Determining the health of river-dominated estuaries using microalgal biomass and community composition

The use of benthic diatom indices, using the programme OMNIDIA, did not provide reliable results that could be used to determine estuarine health. The South African Diatom Index and Trophic Diatom Index gave mixed results that did not correlate well with the other more established methods, contrasting with phytoplankton abundance and community structure and water quality results. However, benthic diatom species diversity results were well aligned with these parameters and will continue to be a useful tool in freshwater requirement studies.