<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Schulte, Nicholas O.</style></author><author><style face="normal" font="default" size="100%">Khan, Alia L.</style></author><author><style face="normal" font="default" size="100%">Smith, Emma W.</style></author><author><style face="normal" font="default" size="100%">Zoumplis, Angela</style></author><author><style face="normal" font="default" size="100%">Kaul, Drishti</style></author><author><style face="normal" font="default" size="100%">Allen, Andrew E.</style></author><author><style face="normal" font="default" size="100%">Adams, Byron J.</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%">Blowin’ in the wind: Dispersal, structure, and metacommunity dynamics of aeolian diatoms in the McMurdo Sound region, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Phycology</style></secondary-title><short-title><style face="normal" font="default" size="100%">Journal of Phycology</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">18S rRNA</style></keyword><keyword><style  face="normal" font="default" size="100%">airborne</style></keyword><keyword><style  face="normal" font="default" size="100%">algae</style></keyword><keyword><style  face="normal" font="default" size="100%">assembly</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacillariophyta</style></keyword><keyword><style  face="normal" font="default" size="100%">biogeography</style></keyword><keyword><style  face="normal" font="default" size="100%">connectivity</style></keyword><keyword><style  face="normal" font="default" size="100%">high-throughput sequencing</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2022</style></year><pub-dates><date><style  face="normal" font="default" size="100%">02/2022</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://onlinelibrary.wiley.com/doi/10.1111/jpy.13223</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">58</style></volume><pages><style face="normal" font="default" size="100%">36-54</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Diatom metacommunities are structured by environmental, historical, and spatial factors that are often attributed to organism dispersal. In the McMurdo Sound region (MSR) of Antarctica, wind connects aquatic habitats through delivery of inorganic and organic matter. We evaluated the dispersal of diatoms in aeolian material and its relation to the regional diatom metacommunity using light microscopy and 18S rRNA high-throughput sequencing. The concentration of diatoms ranged from 0 to 8.76 * 10&lt;sup&gt;6&lt;/sup&gt; valves &amp;middot; g&lt;sup&gt;-1&lt;/sup&gt; dry aeolian material. Up to 15% of whole cells contained visible protoplasm, indicating that up to 3.43 * 10&lt;sup&gt;4&lt;/sup&gt; potentially viable individuals could be dispersed in a year to a single 2 cm&lt;sup&gt;2&lt;/sup&gt;&amp;nbsp;site. Diatom DNA and RNA was detected at each site, reinforcing the likelihood that we observed dispersal of viable diatoms. Of the 50 known morphospecies in the MSR, 72% were identified from aeolian material using microscopy. Aeolian community composition varied primarily by site. Meanwhile, each aeolian community was comprised of morphospecies found in aquatic communities from the same lake basin. These results suggest that aeolian diatom dispersal in the MSR is spatially structured, is predominantly local, and connects local aquatic habitats via a shared species pool. Nonetheless, aeolian community structure was distinct from that of aquatic communities, indicating that intrahabitat dispersal and environmental filtering also underlie diatom metacommunity dynamics. The present study confirms that a large number of diatoms are passively dispersed by wind across a landscape characterized by aeolian processes, integrating the regional flora and contributing to metacommunity structure and landscape connectivity.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Melisa A. Diaz</style></author><author><style face="normal" font="default" size="100%">Welch, Susan A.</style></author><author><style face="normal" font="default" size="100%">Sheets, J. M.</style></author><author><style face="normal" font="default" size="100%">Kathleen A. Welch</style></author><author><style face="normal" font="default" size="100%">Khan, Alia L.</style></author><author><style face="normal" font="default" size="100%">Byron Adams</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">Craig S Cary</style></author><author><style face="normal" font="default" size="100%">W. Berry Lyons</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Geochemistry of aeolian material from the McMurdo Dry Valleys, Antarctica: Insights into Southern Hemisphere dust sources</style></title><secondary-title><style face="normal" font="default" size="100%">Earth and Planetary Science Letters</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">aeolian material</style></keyword><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">major oxides</style></keyword><keyword><style  face="normal" font="default" size="100%">mineralogy</style></keyword><keyword><style  face="normal" font="default" size="100%">rare earth elements</style></keyword><keyword><style  face="normal" font="default" size="100%">trace elements</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">10/2020</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.sciencedirect.com/science/article/pii/S0012821X20304040</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">547</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;In the Southern Hemisphere, the major sources of dust and other aeolian materials are from Patagonia, South Africa, Australia, and New Zealand. Dust from Patagonia and New Zealand has been identified in ice cores throughout Antarctica, suggesting that during arid and windy periods, such as glacial periods, dust can be entrained and transported onto the continent. However, little information exists on modern Antarctic dust sources, transport, and its role in the Southern Hemisphere dust cycle. We present the first geochemical characterization of aeolian materials collected at five heights (between 5 cm and 100 cm) above the surface in four valleys within the McMurdo Dry Valleys, the largest ice-free area in Antarctica. Our mineralogy data indicate that these materials are primarily derived from local rocks of the McMurdo Volcanics, Ferrar Dolerite, Beacon Sandstone and Granite Harbor Intrusives, with varying contributions of each rock type dependent on the valley location. While major oxide, trace element and rare earth element data show that low elevation and coastal locations (with respect to the Ross Sea) are dominated by local sources, high elevation and inland locations have accumulated both local materials and dust from other distant Southern Hemisphere sources. This far-traveled material may not be accumulating today, but represents a paleo source that is resuspended from the soils. By geochemically &amp;ldquo;fingerprinting&amp;rdquo; aeolian materials from the MDV, we can better inform future studies on the transport of materials within Antarctica and between Southern Hemisphere land masses.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Melisa A. Diaz</style></author><author><style face="normal" font="default" size="100%">Byron Adams</style></author><author><style face="normal" font="default" size="100%">Kathleen A. Welch</style></author><author><style face="normal" font="default" size="100%">Sue Welch</style></author><author><style face="normal" font="default" size="100%">Opiyo, Stephen O.</style></author><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><author><style face="normal" font="default" size="100%">Craig S Cary</style></author><author><style face="normal" font="default" size="100%">W. Berry Lyons</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Aeolian material transport and its role in landscape connectivity in the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research: Earth Surface</style></secondary-title><short-title><style face="normal" font="default" size="100%">J. Geophys. Res. Earth Surf.</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2018</style></year><pub-dates><date><style  face="normal" font="default" size="100%">12/2018</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2017JF004589</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">123</style></volume><pages><style face="normal" font="default" size="100%">3323 - 3337</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Arid regions, particularly polar and alpine desert environments, have diminished landscape connectivity compared to temperate regions due to limited and/or seasonal hydrological processes. For these environments, aeolian processes play a particularly important role in landscape evolution and biotic community vitality through nutrient and solute additions. The McMurdo Dry Valleys (MDV) are the largest ice-free area in Antarctica and are potentially a major source of aeolian material for the continent. From this region, samples were collected at five heights (~5, 10, 20, 50, and 100 cm) above the surface seasonally for 2013 through 2015 from Alatna Valley, Victoria Valley, Miers Valley, and Taylor Valley (Taylor Glacier, East Lake Bonney, F6 (Lake Fryxell), and Explorer&amp;rsquo;s Cove). Despite significant geological separation and varying glacial histories, low-elevation and coastal sites had similar major ion chemistries, as did high-elevation and inland locations. This locational clustering of compositions was also evident in scanning electron microscopy images and principal component analyses, particularly for samples collected at ~100 cm above the surface. Compared to published soil literature, aeolian material in Taylor Valley demonstrates a primarily down-valley transport of material toward the coast. Soluble N:P ratios in the aeolian material reflect relative nutrient enrichments seen in MDV soils and lakes, where younger, coastal soils are relatively N depleted, while older, up-valley soils are relatively P depleted. The aeolian transport of materials, including water-soluble nutrients, is an important vector of connectivity within the MDV and provides a mechanism to help &amp;ldquo;homogenize&amp;rdquo; the geochemistry of both soil and aquatic ecosystems.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</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%">McMeeking, Gavin</style></author><author><style face="normal" font="default" size="100%">Schwarz, Joshua P.</style></author><author><style face="normal" font="default" size="100%">Xian, Peng</style></author><author><style face="normal" font="default" size="100%">Kathleen A. Welch</style></author><author><style face="normal" font="default" size="100%">W. Berry Lyons</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%">Near-surface refractory black carbon observations in the atmosphere and snow in the McMurdo Dry Valleys, Antarctica and potential impacts of foehn winds</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research: Atmospheres</style></secondary-title><short-title><style face="normal" font="default" size="100%">J. Geophys. Res. Atmos.</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2018</style></year><pub-dates><date><style  face="normal" font="default" size="100%">01/2018</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://doi.wiley.com/10.1002/2017JD027696</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">123</style></volume><pages><style face="normal" font="default" size="100%">2877 - 2887</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span style=&quot;font-family: TimesNewRomanPSMT; font-size: 12pt;&quot;&gt;Measurements of light absorbing particles in the boundary layer of the high southern latitudes are scarce, particularly in the McMurdo Dry Valleys (MDV),&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;Antarctica. During the 2013 - 2014 austral summer near-surface boundary layer refractory black carbon (rBC) aerosols were measured in air by a single particle soot photometer (SP2) at multiple locations in the MDV. Near-continuous rBC atmospheric measurements were collected at Lake Hoare Camp (LH) over two months and for several hours at more remote locations away from established field camps. We investigated periods dominated by both up and down-valley winds to explore the causes of differences in rBC concentrations and size distributions. Snow samples were also collected in a 1m pit on a glacier near the camp. The range of concentrations rBC in snow were 0.3 &lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;&amp;ndash; &lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;1.2 &amp;plusmn; 0.3 μg-rBC/L-H&lt;/span&gt;&lt;span style=&quot;font-size: 8pt; font-family: TimesNewRomanPSMT; vertical-align: -1pt;&quot;&gt;2&lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;O, and total organic carbon were 0.3 &lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;&amp;ndash; &lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;1.4 &amp;plusmn; 0.3 mg/L. The rBC concentrations measured in this snow pit are not sufficient to reduce surface albedo, however, there is potential for accumulation of rBC on snow and ice surfaces at low elevation throughout the MDV which were not measured as part of this study. At LH, the average background rBC mass aerosol concentrations was 1.3 ng/m&lt;/span&gt;&lt;span style=&quot;font-size: 8pt; font-family: TimesNewRomanPSMT; vertical-align: 5pt;&quot;&gt;3&lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;. rBC aerosol mass concentrations were slightly lower, 0.09 &lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;&amp;ndash; &lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;1.3 ng/m&lt;/span&gt;&lt;span style=&quot;font-size: 8pt; font-family: TimesNewRomanPSMT; vertical-align: 5pt;&quot;&gt;3&lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;, at the most remote sites in the MDV. Concentration spikes as high as 200 ng/m&lt;/span&gt;&lt;span style=&quot;font-size: 8pt; font-family: TimesNewRomanPSMT; vertical-align: 5pt;&quot;&gt;3 &lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;were observed at LH, associated with local activities. During a foehn wind event, the average rBC mass concentration increased to 30-50 ng m&lt;/span&gt;&lt;span style=&quot;font-size: 8pt; font-family: TimesNewRomanPSMT; vertical-align: 5pt;&quot;&gt;-3&lt;/span&gt;&lt;span style=&quot;font-size: 12pt; font-family: TimesNewRomanPSMT;&quot;&gt;. Here we show the rBC increase could be due to resuspension of locally produced BC from generators, rocket toilets, and helicopters, which may remain on the soil surface until redistributed during high wind events. Quantification of local production and long-range atmospheric transport of rBC to the MDV is necessary for understanding the impacts of this species on regional climate.&amp;nbsp;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&amp;nbsp;&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</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%">Wagner, Sasha</style></author><author><style face="normal" font="default" size="100%">Jaffé, Rudolf</style></author><author><style face="normal" font="default" size="100%">Xian, Peng</style></author><author><style face="normal" font="default" size="100%">Williams, Mark</style></author><author><style face="normal" font="default" size="100%">Armstrong, Richard</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%">Dissolved black carbon in the global cryosphere: Concentrations and chemical signatures</style></title><secondary-title><style face="normal" font="default" size="100%">Geophysical Research Letters</style></secondary-title><short-title><style face="normal" font="default" size="100%">Geophys. Res. Lett.</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2017</style></year><pub-dates><date><style  face="normal" font="default" size="100%">06/2017</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://doi.wiley.com/10.1002/2017GL073485</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">44</style></volume><pages><style face="normal" font="default" size="100%">6226-6234</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span style=&quot;font-size: 9pt; font-family: AdvTTe45e47d2;&quot;&gt;Black carbon (BC) is derived from the incomplete combustion of biomass and fossil fuels and can enhance glacial recession when deposited on snow and ice surfaces. Here we explore the in&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: &amp;quot;AdvTTe45e47d2+fb&amp;quot;;&quot;&gt;fl&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: AdvTTe45e47d2;&quot;&gt;uence of environmental conditions and the proximity to anthropogenic sources on the concentration and composition of dissolved black carbon (DBC), as measured by benzenepolycaroxylic acid (BPCA) markers, across snow, lakes, and streams from the global cryosphere. Data are presented from Antarctica, the Arctic, and high alpine regions of the Himalayas, Rockies, Andes, and Alps. DBC concentrations spanned from 0.62 &lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: &amp;quot;AdvTT182ff89e+03&amp;quot;;&quot;&gt;μ&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: AdvTTe45e47d2;&quot;&gt;g/L to 170 &lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: &amp;quot;AdvTT182ff89e+03&amp;quot;;&quot;&gt;μ&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: AdvTTe45e47d2;&quot;&gt;g/L. The median and (2.5, 97.5) quantiles in the pristine samples were 1.8 &lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: &amp;quot;AdvTT182ff89e+03&amp;quot;;&quot;&gt;μ&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: AdvTTe45e47d2;&quot;&gt;g/L (0.62, 12), and nonpristine samples were 21 &lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: &amp;quot;AdvTT182ff89e+03&amp;quot;;&quot;&gt;μ&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: AdvTTe45e47d2;&quot;&gt;g/L (1.6, 170). DBC is susceptible to photodegradation when exposed to solar radiation. This process leads to a less condensed BPCA signature. In general, DBC across the data set was composed of less polycondensed DBC. However, DBC from the Greenland Ice Sheet (GRIS) had a highly condensed BPCA molecular signature. This could be due to recent deposition of BC from Canadian wild&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: &amp;quot;AdvTTe45e47d2+fb&amp;quot;;&quot;&gt;fi&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: AdvTTe45e47d2;&quot;&gt;res. Variation in DBC appears to be driven by a combination of photochemical processing and the source combustion conditions under which the DBC was formed. Overall, DBC was found to persist across the global cryosphere in both pristine and nonpristine snow and surface waters. The high concentration of DBC measured in supraglacial melt on the GRIS suggests that DBC can be mobilized across ice surfaces. This is signi&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: &amp;quot;AdvTTe45e47d2+fb&amp;quot;;&quot;&gt;fi&lt;/span&gt;&lt;span style=&quot;font-size: 9pt; font-family: AdvTTe45e47d2;&quot;&gt;cant because these processes may jointly exacerbate surface albedo reduction in the cryosphere.&amp;nbsp;&lt;/span&gt;&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</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%">Jaffé, Rudolf</style></author><author><style face="normal" font="default" size="100%">Ding, Yan</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%">Dissolved black carbon in Antarctic lakes: chemical signatures of past and present sources</style></title><secondary-title><style face="normal" font="default" size="100%">Geophysical Research Letters</style></secondary-title><short-title><style face="normal" font="default" size="100%">Geophys. Res. Lett.</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2016</style></year><pub-dates><date><style  face="normal" font="default" size="100%">06/2016</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://doi.wiley.com/10.1002/2016GL068609</style></url></web-urls></urls><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span style=&quot;color: rgb(51, 51, 51); font-family: 'Open Sans', Arial, Helvetica, 'Lucida Sans Unicode', sans-serif; font-size: 16px; line-height: 24px; background-color: rgb(249, 249, 249);&quot;&gt;The perennially ice-covered, closed-basin lakes in the McMurdo Dry Valleys, Antarctica, serve as sentinels for understanding the fate of dissolved black carbon from glacial sources in aquatic ecosystems. Here we show that dissolved black carbon can persist in freshwater and saline surface waters for thousands of years, while preserving the chemical signature of the original source materials. The ancient brines of the lake bottom waters have retained dissolved black carbon with a woody chemical signature, representing long-range transport of black carbon from wildfires. In contrast, the surface waters are enriched in contemporary black carbon from fossil fuel combustion. Comparison of samples collected 25&amp;thinsp;years apart from the same lake suggests that the enrichment in anthropogenic black carbon is recent. Differences in the chemical composition of dissolved black carbon among the lakes are likely due to biogeochemical processing such as photochemical degradation and sorption on metal oxides.&lt;/span&gt;&lt;/p&gt;</style></abstract></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>