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

Abstract

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