Presentation Title

Potential Ash Toxicity on Mediterranean Stream Ecosystems

Faculty Mentor

Thomas Vandergon

Start Date

18-11-2017 2:15 PM

End Date

18-11-2017 3:15 PM

Location

BSC-Ursa Minor 89

Session

Poster 3

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Mediterranean ecosystems are chaparral dominated environments characterized by cool wet winters, hot dry summers, and most distinctively, frequent wildfires. In these ecosystems, wildfires are often directly followed by winter rains, resulting in the introduction of ash-loaded runoff into streams. Though wildfire ash is known to contain toxic components, such as EPA regulated heavy metals and polycyclic aromatic hydrocarbons (PAH’s), little is known about the potential toxicity of wildfire ash to stream organisms. In previous studies, ash exposure resulted in inhibitory effects on algal growth and bacterial metabolic activity. The aim of this study is to determine the effect of wildfire ash on aquatic organisms inhabiting Mediterranean streams in local Southern California chaparral. Through a series of bioassays, this study tested the chemical toxicity of aqueous ash extract on standardized biotoxicity test organisms and Santa Monica Mountain native stream organisms. Significant negative effects were found only at the highest ash concentrations in a Vibrio fischeri luminescence assay for biotoxicity. At low concentrations, no significant biotoxicity effects were apparent for either standard or native stream organisms. My results indicated that ash extract may even promote the growth of primary producers at below-toxic concentrations.

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Nov 18th, 2:15 PM Nov 18th, 3:15 PM

Potential Ash Toxicity on Mediterranean Stream Ecosystems

BSC-Ursa Minor 89

Mediterranean ecosystems are chaparral dominated environments characterized by cool wet winters, hot dry summers, and most distinctively, frequent wildfires. In these ecosystems, wildfires are often directly followed by winter rains, resulting in the introduction of ash-loaded runoff into streams. Though wildfire ash is known to contain toxic components, such as EPA regulated heavy metals and polycyclic aromatic hydrocarbons (PAH’s), little is known about the potential toxicity of wildfire ash to stream organisms. In previous studies, ash exposure resulted in inhibitory effects on algal growth and bacterial metabolic activity. The aim of this study is to determine the effect of wildfire ash on aquatic organisms inhabiting Mediterranean streams in local Southern California chaparral. Through a series of bioassays, this study tested the chemical toxicity of aqueous ash extract on standardized biotoxicity test organisms and Santa Monica Mountain native stream organisms. Significant negative effects were found only at the highest ash concentrations in a Vibrio fischeri luminescence assay for biotoxicity. At low concentrations, no significant biotoxicity effects were apparent for either standard or native stream organisms. My results indicated that ash extract may even promote the growth of primary producers at below-toxic concentrations.