Diatom Analysis

Henderson Ecology's diatom expertise is widely recognised with over 18 years experience working with diatoms from lakes, rivers and streams covering a wide range of ecological conditions (see Publications). We have been commissioned to produce numerous quality assurance exercises for other laboratories and national agencies to ensure taxonomic harmonisation between analysts. Gina Henderson is also an Expert Panel member of the Freshwater Diatoms of Britain and Ireland ring test and inter-calibration scheme accredited by the Environment Agency.

Contemporary sampling and Trophic Diatom Index analysis

Due to the sensitivity of diatoms to ecological conditions they can be used to assess water quality in lakes, rivers and streams. Diatoms respond to nutrient changes, acidification and habitat/ water level change and as such are a key component of the EU Water Framework Directive informing lake and river restoration targets and Environmental protection strategies. Henderson Ecology can prepare samples from collected raw material, analyse the diatom composition and prepare summary metric data to aid ecological interpretations. We are expert in using the DARLEQ2 assessment tool and the Trophic Diatom Index (TDI) system to classify freshwater water bodies. We can provide data for one off spot samples or multi- site, long-term monitoring projects as required.


Gina Henderson has carried out many projects for the UK and European environment agencies using diatoms to assess water quality in freshwater systems under the EU Water Framework Directive and contributed to a major research study of sampling methods for littoral diatoms (King et al. 2006, see Publications).

Some of her more recent projects are listed below:

  • 2018, 2017, SheBam/ Environmental Change Network diatom monitoring (Environment Agency).

  • 2017, River Clyde Environmental Change Network Diatom Analysis (SEPA).

  • 2013 to date, Diatom analysis for the Danish Ministry of the Environment monitoring program for Lakes and Streams ca. 150 sites annually. 

  • 2009 to date, UK Uplands Waters Monitoring Network (UWMN), (DEFRA, NRW, EA, Welsh Assembly Government & CEH).

  • 2007 to date, Trophic diatom Index (TDI)- Analysis and nutrient interpretation of river diatoms from UK waters (SEPA, Plant-Soil Interface Scottish Crop Research Institute and Environment Agency).

Quality Control

Our expertise in diatom identification is maintained and developed by participation in taxonomy workshops, European proficiency tests and project-based quality control programmes.

Gina Henderson has been a member of the Expert Panel for the UK Environment Agency’s accredited 'Freshwater Diatoms of Britain and Ireland ring test' since it's initiation in 2007. The Expert Panel's results form the basis of the assurance scheme for diatom analysis throughout the UK and provide the benchmark standard for the assessment of other laboratories results. To date the 'Freshwater Diatoms of Britain and Ireland ring test and inter-calibration scheme' have completed 50+ ring test slides.

Gina also regularly participates in the External Quality Assessment Trials (EQAT) 'Benthic diatom proficiency tests' (2014, 2011) run by the State Reservoir Administration of Saxony, Germany ensuring taxonomic consistencies with the European laboratories. She has consistently accurate results in these tests further demonstrating the quality of her work.

During 2000-2004 Gina was the Diatom Data specialist for the EMERGE project, European Mountain Lake Ecosystems: Regionalisation Diagnostics & Socio- Economic Evaluation project.

© 2018 Henderson Ecology