The KASEAOPE-1 campaign is the first in the New Caledonia component of the ScInObs "Science, Innovations and Underwater Observatories" observatory project, part of Ifremer's exceptional investment plan. It is also part of a collaboration with JAMSTEC to deploy an underwater observatory in the South-West Pacific. Seamounts, key ecosystems that are vulnerable and targeted for protection in the Parc Naturel de la Mer de Corail, which covers the whole of New Caledonia's EEZ, have been selected for the deployment of this observatory. The project follows on from the Kanadeep 2 and Kanarecup campaigns, which provided the first in situ data on several mounts in this region.

Comprising mooring lines and benthic stations, this mobile observatory aims to better understand the functioning and dynamics of seamounts, and in particular to identify the environmental variables that structure benthic and mesopelagic communities. Observation at very high temporal resolution will enable the joint measurement of relevant biological and environmental variables at scales appropriate for understanding ecosystems, with the aim of contributing to reliable predictive models on a regional scale. The data will also enable us to study current/topography interactions, or how seamounts impact the generation and propagation of internal waves and mesoscale eddies.

The KASEAOPE-1 cruise enabled the first elements of the observatory to be deployed: a pilot mooring line equipped with numerous measuring and sampling instruments on the northern slope of Mount Stylaster (Norfolk Ridge), and a camera-equipped EDOKKO observation module from JAMSTEC deployed on the summit of the mountain. Surface acquisitions with EK80 and ADCP echosounders were carried out day and night, along transects on Stylaster and Munida mounds, in order to map the mesopelagic communities. Rosette CTD profiles were also produced to calibrate the oxygen and salinity probes.

The project is led by Ifremer's REM department in collaboration with LOPS researchers, and involves teams already involved in the study of seamounts in NC, notably from IRD. The deployment of the moorings has been coordinated with those of the SWOT-ALIS project, led by LEGOS.