AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Seasonal Changes of Bacteria Measured on a High Elevation Tower in Tokyo
JUN UETAKE, Yutaka Tobo, Ryohei Misumi, Paul DeMott, Thomas Hill, Sonia Kreidenweis, Colorado State University
Abstract Number: 750 Working Group: Bioaerosols
Abstract Atmospheric bioaerosols can have far-reaching impacts on ecosystems, health and climate. Most previous outdoor bioaerosol studies in Japan have been limited to investigate the influence of transported microbes during Asian Dust events in spring. Long term sampling on even a semi-daily basis, which encompass both transitory weather events and seasonal variations, has not been conducted before. In order to understand seasonal airborne bacterial changes over Tokyo, 48-72h samples (from June 2016 to Feb 2017) were collected on filters using a low volume sampler (15-30L/min) housed in temporary science observatory at an elevation of 458 m a.g.l. in the “Tokyo Skytree” the highest tower (634m a.g.l.) in Japan, located in downtown Tokyo. Bacterial 16S rRNA genes (V3, V4) were amplified by PCR, and sequenced by MiSeq. All sequences were clustered into Exact Sequence Variants (ESVs) by the DADA2 program. Bacterial community structures were found to slightly shift month to month, but changed strongly in mid-October, when HYSPLIT trajectory modeling predicted a source region (3 days back trajectory) of particles coming consistently from the Eurasian mainland. Furthermore, lower alpha-diversity was observed during a typhoon occurrence and during the autumn rainy season in September indicating the influence of bacteria of local origin. These results indicate that air over Tokyo was affected by both local emissions and long range transport, and their respective contributions changed with weather and seasons.