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Long-term changes in concentrations and yield of riverine dissolved silicon from the poles to the tropics

October 6, 2023

Riverine exports of silicon (Si) influence global carbon cycling through the growth of marine diatoms, which account for ∼25% of global primary production. Climate change will likely alter river Si exports in biome-specific ways due to interacting shifts in chemical weathering rates, hydrologic connectivity, and metabolic processes in aquatic and terrestrial systems. Nonetheless, factors driving long-term changes in Si exports remain unexplored at local, regional, and global scales. We evaluated how concentrations and yields of dissolved Si (DSi) changed over the last several decades of rapid climate warming using long-term data sets from 60 rivers and streams spanning the globe (e.g., Antarctic, tropical, temperate, boreal, alpine, Arctic systems). We show that widespread changes in river DSi concentration and yield have occurred, with the most substantial shifts occurring in alpine and polar regions. The magnitude and direction of trends varied within and among biomes, were most strongly associated with differences in land cover, and were often independent of changes in river discharge. These findings indicate that there are likely diverse mechanisms driving change in river Si biogeochemistry that span the land-water interface, which may include glacial melt, changes in terrestrial vegetation, and river productivity. Finally, trends were often stronger in months outside of the growing season, particularly in temperate and boreal systems, demonstrating a potentially important role of shifting seasonality for the flux of Si from rivers. Our results have implications for the timing and magnitude of silica processing in rivers and its delivery to global oceans.

Publication Year 2023
Title Long-term changes in concentrations and yield of riverine dissolved silicon from the poles to the tropics
DOI 10.1029/2022GB007678
Authors Kathi Jo Jankowski, Keira Johnson, Lienne R. Sethna, Paul Julian, Adam S. Wymore, Arial J. Shogren, Patrick Thomas, Pamela L. Sullivan, Diane M. McKnight, William H. McDowell, Ruth C. Heindel, Jeremy B. Jones, Wilfred M. Wollheim, Benjamin Abbott, Linda A. Deegan, Joanna C. Carey
Publication Type Article
Publication Subtype Journal Article
Series Title Global Biogeochemical Cycles
Index ID 70249450
Record Source USGS Publications Warehouse
USGS Organization Upper Midwest Environmental Sciences Center