Climate and landform interact to control the source and transport of nitrate in Pacific Northwest rivers

Elizabeth J. Elmstrom; Gordon W. Holtgrieve; Mark David Scheuerell; Andrew J. Schauer; Karrin Leazer

doi:10.1038/s43247-024-01235-8

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Climate and landform interact to control the source and transport of nitrate in Pacific Northwest rivers

Elizabeth J. Elmstrom·Gordon W. Holtgrieve·Mark David Scheuerell·Andrew J. Schauer·Karrin Leazer

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Abstract

The hydrological effects of climate change are documented in many regions; however, climate-driven impacts to the source and transport of river nutrients remain poorly understood. Understanding the factors controlling nutrient dynamics across river systems is critical to preserve ecosystem function yet challenging given the complexity of landscape and climate interactions. Here, we harness a large regional dataset of nitrate (NO 3 – ) yield, concentration, and isotopic composition (δ 15 N and δ 18 O) to evaluate the strength of hydroclimate and landscape variables in controlling the seasonal source and transport of NO 3 – . We show that hydroclimate strongly influenced the seasonality of river NO 3 – , producing distinct, source-dependent NO 3 – regimes across rivers from two mountain ranges. Riverine responses to hydroclimate were also constrained by watershed-scale topographic features, demonstrating that while regional climate strongly influences the timing of river NO 3 – transport, watershed topography plays a distinct role in mediating the sensitivity of river NO 3 – dynamics to future change.

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Communications Earth and Environment Article

Source-reported bounding extent: 34.0589425188774° to 49.988705305763744° latitude; -122.3245432375632° to -113.23223159100554° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Elizabeth J. Elmstrom, Gordon W. Holtgrieve, Mark David Scheuerell, Andrew J. Schauer, Karrin Leazer. 2024-02-20. Climate and landform interact to control the source and transport of nitrate in Pacific Northwest rivers. https://doi.org/10.1038/s43247-024-01235-8

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