Video talks on 16S data analysis posted.

URMAP ultra-fast read mapper posted (paper).

~20% of taxonomy annotations in SILVA and Greengenes are wrong (paper).

Taxonomy prediction is <50% accurate for 16S V4 sequences (paper).

97% OTU threshold is wrong for species, should be 99% for full-length 16S, 100% V4 (paper).

Estimating read depth (sampling effort) from an octave plot

Doubling the number of reads moves the distribution one bin to the right in an octave plot. You can estimate the number of additional reads required to sample the full richness by assuming that the distribution is approximately symmetrical, as in the example below. Here, we would need three to four additional bins to capture all OTUs, which corresponds to 2³ to 2⁴ = 8 to 16 times more reads.