ZymoBIOMICS Microbial Community Standard II (Log Distribution) is a mock microbial community consisting of eight bacterial and two fungal strains. This microbial standard can be used to assess the performance of microbiomics workflows and can also be used as a positive control for routine sequencing. Cells of the ten microbes were mixed in a log-distributed abundance, which allows the user to easily assess the detection limit of their microbiomics workflow. 75 µl of the standard contains about ~100 cells of Staphylococcus aureus, the organism of lowest abundance. If needed, the standard can be spiked into a sample matrix (e.g. soil and blood) to mimic real samples of interest. Theoretical Composition Based on Genomic DNA: Listeria monocytogenes – 89.1%, Pseudomonas aeruginosa – 8.9%, Bacillus subtilis – 0.89%, Saccharomyces cerevisiae – 0.89%, Escherichia coli – 0.089%, Salmonella enterica – 0.089%, Lactobacillus fermentum – 0.0089%, Enterococcus faecalis – 0.00089%, Cryptococcus neoformans – 0.00089%, and Staphylococcus aureus – 0.000089%.