I would like to BLAST the 16S RNA sequence of this organism that comes up at the top of my taxa bar plot, however when I look at the visualisation of my FeatureData[Taxonomy] table, there are multiple features associated with the most abundant organism. How do I know which one is responsible for the taxa bar plot result?
This is going to be impacted by which taxonomic level you are looking at. If you are at the kingdom level, then you are going to see way more features grouped under a particular clade.
Here is one way to get at an answer to your question. I will illustrate using the Moving Pictures tutorial.
In the taxonomy visualization, I pasted the taxonomy string into the search box, and the sorted by taxon to group the unidentified species together (by clicking the word "Taxon" in the header).