The ship was powerful and large, built with a hard steel hull that could crash through Arctic ice up to a metre thick. Bustling with researchers working on any number of projects, day or night you’d find someone typing up notes at a workstation, collecting data, or working in labs on the lower deck. A well-stocked galley provided scientists and crew members with three hearty meals a day. You could get in a quick workout in the gym down below or go up to wander the open-air decks, where you could look at the stars or watch the polar bears.
For Gerard Otiniano, it was the experience of a lifetime.
Otiniano’s previous experience made him the perfect fit: He works on developing and calibrating climate proxies — geochemical or physical indicators of past climate that become archived in the geological record — at high latitude regions. Otiniano figures out the relationship between proxies and temperature, and then applies them to records that span vast periods of time.
Here, he would be collecting cores from the seabed that comprised thousands of years of sediment.
“I’d been interested in marine geosciences and oceanography, but I wasn’t sure how to get into the field,” says Otiniano, who has always worked in the terrestrial realm. “There’s so much interest surrounding it, so many great minds studying it. This was an exciting step for me.”
It was new for Professor Porter as well. He’s long been studying natural indicators of how the environment has changed on land over time, measuring ice cores, tree rings, amber, and permafrost to understand how temperatures have changed. The Arctic region is experiencing some of the most dramatic rates of climate change, and in reconstructions of past climate Porter has seen changes similar to what’s happening now: warming terrestrial regions that impacted the permafrost and destabilized the landscape.
“That research led me to the ocean, where I know the sea ice has been playing a big role in driving the warming trends. It has a huge impact on what the climate ends up being in the continental interiors as well,” says Porter, who notes its troubling effects on parts of Siberia and Alaska and Northwestern Canada. “The next question is: How much more could it change?”
“And, really, we can only answer that question by going back through the sediment.”
So, they did.
The cruise sailed this past November, part of a project funded by the US National Science Foundation (NSF). For Dr. Robert Pickart, principal investigator and Senior Scientist in the Department of Physical Oceanography at the Woods Hole Oceanographic Institution (WHOI), the trip was intended to service a mooring that had been deployed in the Pacific Arctic Boundary Current on the continental slope of the Alaskan Beaufort Sea.
Pickart works in the Pacific Arctic addressing the ecosystem impacts of climate warming — particularly the consequences of the ocean’s physical changes such as sea ice loss, warming temperatures, and storminess. His research project began in the early 2000s and has enabled him to obtain a long-time record of changes in the Chukchi and the Alaskan and Canadian Beaufort Seas. Though his is the core project on these cruises, Pickart always accommodates ancillary programs and invites research teams to join.
“One of the exciting aspects of the ancillary programs is that collaborations naturally arise between the groups — including the work that Trevor and I will do together,” says Pickart. “This allows us to take a more system-wide approach to understanding Arctic climate change.”
On the 2022 cruise, seven projects were carried out, with researchers collecting information on everything from sea birds to black carbon to harmful algal blooms. Everyone was willing to lend a hand, and the researchers worked together to support each other’s projects.
“A lot of these opportunities come about in very spontaneous ways” Porter says, reflecting on the many collaborations he sees take place across the sciences. “We try to have as much of this as possible in the university setting, and we invite researchers from outside U of T to come in to interact with our students and faculty.”
“These types of interactions are really important to keep that cross-pollination, that exchange of ideas going.”
Porter’s own involvement came from a meeting initiated by Professor Kent Moore, a close colleague of Pickart who connected the two when Pickart visited UTSC to deliver a lecture as part of the Centre for Global Change Science’s Distinguished Lecturer Series. An expert in understanding the dynamical processes responsible for changing wind patterns, Moore works with Pickart in interpreting the data collected on these and other cruises to the region.
The Arctic has seen the largest reduction in ice cover; however, due to its harsh climate and remote location, we have only a few decades of high-quality data on it.
“The Beaufort has seen the largest reduction in ice cover over the past 40 years, so there is much to learn about how these changes are impacting the ocean and its ecosystems,” says Moore, explaining the urgent need to extend these records. “The inherent variability in the climate system combined with the short instrumental record means that it’s often a challenge to tease out trends.”
Paleoclimate data offers a solution to this challenge, providing a look back to a time before the impact of fossil fuels and longer records of the climate — though Moore points out that as paleoclimate records never directly measure climate variability, there’s a need to merge the instrumental record with the paleo record.
“It’s been a challenge to find paleoclimate records that have an expression of sea ice variability,” he says. “And that’s where Trevor’s work is of particular importance. The data he collected will allow us to look back in time to see how sea ice varies, which will be important to place the changes we’re seeing now in a long-term context.”
When Porter was invited to join Pickart’s cruise, he immediately reached out to Dr. Anne De Vernal from the L'Université du Québec à Montréal (UQAM). Porter and De Vernal agreed to collaborate on the project and, given the busy time of year, each sent a senior student in their stead to collect two sets of sediment cores.
Here’s how it works: For one of the sets, a large metal device called a "Multi Corer" is lowered into the water and down onto the seabed. Eight cylinders then pushed into the sediment, bringing up “surface cores” which are immediately sectioned off and brought back to the lab for analysis. These cores go back a few thousand years.
The second coring device, known as a “gravity corer,” penetrates much deeper and can go back at least 10 thousand years. These are kept cool and stored in Oregon State University’s core archive, which supports research funded by the NSF. This May, the research team traveled to OSU to sample the long cores and bring them back to the lab. They split the cores open to learn about the sediments, which allows them to tie them to other records that have been developed from the region.
Next, Porter’s group will measure biomarkers, molecules produced by specific organisms. In this case, they’re looking for highly branched isoprenoid alkenes produced by microscopic, single-celled algae called “diatoms,” which dwell in the bottom of the sea ice.
“If it’s there, it will start producing this biomarker," Porter explains, noting that this approach has been applied successfully in other parts of the Arctic. “And that molecule will sort of ‘rain down’ at the bottom of the ocean. The abundance of that molecule will tell us how much sea ice was there, and we’ll be able to figure out the concentrations of sea ice through time.”
Their UQAM collaborators specialize in other types of indicators and will be looking at microorganisms called “dinoflagellates.” The cysts from these are another indicator of sea ice conditions.
“You should never really trust just one indicator,” says Porter. “It’s when multiple indicators start coming together to tell the same thing that you can be more confident, and it’s important that we have this collaborative, multi-proxy approach to establish what really happened in the past.”
As for Otiniano, he’s busy finishing his PhD and has secured a postdoctoral fellowship at the University of Buffalo. He’ll continue to expand his horizons as an Arctic paleoclimate researcher and has kept in touch with many of the researchers he met on the cruise. He hopes to work with them again in the future.
“The number one thing we can do is to keep those interactions going,” says Porter, whose own research is based on one productive collaboration after another. Networking, particularly in the earth sciences, is essential. “We combine biology, chemistry, physics — we’re studying the complex systems and subsystems of the earth, coming at them from different angles.”
And whether encouraging student researchers means bringing in guest lecturers, sending them out to do field work, introducing them to colleagues, or supporting their professional development at conferences, it’s critical for their future success.
“We have to support that,” Porter says. “We’re in a lucky position to be faculty members at U of T, and it’s one of the great joys of supervising these students — to see them succeed, to develop the confidence to start spreading their wings and do their own things. It’s an honour to play a small role in their professional development.”