An international team of 29 researchers and engineers (including 9 researchers and engineers from the MIO) will be criss-crossing the Pacific, between Noumea and the Tonga Volcanic Arc, from 1 November to 5 December 2019 on board the oceanographic vessel L'Atalante. The aim of the TONGA campaign is to study the impact of shallow submarine volcanoes on marine life.
Coordinated by two researchers, Cécile Guieu from the Laboratoire d'Océanographie de l'Institut de la Mer de Villefranche-sur-Mer (CNRS/Sorbonne University) and Sophie Bonnet from the Institut Méditerranéen d'Océanologie (CNRS/IRD/Aix-Marseille University/Université de Toulon), the Tonga project brings together more than 90 scientists from 14 French laboratories based in mainland France and New Caledonia and six international universities (USA, Australia, United Arab Emirates, Germany, Great Britain and Israel).
Aboard L'Atalante, a vessel in the French Oceanographic Fleet operated by Ifremer, 29 researchers and engineers will be sailing for five weeks between Nouméa and the volcanic arc of Tonga. Their aim: to study in detail the role of fluids emitted by underwater volcanoes (rich in trace elements, nutrients or toxins) on micro-algae living in the ocean's surface waters and on the ocean's capacity to trap carbon dioxide from the atmosphere.
After locating one or more shallow active volcanoes, the team hopes to elucidate the role of fluids emitted by volcanoes in fertilising the South Pacific Ocean with iron, a micronutrient essential for life. This fertilisation mechanism could explain the microalgae blooms observed during the austral summer between Australia and the Tonga Arc.
Experimental studies will also be carried out on board the ship on the fertilising or toxic effects of hydrothermal fluids on surface plankton. Fixed along an anchored mooring line for a year, other instruments will be used to monitor the ocean's capacity to biologically sequester CO2, a first in this region.
In addition to the scientists, the Tonga campaign will also involve primary, secondary and high school pupils (including a school in Noumea), thanks to the "Adopt a float" educational project. They will follow the biogeochemical profiling robots and take part in the data collection operations.
To achieve this, the team will be supported by various specialists in the geochemistry of hydrothermal sources, trace element chemistry, physical oceanography and biology. The use of satellite images, automated sensors, in situ robots and modelling will enable real-time acquisition of physical, chemical and biological parameters from the atmosphere to marine sediments.
The Tonga campaign is funded by the TGIR French Oceanographic Fleet, Ifremer, the French National Research Agency (ANR), the Lefe-Cyber and Lefe-GMMC programmes run by the CNRS, the A-MIDEx Foundation, the IRD and partner laboratories.
Follow the campaign on the dedicated website.
The team embarking on the campaign