Quantifying Reaeration Rates in Alpine Streams Using Deliberate Gas Tracer Experiments

Water

Andrew Benson²  Matthew Zane¹  Timothy E. Becker¹  Ate Visser⁴  Stephanie H. Uriostegui¹  Elizabeth DeRubeis³  Jean E. Moran³  Bradley K. Esser⁴ 

[1] Department of Earth Science, University of California, Santa Barbara, CA 93106, USA; E-Mails:;Program of Environmental Studies, University of California, Santa Barbara, CA 93106, USA; E-Mail:;Department of Earth and Environmental Sciences, California State University East Bay, Hayward, CA 94542, USA; E-Mails:;Chemical Science Division, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA; E-Mails:

关键词: reaeration;    field tracer experiment;    sulfur hexafluoride;    xenon;    alpine stream;    dissolved oxygen;   

DOI  :  10.3390/w6041013

来源: mdpi

【 摘 要 】

Gas exchange across the air-water interface is a critical process that maintains adequate dissolved oxygen (DO) in the water column to support life. Oxygen reaeration rates can be accurately measured using deliberate gas tracers, like sulfur hexafluoride (SF₆) or xenon (Xe). Two continuous release experiments were conducted in different creeks in the Sierra Nevada of California: Sagehen Creek in September, 2009, using SF₆ and Martis Creek in August, 2012, using both SF₆ and Xe. Measuring gas loss along the creek, which was approximated with the one-dimensional advection-dispersion equation, allows for the estimation of the SF₆ or Xe reaeration coefficient (K_SF6, K_Xe), which is converted to DO reaeration (K_DO or K₂) using Schmidt numbers. Mean K_SF6 for upper and lower Sagehen and Martis Creeks were, respectively, 34 day⁻¹, 37 day⁻¹ and 33 day⁻¹, with corresponding K_DOs of 61 day⁻¹, 66 day⁻¹ and 47 day⁻¹. In Martis Creek, K_Xe was slightly higher (21%) than K_SF6, but the calculated K_DO from SF₆ agreed with the calculated K_DO from Xe within about 15%; this difference may be due to bubble-enhanced gas transfer. Established empirical equations of K_DO using stream characteristics did a poor job predicting K_DO for both creeks.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.