This summer, faculty from Memorial’s earth sciences department sailed on a research cruise to Endeavour Ridge, Canada’s first Marine Protected Area (MPA).
Located 250 kilometres offshore from Vancouver Island, B.C., and 2,250 metres below the ocean’s surface, Endeavour is a seismically and volcanically active area of the sea floor with hydrothermal venting.
Hydrothermal vents are extreme environments containing unique organisms that don’t depend on sunlight for sustenance. Instead, microbes use a chemosynthetic process to produce organic matter using the energy derived from metabolizing dissolved hydrogen sulfide in the vent fluids.
Very little is known about the day-to-day life of the organisms or how these ecosystems evolve over time.
Protecting biodiversity
Dr. Steve Piercey, professor, economic geology, and Dr. John Jamieson, Canada Research Chair in Marine Geology, were invited to join the Fisheries and Oceans Canada (DFO) and biologists from the University of Victoria to help answer some of those questions. The research cruise was funded by DFO.
“Canada is committed to protecting at least 10 per cent of its ocean waters by 2020, which will make expeditions such as this one more critical in the future,” said Dr. Ben Grupe, the cruise’s chief scientist and a DFO visiting fellow at the Natural Sciences and Engineering Research Council of Canada.
“The more we understand remote ecosystems such as deep-sea hydrothermal vents, the better our ability to assess whether MPAs are doing their job in terms of protecting biodiversity and ensuring ecosystem integrity.”
“One of the things about having a Marine Protected Area is you have to understand what you are protecting.”
Dr. Grupe notes that a vent system at this scale exists nowhere else in Canadian waters, as far as scientists are aware.
Understanding the relationships
“One of the things about having an MPA is you have to understand what you are protecting,” added Dr. Jamieson. “The Endeavour MPA was chosen because of it’s uniqueness, and because it encompasses these active hydrothermal vents.”
Dr. Jamieson says the purpose of this particular cruise was to take an inventory of the types of organisms that live in the Endeavour MPA and to try to understand the relationship between the organisms that live there and the rocks and vents that they’re living on.
Using ROPOS, a remotely operated vehicle operated by the Canadian Scientific Submersible Facility, the team collected photos and video of the sea floor as well as rock samples. In the video below, a hydrothermal vent covered in tube worms and discharging approximately 250°C fluid at a depth of 2,300 metres below sea level can be seen.
An earth sciences master’s student is now looking at dating these samples, as well as examining their mineralogy and geochemistry, to help create a picture of how hydrothermal vents age and change over time.
‘Amazingly diverse’
“One of the big things that struck me is active vents are amazingly diverse, in terms of the biology,” said Dr. Piercey.
“Even inactive chimneys that stopped venting 3,000-4,000 years ago had a lot of organisms living around them. But when you go back in the ancient record, even young massive sulfide deposits that aren’t all that old, maybe 10-30 million years old, a lot of the biological history that exists on the modern seafloor does not exist in the geological record.”
Dr. Piercey says they’re trying to figure out why that is, and how they might understand the processes currently happening in active vents to try to infer what might have happened long ago.
“There’s probably a simple explanation for some of it, but it may be organisms were different in the past.”
Environmental implications
Dr. Jamieson says that, as resource geologists, some of their motivation for studying the vents comes from knowing that some companies and governments are looking to mine hydrothermal vents for the valuable minerals they contain.
If that takes place, understanding the vents as a system — how the rock, biology and fluids interact with each other — is an important component of determining what the environmental implications of mining them will be.
“A lot of the work we did on this cruise was understanding the difference between an active vent and an inactive vent and then seeing how these things are preserved millions of years in the rock record, what are the changes and what are the processes that result in those changes,” said Dr. Jamieson.
He says Endeavour is “one of the best places” to observe the vents because it’s a protected area and it’s just a one-day sail from Victoria, so it’s very accessible. The researchers can also see a lot of different vents, in terms of growth histories and age stage of the vents, all in close proximity.
As geologists, Drs. Jamieson and Piercey are trained mappers, and most research cruises that study anything on the sea floor require a geologist. Geologists understand how to navigate on the sea floor, can provide the context for where the vents are, explain why they are there, where others might be found and literally how to drive up to them on the sea floor.
Geological context
Working with biologists on the expedition was an added bonus, say the researchers.
“DFO and the people at UVic were mostly biologically oriented, and what they were asking from us was to provide geological context to their biological communities,” said Dr. Piercey. “They understand the ecosystem and the interrelationships between the organisms and the differences between them at each site.”
“You can really push the science forward in a way that you otherwise would never have thought of.”
“You spend a lot of time together when you have a multidisciplinary team on a research cruise, and you get to learn about their way of thinking and they learn about yours,” said Dr. Jamieson.
“When you put those two perspectives together, you start to come up with all sorts of ideas that individually we never would have. You can really push the science forward in a way that you otherwise would never have thought of.”
‘Never would have discovered’
In addition, Dr. Grupe says collaborating with academic partners on ventures like the summer research cruise improve the quality of DFO’s science.
He says that that the earth scientists’ ability to interpret the geological history and mineralogy of vent chimneys allowed the team to sample a diversity of habitat types and make better decisions on where to take the ROPOS remotely operated vehicle.
“One of the most exciting moments of the cruise came at the end of a long ROV dive,” he said. “Our sampling at an active vent had been very efficient and we had an extra 90 minutes to explore at the end of the dive.
“John pointed to a feature on a map and explained two or three reasons it might be really interesting to check out. As it turned out, it was an old hydrothermal site with a fascinating biological community that we never would have discovered without geologists on board.”
