Climate, Hydrology, and Nutrients Control the Seasonality of Si Concentrations in Rivers
Abstract The seasonal behavior of fluvial dissolved silica (DSi) concentrations, termed DSi regime , mediates the timing of DSi delivery to downstream waters and thus governs river biogeochemical function and aquatic community condition. Previous work identified five distinct DSi regimes across rivers spanning the Northern Hemisphere, with many rivers exhibiting multiple DSi regimes over time. Several potential drivers of DSi regime behavior have been identified at small scales, including climate, land cover, and lithology, and yet the large‐scale spatiotemporal controls on DSi regimes have not been identified. We evaluate the role of environmental variables on the behavior of DSi regimes in nearly 200 rivers across the Northern Hemisphere using random forest models. Our models aim to elucidate the controls that give rise to (a) average DSi regime behavior, (b) interannual variability in DSi regime behavior (i.e., Annual DSi regime), and (c) controls on DSi regime shape (i.e., minimum and maximum DSi concentrations). Average DSi regime behavior across the period of record was classified accurately 59% of the time, whereas Annual DSi regime behavior was classified accurately 80% of the time. Climate and primary productivity variables were important in predicting Average DSi regime behavior, whereas climate and hydrologic variables were important in predicting Annual DSi regime behavior. Median nitrogen and phosphorus concentrations were important drivers of minimum and maximum DSi concentrations, indicating that these macronutrients may be important for seasonal DSi drawdown and rebound. Our findings demonstrate that fluctuations in climate, hydrology, and nutrient availability of rivers shape the temporal availability of fluvial DSi.
Authors
- Joanna C. Carey (ORCID: https://orcid.org/0000-0003-2365-9185)
- Diane M. McKnight (ORCID: https://orcid.org/0000-0002-4171-1533)
- Keira Johnson (ORCID: https://orcid.org/0000-0003-0671-3901)
- Kathi Jo Jankowski (ORCID: https://orcid.org/0000-0002-3292-4182)
- Hjalmar Laudon (ORCID: https://orcid.org/0000-0001-6058-1466)
- Sidney Bush (ORCID: https://orcid.org/0000-0002-8359-7927)
- Lienne R. Sethna (ORCID: https://orcid.org/0000-0003-1156-172X)
- Jeremy B. Jones (ORCID: https://orcid.org/0000-0003-3540-1392)
- William H. McDowell (ORCID: https://orcid.org/0000-0002-8739-9047)
- Adam S. Wymore (ORCID: https://orcid.org/0000-0002-6725-916X)
- Pirkko Kortelainen (ORCID: https://orcid.org/0000-0002-1448-0688)
- Pamela Sullivan (ORCID: https://orcid.org/0000-0001-8780-8501)
- Amanda Poste (ORCID: https://orcid.org/0000-0001-5255-5356)
- Nicholas J. Lyon (ORCID: https://orcid.org/0000-0003-3905-1078)
Institutions
- United States Geological Survey (US)
- Oregon State University (US)
- University of Alaska Fairbanks (US)
- University of California, Santa Barbara (US)
- University of New Hampshire (US)
- University of Colorado Boulder (US)
- Finnish Environment Institute (FI)
- Norwegian Institute for Water Research (NO)
- Swedish University of Agricultural Sciences (SE)
- National Center for Ecological Analysis and Synthesis (US)
- United States Virgin Islands Department of Health (VI)
- Louisiana Department of Natural Resources (US)
- Norwegian Institute for Nature Research (NO)
- Upper Midwest Environmental Sciences Center
- Babson College (US)
Publication Details
- Journal
- Journal of Geophysical Research Biogeosciences
- Published
- 2024-09-01
- DOI
- https://doi.org/10.1029/2024jg008141
- Citations
- 7
- Primary Topic
- Arsenic contamination and mitigation
- Type
- article
- Field-Weighted Citation Impact
- 1.75
Funders
- National Science Foundation
- U.S. Department of Energy
- U.S. Department of Agriculture
- National Institute of Food and Agriculture
- University of California, Santa Barbara
- U.S. Army Corps of Engineers
- New Hampshire Agricultural Experiment Station
- Office of Experimental Program to Stimulate Competitive Research