Environmental review of geyser basins: resources, scarcity, threats, and benefits

The world's geysers are known for providing one of nature's most unusual water spectacles, with most sending water upwards of about 3 m, but a few "grand" or tall geysers erupt to heights of 60 m or more. A geyser basin is a composite resource made up of geysers and hot springs that cluster around a common hydrothermal reservoir, and might also contain other hydrothermal features like fumaroles and mud pots. The world's remaining geyser basins are exceptionally rare, and are increasingly important recreation, economic, scientific, cultural, spiritual, therapeutic, and national heritage assets. Geyser basins harbor thermophilic microorganisms that contain heat-adapted biomolecules that can be harvested to provide vital components for DNA testing, and other high-temperature industrial processes. However, geysers and other surface hydrothermal features are increasingly vulnerable, and can be quickly and irreversibly damaged. Energy development projects quenched about 249 geysers, or about half of all geysers that were not protected in a national park or reserve. About 100 geysers were driven to extinction in New Zealand, about 46 in Iceland, and about 48 in the USA. Sustaining the world's remaining geyser basins requires protecting the hydrothermal reservoirs that support them based on an integrated management approach that takes into account the distinctive characteristics of surface hydrothermal features and the benefits that society derives from them. A framework is provided that defines geyser basin resources, the scarcity of the remaining geysers, the environmental threats, and preservation benefits. Multiple case studies of mass geyser extinction are highlighted, including a summary of the landscape changes that can accompany geothermal energy development.