College of Natural Science & Mathematics


Students receiving PhDs

Class of 2013

Doctor of Philosophy Degrees for College of Natural Science and Mathematics

Peter Bieniek *
Ph.D. Atmospheric Sciences
Dissertation Title: Assessing River Ice Breakup Date, Coastal Tundra Vegetation and Climate Division in the Context of Alaska Climate Variability

Large-scale drivers of Alaska climate were investigated to advance seasonal forecasting. River ice breakup is earlier when spring temperatures are higher under clearer skies from reduced storminess. Objective methods revealed 13 climate divisions for Alaska, based on homogenous variability. Tundra vegetation responds to snow and sea ice, which impact temperatures. 

Major Professor: Dr. Uma Bhatt

Lori Bogren       
Ph.D. Biochemistry and Molecular Biology
Dissertation Title: Resistance to Multi-Organ Failure and Metabolic Alterations after Global Ischemia/Reperfusion in the Arctic Ground Squirrel

Physiological changes after global ischemia/reperfusion were compared between I/R injury-prone rats and I/R injury-resistant arctic ground squirrels. Arctic ground squirrels were resistant to organ damage, systemic inflammation, and multi organ failure after I/R. This resistance may stem from arctic ground squirrels’ resistance to metabolic alterations during I/R.

Major Professor: Dr. Kelly Drew

Maria Bray         
Ph.D. Biological Sciences
Dissertation Title: Physical Activity, Body Composition and their Associations with Health in Yup'ik People
Activity and the prevention of excess adiposity are important to good health. This dissertation highlights key findings regarding the accuracy of assessment tools for measuring physical activity and body composition, as well as the associations between physical activity and body composition with health-related variables in Yup’ik people.

Major Professor: Dr. Bert Boyer

Robin Bronen #             
Ph.D. Climate Change Adaptation and Human Rights: Interdisciplinary Program
Dissertation Title: Climate-Induced Community Relocations: Creating an Adaptive Governance Framework Based in Human Rights

In Alaska, decreasing Arctic sea ice and thawing permafrost are accelerating flooding and erosion and threatening indigenous communities. This dissertation describes the steps that federal, state, and tribal governments have taken to relocate three of these communities. Guiding human rights principles of climigration and an adaptive governance framework are proposed.  

Major Professor: Dr. F. Stuart “Terry” Chapin III

Helena Buurman                
Ph.D. Geophysics
Dissertation Title: Volcano Seismicity in Alaska

Volcanic earthquakes can show us how volcanic systems work. I use volcano seismicity to track the progression of magma as it moves through the crust during eruptions. I also examine 10 years of volcano seismic data recorded at 46 different volcanoes to determine what controls volcanic activity in Alaska.

Major Professor: Dr. Michael West

Nicole DeRoin #
Ph.D. Geophysics
Dissertation Title: Methods for Monitoring and Forecasting Volcanic Hazards and Eruptions Using Seismology and Other Geophysical Data

The relationship of seismicity and physical characteristics of eruption phenomena at three volcanoes was studied. Correlations between plume heights, rockfall sizes and rockfall run-out distances and seismicity were found. A method for detecting tremor was found by modeling duration-amplitude distributions of volcanic tremor with an exponential law.

Major Professor: Dr. Stephen McNutt

Yuning Fu #         
Ph.D. Geophysics
Dissertation Title: Loading Deformation on Various Timescales Using GPS and GRACE Measurements

The effect of using inconsistent reference frame to correct Ocean Tidal Loading on GPS coordinate solutions was examined. Two geodetic observations, GPS and GRACE, were used to investigate the seasonal and long-term loading deformation in the Nepalese Himalaya, and seasonal hydrology loading effects in southern Alaska.

Major Professor: Dr. Jeffrey Freymueller

Ronni Grapenthin *          
Ph.D. Geophysics
Dissertation Title: Volcano Deformation and Subdaily GPS Products

Daily averages of GPS positions are utilized to infer characteristics of the magmatic systems of Redoubt (Alaska) and Bezymianny (Kamchatka) volcanoes. Subdaily GPS data is used to visualize and analyze the dynamics of the 2011 Tohoku earthquake (Japan) and to demonstrate the detectability of volcanic plumes in GPS data.

Major Professor: Dr. Jeffrey Freymueller

Sarah Henton     
Ph.D. Geology
Dissertation Title: Experiment vs. Nature: Using Amphiboles to Test Models of Magma Storage and Pre-Eruptive Magma Dynamics Preceding the 2006 Eruption of Augustine Volcano, Alaska

An investigation of magma storage and pre-eruptive magma heating preceding the 2006 eruption of Augustine Volcano, Alaska. This study used techniques in petrology and experimental petrology to refine models of the magmatic pulling system of one of Alaska's most active volcanoes. 

Major Professor: Dr. Jessica Larsen

Keiko Herrick    
Ph.D. Biological Sciences
Dissertation Title: Predictive Modeling of Avian Influenza in Wild Birds

Using the Random Forests algorithm, I constructed predictive models for avian influenza virus in wild birds. Various algorithms were evaluated to correct highly imbalanced prevalence often found in wildlife surveillance data. Cold regions consistently displayed the highest relative predicted occurrence scores over the warm and temperate regions usually modeled.

Major Professor: Dr. Falk Huettmann and Dr. Barbara Taylor

Kimberly Iceman               
Ph.D. Biological Sciences
Dissertation Title: Raphé Chemosensory Amplifier: A CO2-Sensitive Brain Network

Three distinct types of brainstem raphé neurons sensitive to CO2/pH were electrophysiologically and histologically characterized in an intact rodent system. Results suggest that together these chemosensitive neuron groups interact as a “raphé chemosensory amplifier” network to sense and respond to changes in tissue CO2/pH, affect ventilation, and promote homeostasis.

Major Professor: Dr. Michael Harris

Elchin Jafarov     
Ph.D. Geology and Geophysics
Dissertation Title: The Effects of Changes in Climate and Other Environmental Factors on Permafrost Evolution

The central objective in this study was to predict permafrost thermal dynamics during the 21st century using high resolution climate datasets. As an additional outcome of this objective, permafrost modeling was improved by using better snow parametrization methods and addressing consequences of forest fires on permafrost.

Major Professor: Dr. Vladimir Romanovsky

Poul Jensen          
Ph.D. Space Physics
Dissertation Title: Analysis of Methods for Solar Wind Propagation from Lagrangian Point L1 to Earth

Several methods for extrapolating solar wind data from an upstream location (Lagrangian Point L1) to the magnetosphere using data from a single satellite were explored. Results may help improve accuracy of such extrapolated data, which is widely used for magnetospheric research and short-term forecasting of geomagnetic activity.

Major Professor: Dr. William Bristow

Ryan Kovach #   
Ph.D. Biological Sciences: Wildlife Biology
Dissertation Title: Salmonid Phenology, Microevolution, and Genetic Variation in a Warming Alaskan Stream

A critical question in ecology is how populations will respond to climate warming. Long-term demographic, genetic, and environmental data were used to determine the patterns, mechanisms, and consequences of climate-induced changes in salmon migration timing. Migration timing shifted substantially, partially due to evolution, but abundances and genetic diversity were stable.

Major Professor: Dr. David Tallmon and Dr. Mark Lindberg   

Dominick Lemas #            
Ph.D. Biochemistry and Molecular Biology
Dissertation Title: Gene-by-Diet Interactions and Obesity Among Yup’ik People Living in Southwest Alaska

An investigation of gene-by-diet interactions that modified genetic risk of developing obesity in Yup’ik people used genetic markers in obesity candidate genes and nitrogen stable isotope ratios of red blood cells as a biomarker for marine-derived n-3 polyunsaturated fatty acids intake to evaluate changes in obesity-related phenotypes.

Major Professor: Dr. Bert Boyer

Carolyn Levings #
Ph.D. Botany: Interdisciplinary Program
Dissertation Title: Anatomical and Mechanical Characteristics of Woods Used to Manufacture Bassoons

Bassoon resonant and non-resonant woods were compared and found to be statistically different using anatomy and tapping. Two Alaska hardwoods were compared to the resonant and non-resonant woods and found to group with the non-resonant wood. Lists of resonant characters and resonant North American hardwoods (incomplete) were compiled.

Major Professor: Dr. Valerie Barber

Taryn Lopez        
Ph.D. Environmental Chemistry
Dissertation Title: Characterization and Interpretation of Volcanic Activity at Redoubt, Bezymianny and Karymsky Volcanoes Through Direct and Remote Measurements of Volcanic Emissions

Volcanic emissions measurements can be used to characterize eruptive activity and infer subsurface processes at active volcanoes. This dissertation uses direct and remote volcanic emissions measurements to: (1) quantify SO2 emissions from Redoubt Volcano, (2) detect magma ascent at Bezymianny Volcano, and (3) remotely characterize diverse activity at Karymsky Volcano.

Major Professor: Dr. Catherine Cahill

Xuanye Ma #        
Ph.D. Space Physics
Dissertation Title: Kelvin-Helmholtz Instability and Magnetic Reconnection at the Earth’s Magnetospheric Boundary

Entropy can strongly increase only for small inflow plasma beta conditions. A field-aligned current can be generated by a guide magnetic field, a perpendicular shear flow, and inclusion of Hall physics. Magnetic reconnection is strongly modified by mutual interaction with Kelvin-Helmholtz modes for southward interplanetary magnetic field conditions.

Major Professor: Dr. Antonius Otto and Dr. Curt Szuberla

Jacob Mongrain #               
Ph.D. Geology
Dissertation Title: Depositional Systems, Paleoclimate, and Provenance of the Late Miocene to Pliocene Beluga and Sterling Formations, Cook Inlet Forearc Basin, Alaska

Investigation of the Beluga and Sterling formations of the Cook Inlet forearc basin, Alaska, revealed significant differences in depositional style. These differences are ascribed to sediment-flux changes between transverse-axial dominated (Beluga Fm.) and axial dominated (Sterling Fm.) fluvial systems attributed to exhumation in the Alaska Range ~11 Ma.

Major Professor: Dr. Paul McCarthy

Sarah Nash
Ph.D. Biological Sciences
Dissertation Title: Developing Stable Isotope Biomarkers of Yup'ik Traditional and Market Foods to Detect Associations with Chronic Disease Risk

This dissertation validated biomarkers of Yup’ik traditional and market food intake based on naturally occurring variations in carbon and nitrogen stable isotope ratios. It then presented applications of these biomarkers to investigate dietary patterns and associations of diet with chronic disease risk factors in Yup’ik people.

Major Professor: Dr. Diane O'Brien

Owen Neill           
Ph.D. Geology
Dissertation Title: Petrologic and Geochemical Tracers of Magmatic Movement in Volcanic Arc Systems: Case Studies from the Aleutian Islands and Kamchatka, Russia

In this dissertation, different geochemical tracers are used to investigate magmatic processes at Kasatochi Island volcano, located in the Aleutian Islands, and at Bezymianny Volcano, located in Kamchatka, Russia.

Major Professor: Dr. Pavel Izbekov and Dr. Jessica Larsen

Amanda Robertson #     
Ph.D. Biological Sciences
Dissertation Title: Acclimation and Migration Potential of a Boreal Forest Tree, Balsam Poplar (Populus Balsamifera L.) in a Changing Climate

Within a species, local adaptation may cause populations to respond differently to climate change. I investigated the roles of acclimation and adaptation in tree-growth responses to increased temperature. Growth of balsam poplar increased 27 – 69percent due to 3 – 8 degree Celsius experimental warming, and differed among populations. Projected climate-change impacts should include population-level differences.

Major Professor: Dr. Matthew Olson and Dr. Naoki Takebayashi

James Stone         
Ph.D. Biological Sciences
Dissertation Title: Experimental and Theoretical Studies of the Pollination Ecology of Gynodioecy

Gynodioecy, describing populations of females and hermaphrodites, is surprisingly common among plants. Pollination ecology helps account for this prevalence as well as the remarkable variation observed in gynodioecious sex ratios. I use theoretical and empirical approaches to describe pollinators' role in the evolution and maintenance of gynodioecy.

Major Professor: Dr. Matthew Olson and Dr. Naoki Takebayashi

Huy Nguyen Tran #
Ph.D. Atmospheric Sciences
Dissertation Title: Analysis of Model and Observation Data for the Development of a Public Pm2.5 Air-Quality Advisories Tool

An air-quality advisory tool that combines mobile measurements of particulate matter less than or equal to 2.5μm in diameter (PM2.5) with outputs of an air-quality model was developed to interpolate PM2.5-measurements into unmonitored neighborhoods in Fairbanks, Alaska, and to provide a spatially differentiated public air-quality advisory.

Major Professor: Dr. Nicole Mölders

Heidi Weigner #                  
Ph.D. Biological Sciences
Dissertation Title: Freshwater Fish Biogeography in the Bering Glacier Region, Alaska

Bering Glacier, Alaska, is Earth’s largest surging glacier. Surges and retreats lead to a dynamic environment for aquatic communities. Purposes of this study are to characterize fish communities and provide information relevant to their management for BLM. Given Bering Glacier’s remoteness, little information exists regarding its fish communities.  

Major Professor: Dr. Kris Hundertmark and Dr. Frank von Hippel



*Summer degree recipient

#December degree recipient