Contributed by Kelle Freel
With my warmest sweatshirt, beanie, and fuzzy socks, I sat in a dark room lit by a set of giant screens secured against one wall. I wasn’t alone. There were two other research scientists sitting at their respective stations along with three engineers trained to guide the remotely operated vehicle (ROV) Jason to the seafloor to collect data and samples. Jason drops to the depths at a rate of 30 meters (~100 feet) per minute, taking about 2 hours to reach the seafloor 4,500 meters (~14,700 feet) below the ship. Once the seafloor came into view on our first dive, the crew moved Jason towards the study site, and slowly out of the darkness the site we had been looking for came into focus. My first research cruise was gearing up to be quite the adventure.
I just returned from a 30-day research cruise aboard the research vessel Atlantis. Our goal? Collect fluid samples from under the seafloor at borehole observatories on the western flank of the Mid-Atlantic ridge—which means loading equipment on to the ROV Jason, which then traveled to the sea floor, and connected to specially designed platforms that were previously installed. These platforms are at about 4,500 meters deep, equal to the elevation of Mt. Whitney and 300 meters deeper than Mauna Kea is high! These platforms are referred to as Circulation Obviation Retrofit Kits (CORKs), and with the help of Jason, they allow access to fluid from under the seafloor, in Earth’s crust.
Once we haul the water (aka crustal fluid) onto the ship, it is divided among various researchers who have experiments ready to go. Some projects involve filtering the fluid, then sequencing the DNA of everything on the filter to better understand the microbial community under the ocean’s floor. Other researchers will use their samples to isolate viruses from the crustal fluid or determine what nutrients and chemical compounds are present. As you might imagine, these samples are difficult to collect, so there is much unknown about the biogeochemistry and microbial community under the seafloor.
The research vessel Atlantis belongs to Woods Hole Oceanographic Institute (WHOI) and we left its home port on October 2nd and reached port in Barbados on November 1st. I’ve never spent so many days on a boat, and was thankful I wasn’t too sea sick the first few days, and luckily it didn’t take me long to get my land legs again once we were back on solid ground. The first few days were a novelty and walking down the hall to match the swell as we moved 10.5 knots towards the middle of nowhere (North Pond, to be exact), took some time. There was a treadmill on board, so I also had my first experience of running on water, which was quite the challenge.
There was a total of 18 researchers on the ship representing various laboratories from all over the US. The chief scientist, Geoff Wheat, is a research scientist at the University of Alaska Fairbanks, although he also works at the Monterey Bay Aquarium Research Institute (MBARI) in California. Along with a handful of us from Hawai‘i, there are researchers from Bigelow Laboratory for Ocean Science, WHOI, the University of Delaware, Texas A&M, University of Southern California, the University of Miami and the University of California, Santa Cruz. It was an amazing opportunity to interact with scientists involved in deep sea research from across the country.
After the first week, I was finally accustomed to all the different passages on the ship. The small quarters (stateroom in “ship talk”) I shared with my roommate in the bunks below the main deck were just for sleeping and showering. However, there was a TV lounge and library upstairs that worked as common areas, other than the lab. The ship seemed big the first few days, but after three weeks and once everything became more familiar, it felt much smaller. With 52 people on board, including the Jason engineers, the crew, and the scientists, you couldn’t go far without running into someone.
After a week of transit, we arrived at North Pond, located in the Atlantic Ocean at 22º45.35’N and 46º04.86’W. We spent the following two weeks sampling and running experiments. There are two main locations on Jason with space for equipment to be loaded. The first, referred to as the “front porch”, sits between the two hydraulic arms on the front of the ROV. The second location is in the rear on a platform underneath the body of the ROV. Our sampling equipment included pumps that were loaded on the front porch along with a large box to hold a bag to fill with fluid samples. We also had a set of six boxes with bags for fluid, set in a frame that was secured on the back platform. As might have been expected, our first attempt at wheeling out our gear and using a million zip ties and hose clamps to ensure everything was ready to be dunked into the ocean took longer than planned, just about an hour. Once we had gone through the motions, however, when the ROV returned to the deck we became a professional pit crew, ready to swap gear and send Jason down again in just about 20 minutes. The video monitors were rolling whenever Jason descended and while operations were underway. Generally, North Pond looks like a deep sea desert, so anytime a sea cucumber or shrimp was spotted it was met with excitement.
After making it through a few operations on that first dive, an oil leak in one of the hydraulic arms forced us to end the dive early. We had to wait until the following day for repairs to be completed and attempt another dive. After that first attempt, we made 5 successful dives to obtain crustal fluid and another set of dives to retrieve various instruments that had been collecting data and samples on the sea floor. Though other problems cropped up along the way, the Jason crew’s troubleshooting game was strong and we now have a great set of samples that will yield valuable and novel data.
I’m thankful that I’ve had the chance to participate on this research cruise. I learned a lot about research in the deep sea, and now have a better idea concerning the challenges and logistics involved in sampling this difficult-to-access habitat. There are only a handful of sites globally at which the fluid from under the seafloor can be obtained, making every expedition to these locations invaluable. The fluid samples we collected will continue to open a bigger window into the microbial community inhabiting this environment. The samples we collected were divided among multiple labs and the collective data ultimately obtained will paint a better picture of the diversity under the seafloor as well as allow us to better understand the biogeochemical processes these communities are involved in.
About the author:
I started my science career at UC San Diego, where I worked in Dr. Paul Jensen’s lab at Scripps Institution of Oceanography on undergrad independent research projects. I then became a graduate student with Paul and studied microdiversity and biogeography of the marine actinomycete Salinispora. After grad school I moved to France to experience la vie abroad and worked with multiple groups: first researching the adaptation of bacteria to toxic environments, and then moving on to study yeast population genomics of non-model species. I am now a postdoc with Dr. Mike Rappé at the Hawai‘i Institute of Marine Biology, exploring the population dynamics, evolution, and diversity of SAR11.