Maupiti, a model lagoon

Understanding the dynamics of lagoons and reefs is the aim of researchers from the Géosciences Montpellier laboratory, who set out to plant sensors and probes on the island of Maupiti in French Polynesia.

Welcome to Maupiti, a small island paradise just 11 km² from Bora-Bora in French Polynesia. Far from mass tourism, Maupiti is a dream destination for lovers of peace and quiet... and for coastal scientists and geophysicists from the Geosciences Montpellier laboratory and GLADYS. With its closed lagoon, where water only exits through a single channel, Maupiti is an ideal model for studying lagoon dynamics," explains Frédéric Bouchette. In particular, we can characterize how waves pass over the coral reef and how wave energy is transformed into current, water level and transport." To understand the dynamics of the lagoon and reef, the researchers carried out two missions to Maupiti in May and from June to August 2018. Pressure, current, tem-perature, wind, water height, waves, topography - the island was packed with sensors and probes that enabled the researchers to study the system in detail. The mission also provided an opportunity for new methodological developments: "We wanted to check whether a seismometer was capable of hearing the sound of waves on the beach itself," explains the researcher. The island is the ideal size: it's small and sparsely populated, so the seismic noise is little disturbed by the presence of man," stresses Erik Doerflinger, " but it still has the infrastructure needed to ensure the logistics of the missions."

Photos © Frédéric Bouchette / Benoit San Nicolas / Damien Sous / Samuel Meule / Erik Doerflinger / Google 2018 CNES - Airbus