Diversity and Ice Nucleation Activity of Microorganisms Collected With a Small Unmanned Aircraft System (sUAS) in France and the United States

Abstract

Many microbes relevant to crops, domestic animals, and humans are transported over long distances through the atmosphere. Some of these atmospheric microbes catalyze the freezing of water at higher temperatures and facilitate the onset of precipitation. We collected microbes from the lower atmosphere in France and the United States with a small unmanned aircraft system (sUAS). 55 sampling missions were conducted at two locations in France in 2014 (an airfield in Pujaut, and the top of Puy de Dôme), and three locations in the U.S. in 2015 (a farm in Blacksburg, Virginia, and a farm and a lake in Baton Rouge, Louisiana). The sUAS was a fixed-wing electric drone equipped with a remote-operated sampling device that was opened once the aircraft reached the desired sampling altitude (40–50 meters above ground level). Samples were collected on agar media (TSA, R4A, R2A, and CA) with and without the fungicide cycloheximide. Over 4,000 bacterial-like colonies were recovered across the 55 sUAS sampling missions. A positive relationship between sampling time and temperature and concentrations of culturable bacteria was observed for sUAS flights conducted in France, but not for sUAS flights conducted in Louisiana. A droplet freezing assay was used to screen nearly 2,000 colonies for ice nucleation activity, and 15 colonies were ice nucleation active at temperatures warmer than −8°C. Sequences from portions of 16S rDNA were used to identify 503 colonies from 54 flights to the level of genus. Assemblages of bacteria from sUAS flights in France (TSA) and sUAS flights in Louisiana (R4A) showed more similarity within locations than between locations. Bacteria collected with sUAS on TSA in France and Virginia were significantly different across all levels of classification tested (P < 0.001 for class, order, family, and genus). Principal Coordinates Analysis showed a strong association between the genera Curtobacterium, Pantoea, and Pseudomonas from sUAS flights in Virginia, and Agrococcus, Lysinibacillus, and Paenibacillus from sUAS flights in France. Future work aims to understand the potential origin of the atmospheric microbial assemblages collected with sUAS, and their association with mesoscale atmospheric processes.

Characterization of Ice‐Nucleating Particles Over Northern India

“…The INP activity in Pantoea spp. has been described previously (Akila et al, 2018;Jimenez-Sanchez et al, 2018;Kozloff et al, 1983;Lindow, 1978;Michaud et al, 2014;Stephanie & Waturangi, 2011 based on an assumed condensed water content of 0.4 g/m 3 (Petters & Wright, 2015). The gray-shaded area shows the envelope of INP observations in precipitation from Petters and Wright (Petters & Wright, 2015).…”

Microbial composition in seasonal time series of free tropospheric air and precipitation reveals community separation

“…Studies focusing on free tropospheric air microbial communities often present data from single campaigns or few flights (Schmale and Ross 2015;Techy et al 2010;Jimenez-Sanchez et al 2018;Smith et al 2018;Maki et al 2017;Xia et al 2013;Zweifel et al 2012) and have shown that microbes present in the free troposphere might originate from long-range travel (Maki et al 2017;Smith and David 2012;Smith et al 2011Smith et al , 2012Brown and Hovmøller 2002;Burrows et al 2009a, b). Air masses above and below PBL differ significantly in microbial composition.…”

Microorganisms Collected from the Surface of Freshwater Lakes Using a Drone Water Sampling System (DOWSE)

“…This system allows water sampling near the shore line without any major disturbances or mixing of the sample area. Future work aims to elucidate the structure and function of entire microbial assemblages within and among the Austrian lakes; diversity analyses of culturable plate growth on the non-selection TSA media could be determined by 16S sequence analysis [28]. Additional analyses of the abundance of ice+ bacteria in surrounding bodies of water, such as glacial streams and rivers, could also be conducted to determine sources and reservoirs of ice nucleating microorganisms.…”