# why otu table show many levels in taxonomy level **URL:** \ **Category:** User Support\ **Created:** [November 4, 2020, 7:44am UTC](https://forum.qiime2.org/t/why-otu-table-show-many-levels-in-taxonomy-level/17330 "2020-11-04T07:44:55Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![SoilRotifer](https://forum.qiime2.org/user_avatar/forum.qiime2.org/soilrotifer/32/21071_2.png) [@SoilRotifer](https://forum.qiime2.org/u/SoilRotifer)\ **Post date:** [November 4, 2020, 2:14pm UTC](https://forum.qiime2.org/t/why-otu-table-show-many-levels-in-taxonomy-level/17330/2 "2020-11-04T14:14:10Z")
Hi @Fatemeh_Abedini, There are several forum threads that address this, but I think you'll find this helpful: > [@Why all taxonomic levels on BarPlot have 'D' letter?](https://forum.qiime2.org/t/why-all-taxonomic-levels-on-barplot-have-d-letter/9239/4): > > I can likely provide some insight here as I am one of the contributors that helped to format SILVA database for QIIME. The D\_X\_\_ convention was chosen to be as much of a unique and "safe" text string as possible, considering many of the bizarre taxonomy text annotations within the SILVA reference database. That is, it was meant as a quick fix to be able to search and parse these taxonomy strings. The 'D' was a way of annotating the "taxonomic Depth". At the time some of the [code](https://github.com/mikerobeson/Misc_Code/tree/master/SILVA_to_RDP) was written, th… That being said, I'd suggest that you upgrade to the _cleaner_ taxonomy formatted SILVA v138 Database, which has GreenGenes-like taxonomic rank prefixes. The some pre-made classifiers are [here](https://docs.qiime2.org/2020.8/data-resources/#taxonomy-classifiers-for-use-with-q2-feature-classifier), and the files used to make them are [here](https://docs.qiime2.org/2020.8/data-resources/#silva-16s-18s-rrna) (should you like to train the classifiers yourself for a different version of QIIME 2). Finally, if you'd like to download and process the SILVA database yourself, you can install the [RESCRIPt plugin](https://github.com/bokulich-lab/RESCRIPt), and use / modify the procedure [here](https://forum.qiime2.org/t/processing-filtering-and-evaluating-the-silva-database-and-other-reference-sequence-data-with-rescript/15494). -Cheers! -Mike --- _[View the full topic](https://forum.qiime2.org/t/why-otu-table-show-many-levels-in-taxonomy-level/17330)._