thumbnail

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Processing, taxonomy, and quality control of benthic macroinvertebrate samples

Open-File Report 2000-212
By: , , , , and 
https://doi.org/10.3133/ofr00212

Metrics

60
Crossref references
Web analytics dashboard Metrics definitions

Links

Abstract

Qualitative and quantitative methods to process benthic macroinvertebrate (BMI) samples have been developed and tested by the U.S. Geological Survey?s National Water Quality Laboratory Biological Group. The qualitative processing method is based on visually sorting a sample for up to 2 hours. Sorting focuses on attaining organisms that are likely to result in taxonomic identifications to lower taxonomic levels (for example, Genus or Species). Immature and damaged organisms are also sorted when they are likely to result in unique determinations. The sorted sample remnant is scanned briefly by a second person to determine if obvious taxa were missed. The quantitative processing method is based on a fixed-count approach that targets some minimum count, such as 100 or 300 organisms. Organisms are sorted from randomly selected 5.1- by 5.1-centimeter parts of a gridded subsampling frame. The sorted remnant from each sample is resorted by a second individual for at least 10 percent of the original sort time. A large-rare organism search is performed on the unsorted remnant to sort BMI taxa that were not likely represented in the sorted grids. After either qualitatively or quantitatively sorting the sample, BMIs are identified by using one of three different types of taxonomic assessment. The Standard Taxonomic Assessment is comparable to the U.S. Environmental Protection Agency Rapid Bioassessment Protocol III and typically provides Genus- or Species-level taxonomic resolution. The Rapid Taxonomic Assessment is comparable to the U.S. Environmental Protection Agency Rapid Bioassessment Protocol II and provides Familylevel and higher taxonomic resolution. The Custom Taxonomic Assessment provides Species-level resolution whenever possible for groups identified to higher taxonomic levels by using the Standard Taxonomic Assessment. The consistent use of standardized designations and notes facilitates the interpretation of BMI data within and among water-quality studies. Taxonomic identifications are quality assured by verifying all referenced taxa and randomly reviewing 10 percent of the taxonomic identifications performed weekly by Biological Group taxonomists. Taxonomic errors discovered during this review are corrected. BMI data are reviewed for accuracy and completeness prior to release. BMI data are released phylogenetically in spreadsheet format and unprocessed abundances are corrected for laboratory and field subsampling when necessary.

Suggested Citation

Moulton, S.R., Carter, J.L., Grotheer, S.A., Cuffney, T.F., Short, T.M., 2000, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Processing, taxonomy, and quality control of benthic macroinvertebrate samples: U.S. Geological Survey Open-File Report 2000-212, vii, 49 p., https://doi.org/10.3133/ofr00212.

ISSN: 2331-1258 (online)

Publication type Report
Publication Subtype USGS Numbered Series
Title Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Processing, taxonomy, and quality control of benthic macroinvertebrate samples
Series title Open-File Report
Series number 2000-212
DOI 10.3133/ofr00212
Year Published 2000
Language English
Publisher U.S. Geological Survey
Contributing office(s) National Water Quality Laboratory, Toxic Substances Hydrology Program
Description vii, 49 p.
Additional publication details