Zooplankton time-series data

Ongoing zooplankton research at the Plymouth Marine Laboratory has established a time series of zooplankton taxa since 1988 at L4, a coastal station off Plymouth. Plankton forms the basis of marine food webs so is an essential component within the marine ecosystem. Zooplankton is an intermediate in the flow of nutrients and energy from primary producers to higher consumers.

Paired samples are collected weekly by vertical net hauls (WP2 net, mesh 200 μm; UNESCO 1968 pp153-157¹) from 50 m to the surface and stored in 4% formalin. Sea floor depth is 54 m and our recent work² (Parry et al 2020) shows that most of the water column zooplankton are sampled by these 0-50m hauls. Zooplankton are identified and enumerated. Current analysts are Andrea McEvoy and Amanda Beesley. The two samples from each time point are analysed separately using sub-sampling. Numbers per whole sample are averaged and abundance is presented as numbers per m³. The level of expertise has generally been consistent, but the user should be aware that levels of taxonomic discrimination may vary during the course of the dataset, for example Cnidarians are discriminated from 2009 onwards. The dominant calanoid copepods are generally well discriminated to species throughout, whereas other groups are recorded as phyla, order, or genera. A further dataset with doi is available where abundance has been converted to biomass for selected taxa.

We view it as essential for all users of L4 plankton data to establish and maintain contact with the nominated current data originators as well as fully consulting the metadata. While not impinging on free data access, this ensures that this large, species-rich but slightly complex species database is being used in the correct way, and any potential issues with the data are clarified. Furthermore, a proper dialogue with these local experts on the time series will enable where appropriate the most recent sampling timepoints and relevant additional data sets to be used. We also kindly request that authorship is offered if cooperation is extensive, but in any case, please follow the data policy link on the WCO data page for guidance on how to acknowledge use of WCO data.

The entire set of zooplankton samples is stored at the Plymouth Marine Laboratory in 4% buffered formalin, and may be available for further taxonomic analysis on request.

For taxonomic queries please consult the main analyst Andrea McEvoy (ajmc@pml.ac.uk)

For general queries on the zooplankton time series please contact Angus Atkinson (aat@pml.ac.uk)

1 UNESCO (ed.) (1968) Monographs on Oceanographic Methodology: Zooplankton Sampling. United Nations, Paris.

2 Parry HE, Atkinson A, Somerfield PJ, Lindeque PK (2020) A metabarcoding comparison of taxonomic richness and composition between the water column and the benthic boundary layer. ICES Journal of Marine Science (2020), doi:10.1093/icesjms/fsaa228