Figure 2

Inventories of genes and transcripts for eight bacterial taxa in surface waters of the Amazon plume. Symbols represent the mean of duplicate analyses at six stations, color-coded by taxon and size fraction (particle-associated or free-living). Lines indicate a 1:1 ratio of transcripts:genes (black) or 10:1 and 1:10 ratios (gray). The purple line indicates the ratio of transcripts:genes for exponentially growing laboratory cultures of Escherichia coli[12, 13]. Dominant bacterial groups are as follows: Oscillatoriales = Trichodesmium; Prochlorales = Prochlorococcus; Chroococcales = Synechococcus; Nostocales = Richelia; Puniceicoccales = Verrucomicrobia.