title: 18S DNA of seawater samples from dust bioassays
design: DNA extracts were obtained using the standard phenol-chloroform method (Sambrook and Russell, 2001). The V4 region of the prokaryotic 16S rDNA gene (~390 bp) was amplified by PCR using the 515F (5-GTGYCAGCMGCCGCGGTAA-3) and 806R (5- GGACTACNVGGGTWTCTAAT-3) primer pair sequences (Apprill et al., 2015; Parada et al., 2016). The same DNA extracts were used to amplify the V9 region of the eukaryotic 18S rDNA gene (~260 50 bp) using primers 1391F (5-GTACACACCGCCCGTC-3) and 1510R (5-TGATCCTTCTGCAGGTTCACCTAC-3) (Amaral-Zettler et al., 2009; Stoeck et al., 2010). Sample processing, library preparation, and sequencing were performed by the Earth Microbiome Project (Thompson et al., 2017; https://earthmicrobiome.org/) at Argonne National Laboratory (Lemont, IL, USA; https://www.anl.gov/).