EPSCoR - Alaska Adapting to Changing Environments

EPSCoR - Alaska Adapting to Changing Environments

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Seasonal variability of organic matter composition in an Alaskan glacier outflow: insights into glacier carbon sources

Glacier ecosystems are a significant source of bioavailable, yet ancient dissolved organic carbon (DOC). Characterizing DOC in Mendenhall Glacier outflow (southeast Alaska) we document a seasonal persistence to the radiocarbon-depleted signature of DOC, highlighting ancient DOC as a ubiquitous feature of glacier outflow. We observed no systematic depletion in Δ 14C-DOC with increasing discharge during the melt season that would suggest mobilization of an aged subglacial carbon store. However, DOC concentration, δ 13C-DOC, Δ 14C-DOC and fluorescence signatures appear to have been influenced by runoff from vegetated hillslopes above the glacier during onset and senescence of melt. In the peak glacier melt period, the Δ 14C-DOC of stream samples at the outflow (−181.7 to −355.3‰) was comparable to the Δ 14C-DOC for snow samples from the accumulation zone (−207.2 to −390.9‰), suggesting that ancient DOC from the glacier surface is exported in glacier runoff. The pre-aged DOC in glacier snow and runoff is consistent with contributions from fossil fuel combustion sources similar to those documented previously in ice cores and thus provides evidence for anthropogenic perturbation of the carbon cycle. Overall, our results emphasize the need to further characterize DOC inputs to glacier ecosystems, particularly in light of predicted changes in glacier mass and runoff in the coming century.

Data and Resources

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    Website :: Publisher Website

    http://iopscience.iop.org/article/10.1088/1748-9326/9/5/055005;jsessionid=861AA86ED2C4517F09E00E89D5FA0431.c6.iopscience.cld.iop.org

Status: Complete
Type: Project
Data Types: Report
Primary Contact
Pyare, Sanjay
Email: sanjay.pyare@uas.alaska.edu
Work: 907-796-6007
Primary Agency
EPSCoR - Alaska Adapting to Changing Environments
Type
Academic

Funding Agency
EPSCoR - Alaska Adapting to Changing Environments
Type
Academic

Other Agencies
National Science Foundation

ISO Topics
inlandWaters

Geo-keywords
Southeast

Collection
Southeast Test Case

Source Portal
Southeast Alaska Science Catalog ::

Direct Record Link
http://epscor.portal.gina.alaska.edu/catalogs/11730-seasonal-variability-of-organic-matter-composit
  • 01c8ceef3d596f40f05bf496ca00d929
    Published by Lisa
    2016-09-28 16:49:03 -0800
  • 01c8ceef3d596f40f05bf496ca00d929
    Updated by Lisa
    2016-09-28 16:48:55 -0800
  • 470f70ddabc3d336a04110c5468ab053
    New record created
    2016-09-15 16:23:13 -0800
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