Understanding how shifting climate regimes and glacier melt will influence dissolved organic carbon quantity and quality in southcentral Alaska
Abstract
The glacierized mountains of Southcentral Alaska provide water for downstream ecosystems as well as carbon that supports metabolism in the riverine and the nearshore marine environment. This water is derived from glacier melt, snow and rainfall. As each of these water sources interact with the watershed, they acquire a unique DOC signature depending on seasonality and flow pathway. The timing and form of precipitation in this region is expected to shift from a snow to rain dominance with shorter storage intervals in winter. This coupled with glacier melt and seasonal ground thaw may strongly alter the concentration and form of DOC exported from these headwater watersheds. We aim to characterize the DOC concentration and lability in the main sources of water and how they change over the season in the Wolverine Glacier watershed, located on the Kenai Peninsula and draining to Prince William Sound in Alaska in order to better predict how the DOC signature will evolve with changing climatic conditions. In order to do so, we collected water samples over three field seasons (spring - fall) from groundwater, glacier outflow, and non-glacier fed headwater streams to measure DOC concentration, DOM fluorescence, and biodegradable DOC. Glacier sourced waters contained lower DOC concentrations but had higher DOM lability as compared to non-glacier source waters. DOC concentrations were typically highest for glacier outflow in the early spring as they release water stored over the winter at the glacier bed, and for tundra streams in late fall due to flushing from rain events. These results provide data that we will use to evaluate how fluxes will change with continued warming, and to better understand potential ecosystem response in a region sensitive to change.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H13H..04B
- Keywords:
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- 0740 Snowmelt;
- CRYOSPHERE;
- 1621 Cryospheric change;
- GLOBAL CHANGE;
- 1813 Eco-hydrology;
- HYDROLOGY;
- 1817 Extreme events;
- HYDROLOGY