Note: Intro -- Preface -- References -- Contents -- 1: A Brief Introduction to Hot Desert Environments: Climate, Geomorphology, Habitats, and Soils -- 1.1 Desert Climatology -- 1.1.1 Desert Precipitation -- 1.1.2 Drought -- 1.2 Desert Geomorphology -- 1.2.1 Desert Landscapes and Sediments -- 1.3 Desert Habitats -- 1.3.1 Introduction -- 1.3.2 Uplands, Inselbergs, and Rocky Outcrops -- 1.3.3 Drainage Systems -- 1.3.4 Saline Basins, Playas, and River End Points -- 1.3.5 Sand Plains and Sand Dunes -- 1.3.6 Desert Plains and Pediplains -- 1.4 Desert Soils -- 1.4.1 Semi-arid and Arid Soils -- 1.4.2 Introduction to Unconsolidated Porous Media -- 1.4.3 The Desert Pedoderm -- 1.4.4 Impeded Infiltration -- 1.4.5 Organic and Inorganic Carbon in Desert Soils -- 1.4.6 Nitrogen Dynamics in Desert Soils -- 1.5 Conclusion -- References -- 2: Novel Methods for Studying the Structure and Function of Hot Desert Microorganisms and Their Communities -- 2.1 Introduction -- 2.2 Multi-omics and Bioinformatic Advances to Explore Community Structure and Functional Potential -- 2.3 Approaches to Probe Active Members -- 2.4 Metabolomics for Studying Nutrient Exchange -- 2.5 High-Resolution Imaging to Resolve Microbial Environments -- 2.6 Conclusion and Future Perspectives -- References -- 3: Phototrophic Mats of the Desert: The Bacteria of the Biological Soil Crust Community -- 3.1 Introduction: What Constitutes a Biocrust? -- 3.2 Distribution of Biocrusts -- 3.3 Ecosystem Services of Biocrusts -- 3.3.1 Soil Stabilization -- 3.3.2 Water Infiltration -- 3.3.3 Nitrogen Fixation -- 3.3.4 Other Ecosystem Services of Biocrusts -- 3.4 The Bacteria of Biocrusts -- 3.4.1 Bacterial Diversity -- 3.4.2 Bacterial Taxonomy and Function in Biocrusts -- 3.4.2.1 Cyanobacteria -- 3.4.2.2 Structural Cyanobacteria -- 3.4.2.3 Cosmopolitan Cyanobacteria -- 3.4.2.4 Sporadic Cyanobacteria. , 3.4.3 Other Phototrophs -- 3.4.4 Heterotrophic Bacteria -- 3.5 Conclusion -- References -- 4: Microbial Ecology of Hot Desert Soils -- 4.1 Introduction -- 4.2 Hot Desert Edaphic Microbial Community Diversity and Assembly -- 4.2.1 Taxonomic Composition and Assembly Processes of Hot Desert Edaphic Communities -- 4.2.1.1 Prokaryotic Communities -- 4.2.1.2 Microeukaryotic Communities -- 4.2.1.3 The Hot Desert Soil Virosphere -- 4.2.2 Desert Soil Microbial Interactomes: Lessons from Co-occurrence Networks -- 4.3 Functional Properties of Desert Edaphic Communities -- 4.3.1 Desert Edaphic Communities Are Active During Dry Spells -- 4.3.2 The Impact of Water on Arid Soil Microbial Communities -- 4.4 Conclusions and Perspectives: Hot Desert Soil Microorganisms in a Changing World -- References -- 5: Biology of Desert Endolithic Habitats -- 5.1 Introduction -- 5.2 The Endolithic Community -- 5.3 Climate and Macroscopic Drivers of Diversity -- 5.4 The Rock Habitat -- 5.5 Adaptive Strategies and Metabolism -- 5.5.1 Metabolic Pathways -- 5.6 Conclusion and Future Directions -- References -- 6: Journey of a Thousand Miles: The Evolution of Our Understanding of Viruses in Hot Deserts -- 6.1 Introduction -- 6.2 Terrestrial Desert Phage Communities: Soil, Sand, and Rock -- 6.3 Aquatic Desert Phage Communities: Wadi´s, Gueltas, and Springs -- 6.4 Eukaryotic Viruses -- 6.5 Conclusion and Outlook -- References -- 7: C, N, and P Nutrient Cycling in Drylands -- 7.1 Carbon in Drylands Soils -- 7.1.1 Soil Organic Carbon in Drylands Soils -- 7.1.2 Soil Inorganic C in Drylands Soils -- 7.1.3 Biomass Organic C in Dryland Soils -- 7.1.3.1 Vegetation -- 7.1.3.2 Microbial Autotrophs -- 7.1.4 Carbon Sequestration and Loss: The Impact of Abiotic and Biotic Factors -- 7.2 Nitrogen in Dryland Soils -- 7.2.1 Biological Nitrogen Fixation (BNF) as N Input in Drylands. , 7.2.2 Atmospheric N Deposition and N Discharges as N Inputs in Drylands -- 7.2.3 Nitrogen Losses in Drylands -- 7.2.4 Nitrification and Denitrification in Desert Soils -- 7.3 Phosphorus in Dryland Soils -- 7.3.1 P Stocks and Redistribution by Biological Processes in Drylands -- 7.3.2 Abiotic and Biotic Control of P Cycling -- 7.4 Role of Biological Soil Crust in Nutrient (C, N, and P) Cycles -- 7.5 Influence of Hydration-Desiccation Pulses on Nutrient (C, N, and P) Cycles -- 7.6 Impact of Climate Change on Nutrient Cycling -- 7.7 Conclusion -- References -- 8: Diversity and Plant Growth-Promoting Properties of Microbiomes Associated with Plants in Desert Soils -- 8.1 Introduction -- 8.2 Plant-Associated Microorganisms in Hot Desert Biomes -- 8.2.1 Microorganisms Associated with Succulent Plants in Arid Ecosystems -- 8.2.2 Microorganisms Associated with the Rhizosheath-Root Systems of Xerophytic Desert Plants -- 8.2.3 Microorganisms Associated with Halophytes Inhabiting Arid Ecosystems -- 8.2.4 Microorganisms Associated with Oasis Date Palm, a Model Crop in Desert Agro-Ecosystems -- 8.3 PGP Microorganisms Associated with Desert-Adapted Plants as a Biotechnological Resource -- 8.3.1 Where to Select Valuable PGP Microorganisms Against Drought and Their Essential Features -- 8.3.2 How to Isolate Powerful PGP Microorganisms -- 8.3.3 The Functional Roles Exerted by Microorganisms Associated to Desert Plants -- 8.4 Conclusions -- References -- 9: Insights of Extreme Desert Ecology to the Habitats and Habitability of Mars -- 9.1 Introduction -- 9.2 Desert Habitats and Ecosystems on Earth -- 9.2.1 Soils -- 9.2.2 Lithic Substrates -- 9.2.3 Sediments -- 9.2.4 Salts -- 9.3 Insights from Extreme Desert Ecology -- 9.3.1 Trends of Ecological Change in Deserts -- 9.4 Potential Desert Habitats on Mars -- 9.4.1 Soils and Regolith -- 9.4.2 Lithic Substrates. , 9.4.3 Sediments of Potential Paleoplayas/Paleolakes on Mars -- 9.4.4 Salts -- 9.5 Extrapolating Terrestrial Deserts to Mars -- References -- 10: Survival under Stress: Microbial Adaptation in Hot Desert Soils -- 10.1 Introduction: Hot Deserts and Their Challenges to Life -- 10.2 Adaptation to Desiccation and Osmotic Stresses -- 10.2.1 Sporulation -- 10.3 Membrane Modifications -- 10.4 Accumulation of Compatible Solutes -- 10.5 Protein Protection -- 10.6 Biofilm Formation and EPS Production -- 10.7 Adaptation to Oligotrophy -- 10.8 Adaptations to UV Radiation -- 10.9 Temperature Adaptations -- 10.10 Concluding Remarks -- References -- 11: The Response of Soil Microbial Communities to Hydration and Desiccation Cycles in Hot Desert Ecosystems -- 11.1 Introduction to Desert Terminology -- 11.2 Response to Hydration in Desert Ecosystems -- 11.2.1 Rhythm of Plant Primary Production -- 11.2.2 Carbon Dioxide Pulse -- 11.2.3 Nitrogen Pulsing -- 11.3 Bacterial Composition in Desert Soils -- 11.3.1 Biological Soil Crust -- 11.3.2 Topsoil Community Composition -- 11.4 Soil Bacteria Response to Hydration-Desiccation Cycles in Desert Ecosystems -- 11.4.1 The Response of Desert Soil Bacteria to Desiccation -- 11.4.2 The Response of Desert Soil Bacteria to Hydration -- 11.4.3 Pulse Theory and Grime´s Hypothesis -- 11.5 Conclusion -- References -- 12: Hot Desert Microbiology: Perspectives in a Warming World -- References.