EMECO

Continuous Plankton Recorder (CPR) Survey

The Continuous Plankton Recorder (CPR) has been measuring the abundance, distribution, and species composition of phytoplankton and zooplankton in the North Atlantic and North Sea since 1931. More recently, as the foundation has become more involved in international projects, work has been expanded to include other regions around the world.

The CPR is operated by the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) based in Plymouth (UK). The survey is finacially supported by 9 agencies from European countries, the European Union, and international organisations. The foundation is a charity and company limited by guarantee and is dependent on the voluntary cooperation of the international shipping community.

The aim of the CPR Survey is to use Continuous Plankton Recorders to monitor the near-surface plankton on a monthly basis using ships of opportunity. The CPR has covered an extensive network of routes over the last 75 years.

The CPR is a plankton sampling instrument designed to be towed from merchant ships on their normal sailings. After a CPR has been towed, it is returned to the laboratory at SAHFOS for analysis. the analysis procedure estimates chlorophyll a concentration using a "green-ness index" known as the Phytoplankton Colour Index (PCI) and zooplankton abundance and species composition. The CPR analysis method has remained unchanged since the 1950s.

The CPR is an ideal platform for sampling oceanographic parameters and the CPR survey routes provide extensive spatial coverage in the marine environment. The combination of these two factors has enabled SAHFOS to add new instruments to the CPRs that provide additional valuable datasets at relatively little extra cost.

Since 1994, CPRs on certain routes have been instrumented to measure temperature, salinity, depth and fluorescence. The datasets are collected to compliment the CPR plankton data and to ground-truth data collected by other sensors used in the same regions.

More information about SAHFOS and the CPR survey