Figure 4From: Alcohol and tobacco consumption affects bacterial richness in oral cavity mucosa biofilms Total species richness found in all three groups. The figure shows the average total number of OTUs with at least 3 reads (0.03% of the individual samples) found for controls, only smokers and smokers/drinkers using three distinct richness indices: observed species metric (S.obs) and two richness estimators; chao1 (S.chao1) and ACE (S.ACE).Back to article page