This thesis focuses on the investigation of extraterrestrial tracers Ir, Pt and 3He in polar ice cores. These tracers may be used to identify characteristics of interplanetary dust particles, and to quantify the flux of extraterrestrial material during impact events, certain volcanic eruptions, and stable background periods. In the first...
The major historical studies that have examined American
biology have emphasized the development of experimental biology at
the end of the nineteenth century. In this characterization, the
descriptive branch of biology has often been treated as less than
important and, in several cases, as a hindrance in the application
of...
Institutions of higher education are working to be more inclusive of underrepresented groups, including first-generation and low-income college students. Broadly, data show a significant population of diverse students are now entering higher education, but completion rates are comparatively lower than entry rates. To combat this, we need to evaluate ways...
According to the U.S. Census Bureau (2017), Latinx people are the fastest growing ethnic group in the nation but are least likely to enroll in institutions of higher education and fewer eventually earn a degree even if enrolled. Enrollment rates for Latinx students with migrant and seasonal farmworker (MSFW) background...
Methane is a product of biogeochemical processes which respond to changes in climate. The history of atmospheric methane is recorded by ice cores providing insight into past changes in these biogeochemical processes. This dissertation is comprised of three studies which focus on centennial- and millenial-scale variability of methane from ice...
Based upon the Pearson Type VIII distribution function,
a general retention function which relates the saturation to
the capillary pressure in disturbed soils has been discovered.
This simple and yet complete function has been
shown to describe precisely the imbibition as well as the
drainage branch of the retention curve....
Understanding how the latitudinal distribution of methane sources changed between stadial and interstadial climate states during the last glacial period can provide important clues about how terrestrial hydroclimate and ecosystems evolved between these different states. The punctuation of the millennial-scale structure by Heinrich events is also of interest in this...
The South Pole ice core (SPC14), drilled in the field seasons of 2014/2015 and 2015/2016, is an intermediate length, 1,751-m ice core which preserves a 54,000-year record of past climate and atmospheric composition. The SPC14 ice core adds to the spatial grid of ice cores in Antarctica extending into the...
Ice cores are considered the gold standard for recording past climate and biogeochemical changes. However, gas records derived from ice core analysis have until now been largely limited to centennial and longer timescales because sufficient temporal resolution and analytical precision have been lacking, except during rare times when atmospheric concentrations...