for National Geographic News
Old Faithful may not be so faithful anymore.
A long-term study of Yellowstone National Park's iconic geysers suggests that dry spells caused by climate change are slowing—and may even stop—the geysers' clockwork-regular eruptions.
Between 1998 and 2006, researchers monitored the schedule of five of the park's geysers using temperature sensors.
The two best known geysers showed the most changes: The time between Old Faithful's eruptions shifted from an hour 15 minutes to an hour 31 minutes, while Daisy Geyser's interval shifted from an hour 40 minutes to two hours 50 minutes.
"Geysers are different from steam vents, mud pots, and hot springs—they have eruptions," said study leader Shaul Hurwitz at the U.S. Geological Survey in Menlo Park, California.
"We wanted to know if we could learn something about Yellowstone's hydrothermal system by analyzing the intervals between these eruptions."
While much remains unknown about how geysers respond to small changes in the environment, clear long-term trends are emerging, the researchers say.
The study appeared in the June issue of the journal Geology.
Yellowstone's most famous geysers, especially Old Faithful, are known for the regularity of their eruptions—it's a pattern solid enough for tourists to make plans around.
But geysers depend upon a unique combination of water supply, heat, and rock fractures, Hurwitz pointed out.
(Related: "Supervolcano Raises Yellowstone, Fuels Geysers, Study Says" [March 1, 2006].)
SOURCES AND RELATED WEB SITES