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为止尚未探索的土壤微藻和蓝藻的特定特征的理想场所。其中包括在营养贫乏的年轻土壤中推断拓荒者物种的定植，在没有人为影响的情况下推断土壤微藻群落的发展，以及在恶劣环境条件下推断维管植物覆盖的发展。该项目的中心研究问题是测试藻类/蓝藻土壤群落变化与土壤不同发育阶段、不同（生物）风化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生物风化过程中为年轻土壤提供能量的作用以及它们对地球化学循环的贡献。最后，分析将允许推断南极土壤藻类可能的功能/生态生理特性。还将调查南极洲的地理位置偏远及其特别恶劣的环境条件是否允许发展特别适应的南极土壤藻类种群，这些种群在基因型水平上与温带地区的同类不同。沿着南极冰川前田（南极海洋和南极东部大陆）的土壤样品，以及干燥的多边形土壤（Coal Nunatak）将进行研究。将通过spp1158内的合作提供它们并确定它们的非生物变量。我们的初步结果已经表明，在不同的土壤发育阶段，绿藻、克雷索兰和叶黄科植物沿着两个冰川前田时间序列存在于不同的土壤发育阶段。

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.