University of Colorado at Boulder

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Graduate Student Alumni

John Knowles

Biogeochemistry; Hydrology; Ecosystem ecology

Ph.D. Geography 2015

Physical Geography
Peter Blanken (Faculty Advisor)

Thesis

2015 - Spacio-temporal patterns of soil respiration and the age of respired carbon from high-elevataion alpine tundra.

Research Interests

My principal research aims to constrain the water and carbon cycle of alpine tundra at Niwot Ridge, Colorado. Alpine ecosystems are vital to resource management and may be especially sensitive climate change indicators, but inherently remote and rugged terrain makes these areas traditionally difficult to research. To better understand the biological underpinnings of this system, I have implemented a multi-scale approach designed to capture both the plot-scale variability and whole-ecosystem magnitude of carbon and water fluxes to the atmosphere. My research also considers the meteorological drivers, overarching cause, and potential impacts of an observed carbon cycle imbalance through the use of modeling and radiocarbon dating techniques.

Selected Publications

Burns SP, Molotch NP, Williams MW, Knowles JF, Seok B, Monson RK, Turnsipseed AA, Blanken PD. (2014). Snow temperature changes within a seasonal snowpack and their relationship to turbulent fluxes of sensible and latent heat. Journal of Hydrometeorology 15: 117-142.

Knowles JF, Burns SP, Blanken PD, Monson RK. (2014). Fluxes of energy, water, and carbon dioxide from mountain ecosystems at Niwot Ridge, Colorado. Plant Ecology & Diversity. doi:10.1080/17550874.2014.904950

Knowles JF, Blanken PD, Williams MW, Chowanski KM. (2012). Energy and surface moisture seasonally limit evaporation and sublimation from snow-free alpine tundra. Agricultural and Forest Meteorology 157: 106-115.

Blanken PD, Williams MW, Burns SP, Monson RK, Knowles J, Chowanski K, Ackerman T . (2009). A comparison of water and carbon dioxide exchange at a windy alpine tundra and subalpine forest site near Niwot Ridge, Colorado. Biogeochemistry 95(1): 61-76.

Publications updated May 2014

Recent courses taught