TY - JOUR
T1 - Meltwater seep patches increase heterogeneity of soil geochemistry and therefore habitat suitability
AU - Ball, Rebecca
AU - Virginia, Ross A.
N1 - Funding Information:
This work would not be possible without the diligent efforts of Susan Matthews, an undergraduate researcher with the Presidential Scholar Program at Dartmouth College. We thank Paul Zietz for assistance with sample processing and analysis and two anonymous reviewers for their helpful input. Logistical support was provided by Raytheon Polar Services Corporation and Petroleum Helicopters, Inc. Additional field and lab support was provided by Katie Moerlein. This research was supported by the National Science Foundation Office of Polar Program grants to the McMurdo Long-Term Ecological Research Program ( ANT-0423595 ).
PY - 2012/11
Y1 - 2012/11
N2 - The planet is undergoing an unequivocal period of climate change, with alterations in both longterm directional change and more local short-term variability. The amplified responses of polar ecosystems, and the potential feedbacks presented through alterations of soil processes, make it important to understand the consequences of climate change in polar soil systems. The McMurdo Dry Valleys of Antarctica have experienced periodic discrete warm climate events that result in melt water pulses from ice reserves, such as meltwater seep patches, alter geochemistry, and change habitat suitability for soil biotic communities and the ecological processes dictated by their activity. To investigate the consequences of soil seeps on soil geochemistry and biological activity, we sampled transects across six soil meltwater seep patches and measured soil water content, ion content, and potential CO 2 flux to compare the seep habitat with the surrounding dry soil. We hypothesized that soils affected by meltwater seeps would be higher in salt content than the surrounding dry soils outside the seep patch. Though the increase in soil moisture in seeps could potentially increase biotic activity, we hypothesize that the osmotic stress resulting from a rise in soil salt concentration at the surface driven by evaporation would cause a decrease in biological activity. Our results show that seep patches increased soil moisture and salt content, particularly at the soil surface. The unaffected areas outside of seep patches differed widely in their ion content, typical of the high spatial geochemical heterogeneity found in the dry valleys. The presence of newly formed ice melt seeps can increase landscape-scale spatial heterogeneity by redistribution of soil salts from depth to the surface zone of the active layer. Seep patches have variable influence on biological activity, with both increases and decreases in respiration observed, related to the relative magnitudes of increases in moisture and salinity.
AB - The planet is undergoing an unequivocal period of climate change, with alterations in both longterm directional change and more local short-term variability. The amplified responses of polar ecosystems, and the potential feedbacks presented through alterations of soil processes, make it important to understand the consequences of climate change in polar soil systems. The McMurdo Dry Valleys of Antarctica have experienced periodic discrete warm climate events that result in melt water pulses from ice reserves, such as meltwater seep patches, alter geochemistry, and change habitat suitability for soil biotic communities and the ecological processes dictated by their activity. To investigate the consequences of soil seeps on soil geochemistry and biological activity, we sampled transects across six soil meltwater seep patches and measured soil water content, ion content, and potential CO 2 flux to compare the seep habitat with the surrounding dry soil. We hypothesized that soils affected by meltwater seeps would be higher in salt content than the surrounding dry soils outside the seep patch. Though the increase in soil moisture in seeps could potentially increase biotic activity, we hypothesize that the osmotic stress resulting from a rise in soil salt concentration at the surface driven by evaporation would cause a decrease in biological activity. Our results show that seep patches increased soil moisture and salt content, particularly at the soil surface. The unaffected areas outside of seep patches differed widely in their ion content, typical of the high spatial geochemical heterogeneity found in the dry valleys. The presence of newly formed ice melt seeps can increase landscape-scale spatial heterogeneity by redistribution of soil salts from depth to the surface zone of the active layer. Seep patches have variable influence on biological activity, with both increases and decreases in respiration observed, related to the relative magnitudes of increases in moisture and salinity.
KW - Desert soils
KW - Ice melt
KW - McMurdo Dry Valleys
KW - Polar soils
KW - Seeps
KW - Water pulse
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U2 - 10.1016/j.geoderma.2012.06.028
DO - 10.1016/j.geoderma.2012.06.028
M3 - Article
AN - SCOPUS:84866505643
SN - 0016-7061
VL - 189-190
SP - 652
EP - 660
JO - Geoderma
JF - Geoderma
ER -