by Christophe Le Gall |
In the morning, we performed the CTD-Rosette water sampling as planned, but during one short transfer, the echosounder detected a gas plume under the ship. This kind of process are known in this region, and this is an opportunity for the scientific crew to collect more information about that.
So a change of plan was decided! The OFOS was immediately sent to record a movie of the ocean floor. We hope to see the gas venting origin. During almost 2 hours, we shoot pictures of sediments, plenty of small shrimps, some fishes, but no gas bubbling… Scientific group leaders had to think about the planning, and it has been decided to perform water analysis, and then to take 1 (maybe 2) sediment cores. But the first attempt arrives with half of the tube empty of sediment. So we decided to immediately reload the MUC and deploy it again. But when it came back, it was worse! Indeed, the MUC lands on a rocky surface, and so cannot collect any sediment. So we did it a third time (each try take close to 1 hour…), with more success. Scientist get additional samples – maybe very interesting ones. Some of the samples were really stinky, due to massive amount of hydrogen sulphur, smell like rotten eggs!
As we spend a lot of time, we immediately move to the next scheduled CTD- station. We still have tasks to perform, and time is shortening…