EPSCoR - Alaska Adapting to Changing Environments

EPSCoR - Alaska Adapting to Changing Environments

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Spatial Variation in the Origin of Dissolved Organic Carbon in Snow on the Juneau Icefield, Southeast Alaska

Dissolved organic carbon (DOC) plays a fundamental role in the biogeochemistry of glacier ecosystems. However, the specific sources of glacier DOC remain unresolved. To assess the origin and nature of glacier DOC, we collected snow from 10 locations along a transect across the Juneau Icefield, Alaska extending from the coast toward the interior. The Δ14C-DOC of snow varied from −743 to −420‰ showing progressive depletion across the Icefield as δ18O of water became more depleted (R2 = 0.56). Older DOC corresponded to lower DOC concentrations in snow (R2 = 0.31) and a decrease in percent humic-like fluorescence (R2 = 0.36), indicating an overall decrease in modern DOC across the Icefield. Carbon isotopic signatures (13C and 14C) combined with a three-source mixing model showed that DOC deposited in snow across the Icefield reflects fossil fuel combustion products (43−73%) and to a lesser extent marine (21−41%) and terrestrial sources (1−26%). Our finding that combustion aerosols are a large source of DOC to the glacier ecosystem during the early spring (April−May) together with the pronounced rates of glacier melting in the region suggests that the delivery of relic DOC to the ocean may be increasing and consequently impacting the biogeochemistry of glacial and proglacial ecosystems in unanticipated ways.

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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

Funding Agency
EPSCoR - Alaska Adapting to Changing Environments

Other Agencies
National Science Foundation

ISO Topics


Southeast Test Case

Source Portal
Southeast Alaska Science Catalog ::

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  • 01c8ceef3d596f40f05bf496ca00d929
    Published by Lisa
    2016-09-12 15:11:05 -0800
  • 01c8ceef3d596f40f05bf496ca00d929
    Updated by Lisa
    2016-09-12 15:10:47 -0800
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    New record created
    2016-09-09 11:58:24 -0800