Singley, Joel G听1听;听Wlostowski, Adam N听2听;听Bergstrom, Anna J听3听;听Sokol, Erick R听4听;听Torrens, Christa L听5听;听Jaros, Chris听6听;听Wilson, Colleen E听7听;听Gooseff, Michael N听8
1听Environmental Studies Program, 麻豆官网
2听Department of Civil, Environmental, and Architectural Engineering, 麻豆官网
3听Department of Geological Sciences, 麻豆官网
4听Institute of Arctic and Alpine Research, 麻豆官网
5听Environmental Studies Program, 麻豆官网
6听Institute of Arctic and Alpine Research, 麻豆官网
7听Department of Civil, Environmental, and Architectural Engineering, 麻豆官网
8听Department of Civil, Environmental, and Architectural Engineering, 麻豆官网
The analysis of concentration-discharge (C-Q) relationships has often been used in an inverse modeling framework to quantify source water contributions and biogeochemical processes occurring within catchments, especially during discrete hydrological events. Yet, the interpretation of C-Q hysteresis is often confounded by catchment complexity, such as a large number of source waters and non-stationarity in their hydrochemical composition. Attempts to overcome these challenges often necessitate ignoring or lumping together potentially important runoff pathways and geochemical sources/sinks. This is especially true of the hyporheic zone because it acts as an integrator of multiple sources and typically lacks a unique hydrochemical signature. Furthermore, these complexities often limit efforts to identify catchment processes responsible for the transience of C-Q hysteresis between discrete hydrological events. To address these challenges, we leverage the hydrologic simplicity and long-term, high frequency Q and electrical conductivity (EC) data from streams in the McMurdo Dry Valleys, Antarctica. In this two end-member system, EC can serve as a proxy for the concentration of solutes derived from the hyporheic zone and reveal the legacy of mixing processes occurring along the stream. We utilize a novel approach to decompose loops into sub-hysteretic EC-Q dynamics in order to identify individual mechanisms governing hysteretic patterns and transience across a wide range of timescales. From this analysis, we find that hydrologic and hydraulic processes govern EC response to diel and seasonal Q variability resulting in discrete hysteretic behavior. We also observe that variable hyporheic turnover rates govern EC-Q patterns at daily, annual, and interannual timescales and contribute differently to transient hysteresis in short and long streams. The framework we utilize to analyze sub-hysteretic dynamics may be applied more broadly to constrain the processes controlling C-Q transience and aid advancements in understanding the evolution of catchment processes and structure over time.