||General Introduction -- Oxygenic Photosynthetic Microorganisms in Extreme Environments -- Phototrophs at High and Low Light -- Effects of Ultraviolet Radiation on Cyanobacteria and their Protective Mechanisms -- The Hidden Life of Algae Underground -- Meromictic Lakes as Habitats for Protists -- Marine Phototrophs in the Twilight Zone -- Phototrophs in the Marine Environment -- Biology of the Chlorophyll D-Containing Cyanobacterium Acaryochloris Marina -- Phylogenetics, Molecular Biology and Ecological Impacts of a Group of Highly Unusual Protists -- Diatoms -- The Margin of the Sea -- Seaweeds on the Abrasion Platforms of the Intertidal Zone of Eastern Mediterranean Shores -- Status of Mangrove Ecosystem -- Intertidal Sandy Beaches as a Habitat Where Plastid Acquisition Processes are Ongoing -- Hydrochemical Key to the Genesis of Calcareous Nonlaminated and Laminated Cyanobacterial Microbialites -- Soil and Freshwater Micro-Algae as a Food Source for Invertebrates in Extreme Environments -- Phototrophs in Cold Environments -- Cold Tolerance in Cyanobacteria and Life in the Cryosphere -- Cyanobacteria in Antarctic Lake Environments -- Green Cryosestic Algae -- Psychrophilic Diatoms -- Algae at Extreme Low Temperatures -- Phototrophs in Hot Alkaline and Acidic Environments and Non-Thermal Acidic Habitats -- Cyanidiophyceae -- Diversity of the Cosmopolitan Thermophile Mastigocladus laminosus at Global, Regional and Local Scales -- The Thermophilic Cyanobacteria of the Zerka Ma'in Thermal Springs in Jordan -- Iron-Tolerant Cyanobacteria -- Extreme Acidophiles -- Eukaryotic Community Structure from Río Tinto (SW, Spain), a Highly Acidic River -- Species Composition of Cyanidiales Assemblages in Pisciarelli (Campi Flegrei, Italy) and Description of Galdieria Phlegrea SP. NOV -- A Genomics Approach to Understanding the Biology of Thermo-Acidophilic Red Algae -- Enigmatic Archaeal and Eukaryotic Life at Hydrothermal Vents and in Marine Subsurface Sediments -- Phototrophs Under Water Stress: Dry and Hypersaline Environments -- North American Desert Microbiotic Soil Crust Communities -- Chroococcidiopsis from Desert to Mars -- Chlorophyta on Land -- Aeroterrestrial Algae Growing on Man-Made Surfaces -- The Systematics of Subaerial Algae -- Diversity, Distribution and Ecology of Green Algae and Cyanobacteria in Urban Habitats -- Diversity of Organic Osmotic Compounds and Osmotic Adaptation in Cyanobacteria and Algae -- Adaptation of Algae to Changing Environments -- Cyanobacteria -- Life in a Hypervariable Environment -- Other Microorganisms and Extreme Habitats -- The Fate of Biological Materials in Acidic Environments of the Río Tinto, Southwestern Spain -- Deep-Sea Microbial Eukaryotes in Anoxic, Microoxic, and Sulfidic Environments -- Fungal Associations at the Cold Edge of Life -- The Early Earth's Record of Supposed Extremophilic Bacteria and Cyanobacteria, at 3.8 to 2.5 GA -- Outlook-Summary -- Algae and Cyanobacteria Under Environmental Extremes. ALGAE AND CYANOBACTRIA IN EXTREME ENVIRONMENTS is a unique collection of essays, contributed by leading scientists from around the world, devoted to algae - and some related microbes - observed in unexpected harsh habits, which it seems are an oasis or Garden of Eden for these organisms. This timely book on Extremophilic alga, including its especially impressive micrographs, may provide clues about the edges of life on Earth and possibly elsewhere in the universe. Defining locations from the anthropomorphic point of view, the environments explored ranges from severe and distant to "normal" places. The algae discussed, microbial oxygenic phototrophs, are classified into various categories according to their habitats. They thrive in various temperature ranges, at the limits of pH values, in salt solutions, under UV radiation, dryness, heavy metals, anaerobic niches, under various levels of illuminations, and under hydrostatic pressure. Authors discuss bio-diversely algal territories ecologically - the hot springs with the thermophiles or acido-thermophiles; Antarctica, the Artic, and permafrost zones with their cold lovers (Psychrophiles); soda lakes with the alkaliphiles, saltine areas with halophiles. In addition to general essays, Algal species discussed in detail include diatoms, Cyanidium, Galdieria, Dunaliella, and Chroococcidiopsis. This volume is a must for students of the field of biodiversity, as well as those in Phycology, ecology and general biological research.