Modeling Terrestrial Dissolved Organic Carbon Loading to Western Arctic Rivers

Area of Science:

• Environmental Science
• Climate Science
• Hydrology

Background:

• Arctic watersheds are critical pathways for dissolved organic carbon (DOC) transfer to the ocean.
• Climate warming and hydrological changes pose risks to Arctic carbon cycling and land-to-ocean transfer.
• Understanding DOC mobilization is vital for predicting Arctic ecosystem responses to climate change.

Purpose of the Study:

• To quantify model-simulated estimates of DOC concentrations and loadings in western Arctic rivers.
• To assess the impacts of hydrological intensification and permafrost thaw on carbon export.
• To provide a framework for understanding Arctic carbon export to coastal waters.

Main Methods:

• Utilized a modeling framework to simulate runoff, surface, and active layer leachate DOC.
• Validated model simulations using existing field measurements, synthesis studies, and modeling efforts.
• Analyzed DOC concentrations and loadings for drainage basins between the Yukon and Mackenzie Rivers.

Main Results:

• Model simulations effectively quantified DOC leaching and captured seasonal DOC cycles.
• A distinct east-west gradient in spring and summer DOC concentrations on the North Slope of Alaska was identified.
• Simulated DOC loadings for major Arctic rivers showed reasonable agreement with existing estimates.
• Comparable DOC loadings were found for rivers draining to the Beaufort Sea and Bering/Chukchi Seas.

Conclusions:

• The modeling framework successfully quantifies Arctic DOC export to coastal waters.
• Results provide a basis for assessing the impacts of climate change on Arctic carbon cycling.
• Understanding these processes is crucial for predicting the future of Arctic coastal ecosystems under warming conditions.