|This cruise is part of the set MOMARSAT : MONITORING THE MID ATLANTIC RIDGE
|11/07/2023 - 29/07/2023
LABORATOIRE ENVIRONNEMENT PROFOND
Centre Ifremer Bretagne
ZI Pointe du Diable
+33 (0)2 98.22.43.04
The MoMARSAT campaign series provides annual maintenance for the EMSO-Açores observatory on the Lucky Strike hydrothermal field. This seafloor observatory has been in operation since 2010 and aims to acquire time series on hydrothermal, tectonic and volcanic processes and ecosystems at an active hydrothermal site on the Mid-Atlantic Ridge. It is part of the EMSO (European Multidiciplinary Seafloor and water column Observatory-ERIC) network, supported in France by the EMSO-FR Research Infrastructure (MESR) and managed by an Ifremer-CNRS collaboration.
The observatory infrastructure includes a surface buoy (BOREL) that ensures data transferto a server on land and communication with the connected instruments, and two seafloor monitoring stations (SEAMON) that provide power and communication via to instruments deployed on the seafloor and communicate acoustically with the surface buoy. The BOREL buoy is also instrumented with a weather station, a geodetic GPS and an automatic identification system (AIS). The first observation station (SEAMON West) is deployed at the center of the fossil lava lake characteristic of the Lucky Strike hydrothermal field, and is dedicated to geophysical studies and monitoring essential ocean variables (EOVs). It connects an Ocean Bottom Seismometer (OBS), a permanent pressure gauge (JPP) and the EGIM European generic instrumentation module equipped with a CTD, hydrophone, optode, turbidimeter and ADCP. The second station (SEAMON EST) is deployed at the base of the active edifice Tour Eiffel and support the study of the interactions between hydrothermal circulation, physico-chemical factors and fauna dynamics at the edifice scale. Seamon East is equipped with a biological observation module (TEMPO- with HDTV camera and 4 projectors, temperature, oxygen and dissolved iron sensors), an autonomous sequential hydrothermal fluid sampler (DEAFS), a network of 4 hydrophones (HYDROCTOPUS), a turbidimeter and a dissolved oxygen and temperature sensor.
The observational array also includes autonomous instruments that store data internally: 4 OBS, 2 permanent pressure gauges (JPP), 36 autonomous temperature probes for hydrothermal fluids and mixing zones, 7 autonomous bottom current meters, 6 biological and microbiological colonizers, and an oceanographic mooring. In situ measurements as well as fluid and biological sampling and colonization / recolonization experiments are carried out to complete the set of parameters and integrate a spatial component into each maintenance operation.
Maintenance operations included the recovery of the BOREL-SEAMON infrastructure and their connected instruments, onboard reconditioning, and the redeployment of the stations. The recovery and deployment of autonomous instruments, in situ measurements and sampling were performed during ROV dives.
The study area is part of Portugal's EEZ and an OSPAR Marine Protected Area.