@article {jankowski_long-term_2023, title = {Long-Term Changes in Concentration and Yield of Riverine Dissolved Silicon From the Poles to the Tropics}, journal = {Global Biogeochemical Cycles}, volume = {37}, year = {2023}, pages = {e2022GB007678}, abstract = {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.}, keywords = {and modeling, biogeochemical cycles, biogeochemistry, hydrologic time series analysis, impacts of global change, nutrients and nutrient cycling, processes, river, silica, trends}, issn = {1944-9224}, doi = {10.1029/2022GB007678}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GB007678}, author = {Jankowski, Kathi Jo and Johnson, Keira and Sethna, Lienne and Julian, Paul and Wymore, Adam S. and Shogren, Arial J. and Thomas, Patrick K. and Sullivan, Pamela L. and McKnight, Diane M. and McDowell, William H. and Heindel, Ruth and Jones, Jeremy B. and Wollheim, Wilfred and Abbott, Benjamin and Deegan, Linda and Carey, Joanna C.} } @inbook {PIE40, title = {Linking biogeochemical processes to higher trophic levels}, booktitle = {Estuarine Science, A Synthetic Approach to Research and Practice}, year = {2000}, note = {PI Synthesis}, pages = {299-246}, publisher = {Island Press}, organization = {Island Press}, address = {Washington, DC}, keywords = {biogeochemical cycles, food web, LTER-PIE, trophic}, author = {Kremer, J. and Kemp, W. and Giblin, A. and Valiela, I. and Seitzinger, S. and Hoffman, E.}, editor = {J. Hobbie} }