Biogenic Volatile Nucleation Precursor Compound Fluxes from Pennsylvania Freshwater Lakes during 2023 Algal Bloom Season
CHRISTINE TROLLER, Coty Jen, Jeffery Butt, Rick Spear, Jamie Detweiler, Carnegie Mellon University
Abstract Number: 99
Working Group: Remote and Regional Atmospheric Aerosol
Abstract
Freshwater algal blooms are becoming increasingly prevalent and are expected to produce emissions that significantly impact regional air quality and Earth’s global climate processes as time proceeds. Microalgae and cyanobacteria emit various volatile organic compounds. These released compounds participate in atmospheric new particle formation, a complex process whereby cloud condensation nuclei are formed and impact cloud properties. Few freshwater lake emission measurements have been reported, thus limiting our understanding of their contribution to air quality degradation and cloud formation dynamics. In this study, nine 7-liter freshwater Pennsylvania lake samples were collected throughout June to September in 2023, peak algal bloom season. Gas fluxes of various compounds (i.e., ammonia, alkylamines, and other organic compounds) were measured from the water samples using a real-time water-to-air flux measurement system connected to a chemical ionization mass spectrometer. We report similar flux trends across the lake water samples regardless of cyanobacterial presence. However, water samples with significant concentrations of cyanobacteria tended to have a constant emission flux over 24 hours of measurements, while samples with little to no cyanobacteria decreased in emission flux. This is potentially due to the biological activity replenishing compounds in the lake water samples. Discovering relationships between lake emission fluxes and cyanobacterial presence will help us better understand how algal blooms may impact environmental dynamics. Additionally, reporting gaseous fluxes for nucleation precursors from freshwater bodies will lead to better modeling of future air quality and atmospheric processes.