Aftermath of Creation
The sinter cone of Castle Geyser is thousands of years old, sitting on an even older platform and is the largest sinter formation in the world. Castle erupts every 13 hours for 20 minutes and its fountain reaches a height of 75 feet (24 m). The eruption is followed by a noisy steam phase of 30 to 40 minutes. The chemistry of the water, especially its acidity and its temperature are essential for the species of microorganisms thriving in it. The hydrothermal waters of the Upper Geyser Basins are neutral to weak alkaline and dissolve several minerals from the volcanic bedrock underground. It is an ideal biotope for thermophile microorganisms living in 131°F (55°C) hot water. The red to brownish microbial mats contains bacteria that feed on iron. The iron oxide contains traces of toxic arsenic and mercury that the microbes adopted to tolerate. The light of dusk is additionally caused by smoke of a nearby forest fire. The smoky scenery reflects in the calm waters of the geyser.
August 2008
Canon 20D, Canon EF-S 10-22mm, f/22, 2 sec, ISO 100, tripod