PARENT SESSION
Poster Session #36: Mycorrhizal Fungi and Root Processes.
Thursday, August 9, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

Mycorrhizae in hydrothermally-altered soils of Yellowstone National Park.

Bunn, Rebecca¹, Zabinski, Catherine¹, ¹

ABSTRACT- While studies have documented the presence of arbuscular mycorrhizal fungi (AMF) in alpine, arid and other high-stress environments, most research on mycorrhizal ecology has taken place in relatively low-stress environments. Our research focused on mycorrhizae in a little-explored high-stress environment, the hydrothermally-altered soils of Yellowstone National Park. These sites are characterized by sparse vegetation cover, neutral to acidic soils, elevated rooting zone temperatures (up to 57^oC), low phosphorous levels, and toxic concentrations of various elements. Mycorrhizae are thought to be important at hydrothermal sites, but no published data exists documenting their presence. Plants from five different hydrothermal sites in Yellowstone were analyzed for mycorrhizal colonization levels. Mycorrhizae were found in plants growing in soil temperatures up to 48^oC and soil pH values down to 3.4. Soil was also collected from sparsely and continuously vegetated zones at one site. Zones differed significantly in average soil rooting temperature (35 vs. 26 ^oC), acidity (pH 3.8 vs. 5.4), electrical conductivity (2.2 vs 0.49 mmhos cm^-1), available iron (181.3 vs. 48.5 mg Kg^-1), available manganese (7.2 vs. 98.2 mg Kg^-1), available zinc (2.3 vs. 4.5 mg Kg^-1), and MIP (26 vs. 46%). We have shown that AMF are present in these soils and that plants at hydrothermal sites are mycorrhizal. Our continuing research focuses on the mycorrhizae effects on plant growth across environmental gradients at hydrothermal areas.

KEY WORDS: mycorrhizae, hydrothermal, high-stress environments, yellowstone