This blog post describes my dive in Alvin on Tuesday, May 2. One of the primary objectives of the dive was to deploy the Vent-Submersible Incubation Device (SID, or Vent-SID) at one of the hydrothermal vent sites on the seafloor. The site is affectionately named Crab Spa, due to the large number of crabs that enjoy bathing in its balmy room temperature fluids that spew out of volcanic chimney. This is a very exciting moment that we have been anticipating and working towards for quite some time.
The Vent-SID works just like its name, it is designed to carryout incubations of hydrothermal fluid on the seafloor, instead of up in the lab. The simplest type of incubation a microbiologist could imagine is putting hydrothermal fluid in a sealed bottle in the lab and adding a chemical to it (in our case nitrate) to measure how fast that chemical is consumed by bacteria in the sample. However, bringing a hydrothermal fluid sample to the surface has its problems. All kinds of artifacts occur when bringing a sample to the surface due dramatic changes in temperature and pressure that stress the organisms and change environmental conditions in the sample, like the concentrations of gasses and the pH. This is why we are going to all the trouble to conduct incubations directly in the environment or in situ, as it is known among scientists, which is notoriously difficult to do in even the most hospitable environments. This explains why no one has successfully done what we are trying to do on this cruise.
The Vent-SID is a complicated instrument, with different pumps, valves, injectors, tubing, heaters, incubation chambers, deep-sea batteries, sample filters and bags, all needing to work together in unison, with electronics and computers to run the instrument that are stored in deep-sea chambers to stay dry under intense pressure at the seafloor. It is a little like designing an instrument to automatically cook dinner, set the table and do the dishes in perfectly timed steps. We are trying to accomplish this at the seafloor at a depth of 2,500 m!
Unfortunately, in today’s deployment we were foiled by a communications glitch between our computer in the sub and on the Vent-SID at the seafloor. We aborted the experiment and sent the instrument back to the surface. Our new plan is to pre-program the instrument to carry out its functions at a certain time after we put the Vent-SID in place at the vent site to altogether avoid any communications issues on the seafloor. The Vent-SID will be put back in place at Crab Spa on Thursday. Luckily, I will be going on this dive. I am very much looking forward to diving again in Alvin!!!
Despite sending the Vent-SID to the surface prematurely, we had a productive dive. We spent a lot of time working around Riftia and mussel beds. I got to watch these communities in wonder, in between taking notes and finding places to sample, watching the crabs poke the heads of Riftia into their tubes, and fish swimming throughout the shimmering, warm vent fluid. The thriving biological communities at the vents continue to amaze me! Overall, we obtained a good haul of samples for scientists on the ship.
Working with Vent-SID delayed our arrival back on the ship, which meant we got to spend some extra time at the seafloor, which I was happy about, except for the extra chill in the sub due to more time in the cold, deep water. Although the vents are spewing warm to boiling hot water into the ocean, the surrounding seawater is cold and the heat from the vents is quickly diluted. We were back on deck just after dinnertime, and luckily there were plates of delicious food set aside for us. Everyone on the ship is quite accommodating and happy to help, which we certainly appreciate for doing science!