This cruise gathers two complementary and integrated long-term surveys conducted in the the Gironde estuary:

- the ecological survey for the Blayais Nuclear Power Plant (coordinated by IFREMER-EDF)

- the long term estuarine monitoring for the SOMLIT Coastal Environment Observation Service (INSU)

The ecological survey has been carried out since 1978 by the University of Bordeaux, it aims to comply with the regulatory framework for ecological monitoring of thermonuclear power plants, operating in an open circuit, which use large volumes of cold water continuously taken from the close environment to cool their condensers.

The SOMLIT estuarine monitoring started in 1997, sampling the same stations but  including a spatio-temporal extension relative to the monitoring for the Nuclear Plant, with an additional sampling station downstream and two additional legs in winter. The measurements collected in the framework of the SOMLIT feed a national database which is dedicated to the long-term evolution of coastal ecosystems. The Gironde estuary is one of the 12 ecosystems monitored by the SOMLIT network; it is representative of a land-ocean transition ecosystem, subject to the main forcing of tidal currents, river flow and characterized by highly turbid waters.