02098nas a2200181 4500008004100000022001400041245014900055210006900204260001200273490000700285520143900292100002101731700002201752700002501774700002001799700002601819856007101845 2024 eng d a1523-043000aAn analysis of McMurdo Dry Valleys’ lotic habitats within Antarctica’s protected area network and addressing gaps in biodiversity protection0 aanalysis of McMurdo Dry Valleys lotic habitats within Antarctica c08/20240 v563 a

The McMurdo Dry Valleys (MDV), Antarctica’s largest ice-free region, hosts unique terrestrial ecosystems, with biodiversity concentrated in the aquatic environments and surrounding soils. Despite being a scientific hub, the creation of the MDV Antarctic Specially Managed Area (ASMA) made significant steps toward protecting the environment from degradation from human usage. However, with sustained human presence within the MDV, increasing human activity across Antarctica, and aquatic ecosystems subject to environmental change, the effectiveness of current protections for biodiversity conservation requires evaluation. This study employs spatial analysis of MDV protected areas, streams, lakes, research camps, and tourist sites to assess the robustness of current protections, identify underprotected areas, and outline steps for future protection. Within the MDV ASMA, five smaller Antarctic Specially Protected Areas (ASPAs) exist. Only two ASPAs contain streams, and only one with a full hydrologic catchment. With roughly 6% of the lotic habitat area protected by ASPAs, the MDV fall short of global goals for freshwater protection. Past successful management of the MDV shows the effectiveness of collaboration and early action, and amongst calls for ASPA network expansion and restructuring, the MDV has the opportunity to be at the forefront again and increase the protection of Antarctic aquatic ecosystems.

1 aWright, Anna, T.1 aBrooks, Cassandra1 aGooseff, Michael, N.1 aHowkins, Adrian1 aChignell, Stephen, M. uhttps://www.tandfonline.com/doi/full/10.1080/15230430.2024.237517602764nas a2200253 4500008004100000022001400041245011400055210006900169260001200238300001100250490000700261520197300268653001502241653002102256653002702277653002202304653001502326653001302341100002102354700002502375700002402400700002402424856006202448 2024 eng d a0885-608700aThe hydrologic and geochemical contributions from snow to streamflow in the McMurdo Dry Valleys of Antarctica0 ahydrologic and geochemical contributions from snow to streamflow c06/2024 ae151950 v383 a

The glacial meltwater streams in the McMurdo Dry Valleys (MDVs), Antarctica only flow during the austral summer and contain abundant algal mats which grow at the onset of flow. Their relative abundance in stream channels of this polar desert make the streams biogeochemical hot spots. The MDVs receive minimal precipitation as snow, which is redistributed by wind and deposited in distinct locations, some of which become persistent snow patches each year. Previous studies identified that MDV streamflow comes from a combination of glacier ice and snow, although snow was assumed to contribute little to the overall water budget. This study uses a combination of satellite imagery, terrain analysis, and field measurements to determine where snow patches accumulate and persist across MDV watersheds, and to quantify the potential hydrologic and biogeochemical contributions of snow patches to streams. Watersheds near the coast have the highest snow-covered area and longest snow persistence. Many of these snow patches accumulate within the stream channels, which results in the potential to contribute to streamflow. During the summer of 2021–2022, stream channel snow patches had the potential to contribute anywhere between <1% and 90% of the total annual discharge in Lake Fryxell Basin streams, and may increase with different hydrometeorological conditions. On average the potential inputs from snow patches to streamflow was between 12% and 25% of the annual discharge during the 2021–2022 season, as determined by snow area and SWE. Snow patches in the majority of the watersheds had higher nitrogen and phosphorous concentrations than stream water, and six streams contained snow with higher N:P ratios than the average N:P in the stream water. This suggests that if such patches melt early in the summer, these nutrient and water inputs could occur at the right time and stoichiometry to be crucial for early season algal mat growth.

10aAntarctica10aephemeral stream10apolar desert hydrology10arunoff generation10asnow patch10asnowmelt1 aWright, Anna, T.1 aGooseff, Michael, N.1 aBergstrom, Anna, J.1 aWelch, Kathleen, A. uhttps://onlinelibrary.wiley.com/doi/abs/10.1002/hyp.1519502186nas a2200313 4500008004100000022001400041245009000055210006900145260001200214300001800226490000700244520123000251653002201481653002401503653002001527653001701547653001501564100002201579700002101601700002101622700002201643700002201665700002401687700002101711700002501732700002101757700002501778856006901803 2024 eng d a2328-427700aResponse of a terrestrial polar ecosystem to the March 2022 Antarctic weather anomaly0 aResponse of a terrestrial polar ecosystem to the March 2022 Anta c08/2024 ae2023EF0043060 v123 a

Record high temperatures were documented in the McMurdo Dry Valleys, Antarctica, on 18 March 2022, exceeding average temperatures for that day by nearly 30°C. Satellite imagery and stream gage measurements indicate that surface wetting coincided with this warming more than 2 months after peak summer thaw and likely exceeded thresholds for rehydration and activation of resident organisms that typically survive the cold and dry conditions of the polar fall in a freeze-dried state. This weather event is notable in both the timing and magnitude of the warming and wetting when temperatures exceeded 0°C at a time when biological communities and streams have typically entered a persistent frozen state. Such events may be a harbinger of future climate conditions characterized by warmer temperatures and greater thaw in this region of Antarctica, which could influence the distribution, activity, and abundance of sentinel taxa. Here we describe the ecosystem responses to this weather anomaly reporting on meteorological and hydrological measurements across the region and on later biological observations from Canada Stream, one of the most diverse and productive ecosystems within the McMurdo Dry Valleys.

10aatmospheric river10aclimate variability10aextreme weather10apolar desert10asoil biota1 aBarrett, John, E.1 aAdams, Byron, J.1 aDoran, Peter, T.1 aDugan, Hilary, A.1 aMyers, Krista, F.1 aSalvatore, Mark, R.1 aPower, Sarah, N.1 aSnyder, Meredith, D.1 aWright, Anna, T.1 aGooseff, Michael, N. uhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023EF004306