02255nas a2200193   4500008004100000245007900041210006900120260001200189300001400201490000800215520163600223100002001859700002501879700002401904700002101928700002201949700002401971856006601995       2017                        eng d00aImpacts of permafrost degradation on a stream in Taylor Valley, Antarctica0 aImpacts of permafrost degradation on a stream in Taylor Valley A  c05/2017  a205 - 2130 v2853 a<p>The McMurdo Dry Valleys (MDV) of Antarctica are an ice-free landscape that supports a complex, microbially dominated ecosystem despite a severely arid, cold environment (b 5 cm water equivalent/y, &minus; 18 &deg;C mean annual air temperature). Recent observations of permafrost degradation in the coastal zones of the MDV suggest that this region is nearing a threshold of rapid landscape change. In 2012, substantial thermokarst development was observed along several kilometers of the west branch of Crescent Stream in Taylor Valley mostly in the form of bank failures, whereas the adjacent east branch was unaffected. The objective of this study was to quantify the changes to the stream banks of the west branch of Crescent Stream and to determine the impacts on the composition of the stream bed material. Three annually repeated terrestrial LiDAR scans were compared to determine the rates of ground surface change caused by thermokarst formation on the stream bank. The areal extent of the thermokarst was shown to be decreasing; however, the average vertical rate of retreat remained constant. Field measurements of bed materials indicated that the west branch and the reach downstream of the confluence (of east and west branches) consistently contained more fines than the unaffected east branch. This suggests that the finer bed material is a result of the thermokarst development on the west branch. These finer bed material compositions are likely to increase the mobility of the bed material, which will have implications for stream morphology, stream algal mat communities, and downstream aquatic ecosystems.</p>1 aSudman, Zachary1 aGooseff, Michael, N.1 aFountain, Andrew, G1 aLevy, Joseph, S.1 aObryk, Maciek, K.1 aVan Horn, David, J.  uhttp://linkinghub.elsevier.com/retrieve/pii/S0169555X1630846700637nas a2200157   4500008004100000245015300041210007000194260001200264300001200276490000700288100002200295700002100317700002100338700002700359856009300386       2017                        eng d00aThe influence of föhn winds on Glacial Lake Washburn and palaeotemperatures in the McMurdo Dry Valleys, Antarctica, during the Last Glacial Maximum0 ainfluence of föhn winds on Glacial Lake Washburn and palaeotempe  c10/2017  a457-4670 v291 aObryk, Maciek, K.1 aDoran, Peter, T.1 aWaddington, E.D.1 aMcKay, Christopher, P.  uhttps://www.cambridge.org/core/product/identifier/S0954102017000062/type/journal_article01797nas a2200253   4500008004100000022001400041245007900055210006900134260001200203300001400215490000700229520101000236100002401246700001601270700001701286700002101303700002001324700002501344700002201369700002101391700002801412700002301440856008001463       2016                        eng d  a0006-356800aThe Impact of a Large-Scale Climate Event on Antarctic Ecosystem Processes0 aImpact of a LargeScale Climate Event on Antarctic Ecosystem Proc  c10/2016  a848 - 8630 v663 a<p>Extreme climate and weather events, such as a drought, hurricanes, or ice storms, can strongly imprint ecosystem processing and may alter ecosystem structure. Ecosystems in extreme environments are particularly vulnerable because of their adaptation to severe limitations in energy, water, or nutrients. The vulnerability can be expressed as a relatively long-lasting ecosystem response to a small or brief change in environmental conditions. Such an event occurred in Antarctica and affected two vastly different ecosystems: a marine-dominated coastal system and a terrestrial polar desert. Both sites experienced winds that warmed air temperatures above the 0&deg;C threshold, resulting in extensive snow and ice melt and triggering a series of cascading effects through the ecosystems that are continuing to play out more than a decade later. This highlights the sensitivity of Antarctic ecosystems to warming events, which should occur more frequently in the future with global climate warming.</p>1 aFountain, Andrew, G1 aSaba, Grace1 aAdams, Byron1 aDoran, Peter, T.1 aFraser, William1 aGooseff, Michael, N.1 aObryk, Maciek, K.1 aPriscu, John, C.1 aStammerjohn, Sharon, E.1 aVirginia, Ross, A.  uhttp://academic.oup.com/bioscience/article-pdf/66/10/848/7510601/biw110.pdf