THEMISTO 2021

Type Oceanographic cruise
Set This cruise is part of the set THEMISTO
Ship Marion Dufresne
Ship owner TAAF
Dates 13/01/2021 - 08/03/2021
Chief scientist(s) COTTE Cédric ORCID

LABORATOIRE D'OCÉANOGRAPHIE ET DU CLIMAT : EXPÉRIMENTATIONS ET APPROCHES NUMÉRIQUES - UMR 7159

Institut Pierre Simon Laplace

Boîte 100

4 place Jussieu

75005 Paris

+33 (1) 44 27 32 48

https://www.locean.ipsl.fr/

DOI 10.17600/18001336
Objective

This cruise is the continuity of the previous THEMISTO campaigns in order to continue the data acquisition and the monitoring of zooplankton and micronekton in the southern Indian ocean during the Obsaustral "monitoring" campaigns. Following the studies on large spatial and seasonal distribution patterns, the aim is to understand and quantify the processes explaining how the environmental variability structures pelagic ecosytems in the southern Indian ocean. The objective will be to study the 3-D distribution of zooplankton and micronekton and their variability related to physical processes and climate. THEMISTO proposes to use active acoustic as a tool to measure the distribution and density of organisms. This project uses the acoustic devices that equip the Marion Dufresne II. The objective will be to acquire continuous measurements from echosoundeur EK80 (5 frequencies, from deeper than 2000m for the 18kHz to 200m for the 200kHz) during transits La Réunion-Crozet-Kerguelen-Amsterdam-La Réunion to i) continue the discrimination of groups and species of zooplankton and micronekton started during the joined echosounding-trawl campaigns and ii) characterise the variability of their 3-D distribution along an important latitudinal gradient (from tropical to polar areas). Physical processes will be investigate simultaneously (in-situ data from the thermosalinograph and remotely-sensed analysis) to define multi-scale critical habitats of keystone species in ecosystems of southern Indian ocean. Including collaborations with recent and ongoing Obsaustral programs, REPCCOAI and OISO, and other campaigns, the ongoing results should contribute to better understand ecosystems and assimilate these in-situ data in trophic models (H2020 MESOPP program).

Data managed by SISMER