AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Tracking the Movement of Microbial Aerosols from Aquatic Systems with High-speed Video
RENEE PIETSCH, Craig Powers, David Schmale, Sunghwan Jung, Shane Ross, Virginia Tech
Abstract Number: 335 Working Group: Bioaerosols
Abstract Aquatic environments contain a great diversity of microorganism, including bacteria. These bacteria are capable of crossing the air-water interface and entering the environments as aerosols. One natural method of aerosol production is wind moving across the surface of a body of water creating droplets that leave the water surface. The droplets are formed by two different mechanisms, either bubble bursting or fragmentation. A laboratory flume was designed to simulate wind moving across the surface of a lake. High speed video was used to capture droplets moving across the air-water interface at four wind speeds (3.5, 4.0, 4.5, and 5.0 m/s). The images were analyzed to determine the diameter as well as initial speed and angle of each droplet as it leaves the water surface. The rate of droplet production increased quadratically with wind speed, while the droplet mass flux decreased slightly before increasing with wind speed. The diameter and speed of the droplets fit gamma distributions. Droplet angle had a narrower distribution at higher wind speeds. The two mechanisms of droplet production (bubble busting and fragmentation) yielded different distributions for diameter, speed, and angle. The capacity for bacterial flux into the atmosphere was calculated based on the droplet production and bacterial concentrations in freshwater systems. The results show significant amounts of bacteria are crossing the air water interface with the potential to be aerosolized. Aerosolized bacteria have the potential to impact the Earth’s radiation budget, precipitation processes, and pathogen transport.