Tuesday 12th February
Isis dive 200 went into the water at midnight local time, and began the one-and-a-half hour descent to the upper slopes of Mount Dent and the Von Damm Vent Field 2.3 km below. We've encountered quite a strong surface current during launches so far, which has previously swept us up to 1200 m west before Isis is ready to leave the surface. Based on that experience, and thanks to the skill of the bridge officers, today's launch had an offset for current that put us right on target for the ROV's planned arrival point at the seafloor.
We moved the ROV quickly to collect hot fluids from the vents here, using the syringe samplers of geochemistry team members Valerie and Alain from Geosciences Environnment in Toulouse. And then we began a survey of the wider marine life of the Von Damm Vent Field. Over the next 20 hours, we saw that almost imperceptible low-level venting (though fortunately not imperceptible to our sensors!) is actually very extensive across a wide area of seafloor here. With that insight, we collected samples to investigate how that low-level venting may influence the distribution of deep-sea creatures.
During today's dive we also had a live video link to a class at Thomas Hardye School in Dorchester. Students watched as the ROV collected specimens of deep-sea creatures, and asked questions about our work and life aboard ship. It really gives us a morale boost out here to have people take an interest and become involved in what we are doing, and we look forward to further live links to schools over the next few days.
Overnight, we revised our immediate plans, which is certainly not unusual at sea and and all part of the job to adapt to changing conditions. The Isis ROV needed some extra time for maintenance after dive 200, so in the meantime we moved the ship off Mount Dent and out over the volcanic rift below. Here we launched the CTD probe to measure the temperature and salinity of the water all the way down to 5000 m depth, where we will be working in a few days time at the world's deepest known undersea vents.
That task was originally scheduled for later in our expedition, but carrying it out now is preferable to just sitting waiting with the ship, which I must avoid at all costs as Principal Scientist given the limited time that we have. I am grateful to the technical team and deck crew for their willingness to prepare a different piece of equipment for deployment at a moment's notice, allowing us to adapt our plans when required.
Experienced sea-going team members seem wryly amused that I have defined four basic "states" for the ship - "in transit", "deploying equipment", "deck work", and "idle" - with standing instructions for scientific watchkeepers to record all changes of the ship's condition between those states; my goal is to eliminate any avoidable "idle" time when we add up the totals at the end of the expedition.
My apologies for the lack of photos in today's entry, with no time to prepare any to post, but I hope to catch up tomorrow.