SOMLIT-Portzic time series (French Research Infrastructure ILICO): long-term core parameter monitoring in the Bay of Brest and Iroise Sea

The SOMLIT-Portzic time-series data characterize the hydrology of the Bay of Brest – Mer d’Iroise ecosystem, located at 48°N (western Brittany). Weekly measurements have been undertaken since 1998 by the IUEM/UBO/CNRS. The SOMLIT-Portzic observation station is a part of the French monitoring network SOMLIT (, accredited by the CNRS as a national Earth Science Observatory (Service National d’Observation : SNO). It aims to detect the long-term evolution of these ecosystems including both natural and anthropogenic forcings.

Implemented on the Ste-Anne-du-Portzic location (48°21'32.17'' N, 4°33'07.21'' W), the SOMLIT-Portzic observation station is among the oldest long-term coastal observation stations of the French Research Infrastructure dedicated to coastal ocean observations (known as ILICO,

The high-frequency hydrological COAST-HF-Iroise time-series and the microphytoplankton PHYTOBS-Portzic time-series are also monitored at this location.

SOMLIT-Portzic samples are collected at 2m-depth of a 9m water column, at high tide, during slack water, with an average coefficient of 70 ± 10. Samples collected are analysed for more than 20 core parameters: SST, SSS, dissolved oxygen, pH, ammonia, nitrates, nitrites, phosphates, silicates, suspended matter, particulate organic carbone, 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:


Biological oceanography, Chemical oceanography, Cross-discipline, Environment, Fisheries and aquaculture, Human activities, Physical oceanography


Environmental time series, Hydrological and biogeochemical data, coastal system evolution, climate impact, Coastal ecology


48.644228N, 48.206804S, -4.188374E, -5.193623W


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

1998 - 2023 data
377 KoCSVQuality controlled data 109743
1998 - 2022 data
353 KoCSVQuality controlled data
How to cite
Rimmelin-Maury Peggy, Grossteffan Emilie, Devesa Jeremy, Perennou Morgan, Delebecq Gaspard, Lambert Christophe, Leynaert Aude, Klein Cecile (2024). SOMLIT-Portzic time series (French Research Infrastructure ILICO): long-term core parameter monitoring in the Bay of Brest and Iroise Sea. SEANOE.

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