PHYTOBS - Phytoplankton Observation Network

Thierry Guyot — 2026-10-22T13:12:45Z

National observation network website : IR-ILICO

National observation network website : CNRS-INSU

PHYTOBS :

The phytoplankton observation network (PHYTOBS) is based on a network of 26 sites along the English Channel, Atlantic and Mediterranean coasts. These sites conduct long-term observations of marine and lagoon phytoplankton, together with measurements of their associated hydrological conditions, at fortnightly intervals.

The PHYTOBS National Observation Service (SNO) originated from two monitoring networks : REPHY (the Phytoplankton and Phycotoxin Observation and Monitoring Network), established by Ifremer in 1984, and SOMLIT (the Coastal Environment Observation Service), established by the CNRS in 1995.

PHYTOBS monitoring follows the strategy defined by SOMLIT : surface water sampling at high tide (at sites subject to tidal influence), every 15 days. In addition to phytoplankton sampling, 11 SOMLIT parameters are measured : temperature, salinity, dissolved oxygen, nitrate, nitrite, ammonium, phosphate, dissolved silica, suspended matter, chlorophyll a and suspended solids. All observations and analyses are carried out under a quality management framework.

Objectives of PHYTOBS :

Analyse the responses of phytoplankton communities to environmental changes ;
Assess the quality of coastal environments using indicators ;
Define ecological niches ;
Detect changes in phenology ;
Promote synergies within the scientific community, strengthen expertise and disseminate knowledge as part of the services provided by the National Observation Service.

At the national level, PHYTOBS is coordinated by Maud Lemoine (Ifremer Nantes) and Pascal Claquin (UMR BOREA, University of Caen).

PHYTOBS in La Rochelle :

Since 2012, the LIENSs laboratory has been sampling one station every 15 days for PHYTOBS in the Pertuis d'Antioche, where the SOMLIT station is located.

Samples are collected using a Niskin bottle aboard L'Estran, the research vessel operated by La Rochelle University (L'Estran).
Lugol-preserved samples are examined and marine phytoplankton are counted under an inverted microscope using sedimentation chambers.

PHYTOBS team at LIENSs

[Scientific coordinator]

Christine Dupuy, La Rochelle University

Pierre-Guy Sauriau, CNRS (until 2023)

[SOMLIT technical coordinator]

Philippe Pineau, CNRS

[PHYTOBS technical coordinator]

Claire Emery, CNRS

[L'ESTRAN vessel operator]

Yves Brizard, La Rochelle University

[Taxonomic analysis coordinator]

Beatrix Beker, private company (since 2018)

Christophe Arnaud, CNRS (until 2018)

Last updated : November 2022]

LIttoral ENvironnement et Sociétés (LIENSs) - UMR 7266

PHYTOBS - Phytoplankton Observation Network

PHYTOBS :

Objectives of PHYTOBS :

PHYTOBS in La Rochelle :

PHYTOBS team at LIENSs