A phyloseq object containing merged information of abundance,
taxonomic assignment, sample data including the measured variables and categorical information
of the samples, and / or phylogenetic tree if available.
method
A list of character strings specifying method to be used to calculate for alpha diversity
in the data. Available methods are: "Observed","Chao1","ACE","Richness", "Fisher", "Simpson", "Shannon", "Evenness","InvSimpson".