环境变化的关系。近年来，水生苔藓(苔藓、细毛苔藓)与蓝藻等藻类共生，形成了一种独特的结构--苔藓支柱。我们对斯卡夫斯内斯湖中的苔藓柱进行了脂肪酸分析。中性脂脂肪酸(NLFA)主要分布在外部和内部，并与下部和下部不同的细菌群有局部联系。干重、碳、氮和叶绿素在苔藓柱中的分布呈异质性，但主要集中在顶端。结果表明，苔藓柱生长广泛发生在苔藓顶端。根据AMS的方法，年龄估计在根尖下约20厘米处，大约250岁。

To know the influences to the biological features in the polar lakes by the global environmental changes during 2002-2005, water sample, lake bottom vegetation, sediment core samples and environmental data given on the lake research project were investigated.Based on the water temperature, salinity, dissolved oxygen and so on, lakes located at the adjacent area of Syowa Station, East Antarctica were categorized to four types (Type 1-4). Type 1 : melt water from glacier flows directly into lakes, Type 2 : melt water flows into lakes through stream, Type 3 : melt water from snow beds flows into lakes and Type 4 : lake water originates from sea water. These lake types also correspond with the biological features. Organic component such as total organic carbon (TOC), total nitrogen (TN), hydrocarbon, fatty acids and sterols in aquatic moss vegetation and sediment core from lake bottoms from the Syowa Station area were studied to clarify their features in relation to paleo-environmental change.Aquatic mosses (Bryum, Leptobryum) have been recently known to form a unique structure called "moss pillar", in association with algae including cyanobacteria. We have studied a moss pillar from the lake in Skarvsnes by fatty acid analysis. Neutral lipid fatty acid (NLFA) profiles were largely groped exterior and interior parts and locally associated with different bacterial groups in the lower-interior and lower-exterior parts. Dry weight, carbon, nitrogen and chlorophyll distributions in the moss pillar took heterogeneous pattern, but they were largely centered at apical parts. It is suggested that growth of moss pillar occurred extensively at the apical part. The age was estimated ca.250 years at ca.20 cm below the apical top by the AMS method.