From April 19 to May 24, 2022, the RESILIENCE cruise took place in the Mozambique Channel and along the east coast of South Africa. This multidisciplinary campaign focused on the influence of small-scale physical processes on biological production at the edge of oceanic eddies present in the area. It brought together scientists from many countries including South Africa, Mozambique and Mauritius.
Jean-François Ternon, coordinator of the DiDEM High Seas component, participated as cruise leader.
The RESILIENCE logo - original drawing by Guillaume Chandelier (Université de la Réunion)
(http://dx.doi.org/10.17600/1800191) cruise is a multidisciplinary research operation conducted by researchers in physical, chemical and biological oceanography, specialized in the measurement of small-scale physical processes (of the order of a few kilometers), first trophic levels (phyto- and zooplankton) and marine megafauna (seabirds and marine mammals). The scientific team was composed of about fifty researchers and students from French research institutes and universities but also from several universities in South Africa and Mozambique. It took place on board the R/V Marion Dufresne in the southwestern Indian Ocean (Mozambique Channel and the east coast of South Africa). The team responsible for the project is composed of researchers from IRD (UMR MARBEC and LOPS), the Université de Bretagne Occidentale (UBO) and the Nelson Mandela University (NMU) in South Africa. The campaign hosted a Floating University gathering about twenty French, South African and Mozambican students supervised by two research teachers.
To understand the role of physical processes at small scale on biological productivity and structuring of pelagic ecosystems
The main objective of the RESILIENCE project is to study the physical-biological interactions at small scale (~1-10 km), especially on the frontal zones at the edge of mesoscale eddies (~100km) numerous in the Mozambique Channel. The aim of the mission is to understand the role of physical processes (vertical exchanges in particular) at small scale - well described by modeling but difficult to observe at sea - on biological productivity and structuring of pelagic ecosystems up to top predators. In the context of climate change, it is predicted that the intensity of these fronts will vary in the future with possible consequences on these ecosystems. The results of the cruise will therefore contribute to a study of the consequences of these changes on the exploited ecosystems of the area.
Deployment of the MVP (Mooving Vessel Profiler), towed at the rear of the vessel and performing vertical profiles between the surface and 300m. The “fish” is equipped with several sensors (CTD, fluorometer) and allows high spatial resolution measurements.
Crédit : Clément Panelle (UF RESILIENCE)
The central Mozambique Channel and the east coast of South Africa
The geographical area sampled is the central Mozambique Channel and the east coast of South Africa. There are marked eddy structures, in contrasting hydrodynamic contexts. The eddies studied being by nature mobile structures, the sampling plan was continuously adapted by a real time analysis of satellite data (altimetry and ocean color). Additional themes were addressed during the campaign: analysis of trace metals on the surface, environmental DNA measurements, measurement of CO2 cycle parameters, observation and counting of plastic macro-waste. For all the observations carried out during the campaign, innovative devices were used.
The campaign was financially supported by the French Oceanographic Fleet, the LEFE program (CNRS, France), the Belmont Forum (OceanFront Change project, International Conservation, USA), the IsBlue program (IUEM, Brest) and the National Research Foundation (NRF) in South Africa.
Multicolor flying fish “Yellow Bandwing”. Flying fish (several species) have been observed mostly in the Mozambique Channel.
Crédit : Peter Ryan (UCT)
The scientists and students of RESILIENCE have now returned home, rich with an unforgettable experience of 35 days at sea. In a few weeks, all the samples collected during the mission will be recovered and analyzed in the different laboratories. The scientific analysis of all the material collected will take several months - even years. In the meantime, the progress of the mission can be discovered on the website set up during the cruise by the students of the Floating University.
Visit the website : https://www.isblue.fr/universite-flottante-campagne-resilience-2022/