Intercomparison exercises are carried out annually and involve all SOMLIT stations. They concern all the parameters sampled (i.e. all the parameters of the hydrological and pico-nanoplankton series except temperature and salinity which are recorded directly).

The intercomparaison exercises (annual events) have several objectives:

  • To measure the repeatability (inter-station) and reproducibility (between stations) of the measurements

  • To refine the common protocols on the basis of the results, if necessary

  • To enable field operators and analysts from SOMLIT’s distributed stations to meet and provide the opportunity for national team-building

  • To participate in staff training

The intercomparisons unfold as follows: field operators and analysts from SOMLIT teams meet in one of the network’s marine stations for three (3) days. The day after the equipment is installed, large volumes of water are taken and stored in jerrycans (between 700 and 1000 litres!). The water is transferred to a 350 litre stainless steel sampling tank with 15 Niskin taps. The water is sampled simultaneously by one member of each team directly from the tank using the bottle normally used in each station. The usual protocol is then carried out on each sample. Dissolved parameters related to gases (Oxygen, pH) are sampled first, followed by nutrients. For particulate parameters, the tank is refilled. Homogenisation is ensured by two mixing blades located at different levels in the tank. The samples are then taken simultaneously and processed according to protocol, parameter by parameter. Five replicates are carried out for each parameter and by team. Sampling and sample processing (addition of reagents, filtration, etc.) for all the intercomparison parameters are carried out immediately after the sampling.

The analyses are carried out in the following days or weeks, back in each team’s respective laboratory. The final intercomparison day is devoted to workshops, generally dedicated to specific work on a particular protocol.

The results are processed statistically in order to identify satisfactory, questionable and doubtful results and the possible causes of non-conformity of results. At the end of each annual intercomparison, a report is prepared summarising all the information and results obtained as well as the corrective and/or preventive actions taken if necessary. A summary of all the intercomparisons is also produced highlighting the continuous improvement of results since the implementation of the quality approach in the SOMLIT network.


Past intercomparaisons
2022 Marseille Affiche
2021 Brest Affiche
2020 Sète  
2019 Roscoff Affiche
2018 Arcachon Affiche
2017 Marseille Affiche
2016 Dinard  
2015 Banyuls sur mer Affiche
2014 La Rochelle Affiche
2013 Wimereux Affiche
2012 Brest Affiche
2011 Villefranche sur mer  
2010 Luc sur mer  
2009 Roscoff  
2008 Marseille  
2007 Arcachon  
2006 Banyuls sur mer  
2005 Brest  
2004 Villefranche sur mer  
2003 Roscoff  
2002 Banyuls sur mer  
2001 Wimereux  
2000 Arcachon  
1999 Marseille