Plankton abundance measured by flow cytometry from long term time series at Station L4 in the Western English Channel from 2024

This dataset contains depth profiles of the mean abundance of groups of plankton as cells per millilitre, measured using flow cytometry from the long-term sampling station, L4 (50°15.0'N; 4°13.0'W) situated off the south-west coast of England, United Kingdom. The groups quantified are divided into phytoplankton and heterotrophs. Phytoplankton groups quantified are: Synechococcus sp. (cyanobacteria)(Syn), picoeuakryotes (smaller than 2 μm) (Peuk), cryptophytes (Crypto), coccolithophores (Cocco), small dinoflagellates (<20 μm) (Dino), Phaeocystis sp. (Pcystis) and nanoeukaryotes (Neuk) not already mentioned (2-20 μm). Heterotrophs quantified are: heterotrophic nanoflagellates (HNAN), bacteria with relatively high nucleic acid content (HNA) and bacteria with relatively low DNA. Samples were collected and analysed in duplicate (heterotrophs) or triplicate (phytoplankton) from 2 m, 10 m, 25 m and 50 m depth. In 2007 the Secchi depth was sampled instead of the 10 m depth. NOTE: In 2013 an extra column appears in the abundance section and in the standard deviation section. The columns are labelled 'Pnitz'; possibly the chain-forming diatom Pseudo-nitzschia delicatissima. It is also present in 2011 and 2012 where the samples were run using the newest flow cytometer at PML – data still to be supplied. Discrimination is down to better measurement of forward light scatter with the new flow cytometer (a BD Accuri C6).