Revealing biogeochemical signatures of Arctic landscapes with river chemistry

• Published in: Scientific Reports
• Main Authors: Shogren, Arial J., Zarnetske, Jay P., Abbott, Benjamin W., Iannucci, Frances, Frei, Rebecca J., Griffin, Natasha A., Bowden, William B.
• Other Authors: National Science Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2019
• Subjects: Multidisciplinary; Arctic; Arctic Ocean; Glacial Lake; permafrost; Tundra; Alaska
• Online Access: http://dx.doi.org/10.1038/s41598-019-49296-6; http://www.nature.com/articles/s41598-019-49296-6.pdf; http://www.nature.com/articles/s41598-019-49296-6

Abstract Riverine fluxes of carbon and inorganic nutrients are increasing in virtually all large permafrost-affected rivers, indicating major shifts in Arctic landscapes. However, it is currently difficult to identify what is causing these changes in nutrient processing and flux because most long-term records of Arctic river chemistry are from small, headwater catchments draining <200 km 2 or from large rivers draining >100,000 km 2 . The interactions of nutrient sources and sinks across these scales are what ultimately control solute flux to the Arctic Ocean. In this context, we performed spatially-distributed sampling of 120 subcatchments nested within three Arctic watersheds spanning alpine, tundra, and glacial-lake landscapes in Alaska. We found that the dominant spatial scales controlling organic carbon and major nutrient concentrations was 3–30 km 2 , indicating a continuum of diffuse and discrete sourcing and processing dynamics. These patterns were consistent seasonally, suggesting that relatively fine-scale landscape patches drive solute generation in this region of the Arctic. These network-scale empirical frameworks could guide and benchmark future Earth system models seeking to represent lateral and longitudinal solute transport in rapidly changing Arctic landscapes.