Abundance of phytoplankton, heterotrophic nanoflagellates and bacteria through the water column at time series station L4 in the Western English Channel, 2007-2016.

(1) Plymouth Marine Laboratory

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 data were collected between 23rd April 2007 and 19th December 2016. 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 (LNA). Samples were collected and analysed in duplicate (HNAN and some heterotrophic bacteria) or triplicate (phytoplankton and some heterotrophic bacteria) 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).