EXPAND will spend over 100 days at sea across three ambitious legs, made possible by the support of the French Oceanographic Fleet. The expedition will sail more than 26,500 km through the vast and remote subtropical desert of the Indian Ocean.

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Pourquoi Pas

The first leg is scheduled on the R/V Marion Dufresne in December 2026, the second leg on the R/V Pourquoi Pas ? in April 2027, and the third leg on the R/V Marion Dufresne in December 2027.

A main innovation of EXPAND is to measure nitrogen and carbon fixation rates over a full year, thanks to automated equipment designed and built at NOC. The automated ‘iN sItU tracEr incubator’ (NIUE) will collect surface seawater on a monthly basis and incubate it with isotope labelled substrates to measure nitrogen and carbon fixation rates. It will be integrated along an automated DNA sampler (RoCSI). Both instruments will be installed at 30 m below the surface on instrumented mooring lines located at the centre and borders of the Indian Ocean Subtropical Gyre.