Experimental formation of pore fluids in McMurdo Dry Valleys soils

AbstractThe aim of the study was to determine if soil salt deliquescence and brine hydration can occur under laboratory conditions using natural McMurdo Dry Valleys soils. The experiment was a laboratory analogue for the formation of isolated patches of hypersaline, damp soil, referred to as ‘wet patches’. Soils were oven dried and then hydrated in one of two humidity chambers: one at 100% relative humidity and the second at 75% relative humidity. Soil hydration is highly variable, and over the course of 20 days of hydration, ranged from increases in water content by mass from 0–16% for 122 soil samples from Taylor Valley. The rate and absolute amount of soil hydration correlates well with the soluble salt content of the soils but not with grain size distribution. This suggests that the formation of bulk pore waters in these soils is a consequence of salt deliquescence and hydration of the brine from atmospheric water vapour.

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Glacier mass balances (1993–2001), Taylor Valley, McMurdo Dry Valleys, Antarctica

Journal of Glaciology ◽

10.3189/172756506781828511 ◽

2006 ◽

Vol 52 (178) ◽

pp. 451-462 ◽

Cited By ~ 43

Author(s):

Andrew G. Fountain ◽

Thomas H. Nylen ◽

Karen L. MacClune ◽

Gayle L. Dana

Keyword(s):

Mass Balance ◽

Piecewise Linear ◽

Objective Assessment ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Mass Balances ◽

Missing Measurements ◽

Wind Speeds ◽

Taylor Valley ◽

Air Temperatures

AbstractMass balances were measured on four glaciers in Taylor Valley, Antarctica, from 1993 to 2001. We used a piecewise linear regression, which provided an objective assessment of error, to estimate the mass balance with elevation. Missing measurements were estimated from linear regressions between points and showed a significant improvement over other methods. Unlike temperate glaciers the accumulation zone of these polar glaciers accumulates mass in summer and winter and the ablation zone loses mass in both seasons. A strong spatial trend of smaller mass-balance values with distance inland (r2 = 0.80) reflects a climatic gradient to warmer air temperatures, faster wind speeds and less precipitation. Annual and seasonal mass-balance values range only several tens of millimeters in magnitude and no temporal trend is evident. The glaciers of Taylor Valley, and probably the entire McMurdo Dry Valleys, are in equilibrium with the current climate, and contrast with glacier trends elsewhere on the Antarctic Peninsula and in temperate latitudes.

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Episodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica

Antarctic Science ◽

10.1017/s0954102021000341 ◽

2021 ◽

pp. 1-15

Author(s):

Joseph Levy

Keyword(s):

Soil Moisture ◽

Relative Humidity ◽

Mcmurdo Dry Valleys ◽

Limiting Factor ◽

High Humidity ◽

Dry Valleys ◽

Surface Soils ◽

Basin Scale ◽

Soil Reflectance

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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An englacial hydrologic system of brine within a cold glacier: Blood Falls, McMurdo Dry Valleys, Antarctica

Journal of Glaciology ◽

10.1017/jog.2017.16 ◽

2017 ◽

Vol 63 (239) ◽

pp. 387-400 ◽

Cited By ~ 12

Author(s):

JESSICA A. BADGELEY ◽

ERIN C. PETTIT ◽

CHRISTINA G. CARR ◽

SLAWEK TULACZYK ◽

JILL A. MIKUCKI ◽

...

Keyword(s):

Latent Heat ◽

Flow Direction ◽

Salt Content ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Outlet Glacier ◽

Air Temperatures ◽

Radio Echo Sounding ◽

Hydrologic System ◽

Taylor Glacier

ABSTRACTTaylor Glacier hosts an active englacial hydrologic system that feeds Blood Falls, a supraglacial outflow of iron-rich subglacial brine at the terminus, despite mean annual air temperatures of −17°C and limited surface melt. Taylor Glacier is an outlet glacier of the East Antarctic ice sheet that terminates in Lake Bonney, McMurdo Dry Valleys. To image and map the brine feeding Blood Falls, we used radio echo sounding to delineate a subhorizontal zone of englacial brine upstream from Blood Falls and elongated in the ice flow direction. We estimate volumetric brine content in excess of 13% within 2 m of the central axis of this zone, and likely much higher at its center. Brine content decreases, but remains detectable, up to 45 m away along some transects. Hence, we infer a network of subparallel basal crevasses allowing injection of pressurized subglacial brine into the ice. Subglacial brine is routed towards Blood Falls by hydraulic potential gradients associated with deeply incised supraglacial valleys. The brine remains liquid within the subglacial and englacial environments through latent heat of freezing coupled with elevated salt content. Our findings suggest that cold glaciers could support freshwater hydrologic systems through localized warming by latent heat alone.

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Extreme southern locations for moss sporophytes in Antarctica

Antarctic Science ◽

10.1017/s0954102092000087 ◽

1992 ◽

Vol 4 (1) ◽

pp. 37-39 ◽

Cited By ~ 23

Author(s):

R.D. Seppelt ◽

T.G.A. Green ◽

A-M.J. Schwarz ◽

A. Frost

Keyword(s):

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Southern Limit ◽

Taylor Valley ◽

Victoria Land

Abundant immature sporophytes of the moss Pottia heimii are reported from the Lower Taylor Valley, McMurdo Dry Valleys and from Cape Chocolate, Victoria Land. These finds extend the reported southern limit for the occurrence of abundant moss sporophytes to 77° 55′S.

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Lake ice ablation rates from permanently ice-covered Antarctic lakes

Journal of Glaciology ◽

10.3189/2013jog12j080 ◽

2013 ◽

Vol 59 (215) ◽

pp. 491-498 ◽

Cited By ~ 23

Author(s):

H.A. Dugan ◽

M.K. Obryk ◽

P.T. Doran

Keyword(s):

Ice Cover ◽

Mcmurdo Dry Valleys ◽

Meteorological Variables ◽

Dry Valleys ◽

Lake Ice ◽

Antarctic Lakes ◽

Closed Basin ◽

Taylor Valley ◽

Surface Melt

AbstractIn the McMurdo Dry Valleys of Antarctica, three large, permanently ice-covered, closed-basin lakes exist along the floor of Taylor Valley. Lake ice ablation (loss of ice mass) is calculated as the sum of sublimation and surface melt, and is the driver of ice-cover turnover in these systems. In Taylor Valley, both manual and automated lake ice ablation rates have been calculated from 2001 to 2011. Results indicate relatively consistent winter ablation of 0.07–0.21 m (0.2–0.7 mm w.e. d−1). Summer ablation of lake ice is more variable and ranges from 0.25 to 1.62 m (5–31 mm w.e. d−1) over an average 51 day period. Previous to this study, ablation rates have been cited as 0.35 m a−1in the dry valleys from sublimation modeling based on meteorological variables. We show that this value has significantly underestimated mean ablation and ice-cover turnover on the Taylor Valley lakes.

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Water tracks intensify surface energy and mass exchange in the Antarctic McMurdo Dry Valleys

10.5194/tc-2019-8 ◽

2019 ◽

Author(s):

Tobias Linhardt ◽

Joseph S. Levy ◽

Christoph K. Thomas

Keyword(s):

Climate Change ◽

Energy Balance ◽

Surface Energy ◽

Surface Energy Balance ◽

Heat Fluxes ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Sensible Heat ◽

Taylor Valley ◽

The Antarctic

Abstract. We evaluated the hypotheses that water tracks alter the surface energy balance in the Antarctic McMurdo Dry Valleys and may serve as an indicator of landscape response to climate change in this dry, cold and ice-sheet-free environment. Water tracks are channel-shaped high moisture zones in the active layer of polar soils. The surface energy balance was measured for one water-track and two non-water-track reference locations in Taylor Valley during the Antarctic summer of 2012–2013. Turbulent atmospheric fluxes of sensible heat and evaporation were observed using the eddy-covariance method in combination with flux footprint modeling, which was the first application of this state-of-the-art technique in the Dry Valleys. Soil heat fluxes were analyzed separately for thawed and frozen layers at all locations via computing the change of the heat storage in the thawed layer from measurements. The results showed that for both water track and reference locations over 50 % of the net radiation was transferred to sensible heat exchange, about 30 % to melting the seasonally thawed layer, and the remainder to evaporation. The net energy flux in the thawed layer was zero. For the water track location, evaporation was increased by a factor of 3.0 relative to the references, ground heat fluxes by 1.4, and net radiation by 1.1, while sensible heat fluxes were reduced down to 0.7. Entertaining a realistic scenario of climate change in Taylor Valley in which the land cover fraction of water tracks increases by 50 %, the total evaporation from lower Taylor Valley would increase by 4 % to 0.30 mm d−1. In summary, our findings show that water tracks have a strong impact on the surface energy balance in ice-sheet free Antarctic regions. Water tracks are hot spots of change and are likely to respond faster to climate change signals than the dominant dry glacial till in the McMurdo Dry Valleys. Their spatiotemporal dynamics may therefore serve as indicator of high-sensitivity for change in permafrost-dominated cold landscapes.

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Characterization of 15 selected coccal bacteria isolated from antarctic rock and soil samples from the McMurdo-Dry Valleys (South-Victoria Land)

Polar Biology ◽

10.1007/bf00441762 ◽

1988 ◽

Vol 9 (1) ◽

pp. 37-44 ◽

Cited By ~ 52

Author(s):

J. Siebert ◽

P. Hirsch

Keyword(s):

Soil Samples ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Victoria Land ◽

Rock And Soil

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Spatial variations in the geochemistry of glacial meltwater streams in the Taylor Valley, Antarctica

Antarctic Science ◽

10.1017/s0954102010000702 ◽

2010 ◽

Vol 22 (6) ◽

pp. 662-672 ◽

Cited By ~ 68

Author(s):

Kathleen A. Welch ◽

W. Berry Lyons ◽

Carla Whisner ◽

Christopher B. Gardner ◽

Michael N. Gooseff ◽

...

Keyword(s):

Chemical Weathering ◽

Freezing Point ◽

Mcmurdo Dry Valleys ◽

Dry Valleys ◽

Stream Chemistry ◽

Glacial Meltwater ◽

Taylor Valley ◽

Air Temperatures ◽

Wide Range ◽

Long Term Ecological Research

AbstractStreams in the McMurdo Dry Valleys, Antarctica, flow during the summer melt season (4–12 weeks) when air temperatures are close to the freezing point of water. Because of the low precipitation rates, streams originate from glacial meltwater and flow to closed-basin lakes on the valley floor. Water samples have been collected from the streams in the Dry Valleys since the start of the McMurdo Dry Valleys Long-Term Ecological Research project in 1993 and these have been analysed for ions and nutrient chemistry. Controls such as landscape position, morphology of the channels, and biotic and abiotic processes are thought to influence the stream chemistry. Sea-salt derived ions tend to be higher in streams that are closer to the ocean and those streams that drain the Taylor Glacier in western Taylor Valley. Chemical weathering is an important process influencing stream chemistry throughout the Dry Valleys. Nutrient availability is dependent on landscape age and varies with distance from the coast. The streams in Taylor Valley span a wide range in composition and total dissolved solids and are surprisingly similar to a wide range of much larger temperate and tropical river systems.

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