Spatiotemporal Patterns of Microbial Composition and Diversity in Precipitation

Ken Aho,Rachel Joyce,Aurora L H Bayless‐Edwards,Cindy E Morris,Carolyn F Weber,Jason T Werth,Boris A Vinatzer,David G Schmale,Kevin Failor,Brent C Christner

doi:10.1002/bes2.1653

Abstract

We characterized trends of bacteria and fungi assemblages from 72 precipitation events in three US states over four seasons. We determined that (1) bacterial assemblages were associated with season and high-altitude characteristics of storms, whereas fungal assemblages were correlated with particular spatial locations; and (2) bacterial assemblages had higher contributions to total β-diversity from nestedness, due to taxa losses during dispersal, particularly among potentially ice-nucleating bacteria, whereas fungal assemblages had higher contributions to total β-diversity from taxa turnover. Our findings advance the understanding of aerosolized microbial deposition and the development of theory concerning potential assembly rules for bioaerosol assemblages. These photographs illustrate the article “Spatiotemporal patterns of microbial composition and diversity in precipitation” by K. Aho, C. F. Weber, B. C. Christner, B. A. Vinatzer, C. E. Morris, R. Joyce, K. Failor, J. T. Werth, A. L. H. Bayless-Edwards, and D. G. Schmale III, published in Ecological Monographs. https://doi.org/10.1002/ecm.1394

Highlights

Of growing interest to ecologists are the properties of precipitation-borne microbes, species and strains that may trigger precipitation through the formation of ice in clouds
We determined that: 1) bacterial operational taxonomic unit (OTU) composition of precipitation was strongly associated with macroscale drivers including season and high altitude characteristics of storms; 2) fungal operational taxonomic units (OTUs) composition was strongly correlated with mesoscale drivers including particular spatial locations; 3) β-diversity for both bacteria and fungi was largely maintained by turnover of taxa; 4) bacterial assemblages had higher contributions to total β-diversity from nestedness, due to losses of taxa during dispersal, among potential ice nucleation active bacteria; and 5) fungal assemblages had higher contributions to total β-diversity from turnover due to OTU replacement
Similar patterns were apparent for stratiform/convective classes with significant differences occurring with season (p = 0.003), due to the absence of stratiform storms during summer months, but a lack of strong differences with site (p = 0.102)

Summary

Introduction

Of growing interest to ecologists are the properties of precipitation-borne microbes, species and strains that may trigger precipitation through the formation of ice in clouds (i.e., bioprecipitation, Sands et al 1982, Morris et al 2014a, Hummel et al 2018). The ice nucleation-active (INA) phenotype allows broad dissemination of aerosolized microbes (Sands et al 1982, Fitt et al 1989) while limiting prolonged exposure to damaging stresses (e.g., desiccation, UV radiation) associated with atmospheric transport (Attard et al 2012, Hill et al 2017). Despite this information, the community ecology of these processes is poorly understood. It is largely unknown if atmospheric spatiotemporal characteristics, including site locations and season, correspond to general trends in precipitation-borne microbial taxa or taxa assemblages (Amato et al 2017, pg. 8, but see Cáliz et al 2018)

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Discussion

Conclusion