SOMLIT-Roscoff time series (French Research Infrastructure ILICO): long-term core parameter monitoring in the Western English Channel

To characterize the hydrology of the Western English Channel, the Station Biologique de Roscoff, Sorbonne Université/CNRS, performs the SOMLIT-Roscoff time series. Since 1997, samples are collected at two fixed stations: a/ the near shore station SOMLIT-Estacade, close to the pier of Roscoff strongly influenced by coastal waters and b/ the offshore station SOMLIT-Astan, at 2 nautical miles off Roscoff with a permanently mixed water column (around 60 m depth). Those stations are part of the French coastal environment monitoring network SOMLIT ( accredited by the CNRS as a national Earth Science Observatory (Service National d’Observation: SNO). The objective of the SOMLIT network is to characterize coastal and nearshore ecosystems in a context of natural and anthropic climate change. The SOMLIT network is part of the IR ILICO France’s multi-agency Research Infrastructure for coastal ocean observation (

Twice a month during the highest neap tide samples are collected at SOMLIT-Estacade and SOMLIT-Astan, at 2m depth for both stations and 60m depth for SOMLIT-Astan. Water samples are analysed for more than 20 core parameters: SST, SSS, dissolved oxygen, pH (spectroscopic method since 01/01/2018), ammonia, nitrates, nitrites, phosphates, silicates, suspended matter, particulate organic carbon, particulate organic nitrogen, chlorophyll, delta15N, delta13C; pico- and nano-plankton ; CTD-PAR-profile.

The SOMLIT network quality management system is in line with the ISO/IEC 17025:2017 standard: “General requirements for the competence of testing and calibration laboratories”. Further information on standard operating procedures for sample collection and data acquisition are available at: For more information on the quality flagging scheme:

In the frame of the IR ILICO, additional time series are also performed by the Station Biologique de Roscoff: a/ COAST-HF, high frequency hydrological monitoring national network close to SOMLIT-Astan station (; b/ PHYTOBS-Network, national network of microphytoplankton monitoring at SOMLIT-Astan station ( and c/ BENTHOBS national network of macrozoobenthos at two stations in the bay of Morlaix (


Biological oceanography, Chemical oceanography, Cross-discipline


coastal environments, physico-chemical parameters, phytoplankton, time-series, Earth Science Observatory, climate impact, Western English Channel


48.7778N, 48.7322S, -3.98278E, -3.9375W


A SBE-19Plus-V2 profiler is used for CTDPAR measurements. To guarantee best performances, the sensors return to the constructor every two years for calibration.


Alternative access to data

Hydro data Roscoff Astan
215 KoCSVQuality controlled data
Piconano data Roscoff Astan
111 KoCSVQuality controlled data
CTD data Roscoff Astan
5 MoCSVQuality controlled data
Hydro data Roscoff Estacade
123 KoCSVQuality controlled data
Piconano data Roscoff Estacade
86 KoCSVQuality controlled data
How to cite
Bureau Sarah, Rigaut-Jalabert Fabienne, Bozec Yann, Boulart Cedric, Blondel Lucie, Cariou Thierry, Crec'Hriou Romain, Gac Jean-Philippe, Leroux Cédric, Macé Eric, Marie Dominique, Riera Pascal, Simon Nathalie, Thiébaut Eric (1997). SOMLIT-Roscoff time series (French Research Infrastructure ILICO): long-term core parameter monitoring in the Western English Channel. SEANOE.

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