Effects of Wildfires and Ash Leaching on Stream Chemistry in the Santa Ynez Mountains of Southern California

Water

John Melack¹  Carl Swindle²  Parker Shankin-Clarke³  Jean Carlson³  Matthew Meyerhof⁴ 

[1] Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106, USA;Department of Earth Science, University of California, Santa Barbara, CA 93106, USA;Department of Physics, University of California, Santa Barbara, CA 93106, USA;Marine Science Institute, University of California, Santa Barbara, CA 93106, USA;

关键词: major cations;    potassium;    stream chemistry;    fire;    ash;   

DOI  :  10.3390/w13172402

来源: DOAJ

【 摘 要 】

Wildfires can change ecosystems by altering solutes in streams. We examined major cations in streams draining a chaparral-dominated watershed in the Santa Ynez Mountains (California, USA) following a wildfire that burned 75 km² from July 8 to October 5, 2017. We identified changes in solute concentrations, and postulated a relation between these changes and ash leached by rainwater following the wildfire. Collectively, K⁺ leached from ash samples exceeded that of all other major cations combined. After the wildfire, the concentrations of all major cations increased in stream water sampled near the fire perimeter following the first storm of the season: K⁺ increased 12-fold, Na⁺ and Ca²⁺ increased 1.4-fold, and Mg²⁺ increased 1.6-fold. Our results suggested that the 12-fold increase in K⁺ in stream water resulted from K⁺ leached from ash in the fire scar. Both C and N were measured in the ash samples. The low N content of the ash indicated either high volatilization of N relative to C occurred, or burned material contained less N.

【 授权许可】

Unknown