To protect the ocean, it's crucial to understand the people who inhabit it: the billions of micro-organisms that make up the ocean microbiome, essential to life on Earth. To study this invisible universe in the face of climate change, the Ocean Institute of the Sorbonne University Alliance and the French Navy are joining forces with the international Plankton Planet program for a unique scientific mission: the Bougainville Mission. This year, six new Volunteer Officers in training (VOAs) join the adventure.