Articles | Volume 12, issue 21
Biogeosciences, 12, 6337–6349, 2015
Biogeosciences, 12, 6337–6349, 2015

Research article 06 Nov 2015

Research article | 06 Nov 2015

Characterization of active and total fungal communities in the atmosphere over the Amazon rainforest

A. M. Womack1, P. E. Artaxo2, F. Y. Ishida3,4, R. C. Mueller1,5, S. R. Saleska6, K. T. Wiedemann2,7, B. J. M. Bohannan1, and J. L. Green1,8 A. M. Womack et al.
  • 1Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA
  • 2Institute of Physics, University of São Paulo, São Paulo, Brazil
  • 3Large-Scale Biosphere-Atmosphere Experiment, Instituto Nacional de Pesquisas da Amazonia, Manaus, Brazil
  • 4School of Marine and Tropical Biology, James Cook University, Cairns, Qld, Australia
  • 5Los Alamos National Laboratory, Biosciences Division, Los Alamos, NM, USA
  • 6Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
  • 7School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
  • 8Santa Fe Institute, Santa Fe, NM, USA

Abstract. Fungi are ubiquitous in the atmosphere and may play an important role in atmospheric processes. We investigated the composition and diversity of fungal communities over the Amazon rainforest canopy and compared these communities to fungal communities found in terrestrial environments. We characterized the total fungal community and the metabolically active portion of the community using high-throughput DNA and RNA sequencing and compared these data to predictions generated by a mass-balance model. We found that the total community was primarily comprised of fungi from the phylum Basidiomycota. In contrast, the active community was primarily composed of members of the phylum Ascomycota and included a high relative abundance of lichen fungi, which were not detected in the total community. The relative abundance of Basidiomycota and Ascomycota in the total and active communities was consistent with our model predictions, suggesting that this result was driven by the relative size and number of spores produced by these groups. When compared to other environments, fungal communities in the atmosphere were most similar to communities found in tropical soils and leaf surfaces. Our results demonstrate that there are significant differences in the composition of the total and active fungal communities in the atmosphere, and that lichen fungi, which have been shown to be efficient ice nucleators, may be abundant members of active atmospheric fungal communities over the forest canopy.

Short summary
Fungi in the atmosphere can affect precipitation by nucleating the formation of clouds and ice. This process is important over the Amazon rainforest where precipitation is limited by the types and amount of airborne particles. We found that the total and metabolically active fungi communities were dominated by different taxonomic groups, and the active community unexpectedly contained many lichen fungi, which are effective at nucleating ice.
Final-revised paper