Concentration–discharge patterns of weathering products from global rivers  

作　　者：Daniel E.Ibarra Seulgi Moon Jeremy K.Caves C.Page Chamberlain Kate Maher 

机构地区：[1]Earth System Science, Stanford University, Stanford,CA 94305-4216, USA [2]Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095-1567, USA [3]Earth Science, ETH Ziirich, 8092 Zurich, Switzerland [4]Geological Sciences, Stanford University, Stanford,CA 94305-2115, USA

出　　处：《Acta Geochimica》2017年第3期405-409,共5页地球化学学报（英文）

基　　金：supported by a Stanford EDGE-STEM Fellowship;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

摘　　要：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 Damkohler coefficient. These results are also compared to those derived using average concentration–discharge pairs.Both the power law exponent and the Damkohler coefficient increase and asymptote as catchments exhibit increasingly chemostatic behavior, resulting in an inverse relationship between the two parameters. We also show that using thedistribution 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.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 Damko¨hler coefficient. These results are also compared to those derived using average concentration–discharge pairs.Both the power law exponent and the Damk?hler coefficient increase and asymptote as catchments exhibit increasingly chemostatic behavior, resulting in an inverse relationship between the two parameters. We also show that using thedistribution 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.

关 键 词：Concentration–discharge RIVERS Silicate weathering SOLUTES 

分 类 号：P343[天文地球—水文科学] P512.1[天文地球—地球物理学]