Diversity, ecology and age of endolithic cyanobacterial and algal communities from the Ross Desert, McMurdo Dry Valleys Antarctica

原生和真核藻类在岩石中生长是全球干旱/半干旱景观的普遍现象。虽然南极砂岩中的内石器群落得到了很好的描述，但我们对花岗岩和方解石中的这些群落的了解却很少。在2002/2003年的野外活动中，我们发现南极干谷的内生蓝藻生长比以前认为的要普遍得多。在方解石和花岗岩中分别测定了41和50 mg叶绿素a/m²。Bonani et al.（1988）确定Beacon砂岩的年龄为10³年。然而，我们确定花岗岩群落的年龄为~70年。虽然年龄测量只能是一个猜测，但从我们的结果中得出的结论是，生产力必须远远高于预期。水是限制因素，我们假设，除了雪融化，由温度反转的基质和空气凝结是一个频繁的供水。据我们所知，关于格陵兰岛北极岩石中石器时代群落的报道仅限于化石记录。来自格陵兰岛的第一个岩石样本揭示了一个以绿藻为主的繁茂生长的隐石器群落。我们将在本项目中详细描述它们。由蓝藻光合作用引起的生物碱化在热带硅酸盐岩石的风化中起着重要作用，这将是这里的另一个主要话题。

The presence of endolithic growth of pro- and eukaryotic algae in light penetrated rock parts is a common phenomenon of arid/semi-arid landscapes world wide. While endolithic communities from Antarctic sandstones are well described, our knowledge of these communities inside granite and calcite is sparse. During the field campaign 2002/2003, we found that endolithic cyanobacterial growth is much more common than previously thought in the Dry Valleys of Antarctica. 41 and 50 mg chlorophyll a/m² were determined in calcite and granite, respectively. Bonani et al. (1988) determined an age in Beacon sandstone in the order of magnitude of 10³ years. However, we determined an age of ~70 years for the granite communities. Although age measurements can only be a guess, concluded from our results, productivity must be by far higher than expected. Water is the limiting factor and we hypothesize, that in addition to snow melt, condensation by temperature reversal of substratum and air is a frequent water supply. Reports about endolithic communities in the rocks of Arctic Greenland are, to our knowledge, limited to the fossil record. A first rock sample from Greenland revealed a luxuriantly growing cryptoendolithic community dominated by green algae. We will characterize them in detail in this project. Bioalkalization due to photosynthetic activity of cyanobacteria plays a major role in the weathering of silicate rocks in the tropics and shall be another major topic here.