Every cruise on board the R/V Atlantis with the DSV ALVIN has one thing in common – amazing discoveries and fun initiation rituals. Each day begins around 6:30, with final checks of the sub and ultimately loading the science observers of the day into the ALVIN (Melitza Crespo is shown below). We have several scientists who’ve never been in ALVIN before and for them there is a special treat upon returning to the surface, you can look forward to a bath in lots of 4ºC water. Brrrr. There’s even a special throne where one sits while receiving this special treat (shown here is Dr. Kirsten Habicht’s initiation from two days ago).
We are working at depths around 500-2000m. It takes about half an hour to go 500m so two hours to descend 2000m. Once you’re on the bottom, you have about 5 hours of time to collect samples. Then, the sub returns to the surface and is picked up by the ship. We spent our first four dives working in the Alaminos Canyon area and saw some unbelievable features on the bottom. We built a special sampler, we’re working on a name for the gadget but for now it is “BAFS” (Brine Anoxic Fluid Samper) [shown below] that we use to sample targeted (specific) brine layers.
The reel allows us to lower an intake hose to a specific depth and then we use a pump to introduce brine sample into the chamber. We can collect 12 brine samples at a time and when the sub returns to the surface, we take the bottles off the sub and move them to the cold room for sampling [shown below]. The bottles keep the brine from heating up and keep the samples from losing the dissolved gas on the way up. Everyone spends a lot of time in the cold room processing sediment and brine samples (see below) but it's worth it because, eventually, you get a close-up view of the seafloor in your own ALVIN dive in addition to the fantastic data on these unique habitats. The Alaminos Canyon “Red Crater” stands out as the most spectacular site we’ve visited so far. The red (iron) minerals present at the seafloor are not stable at surface pressures and rapidly degrade. We’re eager to get them home to see what they are made of.