On 22/23 September 2011, the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) hosted Plankton 2011 to celebrate of the 80^th year of the Continuous Plankton Recorder Survey. 

Plankton 2011 focused on plankton biodiversity and global change and brought together scientists working on long-term time series in fresh and marine waters from all continents of the world.  The symposium was held in Plymouth's beautiful  Guildhall and was attended by 180 delegates from 30 countries.

The symposium covered a wide range of topics which are identified here by the keynote talks. These started with an informative and entertaining talk from John Spicer (University of Plymouth) on 'Alister Hardy - the man and his beliefs'. Chris Reid (SAHFOS) then gave a personal view on Celebrating Past Successes' of the CPR Survey over its 80 year old history. Following this Trevor Platt (Plymouth Marine Laboratory and Dalhousie University) spoke about Visible Spectral Radiometry: Phytoplankton Time Series from Remote Sensing of Ocean Colour'.  The symposium then moved into lakes with a talk Freshwater plankton: monitoring, mechanisms and models to comprehend the past and forecast the future given by Stephen Maberly (Centre for Ecology & Hydrology, Lancaster).  A panel debate, which included an invited public session, on the 'large scale changes in ocean phytoplankton' was chaired by John Field (University of Cape Town) following presentations by speakers from Canada, UK and Netherlands who gave their differing views on whether phytoplankton are increasing or decreasing at ocean basin scales. A key conclusion made was the importance of collaboration. The Deputy Lord Mayor of Plymouth, Edward Delbridge welcomed delegates to Plymouth while all enjoyed cake (shaped as a CPR) and wine after the debate. 

Day two was equally varied looking at satellite data to show primary production, changes in plankton communities and consequences for the future. The final session of the symposium was on Looking over the horizon at the future which started with a talk entitled The future of plankton observations given by  Dave Checkley of the Scripps Institution of Oceanography. This session dealt with molecular techniques and automated cell imaging.  The symposium closed with an open discussion on where next for long-term plankton monitoring? Conclusions reached emphasised the need for collaborations, data being freely available and the benefit of meetings with wide and varied topics.  

The symposium celebrated plankton as art as well as science. Local artists submitted their interpretations for display; this included an 8 foot metal sculptor inspired by the CPR, a series of plankton metal works, and prints obtained from copper etchings. Local schools were involved and their artwork included a giant jellyfish hanging and twinkling as it swayed as delegates moved past.

The art competition had 34 entries and delegates voted on their winners for each category. These were All Saints Primary School in the under 5-10 year olds, Dan Douglas for the 11-18 year olds and Wendy Wates for the Over 19 year olds.  Wendy Wates also won the overall prize for best artwork.

The Symposium also incorporated social and networking opportunities including ice-breaker drinks at the 25th Annual Plymouth Marine Science Lecture with a stimulating talk by John Field (University of Cape Town) on 'Looking back in order to project into the future: new developments in marine science'.  A wine reception followed the first days of events which included cutting of a CPR designed cake to celebrate 80 years of the CPR survey, and an evening spent at the National Marine Aquarium marveling at the marine life and enjoying a three course dinner set against a most impressive backdrop of the Atlantic Reef tank. It was an evening - and indeed a symposium-  that we will always remember.