KiEco Freshwater Ecology: Diatoms

Quality Control

NRW analysts all take part in a ring test to ensure competence but otherwise there has been no formal QA of our data. Prior to this upload there was currently very little diatom data on NBN Atlas to use in validating our species distributions. Therefore, NRW would welcome any verification of this dataset from experts

Method steps

1. A strict methodology is applied when sampling for freshwater diatoms. There is a core network of sites which are monitored on a three-yearly rolling programme. These sites may be added to for investigative work, or on an ad hoc basis. Sampling areas are located with a larger survey area and must be representative of the overall survey area. A stone scrape method is the most commonly used method for sampling freshwater diatoms. However, where necessary alternative methods are used, for example in areas with no suitable substrate. Natural Resources Wales collect and analyse in excess of 350 diatom samples from rivers and lakes every year. Once samples are collected they are sent to the laboratory for analysis.