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Full-Text Articles in Physical Sciences and Mathematics

The Carbon Budget Impact Of Sagebrush Degradation, Andrew Connor Austreng May 2012

The Carbon Budget Impact Of Sagebrush Degradation, Andrew Connor Austreng

Boise State University Theses and Dissertations

More than 20,000 km2 of sagebrush (Artemesia spp.) ecosystems within the Great Basin have been replaced, often following wildfire, by the nonnative winter annual cheatgrass (Bromus tectorum). At a field site in the central Snake River Plain of southern Idaho, the impact of this invasion on the soil carbon (C) reservoir has been evaluated and the potential soil C benefits of bunchgrass (Agropyron cristatum) seeding was assessed. Using a large soil C dataset (n = 850), differences in total organic carbon and root biomass were quantified in immediately-adjacent sagebrush, cheatgrass, and bunchgrass communities. Statistical …


Quantifying Pedogenic Carbon Content Within The Boise River Terraces Using Pressurized Calcimetry, Dawn Jarrels, Annika Quick, Jennifer L. Pierce Apr 2012

Quantifying Pedogenic Carbon Content Within The Boise River Terraces Using Pressurized Calcimetry, Dawn Jarrels, Annika Quick, Jennifer L. Pierce

College of Arts and Sciences Poster Presentations

Soil carbon is the third largest carbon pool within the global carbon cycle; however, soil carbon amounts are not well quantified, and exchange rates of soil carbon are not well understood. Soil carbon can be divided into organic carbon and inorganic carbon, where inorganic carbon (pedogenic carbonate) is precipitated during soil formation and accumulates over time in semi-arid and arid environments. Calcic soils within the semiarid regions of the Boise Valley result from active pedogenic accumulation of secondary CaCO3 resulting in prominent 'caliche' layers in soils formed on many of the Boise River terraces. The larger goals of this …


Molecular Beam Epitaxy Approach To The Graphitization Of Gaas(100) Surfaces, Paul J. Simmonds, John Simon, Jerry M. Woodall, Minjoo Larry Lee May 2011

Molecular Beam Epitaxy Approach To The Graphitization Of Gaas(100) Surfaces, Paul J. Simmonds, John Simon, Jerry M. Woodall, Minjoo Larry Lee

Paul J. Simmonds

The authors present a method for obtaining graphitized carbon on GaAs(100) surfaces. Carbon-doped GaAs is grown by molecular beam epitaxy before controlled thermal etching within the growth chamber. An AlAs layer beneath the carbon-doped GaAs acts as a thermal etch stop. As the GaAs is etched away, the carbondopant atoms remain on the surface due to their low vapor pressure. The total number of carbon atoms available is precisely controllable by the doping density and thickness of the carbon-doped GaAs layer. Characteristic phonon modes in Raman spectra from the thermally etchedsurfaces show that the residual surfacecarbon atoms form sp2 …


Graphitized Carbon On Gaas(100) Substrates, J. Simon, P. J. Simmonds, J. M. Woodall, M. L. Lee Feb 2011

Graphitized Carbon On Gaas(100) Substrates, J. Simon, P. J. Simmonds, J. M. Woodall, M. L. Lee

Paul J. Simmonds

We report on the formation of graphitized carbon on GaAs(100) surfaces by molecular beam epitaxy. We grew highly carbon-doped GaAs on AlAs, which was then thermally etched in situ leaving behind carbon atoms on the surface. After thermal etching, Raman spectra revealed characteristic phonon modes for sp2-bonded carbon, consistent with the formation of graphitic crystallites. We estimate that the graphitic crystallites are 1.5–3 nm in size and demonstrate that crystallite domain size can be increased through the use of higher etch temperatures.


Identifying Controls On Surface Carbon Dioxide Efflux In A Semi-Arid Ecosystem, Katrina Elsie Ladd May 2010

Identifying Controls On Surface Carbon Dioxide Efflux In A Semi-Arid Ecosystem, Katrina Elsie Ladd

Boise State University Theses and Dissertations

This study focused on soil respiration, the least constrained process in the terrestrial carbon cycle, and a source of uncertainty for model predicted ecosystem response to climate change. Respiration processes that make up soil respiration respond to environmental influencing factors, temperature, and moisture. Respiration responses vary by site, time of year, and also year to year, confounding determination of individual influence of the factors, making soil respiration difficult to model. This research took advantage of the climate characteristics of a semi-arid system, in order to observe soil temperature and moisture influence on soil respiration. Field measurements of soil surface CO …