Reduction of taxonomic bias in diatom species data

Limnology and Oceanography: Methods
By: , and 



Inconsistency in taxonomic identification and analyst bias impede the effective use of diatom data in regional and national stream and lake surveys. In this study, we evaluated the effect of existing protocols and a revised protocol on the precision of diatom species counts. The revised protocol adjusts four elements of sample preparation, taxon identification and enumeration, and quality control (QC). We used six independent datasets to assess the effect of the adjustments on analytical outcomes. The first dataset was produced by three laboratories with a total of five analysts following established protocols (Charles et al. 2002), or their slight variations. The remaining datasets were produced by 1-3 laboratories with a total of 2-3 analysts following a revised protocol. The revised protocol included the following modifications: 1) development of coordinated pre-count voucher floras based on morphological operational taxonomic units (mOTUs), 2) random assignment of samples to analysts, 3) post-count identification and documentation of taxa (as opposed to an approach in which analysts assign names while they enumerate), and 4) increased use of QC samples. The revised protocol reduced taxonomic bias, as measured by reduction in analyst signal, and improved similarity among QC samples. Reduced taxonomic bias improves the performance of biological assessments, facilitates transparency across studies, and refines estimates of diatom species distributions.
Publication type Article
Publication Subtype Journal Article
Title Reduction of taxonomic bias in diatom species data
Series title Limnology and Oceanography: Methods
DOI 10.1002/lom3.10350
Volume 18
Issue 6
Year Published 2020
Language English
Publisher Association for the Sciences of Limnology and Oceanography
Contributing office(s) WMA - Earth System Processes Division
Description 9 p.
First page 271
Last page 279
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