Fig. 2.

Microbial diversity varies widely by sample type across the planet, as measured across 9787 samples from the Earth Microbiome Project [1]. A, Boxplots measuring the distribution of alpha diversity (as Shannon entropy) in each sample type (boxes show quartile values, diamonds indicate outlier values). B, Unweighted UniFrac principal coordinates analysis (PCoA) measures similarity between samples based on community-wide phylogenetic similarity. Samples are categorized by their “empo_3” sample type. Pre-computed data (Shannon diversity and PCoA coordinates) were collected from the published EMP study data at ftp://ftp.microbio.me/emp/.