Contents Foreword...... 4

Acknowledgment...... 5

Chapter 1: Introduction...... 10

1.1.1 Being an algae: one of the oldest jobs on Earth...... 13

1.1.2 Lichens: you better make it together...... 17

1.2 If it all comes together: biological soil crusts...... 19

1.3 Survival experts: how to conquer everything...... 22

1.4 Life at its edge: cryptogams as cosmopolitan extremophiles...... 26

1.5 Hidden diversity: microhabitats and biogeography...... 29

1.6 Projects and sites of this thesis...... 33

1.6.1 The Arctic, Antarctic and European Alpine sites...... 36

1.6.2 The precipitation gradient along the Chilean Cordillera...... 38

1.6.3 The Atacama Desert...... 40

1.7 Aims and course of this thesis...... 43

Chapter 2: Biodiversity Coldspot: structure and richness of Arctic, Antarctic and European Alpine biocrusts...... 46

Uncovering biological soil crusts: carbon content and structure of intact Arctic, Antarctic and alpine biological soil crusts...... 47 Genus richness of microalgae and Cyanobacteria in biological soil crusts from Svalbard and Livingston Island: morphological versus molecular approaches...... 61 Strong in combination: Polyphasic approach enhances arguments for cold-assigned cyanobacterial endemism...... 78 Assessing recovery of biological soil crusts across a latitudinal gradient in Western Europe...... 94 Chapter 3: Precipitation gradient of the Chilean Coastal Cordillera: variability and geochemical cycling of biocrusts...... 108

Pedogenic and microbial interrelations to regional climate and local topography: New insights from a climate gradient (arid to humid) along the Coastal Cordillera of Chile...... 109 Biological soil crusts along a climatic gradient in Chile: Richness and imprints of phototrophic microorganisms in phosphorus biogeochemical cycling...... 132 7 Chapter 4: Sophisticated systems: ecological niches of cryptogams in the Atacama Desert and their adaptations...... 149

A Case Study on Fog/Low Stratus Occurrence at Las Lomitas, Atacama Desert (Chile) as a Water Source for Biological Soil Crusts...... 150 Distinct Refugia: edaphic and lithic cyanobacterial communities of the Atacama Desert...... 168 Estimating Net Photosynthesis of Biological Soil Crusts in the Atacama Using Hyperspectral Remote Sensing...... 219 Desert breath - the Atacama Desert's unexpected living skin...... 238 Chapter 5: Synthesis...... 265

5.1 Microhabitats matter...... 266 5.2 Diversity patterns of functional groups...... 270 5.3 Biogeography of cyanobacteria...... 275 6. Outlook...... 279

7. Summary...... 281

8. References...... 283

9. Appendix...... 290

9.1 Scientific comic: Uncovering the Earth's skin...... 290 9.2 Cyanobacterial micrographs...... 294 9.3 Curriculum Vitae...... 296 9.4 Declaration...... 298

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