The Mcmurdo Dry Valleys Long‐Term Ecological Rsearch Program: New understanding of the biogeochemistry of the Dry Valley Lakes: A review1

Abstract Outside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of < 0.5 wt.% to 2–3 wt.%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.

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Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica

Botany ◽

10.1139/b08-100 ◽

2008 ◽

Vol 86 (12) ◽

pp. 1378-1392 ◽

Cited By ~ 36

Author(s):

R. M.M. Esposito ◽

S. A. Spaulding ◽

D. M. McKnight ◽

B. Van de Vijver ◽

K. Kopalová ◽

...

Keyword(s):

Austral Summer ◽

Mcmurdo Dry Valleys ◽

Size Spectrum ◽

Dry Valleys ◽

Dominant Group ◽

Lower Range ◽

Glacial Ice ◽

Dry Valley ◽

James Ross Island ◽

Harsh Conditions

Diatom taxa present in the inland streams and lakes of the McMurdo Dry Valleys and James Ross Island, Antarctica, are presented in this paper. A total of nine taxa are illustrated, with descriptions of four new species ( Luticola austroatlantica sp. nov., Luticola dolia sp. nov., Luticola laeta sp. nov., Muelleria supra sp. nov.). In the perennially ice-covered lakes of the McMurdo Dry Valleys, diatoms are confined to benthic mats within the photic zone. In streams, diatoms are attached to benthic surfaces and within the microbial mat matrix. One species, L. austroatlantica, is found on James Ross Island, of the southern Atlantic archipelago, and the McMurdo Dry Valleys. The McMurdo Dry Valley populations are at the lower range of the size spectrum for the species. Streams flow for 6–10 weeks during the austral summer, when temperatures and solar radiation allow glacial ice to melt. The diatom flora of the region is characterized by species assemblages favored under harsh conditions, with naviculoid taxa as the dominant group and several major diatom groups conspicuously absent.

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Long‐term shifts in feedbacks among glacier surface change, melt generation, and runoff, McMurdo Dry Valleys, Antarctica

Hydrological Processes ◽

10.1002/hyp.14292 ◽

2021 ◽

Author(s):

Anna Bergstrom ◽

Michael Gooseff ◽

Andrew Fountain ◽

Matthew Hoffman

Keyword(s):

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Glacier Surface ◽

Surface Change ◽

Melt Generation

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Reactivation of a cryptobiotic stream ecosystem in the McMurdo Dry Valleys, Antarctica: A long-term geomorphological experiment

Geomorphology ◽

10.1016/j.geomorph.2006.07.025 ◽

2007 ◽

Vol 89 (1-2) ◽

pp. 186-204 ◽

Cited By ~ 49

Author(s):

D.M. McKnight ◽

C.M. Tate ◽

E.D. Andrews ◽

D.K. Niyogi ◽

K. Cozzetto ◽

...

Keyword(s):

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Stream Ecosystem

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Long-term experimental warming reduces soil nematode populations in the McMurdo Dry Valleys, Antarctica

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2009.07.009 ◽

2009 ◽

Vol 41 (10) ◽

pp. 2052-2060 ◽

Cited By ~ 54

Author(s):

B.L. Simmons ◽

D.H. Wall ◽

B.J. Adams ◽

E. Ayres ◽

J.E. Barrett ◽

...

Keyword(s):

Mcmurdo Dry Valleys ◽

Soil Nematode ◽

Dry Valleys ◽

Experimental Warming

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Extreme streams: flow intermittency as a control on diatom communities in meltwater streams in the McMurdo Dry Valleys, Antarctica1This article is derived from a special session entitled “A New Hydrology: Inflow Effects on Ecosystem Form and Functioning” that took place at the February 2011 ASLO Aquatic Sciences conference in San Juan, Puerto Rico.

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2012-022 ◽

2012 ◽

Vol 69 (8) ◽

pp. 1405-1419 ◽

Cited By ~ 20

Author(s):

Lee F. Stanish ◽

Tyler J. Kohler ◽

Rhea M.M. Esposito ◽

Breana L. Simmons ◽

Uffe N. Nielsen ◽

...

Keyword(s):

Community Composition ◽

Endemic Species ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Intermittent Streams ◽

Diatom Community ◽

Diatom Communities ◽

Dry Valley ◽

Flow Intermittency ◽

Diatom Community Composition

In the McMurdo Dry Valleys of Antarctica, stream biota is limited by the brief availability of liquid water. The benthic microbial mats harbor diatoms that have adapted to hydrologic stresses, including numerous endemic species. We found a strong relationship between diatom community composition and flow intermittency in a data set including seven streams that spanned a gradient in flow intermittency. In particular, two genera represented by numerous endemic species in Dry Valley habitats, Hantzschia and Luticola , had high abundances in moderately and highly intermittent streams, respectively. The Shannon Index of diversity was greatest in streams with intermediate flow intermittency, with lower diversity in more stable streams resulting from lower evenness, and lower diversity in highly intermittent streams resulting from lower richness. These results indicate that multiple metrics of biodiversity may be useful in assessing the response of diatom communities to changing hydrologic regime. We propose that flow intermittency acts as a species filter that increases habitat heterogeneity in Dry Valley streams and may allow endemic species to persist. Future Antarctic warming may alter diatom community composition and habitats that act as refugia for desiccation-tolerant taxa.

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Pseudovertical Temperature Profiles Give Insight into Winter Evolution of the Atmospheric Boundary Layer over the McMurdo Dry Valleys of Antarctica

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-13-034.1 ◽

2013 ◽

Vol 52 (7) ◽

pp. 1664-1669 ◽

Cited By ~ 5

Author(s):

Peyman Zawar-Reza ◽

Marwan Katurji ◽

Iman Soltanzadeh ◽

Tanja Dallafior ◽

Shiyuan Zhong ◽

...

Keyword(s):

Boundary Layer ◽

Weather Prediction ◽

Atmospheric Temperature ◽

Numerical Weather Prediction Model ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Cold Pools ◽

Routine Monitoring ◽

Strong Winds

AbstractMeasuring routine vertical profiles of atmospheric temperature is critical in understanding stability and the dynamics of the boundary layer. Routine monitoring in remote areas such as the McMurdo Dry Valleys (MDV) of Antarctica is logistically difficult and expensive. Pseudovertical profiles that were derived from a network of inexpensive ground temperature sensors planted on valley sidewalls (up to 330 m above valley floor), together with data from a weather station and a numerical weather prediction model, provided a long-term climatological description of the evolution of the winter boundary layer over the MDV. In winter, persistent valley cold pools (VCPs) were common, lasting up to 2 weeks. The VCPs were eroded by warm-air advection from aloft associated with strong winds, increasing the temperature of the valley by as much as 25 K. Pseudovertical datasets as described here can be used for model validation.

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The aeolian flux of calcium, chloride and nitrate to the McMurdo Dry Valleys landscape: evidence from snow pit analysis

Antarctic Science ◽

10.1017/s095410200600054x ◽

2006 ◽

Vol 18 (4) ◽

pp. 497-505 ◽

Cited By ~ 51

Author(s):

Rebecca A. Witherow ◽

W. Berry Lyons ◽

Nancy A.N. Bertler ◽

Kathleen A. Welch ◽

Paul A. Mayewski ◽

...

Keyword(s):

Calcium Chloride ◽

Great Influence ◽

Strong Relationship ◽

Snow Accumulation ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Dust Transport ◽

Atmospheric Flux ◽

Dry Valley ◽

Nitrogen Concentrations

We have determined the flux of calcium, chloride and nitrate to the McMurdo Dry Valleys region by analysing snow pits for their chemical composition and their snow accumulation using multiple records spanning up to 48 years. The fluxes demonstrate patterns related to elevation and proximity to the ocean. In general, there is a strong relationship between the nitrate flux and snow accumulation, indicating that precipitation rates may have a great influence over the nitrogen concentrations in the soils of the valleys. Aeolian dust transport plays an important role in the deposition of some elements (e.g. Ca2+) into the McMurdo Dry Valleys' soils. Because of the antiquity of some of the soil surfaces in the McMurdo Dry Valleys regions, the accumulated atmospheric flux of salts to the soils has important ecological consequences. Although precipitation may be an important mechanism of salt deposition to the McMurdo Dry Valley surfaces, it is poorly understood because of difficulties in measurement and high losses from sublimation.

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