Stream biogeochemical and suspended sediment responses to permafrost degradation in stream banks in Taylor Valley, Antarctica
Stream channels in the McMurdo Dry Valleys are characteristically wide, incised, and stable. At typical flows, streams occupy a fraction of the oversized channels, providing habitat for algal mats. In January 2012, we discovered substantial channel erosion and subsurface thermomechanical erosion und...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-03-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/1723/2016/bg-13-1723-2016.pdf |
| Summary: | Stream channels in the McMurdo Dry Valleys are characteristically wide,
incised, and stable. At typical flows, streams occupy a fraction of the
oversized channels, providing habitat for algal mats. In January 2012, we
discovered substantial channel erosion and subsurface thermomechanical
erosion undercutting banks of the Crescent Stream. We sampled stream water along
the impacted reach and compared concentrations of solutes to the long-term
data from this stream ( ∼ 20 years of monitoring).
Thermokarst-impacted stream water demonstrated higher electrical
conductivity, and concentrations of chloride, sulfate, sodium, and nitrate
than the long-term medians. These results suggest that this mode of lateral
permafrost degradation may substantially impact stream solute loads and
potentially fertilize stream and lake ecosystems. The potential for sediment
to scour or bury stream algal mats is yet to be determined, though it may
offset impacts of associated increased nutrient loads to streams. |
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| ISSN: | 1726-4170 1726-4189 |