Quantifying the functional relationships relating river discharge and weathering products places key constraints on the negative feedback between the silicate weathering and climate. In this study we analyze the concentration–discharge relationships of weathering products from global rivers using previously compiled time-series datasets for concentrations and discharge from global rivers. To analyze the nature of the covariation between specific discharge and concentrations, we use both a power law equation and a recently developed solute production equation. The solute production equation allows us to quantify weathering efficiency, or the resistance to dilution at high runoff, via the Damköhler coefficient. These results are also compared to those derived using average concentration–discharge pairs. Both the power law exponent and the Damköhler coefficient increase and asymptote as catchments exhibit increasingly chemostatic behavior, resulting in an inverse relationship between the two parameters. We also show that using the distribution of average concentration–discharge pairs from global rivers, rather than fitting concentration–discharge relationships for each individual river, underestimates global median weathering efficiency by up to a factor of ~10. This study demonstrates the utility of long time-series sampling of global rivers to elucidate controlling processes needed to quantify patterns in global silicate weathering rates.
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Daniel E. Ibarra is partially supported by a Stanford EDGE-STEM Fellowship. This work was initiated under NSF EAR-1254156 to Kate Maher and was also supported by the California Alliance Research Exchange NSF HRD-1306595 to C. Page Chamberlain.
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Conflict of interest
The authors declare that they have no conflict of interest.
Ibarra DE, Caves JK, Moon S et al (2016) Differential weathering of basaltic and granitic catchments from concentration–discharge relationships. Geochim Cosmochim Acta 190:265–293CrossRefGoogle Scholar
Kump LR, Arthur MA (1997) Global chemical erosion during the cenozoic: weatherability balances the budgets. Tectonic uplift and climate change. Springer, Boston, pp 399–426CrossRefGoogle Scholar
Kump LR, Brantley SL, Arthur MA (2000) Chemical weathering, atmospheric CO2, and climate. Annu Rev Earth Planet Sci 28:611–667CrossRefGoogle Scholar
Maher K (2010) The dependence of chemical weathering rates on fluid residence time. Earth Planet Sci Lett 294:101–110CrossRefGoogle Scholar
Maher K (2011) The role of fluid residence time and topographic scales in determining chemical fluxes from landscapes. Earth Planet Sci Lett 312:48–58CrossRefGoogle Scholar
Maher K, Chamberlain CP (2014) Hydrologic regulation of chemical weathering and the geologic. Science 343:1502–1504CrossRefGoogle Scholar
Moon S, Chamberlain CP, Hilley GE (2014) New estimates of silicate weathering rates and their uncertainties in global rivers. Geochim Cosmochim Acta 134:257–274CrossRefGoogle Scholar
Torres MA, West AJ, Clark KE (2015) Geomorphic regime modulates hydrologic control of chemical weathering in the Andes–Amazon. Geochim Cosmochim Acta 166:105–128CrossRefGoogle Scholar
Torres MA, Baronas JJ, Clarke KE, Feakins SJ, West AJ (2017) Mixing as a driver of temporal variations in river hydrochemistry. Part 1: insights from conservative traces in the Andes–Amazon transition. Water Resour Res. doi:10.1001/2016WR019733Google Scholar
von Blanckenburg F, Bouchez J, Ibarra DE, Maher K (2015) Stable runoff and weathering fluxes into the oceans over Quaternary climate cycles. Nat Geosci 8:538–542CrossRefGoogle Scholar