Several DCO researchers were aboard R/V Falkor from 30 May-30 June 2013. Oases 2013, led by Dr. Chris German of the Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA, explored hydrothermal activities at the Mid-Cayman Rise. Investigations into hydrothermal vent ecosystems there will expand on previous work in the area, with scientists researching various aspects of rock/life interaction.
The following article was written before scientists set sail:
The Mid-Cayman Rise is a unique piece of oceanic crust. It comprises the tectonic boundary between the North American and Caribbean Plates, which are slowly moving apart. While deep ocean hydrothermal activity is not peculiar to the Mid-Cayman Ridge, much of the geological and biological activities observed there are: The hydrothermal vents previously studied at the “Piccard” and “Von Damm” fields show unprecedented levels of species diversity.
The current expedition is heading for two new hydrothermal vent fields, “Europa” and “Walsh”, which researchers intend to explore from chemical, physical, and biological perspectives. Integral to this operation is the hybrid remotely operated vehicle (HROV) Nereus, a submersible engineered at WHOI to both swim freely and autonomously, and explore the seafloor under control of scientists and engineers onboard Falkor.
It is this second feature of Nereus that the DCO’s Max Coleman will exploit on the second leg of Falkor’s expedition. Coleman, an astrobiologist at NASA-JPL, Caltech (Pasadena, CA) and member of the Deep Energy Community, is particularly interested in how hydrothermal vent ecosystems get their energy. Previous work at Piccard and Von Damm showed that such deep life operates independently from sunlight. It is not surprising that no light penetrates to these great depths, however, very small amounts of material produced at the surface by photosynthesis could drift down to the bottom. In fact, they are completely absent at the Piccard vent field, 4960 m below sea level. Instead, microorganisms use a process called chemosynthesis to harness chemical energy present in vent fluids. Coleman is particularly interested in hydrothermal vents as they represent an analog for Jupiter’s moon Europa, where a salty ocean exists, albeit encased in ice, with the potential for similar water/rock interactions and thus habitats for extraterrestrial life.
“There is a further parallel between oceanography and space exploration,” Coleman said. “In both I am fortunate as a scientist to have the privilege to work with really great engineers. Those at JPL can get a spacecraft to a distant planet, while the great engineers from WHOI allow us to observe and sample from a completely different extreme environment.”
"It is truly amazing to see the proliferation of life around the vents," he added, "and then you realize that the whole of this flourishing ecosystem is dependent on the chemosynthetic bacteria, the base of the food chain. This is my third visit to this area and I can't wait to get new samples back to the lab to see how much more we can learn about this amazing system.”
Also on Leg 2 of the expedition is Deep Life’s Julie Huber of the Marine Biological Laboratory in Woods Hole, MA, and her postdoctoral fellow Julie Reveillaud. Huber and Reveillaud will be collecting data as part of DCO Deep Life’s Rock-Hosted Life project. This initiative is being conducted in collaboration with Matt Schrenk at East Carolina University, Greenville, NC, Doug Barlett at Scripps Institution of Oceanography, San Diego, CA, and Ramunas Stepanauskas at Bigelow Laboratory for Ocean Sciences, Boothbay, ME. Huber is particularly interested in how microbes living within the rocks of the seafloor process hydrogen and methane, especially at high temperatures. Her initial studies of fluids from the Mid-Cayman Rise indicate there are active Archaea eating simple carbon substrates from hydrothermal reactions in the subseafloor.
“The Mid-Cayman Rise is one of my favorite spots on the seafloor,” says Huber. “The fluids here host a large diversity of bacteria and Archaea that have interesting metabolisms and evolutionary relationships. I look forward to finding more sites along the MCR, as well as doing targeted sampling and experiments at the sites we have visited previously.”
To keep up with Coleman and Huber, check out the Schmidt Ocean Institute’s website, where scientists aboard Falkor will be regularly posting updates and photos to the expedition Cruise Log. During Leg 2, there will also be live-streaming video from HROV Nereus on the seafloor, and viewers are encourage to ask questions via Twitter (tweet @SOICruises for live events using #Oases13). You can also keep up with all of this summer’s expeditions by following Schmidt on Twitter @SchmidtOcean, Facebook, and Google+.
Photo credit: Chris German & SOI