Rainwater Metagenomic Long-Read Sequencing

During the month of February in 2019, the Western USA experienced elevated precipitation levels ending a drought period. Rainwater samples were collected at four time points in February; one of these collections overlapped with an atmospheric river event. The rainwater samples were analyzed by microscopy, analytical chemistry, and long-read sequencing methods. Quantification of primary bioaerosol particles (whole cells) showed concentrations of > 106 cells/L. Imaged cells from fluorescent and scanning electron microscopy included microeukaryotes. Analytic chemistry detected Na+ and Cl- ions, which was in agreement with back-trajectories of an oceanic origin. Taxonomic investigation of long-read sequences resulted in a high proportion of read assignments to fungal groups. For bacterial taxonomies, common rainwater-associated bacterial genera where present at higher proportions than other bacterial groups: Erwinia, Hymenobacter, Pseudomonas, and Pantoea.