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Hydrothermal Influx


Close up view of a mud snail
Photo credit: Dan Gustafson, Montana State University

New Zealand mud snails, first found in Yellowstone in 1994, are now present in many of the park's streams. The mud snails are abundant in the Firehole River downstream of the thermal additions, but almost nonexistent in the upstream portion. Researchers think the numbers and distribution of New Zealand mud snails are determined more by changes in the river's chemistry rather than by temperature changes. Also algae, a major food source for the mud snails, are much more abundant in the thermally-influenced parts of the Firehole River.

The effect of the mud snails on fish is not fully known, although studies indicate that the snails can pass through a trout unharmed, while offering no nutritional value. The snails also consume algae, an important food source for fish.

Tens of thousands of empty mud snail shells

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This work is supported by

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