The SNO Phytobs observation series

In a context of global change and increasing anthropisation of coastal areas, which may result in changes in the distribution of organisms, the objective is to describe and monitor the evolution of phytoplankton biodiversity in order to understand and predict the evolution of pelagic ecosystems. The long-term monitoring of microalgae is part of this framework.

This monitoring of the structure of phytoplankton communities aims to highlight temporal changes on various time scales: seasonal changes (e.g. spring blooms), interannual changes (e.g. appearance/ disappearance of species) and even decadal changes (e.g. changes linked to natural or anthropogenic forcings).

The observatory carries out this series of phytoplankton observations at two sites in Brest harbour. The first site, at Ste Anne du Portzic, was set up in 1998. Monitoring at the second site, located in the southern basin of the Rade de Brest, was set up in 2010. The monitoring at this site has the particularity of simultaneously sampling the microalgae in the water column (pelagic) and the microalgae that develop on the bottom (benthic), which are called microphytobenthos. The latter sampling is carried out by diving.

The data acquired in this series are made available in the PHYTOBS database. PHYTOBS is a National Observation Service (SNO) of the Ilico Research Infrastructure. It is designed to monitor microphytoplankton and is deployed on the French coasts and supported by Ifremer, CNRS and the Marine Universities. A common protocol applies for sampling, analysis and identification. The physico-chemical parameters associated with each sample are available with the PHYTOBS data. In the Rade de Brest, these parameters are acquired by the SOMLIT network.