scholarly journals Soil Moisture Controls the Thermal Habitat of Active Layer Soils in the McMurdo Dry Valleys, Antarctica

2018 ◽  
Vol 123 (1) ◽  
pp. 46-59 ◽  
Author(s):  
A. N. Wlostowski ◽  
M. N. Gooseff ◽  
B. J. Adams
Keyword(s):  
Soil Moisture ◽  
Active Layer ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Thermal Habitat

Thermal characterisation of active layer across a soil moisture gradient in the McMurdo Dry Valleys, Antarctica

2009 ◽  
Vol 20 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Scott J. Ikard ◽  
Michael N. Gooseff ◽  
John E. Barrett ◽  
Cristina Takacs-Vesbach
Keyword(s):  
Soil Moisture ◽  
Active Layer ◽  
Moisture Gradient ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Soil Moisture Gradient

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

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.

scholarly journals Reconstructing 15 Myr of environmental change in the McMurdo Dry Valleys through permafrost geochemistry

2021 ◽  
Author(s):  
Marjolaine Verret
Keyword(s):  
Active Layer ◽  
Arid Environment ◽  
Trophic Levels ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Ground Ice ◽  
Paleoenvironmental Changes ◽  
Table Mountain ◽  
Continental Antarctica ◽  
High Elevations

<p><b>The McMurdo Dry Valleys of Antarctica are the largest ice-free region in Antarctica. Valley downcutting by major outlet glaciers and post-glacial uplift since the mid-Miocene have resulted in predominantly younger surficial sediments in the low elevation, coastal areas and significantly older sediments in high elevation, inland areas. The hyper-arid conditions that prevail in the high elevations (> 1000 m a.s.l.) of the McMurdo Dry Valleys have protected these surfaces from alteration and weathering, and provide important sediment records of paleoenvironments dating back to the early Miocene. The Friis Hills (77°45’S, 161°30’E, 1200–1500 m a.s.l.) are a 12 km-wide inselberg situated at the head of Taylor Valley. This unique location allowed Miocene-age sediments to be preserved and protected from subsequent ice sheet expansions. Permafrost within these sediments is potentially the oldest on Earth. </b></p><p>As sediments accumulate in periglacial environments, permafrost aggrades with minimal lag time and potentially preserves sediments, organic material and ground ice. The 2016 Friis Hills Drilling Project retrieved a ∼50 m thick permafrost sequence, which not only consists of an archive of Antarctic environmental changes from approximately 14–15 Ma but also records the paleoenvironmental changes of the Neogene and provides insight on the modern hyper-arid environment. The main objective of this project is to understand the unique geochemical characteristics of these permafrost cores and document 15 Myr of change in the upper elevations of the McMurdo Dry Valleys. </p><p>Paleoenvironmental reconstructions of interglacial periods suggest a tundra-like environment in the high elevations of continental Antarctica through the mid-Miocene. Plants such as lichens, liverworts, mosses, grasses and sedges, dicots and Nothofagaceae occupied the Friis Hills during the mid-Miocene. The δ13C signal of C3 plants (-25.5 ± 0.7 ‰ VPDB) corresponds to a semi-arid environment with a mean annual precipitation ranging from 300 to 850 mm yr-1. The unusually high δ15N reflects an ecosystem with up to three trophic levels, supported by the presence of insect fragments, feathers barbs (birds) and tardigrades fragments within the sediment. The deep ice lenses and their meteoric signature suggest a near-saturated active layer during the mid-Miocene. Temperature reconstructions based on the corrected δ18O value of the deep ground ice and change in paleogeography imply that the mid-Miocene (11.1–13.9 Ma) was ∼6 to 12°C warmer. These paleoenvironmental conditions are comparable to those found in the modern Arctic, such as in west Greenland. </p><p>A dominant trend of literature suggests that the high elevations of the McMurdo Dry Valleys have remained under a hyper-arid polar climate since ∼13.8 Ma. However, the presence of 10Bemet in the upper section of the Friis Hills and Table Mountain cores provides evidence for the translocation of clays, which is only possible under a warmer and wetter climate. The 10Bemet concentrations imply that these conditions were present until ∼6.0 Ma at Friis Hills and Table Mountain, consequently challenging the idea that the upper McMurdo Dry Valleys have remained frozen under hyper-arid climate since the mid-Miocene climate transition. Hence, this finding supports the hypothesis that the Miocene has undergone progressive cooling with onset of polar aridity between 7 and 5.4 Ma. The erosion-corrected paleo-active layer depth suggests mean annual air temperatures ranging from -12 to -9°C ∼6.0 Ma. In other words, this thesis shows that the upper McMurdo Dry Valleys have been frozen under hyperarid conditions only since ∼6 Ma and not for 14 Myr as previously thought. </p><p>The ground ice in the uppermost 1 m originates from the modern freezing of evaporated snowmelt and the presence of high salt content which allows unfrozen water in the near-surface. The conformity of dry permafrost samples to biological ratios suggests that the modern environment is regulated by biochemical processes and the current pool of organic carbon in the dry permafrost appears to be in equilibrium with a modern climate and ecosystem. These findings not only characterize the paleoenvironmental changes of continental Antarctica through the late Miocene but also provide a better understanding of the modern ultraxerous conditions of the McMurdo Dry Valleys.</p>

scholarly journals Hyperspectral measurements of wet, dry and saline soils from the McMurdo Dry Valleys: soil moisture properties from remote sensing

2014 ◽  
Vol 26 (5) ◽  
pp. 565-572 ◽  
Author(s):  
Joseph Levy ◽  
Anne Nolin ◽  
Andrew Fountain ◽  
James Head
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Thermal State ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Non Invasive ◽  
High Concentrations ◽  
Remote Sensing Techniques ◽  
Moisture Conditions ◽  
Chloride Salts

AbstractSoil moisture is a spatially heterogeneous quantity in the McMurdo Dry Valleys of Antarctica that exerts a large influence on the biological community and on the thermal state of Dry Valleys permafrost. The goal of this project was to determine whether hyperspectral remote sensing techniques could be used to determine soil moisture conditions in the Dry Valleys. We measured the spectral reflectance factors of wetted soil samples from the Dry Valleys under natural light conditions and related diagnostic spectral features to surface layer soil moisture content. Diagnostic water absorption features in the spectra at 1.4 µm and 1.9 µm were present in all samples, including samples doped with high concentrations of chloride salts. The depth of the 1.4 µm absorption is shown to increase linearly with increasing gravimetric water content. These results suggest that airborne hyperspectral imaging of the Dry Valleys could generate soil moisture maps of this environment over large spatial areas using non-invasive remote-sensing techniques.

scholarly journals Reconstructing 15 Myr of environmental change in the McMurdo Dry Valleys through permafrost geochemistry

2021 ◽  
Author(s):  
Marjolaine Verret
Keyword(s):  
Active Layer ◽  
Arid Environment ◽  
Trophic Levels ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Ground Ice ◽  
Paleoenvironmental Changes ◽  
Table Mountain ◽  
Continental Antarctica ◽  
High Elevations

<p><b>The McMurdo Dry Valleys of Antarctica are the largest ice-free region in Antarctica. Valley downcutting by major outlet glaciers and post-glacial uplift since the mid-Miocene have resulted in predominantly younger surficial sediments in the low elevation, coastal areas and significantly older sediments in high elevation, inland areas. The hyper-arid conditions that prevail in the high elevations (> 1000 m a.s.l.) of the McMurdo Dry Valleys have protected these surfaces from alteration and weathering, and provide important sediment records of paleoenvironments dating back to the early Miocene. The Friis Hills (77°45’S, 161°30’E, 1200–1500 m a.s.l.) are a 12 km-wide inselberg situated at the head of Taylor Valley. This unique location allowed Miocene-age sediments to be preserved and protected from subsequent ice sheet expansions. Permafrost within these sediments is potentially the oldest on Earth. </b></p><p>As sediments accumulate in periglacial environments, permafrost aggrades with minimal lag time and potentially preserves sediments, organic material and ground ice. The 2016 Friis Hills Drilling Project retrieved a ∼50 m thick permafrost sequence, which not only consists of an archive of Antarctic environmental changes from approximately 14–15 Ma but also records the paleoenvironmental changes of the Neogene and provides insight on the modern hyper-arid environment. The main objective of this project is to understand the unique geochemical characteristics of these permafrost cores and document 15 Myr of change in the upper elevations of the McMurdo Dry Valleys. </p><p>Paleoenvironmental reconstructions of interglacial periods suggest a tundra-like environment in the high elevations of continental Antarctica through the mid-Miocene. Plants such as lichens, liverworts, mosses, grasses and sedges, dicots and Nothofagaceae occupied the Friis Hills during the mid-Miocene. The δ13C signal of C3 plants (-25.5 ± 0.7 ‰ VPDB) corresponds to a semi-arid environment with a mean annual precipitation ranging from 300 to 850 mm yr-1. The unusually high δ15N reflects an ecosystem with up to three trophic levels, supported by the presence of insect fragments, feathers barbs (birds) and tardigrades fragments within the sediment. The deep ice lenses and their meteoric signature suggest a near-saturated active layer during the mid-Miocene. Temperature reconstructions based on the corrected δ18O value of the deep ground ice and change in paleogeography imply that the mid-Miocene (11.1–13.9 Ma) was ∼6 to 12°C warmer. These paleoenvironmental conditions are comparable to those found in the modern Arctic, such as in west Greenland. </p><p>A dominant trend of literature suggests that the high elevations of the McMurdo Dry Valleys have remained under a hyper-arid polar climate since ∼13.8 Ma. However, the presence of 10Bemet in the upper section of the Friis Hills and Table Mountain cores provides evidence for the translocation of clays, which is only possible under a warmer and wetter climate. The 10Bemet concentrations imply that these conditions were present until ∼6.0 Ma at Friis Hills and Table Mountain, consequently challenging the idea that the upper McMurdo Dry Valleys have remained frozen under hyper-arid climate since the mid-Miocene climate transition. Hence, this finding supports the hypothesis that the Miocene has undergone progressive cooling with onset of polar aridity between 7 and 5.4 Ma. The erosion-corrected paleo-active layer depth suggests mean annual air temperatures ranging from -12 to -9°C ∼6.0 Ma. In other words, this thesis shows that the upper McMurdo Dry Valleys have been frozen under hyperarid conditions only since ∼6 Ma and not for 14 Myr as previously thought. </p><p>The ground ice in the uppermost 1 m originates from the modern freezing of evaporated snowmelt and the presence of high salt content which allows unfrozen water in the near-surface. The conformity of dry permafrost samples to biological ratios suggests that the modern environment is regulated by biochemical processes and the current pool of organic carbon in the dry permafrost appears to be in equilibrium with a modern climate and ecosystem. These findings not only characterize the paleoenvironmental changes of continental Antarctica through the late Miocene but also provide a better understanding of the modern ultraxerous conditions of the McMurdo Dry Valleys.</p>

Permafrost distribution and active-layer depths in the McMurdo Dry Valleys, Antarctica

2007 ◽  
Vol 18 (3) ◽  
pp. 217-227 ◽  
Author(s):  
James G. Bockheim ◽  
Iain B. Campbell ◽  
Malcolm McLeod
Keyword(s):  
Active Layer ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys

THE IMPACT OF CLIMATE CHANGE ON LAKE VANDA, MCMURDO DRY VALLEYS, ANTARCTICA

2016 ◽  
Author(s):  
Devin Castendyk ◽  
◽  
Maciej K. Obryk ◽  
Sasha Z. Leidman ◽  
Michael Gooseff ◽  
...  
Keyword(s):  
Climate Change ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Impact Of Climate Change ◽  
The Impact

PRELIMINARY CHARACTERIZATION OF WIND-BLOWN DUST FROM THE MCMURDO DRY VALLEYS OF ANTARCTICA

2016 ◽  
Author(s):  
Melisa A. Diaz ◽  
◽  
Susan A. Welch ◽  
Kathleen A. Welch ◽  
Alia L. Khan ◽  
...  
Keyword(s):  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Preliminary Characterization
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