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Niwot Ridge. By: Kate Edwards. GEOG 4401/5401 Soils Geography Fall 2007 – Univ of Colorado, Boulder. Niwot Ridge is located approximately 35 km west of Boulder, Colorado Lying above 3000 m elevation
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Niwot Ridge By: Kate Edwards GEOG 4401/5401 Soils Geography Fall 2007 – Univ of Colorado, Boulder
Niwot Ridge is located approximately 35 km west of Boulder, Colorado Lying above 3000 m elevation This region is composed of sub-alpine forests, extensive alpine tundra, a variety of glacial landforms, talus slopes, and permafrost. Location
Niwot Ridge Landscape • Talus soils: • Snow-covered and barren • Wet meadow tundra soils: • Carex scopulorum • Dry meadow tundra Soils: • Tussock-forming sedge Kobresia myosuroides
Talus Slopes and Glaciated Region Wet Meadow Tundra Dry Meadow Tundra
Climate • Low temperatures throughout the year • Annual mean temperature at -3.7 degrees Celsius • Mean annual precipitation is about 930 mm • Most occurs as snow during the Winter and Spring. • High solar radiation, high wind velocities, and abbreviated growing seasons
Wrong Assumptions • Microbial growth under snow does not ceases at low temperatures • Microbial growth is an important contributor to primary productivity during the short alpine tundra growing season.
Microbial Diversity in Alpine Tundra Wet Meadow Soil: • The soils are acidic (pH from 4.3 to 5.3) and are classified as loamy-skeletal histic pergalic Cryaquepts.
Soil Characteristics along Seasonal Gradient • Spring periods have long-term temperature stability near 0 degrees Celsius. • Spring snow melt increases microbial community complexity and diversity. • Bacterial and Archaea diversity was amplified from saturated spring soil.
Soil Depth Gradient • Bacteria diversity and complexity shifts along depth gradient. • Bacterial community profile occurred at the surface to subsurface transition.
Summary • Microbial growth does exsist in frozen soils. • Snow melt during the Spring increases microbial community complexity and diversity in alpine tundra soils. • Bacterial community occurs at the surface to subsurface transition.
References: • Costello, Elizabeth, Meyer, Allen, Nemergut, Diana, Pescador, Monte, Schmidt, Steven, Weintraub, Michael. “Structure and Function of Alpine and Arctic Soil Microbial communities”.Science Direct. 12/1/07 www.sciencedirect.com • Costello, Elizabeth, Schimidt, Steven. “Microbial Diversity in Alpine Tundra Wet Meadow Soil”. Environmental Microbiology (2006) 8(8), 1471-1486. 12/1/07. <www.iternet.edu/sites/>