@article {4577, title = {Geochemistry of contrasting stream types, Taylor Valley, Antarctica}, journal = {GSA Bulletin}, volume = {133}, year = {2021}, month = {01/2021}, pages = {425-448}, abstract = {

The McMurdo Dry Valley region is the largest ice-free area of Antarctica. Ephemeral streams flow here during the austral summer, transporting glacial meltwater to perennially ice-covered, closed basin lakes. The chemistry of 24 Taylor Valley streams was examined over the two-decade period of monitoring from 1993 to 2014, and the geochemical behavior of two streams of contrasting physical and biological character was monitored across the seven weeks of the 2010\–2011 flow season. Four species dominate stream solute budgets: HCO3\–, Ca2+, Na+, and Cl\–, with SO42\–, Mg2+, and K+ present in significantly lesser proportions. All streams contain dissolved silica at low concentrations. Across Taylor Valley, streams are characterized by their consistent anionic geochemical fingerprint of HCO3 \> Cl \> SO4, but there is a split in cation composition between 14 streams with Ca \> Na \> Mg \> K and 10 streams with Na \> Ca \> Mg \> K.


Andersen Creek is a first-order proglacial stream representative of the 13 short streams that flow \<1.5 km from source to gage. Von Guerard is representative of 11 long streams 2\–7 km in length characterized by extensive hyporheic zones. Both streams exhibit a strong daily cycle for solute load, temperature, dissolved oxygen, and pH, which vary in proportion to discharge. A well-expressed diurnal co-variation of pH with dissolved oxygen is observed for both streams that reflects different types of biological control. The relative consistency of Von Guerard composition over the summer flow season reflects chemostatic regulation, where water in transient storage introduced during times of high streamflow has an extended opportunity for water-sediment interaction, silicate mineral dissolution, and pore-water exchange.

}, keywords = {LTER-MCM}, doi = {10.1130/B35479.1}, url = {https://pubs.geoscienceworld.org/gsa/gsabulletin/article/133/1-2/425/587799/Geochemistry-of-contrasting-stream-types-Taylor}, author = {Harmon, Russell S. and Leslie, Deborah L. and W. Berry Lyons and Kathleen A. Welch and Diane M. McKnight} } @article {4471, title = {Geochemistry of aeolian material from the McMurdo Dry Valleys, Antarctica: Insights into Southern Hemisphere dust sources}, journal = {Earth and Planetary Science Letters}, volume = {547}, year = {2020}, month = {10/2020}, abstract = {

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 \“fingerprinting\” aeolian materials from the MDV, we can better inform future studies on the transport of materials within Antarctica and between Southern Hemisphere land masses.

}, keywords = {LTER-MCM, aeolian material, Antarctica, major oxides, mineralogy, rare earth elements, trace elements}, doi = {10.1016/j.epsl.2020.116460}, url = {https://www.sciencedirect.com/science/article/pii/S0012821X20304040}, author = {Melisa A. Diaz and Welch, Susan A. and Sheets, J. M. and Kathleen A. Welch and Khan, Alia L. and Byron Adams and Diane M. McKnight and Craig S Cary and W. Berry Lyons} } @article {4450, title = {The Geochemistry of Englacial Brine From Taylor Glacier, Antarctica}, journal = {Journal of Geophysical Research: Biogeosciences}, volume = {124}, year = {2019}, month = {03/2019}, abstract = {

Blood Falls is a hypersaline, iron-rich discharge at the terminus of the Taylor Glacier in the McMurdo Dry Valleys, Antarctica. In November 2014, brine in a conduit within the glacier was penetrated and sampled using clean-entry techniques and a thermoelectric melting probe called the IceMole. We analyzed the englacial brine sample for filterable iron (fFe), total Fe, major cations and anions, nutrients, organic carbon, and perchlorate. In addition, aliquots were analyzed for minor and trace elements and isotopes including δD and δ18O of water, δ34S and δ18O of sulfate, 234U, 238U, δ11B, 87Sr/86Sr, and δ81Br. These measurements were made in order to (1) determine the source and geochemical evolution of the brine and (2) compare the chemistry of the brine to that of nearby hypersaline lake waters and previous supraglacially sampled collections of Blood Falls outflow that were interpreted as end-member brines. The englacial brine had higher Cl\− concentrations than the Blood Falls end-member outflow; however, other constituents were similar. The isotope data indicate that the water in the brine is derived from glacier melt. The H4SiO4 concentrations and U and Sr isotope suggest a high degree of chemical weathering products. The brine has a low N:P ratio of ~7.2 with most of the dissolved inorganic nitrogen in the form of NH4+. Dissolved organic carbon concentrations are similar to end-member outflow values. Our results provide strong evidence that the original source of solutes in the brine was ancient seawater, which has been modified with the addition of chemical weathering products.

}, keywords = {LTER-MCM}, doi = {10.1029/2018JG004411}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JG004411}, author = {W. Berry Lyons and Jill A. Mikucki and German, Laura A. and Kathleen A. Welch and Sue Welch and Christopher B. Gardner and Tulaczyk, Slawek M. and Pettit, Erin C. and Kowalski, Julia and Dachwald, Bernd} } @article {1086, title = {Garwood Valley, Antarctica: A new record of Last Glacial Maximum to Holocene glaciofluvial processes in the McMurdo Dry Valleys}, journal = {Geological Society of America Bulletin}, volume = {125}, year = {2013}, month = {09/2013}, pages = {1484 - 1502}, keywords = {LTER-MCM}, doi = {10.1130/B30783.1}, url = {http://bulletin.geoscienceworld.org/content/early/2013/06/07/B30783.1.abstract}, author = {Joseph S. Levy and Andrew G Fountain and O{\textquoteright}Connor, J. E. and Kathleen A. Welch and W. Berry Lyons} } @article {1104, title = {The geochemistry of upland ponds, Taylor Valley, Antarctica}, journal = {Antarctic Science}, volume = {24}, year = {2012}, month = {2/2012}, pages = {3 - 14}, keywords = {LTER-MCM}, doi = {10.1017/S0954102011000617}, url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online\&aid=8483351}, author = {W. Berry Lyons and Kathleen A. Welch and Christopher B. Gardner and Chris Jaros and Daryl L. Moorhead and Knoepfle, J and Peter T. Doran} } @article {1297, title = {The Geochemistry of Supraglacial Streams of Canada Glacier, Taylor Valley (Antarctica), and their Evolution into Proglacial Waters}, journal = {Aquatic Geochemistry}, volume = {11}, year = {2005}, pages = {391-412}, keywords = {LTER-MCM}, author = {Sarah Fortner and Martyn Tranter and Andrew G Fountain and W. Berry Lyons and Kathleen A. Welch} } @article {1299, title = {Groundwater seeps in Taylor Valley Antarctica: An example of a subsurface melt event}, journal = {Annals of Glaciology}, volume = {40}, year = {2005}, pages = {200-206}, keywords = {LTER-MCM}, doi = {LTER}, author = {W. Berry Lyons and Kathleen A. Welch and Anne E. Carey and Diana H. Wall and Ross A. Virginia and Andrew G Fountain and Peter T. Doran and Csatho, B and Tremper, C} } @article {1459, title = {Geomicrobiology of sub-glacial ice above Vostok Station}, journal = {Science}, volume = {286}, year = {1999}, pages = {2141-2144}, keywords = {LTER-MCM}, doi = {10.1126/science.286.5447.2141}, author = {John C. Priscu and Edward E. Adams and W. Berry Lyons and Mary A. Voytek and David W. Mogk and Robert L. Brown and Christopher P. McKay and Cristina D. Takacs-Vesbach and Kathleen A. Welch and Craig F. Wolf and Julie D. Kirshtein and Recep Avci} } @inbook {1499, title = {Geochemical Linkages Among Glaciers, Streams, and Lakes Within the Taylor Valley, Antarctica}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, volume = {72}, year = {1998}, pages = {77-92}, keywords = {LTER-MCM}, author = {W. Berry Lyons and Kathleen A. Welch and Klaus Neumann and Jeffrey K. Toxey and Robyn McArthur and Changela Williams and Diane M. McKnight and Daryl L. Moorhead} }