MIO staff are taking part in this study
A multidisciplinary team of 17 French and Brazilian researchers will be embarking from 27 August to 8 October aboard the ANTEA, an ocean-going vessel in the French Oceanographic Fleet operated by Ifremer. Leaving Cayenne, the ship will head for Brazilian waters and explore the mouth of the Amazon over more than 6,000 km to study the impact of currents, the Amazon plume and turbulent processes on the functioning of the marine ecosystem.
AMAZOMIX project: Study of physical processes and their impact on the marine ecosystem at the mouth of the Amazon River
Called AMAZOMIX, this campaign will cover the Amazonian shelf and continental slope to study the impact of fine-scale currents, plume1 and turbulent processes2 on the structure and functioning of marine ecosystems from a physical, biogeochemical and biological point of view. The expedition also aims to trace the origin and distribution of pollutants, heavy metals and microplastics, and to determine their role in the trophic chain.
What is the biodiversity at the river mouth? What influence do tidal waves have on this ecosystem? Although the Amazon brings a considerable load of water and sediment to the oceans, its mouth has been little studied and many aspects remain to be discovered: biodiversity, from bacteria to large mammals, is poorly understood; despite the turbidity of the waters, coral reefs can be found without being able to explain the mechanisms at work; in addition to the direct impact of the Amazon, tides generate very energetic waves whose consequences on the ecosystem are poorly described. Finally, the connectivity of species in the tropical Atlantic remains poorly understood: the Caribbean region is the most bio-diverse, and one hypothesis is that the Amazon feather, which can extend up to 3,000 km off its mouth, constitutes a barrier for certain organisms.
To achieve this, scientists from more than 20 disciplines in physics, biogeochemistry and biology, led by Ariane Koch-Larrouy (UMR LEGOS) on land and Arnaud Bertrand (UMR MARBEC) at sea, are on board the French vessel ANTEA.s by Ariane Koch-Larrouy (UMR LEGOS) on land and Arnaud Bertrand (UMR MARBEC) at sea, on board the French vessel ANTEA, will cover more than 6,000 km to collect data on abiotic compartments - such as water samples - and biotic compartments - from phytoplankton to large animals - using a wide range of tools (acoustic, optical, turbulence sensors, autonomous submarines, deep moorings, plankton nets and trawls, etc.).). The biological samples will be subjected to a wide range of analyses (isotopic, genetic, etc.) and the concentration of pollutants such as heavy metals and microplastics will also be measured.
The ship will make two stopovers in Cayenne on 13-14 and 28-30 September, with a stopover in Porto Vigia, near Belém, on 26 September to unload the biological samples. At sea, on 30 August, AMAZOMIX will cross paths with the schooner TARA as it circumnavigates Latin America and the Caribbean, with a view to scientific collaboration: a common protocol will enable the two teams to compare their data and thus increase the space-time coverage and the quantity of samples collected.
The result of longstanding Franco-Brazilian cooperation
In addition to the scientists on board, AMAZOMIX has a whole team staying on land: a total of around 70 researchers from Brazil, France and other countries are involved in the campaign, which will also have a research training role for around fifty international students. AMAZOMIX is the result of a long-standing joint effort based on a number of funded projects, including the European TRIATLAS project, and coordinated via the TAPIOCA LMI (IRD, UFPE, UFRPE). It should also be noted that the analysis of the data collected will be carried out jointly by the various partners and that the results will be pooled.