Diversity of microalgae and cyanobacteria communities in Antarctic soils: changes along soil developmentalstages and abiotic variables and testing for endemism/geographical distribution

南极土壤是研究迄今尚未开发的土壤微藻和蓝藻的特殊特征的理想场所。其中包括在营养贫乏的年轻土壤的定居以及在没有人为影响的情况下土壤微藻群落的发展以及在恶劣环境条件下维管植物复盖的情况下推断先锋物种。该项目的中心研究问题是测试藻类/蓝藻土壤群落的变化与土壤的不同发育阶段、(生物)风化的不同阶段以及一系列非生物土壤变量之间的可能相关性。这些分析将阐明微藻和蓝藻在为年轻土壤提供生物风化过程所需能量方面的作用，以及它们对地球化学循环的贡献。最后，这些分析将允许推断南极土壤藻类可能的功能/生态生理特征。还将调查南极洲的地理位置偏远及其特殊的恶劣环境条件是否允许发展在基因水平上有别于温带地区的特别适应的南极土壤藻类种群。将调查南极冰川前区(南极海洋和东南极大陆)以及干燥的多边形土壤(Coal Nunatak)沿时间序列的土壤样本。将提供它们，并通过SPP 1158内的合作确定它们的非生物变量。我们的初步结果已经表明，在两个冰川FOREFIELD年代序列上，绿藻门、克雷伯索米亚和黄藻门在不同的土壤发育阶段都存在，这是利用独立于培养的组特异性PCR扩增和测序得到的。

Antarctic soils are ideal places to study particular features of soil microalgae and cyanobacteria left unexplored so far. These include inferring pioneer species at the colonization of young soils poor in nutrients and the development of soil microalgal communities without anthropogenic influence and that of vascular plant cover under harsh environmental conditions. The central research question of the project is to test for possible correlations of changes in algal/cyanobacteria soil communities with various developmental stages of soil, at different stages of (biogenic) weathering as well as a of a range of abiotic soil variables. The analyses will clarify the role of microalgae and cyanobacteria in the fueling of young soils with energy for biogenic weathering processes as well as their contribution to geochemical cycles. Finally, the analyses will allow inferring possible functional/ecophysiological traits of Antarctic soil algae. It will also be investigated whether the geographical remoteness of Antarctica and its particular harsh environmental conditions allowed for the development of particularly adapted Antarctic soil algal populations distinct at the genotypic level from their counterparts of temperate regions. Soil samples along chronosequences from Antarctic glacier forefields (Maritime Antarctica and East Antarctica Continent), but also the dryer Polygon soils (Coal Nunatak) will be investigated. They will be provided and their abiotic variables determined through collaborations within the SPP 1158. Our preliminary results already showed the presence of Chlorophyta, Klebsormidium and Xanthophyceae at different soil developmental stages along two glacier forefield chronosequences using culture-independent group-specific PCR amplification and sequencing.