Routine determination of plankton community composition and size structure: a comparison between FlowCAM and light microscopy

Samples from a monthly monitoring programme in the Cantabrian Sea were analysed a FlowCAM-based automated technique. The estimates of abundance, size spectra and taxonomic diversity of nano- and microplankton communities compared with those obtained by traditional microscopical analysis of the samples. The structure and abundance of a preserved plankton sample determined FlowCAM showed minimal differences compared with traditional estimates. The effects of sample preservation and inaccuracies in the classification are the main causes of discrepancies in the size structure determination the two approaches. However, the synoptic understanding of seasonal variation in the abundance, biomass and diversity obtained from the methods is similar. Our results suggest that the natural variations in the community explored are of greater magnitude than the error introduced by the and that the fully automatic method is adequate to explore these variations.