<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>32</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mass, Alex Q.</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Biogeochemistry, contaminant transport, and atmospheric exchange in glacial cryoconite meltwater of the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Department of Civil, Environmental, and Architectural Engineering</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">applied sciences</style></keyword><keyword><style  face="normal" font="default" size="100%">contaminant transport</style></keyword><keyword><style  face="normal" font="default" size="100%">cryoconite</style></keyword><keyword><style  face="normal" font="default" size="100%">earth sciences</style></keyword><keyword><style  face="normal" font="default" size="100%">glacier</style></keyword><keyword><style  face="normal" font="default" size="100%">hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">melt</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2018</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2018</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://search.proquest.com/docview/2048314678</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">University of Colorado</style></publisher><pub-location><style face="normal" font="default" size="100%">Boulder, CO</style></pub-location><volume><style face="normal" font="default" size="100%">Ph.D.</style></volume><pages><style face="normal" font="default" size="100%">245</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Polar regions serve as a global sink for many forms of semi-volatile pollution emitted from low- or midlatitudes of the populated world. This study examined the longrange atmospheric transport, fate, and phase partitioning of semi-volatile organic contaminants from air masses into meltwater and aeolian sediment on six glaciers in the McMurdo Dry Valleys of Antarctica. A novel low-cost, field-portable instrument was developed for the in-situ solid-phase extraction of trace contaminants in extreme environmental conditions without access to electricity or traditional laboratory facilities. Beyond polar research, this equipment is applicable for rapid field extraction and stabilization of samples assessing air and water quality after natural disasters. This is the first published study to identify the presence of anthropogenic perfluorinated compounds in the Transantarctic Mountain region and indicates a longer range of poleward contaminant transport than prior estimates in the Southern Hemisphere. Additional research examined the biochemistry and climatic variability of open and sealed cryoconite holes on glacial surfaces throughout the initial melt, equilibrium, and refreezing periods in 2013&amp;ndash;2015. High solute concentrations relative to glacial ice indicate that the pools can remain isolated from hydrologic connectivity for more than a decade. Microbial carbon cycling in pools enclosed by ice led to atmospheric disequilibrium and extreme pH. Analysis of unique air, liquid, and ice stratification in cryoconite holes revealed vertical patterns representing a highly accurate, multi-year record of past weather conditions sensitive enough to identify individual dates. This research identifies fluctuations in atmospheric contaminant transport, specific timeframes for deposition events, and may be used in back-trajectory models to help identify the source and variability of semi-volatile emissions in the Southern hemisphere.&lt;/p&gt;</style></abstract><work-type><style face="normal" font="default" size="100%">doctoral</style></work-type></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>32</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Khan, Alia L.</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Quantifying sources, distribution, and processing of light absorbing aerosols in the cryosphere: A comparison of dissolved and refractory black carbon in polar and high mountain regions</style></title><secondary-title><style face="normal" font="default" size="100%">Department of Civil and Environmental Engineering</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">applied sciences</style></keyword><keyword><style  face="normal" font="default" size="100%">black carbon</style></keyword><keyword><style  face="normal" font="default" size="100%">cryosphere</style></keyword><keyword><style  face="normal" font="default" size="100%">earth sciences</style></keyword><keyword><style  face="normal" font="default" size="100%">glacial melt</style></keyword><keyword><style  face="normal" font="default" size="100%">health and environmental sciences</style></keyword><keyword><style  face="normal" font="default" size="100%">light absorbing aerosols</style></keyword><keyword><style  face="normal" font="default" size="100%">polar regions</style></keyword><keyword><style  face="normal" font="default" size="100%">snow</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2016</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://search.proquest.com/docview/1834518541?accountid=14503</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">University of Colorado</style></publisher><pub-location><style face="normal" font="default" size="100%">Boulder, CO</style></pub-location><volume><style face="normal" font="default" size="100%">Ph.D.</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;div title=&quot;Page 4&quot;&gt;&lt;div&gt;&lt;div&gt;&lt;p&gt;Light absorbing aerosols (LAAs) in snow and ice are one of the least understood parameters in global climate models due to complicated physical processes within the cryosphere and too few&amp;nbsp;in situ&amp;nbsp;observations. Ground observations are limited due to the difficulty of collecting and preserving samples for analysis from remote environments.&lt;br /&gt;In order to help build a larger repository of ground observations, this dissertation explores the concentration and composition of black carbon (BC) in snow and glacial melt-water across the polar regions in the Arctic and Antarctic, as well as major mountain regions such as the Himalayas, Rockies, and Andes Mountains.&lt;/p&gt;&lt;p&gt;Three state-of-the-art methods for BC detection are applied in this dissertation. The first chapter identifies chemical signatures of past and present sources of dissolved black carbon (DBC) in Antarctic lakes, utilizing a DBC molecular marker method. Here we find that DBC with a woody signature is preserved in the deep, ancient brines of Antarctic lake bottom waters. In contrast, the surface waters are enriched in BC from fossil fuels. The second chapter, which also utilizes the DBC molecular marker&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;div&gt;&lt;p&gt;iii&amp;nbsp;&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;div title=&quot;Page 5&quot;&gt;&lt;div&gt;&lt;div&gt;&lt;p&gt;technique, explores DBC across the cryosphere. We show that DBC concentrations are surprisingly high in the bottom waters of Antarctic lakes compared to other remote regions of the cryosphere, even those located near point sources. Aged snow also contains higher DBC concentrations than fresh snow suggesting that dry deposition brings the majority of BC to the cryosphere. Additionally, the DBC composition across samples from the cryosphere are similar due to high amounts of solar exposure leading to photodegradation, except in fresh snow with a wildfire signature. The third and fourth chapters utilize the Single Particle Soot Photometer to measure refractory black carbon (rBC). The third chapter also applies spectral albedo measurements and the light absorption heating method to find that&amp;nbsp;coal dust from an active mine in Svalbard, Norway significantly reduces the spectral reflectance of the surrounding Arctic surface snow.&amp;nbsp;The fourth chapter reports aerosol rBC concentrations in the boundary layer of the McMurdo Dry Valleys, as well as in snow from the accumulation area of the Commonwealth Glacier. Here we determine that aerosol concentrations increase during high wind events, but there is no significant trend in deposition in the snow pit. This could be due to sporadic deposition during katabatic wind events.&lt;/p&gt;&lt;p&gt;These findings support the importance of real&amp;nbsp;in-situ&amp;nbsp;observations in order to fully understand the role of BC in the global carbon cycle. It is also evident that local environmental processes can control the concentrations and composition of BC in the cryosphere. These ground-based measurements will likely serve as ground validation for future remote sensing of snow/ice impurities and LAAs deposition models.&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;p&gt;&amp;nbsp;&lt;/p&gt;</style></abstract><work-type><style face="normal" font="default" size="100%">doctoral</style></work-type></record></records></xml>