Plymouth L4 time series (1988-2017) of zooplankton abundance, biomass and traits.

The file "Plymouth L4_1988-2017 zooplankton abundance and biomass_v15.2.19" contains a user-friendly 30-year time series of zooplankton abundance, biomass and traits. The other files contain information on the methods used and the length measurements used to convert abundance to biomass estimates. This time series is built from our basic zooplankton time series whose sampling method is summarised in Atkinson et al. 2015 (Progr Oceanogr 137: 498-512 http://dx.doi.org/10.1016/j.pocean.2015.04.023). Briefly, every week zooplankton are sampled from station L4 using a pair of 57cm diameter, 200 micron mesh WP2 nets hauled from 50m to the surface vertically. These take typically ~5 minutes total per haul. The source data thus contains numerical abundances, no. m-3 of each taxon, based on the mean value of the two hauls analysed separately. Over the years the level of taxonomic resolution has varied, making the time series a bit tricky to use. Therefore, we have made this time series more useful by a) pooling species, where necessary, to higher taxonomic levels and listing only these counts, so that we have a time series of only those metazoan taxa that were reasonably consistently identified throughout the whole time series; b) converting taxon numerical densities (nos m-3) to biomass densities (μg C m-3) to present alongside the original densities, and c) providing additional trait data such as estimated mean body carbon per individual, maximum body length, and trait allocation (e.g. meroplankton or holoplankton). These modifications are aimed to provide added utility to the existing time series, allowing it to be used for more purposes. It is important to note that the biomass values should only be used if it is essential to estimate biomass rather than abundance; abundance should be used wherever possible since these were determined directly. Users of these data should please quote the doi. of the data and contact the data originators (contact point Angus Atkinson [e-mail] ) so that we can log the data usage to help justify to our funders that ongoing sampling is value for money. If the data form a major part of the study we would also appreciate more involvement with the study, to ensure that the source data and their caveats were interpreted correctly.