AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Wildfire Impact on Indicators of Primary Biological Load and Genotoxic Potential of Airborne Particulate Matter in Pristine Sub-Alpine Forests
ALINA M. HANDOREAN, Odessa Gomez, Jane Turner, Benjamin J. Miller, Mark T. Hernandez, University of Colorado Boulder
Abstract Number: 321 Working Group: Bioaerosols: Characterization and Environmental Impact
Abstract Primary biopolymers can contribute to a significant fraction of airborne organic carbon (OC) pools in some atmospheric environments, yet the potential biological activity of these pools remains relatively unknown. In an effort to better characterize organic aerosols as they exist in relatively pristine settings, we monitored and compared the polysaccharides, lipids, and DNA recovered from size segregated particulate matter (PM) during several summer seasons in a sub-alpine forest belt (Colorado, USA) — including a season with a large wildfire. Particulate matter was eluted from filters which continuously collected aerosol during July and/or August of three years between 2008 and 2012. As judged by specific carbohydrate, phospholipid and gene content, airborne PM analyzed for this primary biological load was juxtaposed to relative microbial abundance, as well as the potential to induce genotoxic activity.
Carbohydrate content was measured using a colorimetric assay of monosaccharide phenol conjugates, with glucose as a standard. Phospholipid content was measured using a colorimetric assay of chloroform-methanol extracts subjected to persulfate digestion, and calibrated against a ß-glycerol phosphate standard. Genomic DNA was extracted with ammonium acetate using glycogen as a carrier, and amplified by polymerase chain reaction using universal ribosomal subunit primers for bacteria and fungi. The mass and OC fraction of these biopolymers was significant in most cases (c.a. > 10 %) and presented a conservative index of airborne vegetative detritus and microbial biomass (PMBIO), considering microorganism types. Biopolymer load was relatively consistent across seasons and sites; however, biopolymer contributions were significantly different near the fire site. As judged by SOS induction in Salmonella typhimurium cultures genetically engineered to report genotoxic activity, PM collected in the proximity of a week-long wild fire presented greater genotoxic potential than summer samples collected from nearby pristine forests.