An operational zooplankton data service | Emodnet Biology

An operational zooplankton data service

A long term monitoring program: worth more than gold

Our story starts - and was only possible - with the long term effort of the Continuous Plankton Recorder (CPR) survey. This sampling program is measuring the abundance of Marine plankton in the North Atlantic and the North Sea since the 1930s. The analysis method has remained unchanged since the 1950s and the dataset therefore is unique in containing comparable data on the geographical distribution, seasonal cycles and year-to-year changes in abundance of plankton over a large spatial area.


The CPR is collecting samples of zooplankton, including Copepods. These tiny Crustaceans are usually the dominant members of the zooplankton, and are major food organisms for small fish. Therefore the importance of these copepods to the global marine ecosystem cannot be overstated. They are diverse (WoRMS lists currently 14.546 accepted species), but our story is about the top 6 most abundant species monitored by the CPR.

Looking for data driven advice

The International Council for the Exploration of the Sea (ICES), located in Copenhagen is an organisation providing scientific advice in the North Atlantic on the exploitation and stewardship of the marine ecosystem and marine living resources. Within this role, it is developing an integrated ecosystem advice at a regional level which will be appropriate to managers, policy developers and interested stakeholders. As part of this ICES has recently constructed “Ecosystem Overviews” which describe the trends in pressures and state of regional ecosystems. These advice processes require regular inputs of monitoring information on the oceanography and hydrology of the regions, called Operational Oceanographic Products and Services (OOPS).

Gridded products - spatial interpolation

EMODnet Biology’s data products were selected as provider for ICES’ Plankton OOPS. The EMODnet products include a set of gridded map layers showing the average abundance of marine species for different time windows (seasonal, annual) using geospatial modelling. The spatial modelling tool used to calculate the gridded abundance maps is based on DIVA. DIVA (Data-Interpolating Variational Analysis) is a tool to create gridded data sets from discrete point measurements of the ocean. For the representation of time dynamics, it was decided to produce gridded maps for sliding time windows, e.g. combining years 1-10 in one gridded map, years 2-11 in the next etc., so that relatively smooth animated GIF presentations can be produced that show the essential change over time.

Shifts in the spatial distribution of Calanus species have been well documented in the literature (e.g. Beaugrand et al ., 2002, Science 1692:296). We used the original SAHFOS abundance data to grid the density of both species per season and for sliding time windows of 10 years. The movies below visualizes (summer distributions per decade) from this series. It can clearly be seen how both species shift their distribution to the north, leading to a considerable species shift in the North Sea as one of the consequences.

=>Calanus finmarchicus.

=>Calanus helgolandicus.


The gridded abundance values were summarized per OOPS region and converted to a timeseries object in R. We applied a seasonal trend decomposition analysis using Loess (stl). The four graphs below are the original data, the seasonal component, the trend component and the remainder. The bar at the right hand side of each graph allows a relative comparison of the magnitudes of each component. Using the interactive shiny application you can select the the copepod species per OOPS region to visualize its temporal trend. The time frame can also be changed using the slider bar. Selecting the Calanus species for the Greater North Sea shows the apparent decreasing (C. finmarchicus) and increasing (C. helgolandicus) abundance trends.

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