Potential for cross-contamination of benthic diatom samples when using toothbrushes

Abstract

The use of instruments such as toothbrushes for sampling diatoms from hard surfaces is a potential source of uncertainty in ecological status assessments as diatoms may be inadvertently transferred from one sample to another. The scale of this contamination was investigated by sampling two sites differing in a number of key environmental properties resulting in different diatom assemblages. Fewer than 1% of the total valves counted represented taxa that might have been transferred between samples and this had no significant effect on the values of diatom-based indices calculated from the two sites.

Keywords:

• diatoms
• sampling
• freshwaters
• monitoring
• toothbrush