Continuous Plankton Recorder (Type II CPR) – the census of the sea

No. 75

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Looking like a leftover from a 1950’s sci-fi film, this instrument is still at the forefront of scientific research in our oceans. The Continuous Plankton Recorder (CPR) was first designed by British scientist, Sir Alister Hardy, in the mid 1920s and it made a radical development in how plankton – tiny crustaceans that are to be found worldwide – is surveyed.

Rather than spot net sampling, which can be inaccurate due to the unique patchy distribution and behaviour of plankton, the CPR is towed behind a ship and gathers samples continuously for up to 450 nautical miles. Between 1990 and 1995, the Australian Antarctic Division (AAD) took Hardy’s original design and slightly modified it, creating a Type II version that, while essentially very similar to Hardy’s original design, is more streamlined, built from marine-grade stainless steel (rather than phosphor bronze) and has an easier reload mechanism.

The instrument is now used on all AAD voyages to Antarctica, as well as in partnership with Japanese Antarctic vessels, and it has allowed scientists to compare data from both the northern hemisphere and the southern hemisphere. This data has shown some significant changes in the composition of plankton since the project began in 1991 – notably, there is a greater amount of smaller plankton compared to krill (particularly copepods).

The CPR forms an important part of measuring changes in ocean life, as well as the ocean’s physical conditions – and it is revealing critical information concerning climate change. Tasmanian-based scientists have led the world in Antarctic and Southern Ocean studies, and Hobart has become a hub in this vital field of research and education.

Comments on this object

  • It is really pleasing to see the Continuous Plankton Recorder listed as one of the 100 items Shaping Tasmania. It helps highlight the role of the AAD and Tasmania in leading the world in plankton monitoring. The article notes the partnership with Japan, but we have now grown that collaboration significantly with CPRs towed on Antarctic vessels operated by partners from New Zealand, UK, USA, Russia, Germany, Brazil, Chile, Peru, South Africa and France. The international Scientific Committee on Antarctic Research (SCAR) recognises the Southern Ocean CPR Survey as an official international plankton monitoring/observational survey. We have now gone a step further in banding with eight other regional CPR surveys around the world (e.g. Atlantic, North Sea, North Pacific, South Africa, around Australia etc) to create the Global Alliance of CPR Surveys (GACS) which aims to get a global perspective of changes in plankton biodiversity. GACS was initiated by the UK based Survey at the Sir Alister Hardy Foundation for Ocean Science but as Director of the SO-CPR Survey and Chair of GACS I coordinate both from Tasmania. Note: the particular CPR on display (No. 122, a Type II Mark III CPR) was actually built in Leith for the UK CPR survey before purchased by the AAD, and serving our Southern Ocean CPR Survey for many years. However, before retirement to the TMAG, 122 was the model for the redesign and manufacture of the AAD Type II Mark V CPR, mentioned in the text. I should probably send you a high resolution photograph of the AAD CPR to go with the display of CPR 122. I look forward to seeing the new TMAG! Best wishes Dr Graham Hosie, AAD Director, SCAR Southern Ocean CPR Survey Chair, Board of Governance of GACS Dr Graham Hosie, AAD