Arctic

Arctic

Climate Change

Earth Sciences

Graduate Students

Subheadline

Minoli Dias says the baseline data she and her fellow researchers are constructing could "inform model projections that predict what future conditions will look like”

Minoli Dias’s interest in sea ice began in an unlikely place: polar bear poop.

She was studying microplastics in polar bear feces and intestinal tracts as part of a research project during her undergraduate years at Queen’s University.

“It was a smelly job, but it was really interesting,” says Dias, who is now a PhD student in the department of Earth sciences at U of T Mississauga.

Her early work revealed some troubling trends: for instance, declining sea ice levels meant that certain species of polar bears were being driven inland – with garbage and landfills increasingly serving as their food sources. At the same time, members of northern communities, particularly the Inuit, had noted in their own experiences, observations and research that declining sea ice levels had impacted access to essential needs – such as transportation, food security through hunting, and other culturally important activities.

It wasn't long before Dias decided she wanted to pursue sea ice research – and ultimately chose to study at U of T Mississauga after speaking with Jochen Halfar, a paleoclimate and paleontology professor and researcher in U of T Mississauga’s Climate Geology Research Group. “UTM gave him a wonderful lab, and we have incredible facilities. But his research and his passion for the work was what really drew me,” she says.

Now part of Halfar’s research group studying changes in sea ice cover in northern Labrador, Dias and her co-researchers are developing sea-ice cover records for the past 1,000 years off the coast of Nunatsiavut and are examining coralline algae as part of their research.

Minoli Dias's view from the research vessel off the coast of Newfoundland and Labrador (photo by Minoli Dias)

Dias says that coralline algae live for approximately 1,500 years and they grow in annual layers (like tree rings). The growth, she explains, is dependent on light. When the algae have more light, meaning there’s less sea ice in the water, they grow a lot thicker. When they have less light, meaning there’s more sea ice cover, the layers grow thinner. By examining these variations and growth over time along with chemical tracers, the research team can essentially watch the sea ice cover change.

Dias conducted field work in the community of Agvituk (Hopedale), N.L. this past summer. The lab also explored multiple sites in Greenland, Norway, Nunavut and the Labrador coast.

“If we can create a network of these types of ocean reconstructions, we’ll be able to have this baseline data going back several centuries that can then hopefully inform model projections that predict what future conditions will look like,” she says.

Since joining the lab, Dias says she has had some incredible experiences – including a recent opportunity to work with members of the Hopedale community.

“We’re not the experts. We don’t live there. It’s the people who live along the coast – and actually live the change and see the change – who are the experts,” she says. “When you speak to community members, they have a clear understanding of how changes occurred over time, and what is the importance of sea ice to these ecosystems.”

Once she completes her PhD, Dias hopes to continue pursuing climate research by either working directly with impacted communities or working to address the effects of pollution or climate change.

Dias says she feels inspired by the many women scientists who came before her, including her female professors who have served as role models in what traditionally has been a male-dominated field.

“They paved the way for us to be able to do the work that we do, and to do it in relative comfort,” she says. “Having these women to look up to is what makes it possible for me to do the type of work that I do, and I hope I can make a similar contribution and pay it forward to the women that are coming after me.”

New research underscores need to protect 'oasis of the Arctic'

siddiq22 — Fri, 07 Jul 2023 13:59:46 +0000

New research underscores need to protect 'oasis of the Arctic'

siddiq22 Fri, 07/07/2023 - 09:59

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A beached iceberg on the Nares Strait, which is surrounded by the oldest and thickest sea ice in the world (photo by DeAgostini/Getty Images)

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Subheadline

Kent Moore, a professor of atmospheric physics at U of T Mississauga, collaborated with scientists from Environment and Climate Change Canada to study the North Water polynya

A new study by scientist Kent Moore shows that the unique marine ecosystem supporting a web of diverse natural life in the frozen Arctic is managing to sustain itself against the impacts of climate change – so far.

His findings, in partnership with researchers from Environment and Climate Change Canada, were recently published in the journal Scientific Reports.

Kent Moore (supplied image)

A professor of atmospheric physics in the department of chemical and physical sciences at the ��Ƶ Mississauga, Moore is studying an 85-000-square-foot expanse known as a polynya – the name for a year-round open-water area surrounded by sea ice.

Located in north Baffin Bay between Canada and Greenland, it creates a relatively warmer microclimate with melted freshwater, which triggers an abundant bloom of phytoplankton each spring.

The site attracts diverse species of fish, birds, walruses, narwhals, whales, seals and polar bears who come to feed, mate and rest. For several millennia, the polynya has also been a source of traditional food for local Indigenous peoples.

Scientists refer to this site as the North Water (NOW) polynya, while it is known among some Inuit in Canada and Greenland as Pikialasorsuaq. Whatever name is used, Moore wants to underscore its ecological importance.

“The Arctic is mostly like a desert – it's difficult for a lot of wildlife to survive," Moore said. “But the North Water is quite amazing, because it’s the most biologically productive ecosystem in the region … You can think of it as an oasis in the Arctic."

The Nares Strait region, including northern Baffin Bay (NBB); Smith Bay (SB); Inglefield Fjord (IF); Smith Sound (SS); Kane Basin (KB); Humboldt Glacier (HG); Kennedy Channel (KC); Hall Basin (HB): Robeson Channel (RC); and Lincoln Sea (LS). Blue lines show the approximate location of the North Water polynya. (Map: Scientific Reports)

The NOW is below the Nares Strait, a waterway separating northwest Greenland from Ellesmere Island, surrounded by the oldest and thickest sea ice in the world.

Each winter, ice arches up to 100 kilometres in length from along the northern and southern ends of the strait. They stabilize the ice for seven or eight months, preventing any breaking ice floes from traveling down into the NOW.

To understand how the warming Earth is affecting the region, Moore collaborated with two scientists from Environment and Climate Change Canada to study the ice arches. Their 2021 study found that thinning ice is causing these arches to collapse earlier each year.

“There’s been a lot of work suggesting that without the arches, the NOW will dramatically change,” Moore said. “That change would mean a reduction in productivity, fewer species in the region and just a general decline in the richness of the ecosystem.”

Recently, Moore partnered again with the same scientists to examine satellite data showing patterns of ice arch formation and disintegration each winter since 2007. They also developed weather prediction models to estimate how, in the absence of ice arches, winds will blow ice downstream into the NOW.

They found that when arches do not form, the presence of sea ice tends to be about 10 per cent higher than usual. However, despite variations in ice arch activity, biological productivity in the NOW has held steady.

Moore said this may be because the region’s strong winds push the ice into – and then out of – the polynya, leaving them no time to disturb the ecosystem.

“It’s kind of a good news story that the polynya appears to be more stable than people thought,” Moore said. “We can breathe a bit easier about the NOW for the next few years.”

But as climate change intensifies, the NOW could be at risk. As a critical habitat for so many diverse species, and a key contributor to the food security of nearby Indigenous communities, it needs to continue to be monitored, Moore noted.

“The underlying issue is that we’re still warming the planet up. And there are many other stresses on the environment and the animals in that region,” he said.

“If you go to a scenario where we lose all the ice in the Arctic, then the NOW won’t be there anymore.”

U of T grad student tracks 70 years of snow and ice data in the High Arctic

Christopher.Sorensen — Wed, 08 Mar 2023 14:53:13 +0000

U of T grad student tracks 70 years of snow and ice data in the High Arctic

Christopher.Sorensen Wed, 03/08/2023 - 09:53

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Brianna Lane, a master's student at U of T Mississauga, is developing an accessible method to monitor lake ice and snow levels in the High Arctic amid a changing climate (photo courtesy of Brianna Lane)

Tina Adamopoulos

Topic

Black Research Network

Arctic

Climate Change

Faculty of Arts & Science

Brianna Lane, a second-year master’s student studying physical geography at the ��Ƶ Mississauga, is developing an accessible method for snow and ice data quantification using ground-based trail cameras in the Central Canadian High Arctic – making vital research underway easier for experts to assess.

Working with Laura Brown, an associate professor in U of T Mississauga’s department of geography, geomatics and environment, Lane is monitoring lake ice and snow in the Central Canadian High Arctic in Nunavut.

Her research will provide insight into the historical changes in the region when compared with climate data from 1953 to the present day.

“If the air temperatures are getting warmer, then we will expect that the lake ice duration is shrinking – so less time that the lakes are staying frozen,” Lane says. “If it’s staying the same, that may just be an indication that nothing has changed in the area.”

Lane is one of five recipients of the 2022 Black Graduate Scholar Award in Geography and Planning. The initiative, a partnership between the Black Research Network and the university’s tri-campus Graduate Geography and Planning, recognizes the exceptional academic and professional achievements of Black graduate students.

Lane is conducting research on five lakes: Hunting Camp Lake in the Nanuit Itillinga National Wildlife Area; Resolute Lake, Small Lake, Plateau Lake and North Lake near the community of Resolute/Qausuittuq, Nunavut.

The lakes – each about one-square-kilometer – are located near the town of Resolute, one of Canada’s northernmost communities. Typically, the lakes are used by local communities for fishing and, when frozen, transportation.

In the Central Canadian High Arctic, lakes stay frozen for up to a 10-month period from September to June.

Students install a ground-based camera near Resolute, Nunavut (photo courtesy of Brianna Lane)

The ground-based cameras Lane is using allow researchers to determine how much of the lake is snow, ice or water. The cameras take pictures twice daily, which allows Lane to monitor when lake ice forms and melts, including the spatial distribution of the snow and the ice. Rather than manually reviewing images from the trail cameras, the method digitizes data. A Shallow Water Ice Profiler (SWIP) is also used to measure lake ice.

“Ground-based cameras provide a way for us to consistently monitor the lakes,” Lane says. “The field sites we are looking at are inaccessible and hard to get to. A lot of recent research is using satellite imagery, but the lakes that I’m looking at are small and it’s hard to distinguish what is happening on the lakes because the resolution isn’t great.”

There are two vital periods that Lane is measuring – the freeze-up and break-up of a lake. Lane explains that lake features such as size and depth determine the freeze-up period, while the break-up period happens when temperatures rise above 0 C and is also controlled by lake features.

With a surface area of 540 square kilometers, Lake Hazen, the High Arctic’s largest freshwater ecosystem and the world’s biggest High Arctic lake is rapidly responding to climate changes – experiencing warming and shorter lake ice coverage over the last 10 years.

Lane says there haven’t been dramatic changes at her research sites so far, but noted she is still sorting through data.

“In the past few years, there haven’t been any drastic changes,” she says. “We aren’t seeing that the timing is changing dramatically, which over a long period of time is what we expect with climate change and the warming temperatures.”

Researchers identify mechanism responsible for temperature and salinity 'staircases' in Arctic Ocean

Christopher.Sorensen — Wed, 28 Sep 2022 19:08:56 +0000

Researchers identify mechanism responsible for temperature and salinity 'staircases' in Arctic Ocean

Christopher.Sorensen Wed, 09/28/2022 - 15:08

Cutline

Understanding how temperature and salinity “staircases” form could shed more light on the causes and consequences of rapid Arctic sea ice loss amid climate change (photo by imagebear via Getty Images)

Topic

Graduate Students

Physics

Researchers at the ��Ƶ have identified the mechanism responsible for the formation of temperature and salinity “staircases” in the Arctic Ocean, resolving a mystery that has confounded oceanographers and climatologists alike for more than half a century.

Understanding how these vertical structures work promises to shed more light on the causes and consequences of rapid Arctic sea ice loss amid climate change.

“Our discovery of a new mechanism of hydrodynamic instability provides insights into the formation of staircase-like structures resulting from the mixing of warm salt water and cooler fresh water,” said Yuchen Ma, a PhD candidate in the department of physics in the Faculty of Arts & Science and lead author of a study published in Physical Review Fluids describing the findings.

“These structures were first observed in the late 1960s but the mechanism responsible for their existence has never been explained.”

Known as thermohaline staircases, these step-like variations of temperature and salt concentration are common in a wide range of regions of the global ocean.

A simulation depicts the strongly defined changes in temperature and salt that form staircase-like structures within the Arctic Ocean (image courtesy of Yuchen Ma and W. Richard Peltier)

The findings reported in Physical Review Fluids – which have attracted significant positive response from the research community – fully verify a previous analysis by the same authors published in the Journal of Fluid Mechanics in 2020 that documented the existence of this new hydrodynamic instability. The verification was accomplished by designing a series of direct numerical simulations of turbulence in the Arctic Ocean to better understand global ocean circulation.

“The ocean is typically thought of as a highly chaotic and turbulent environment, so it is striking to see such strongly defined layers of salt and heat within it,” says Ma.

The flow of heat out of the ocean into the overlying sea ice is strongly enhanced by the presence of thermohaline staircases. Thus, understanding the staircase formation process in the polar oceans is important for developing future global warming projections and informing efforts to mitigate sea ice loss.

“In this era of global warming, it is a well-recognized fact that the loss of Arctic Ocean sea ice cover is a critical aspect of this global process,” said University Professor W. Richard Peltier, of the department of physics who is a co-author of the studies and Ma’s PhD supervisor.

“While the extent to which staircase formation is contributing to this loss has yet to be quantified, we can certainly say that the ocean component of the climate models employed to make projections of the global warming process are not able to resolve the staircase formation process.”

The research builds on previous work that focused on understanding global ocean circulation under the ice age conditions from 30,000 to 70,000 years ago.

In the previously developed model of glacial climate, the rapid transitions from cold to warm weather were shown to be caused by an extensive “hole” in the sea ice cover of the North Atlantic Ocean resulting from heat flow out of the ocean into the sea ice. The magnitude of this heat flow was determined by the assumption that a staircase had formed in the ocean below.

Support for the research was provided by the Natural Sciences and Engineering Research Council of Canada. The computations on which the study is based were performed on the Niagara supercomputer cluster at the SciNet High Performance Computing facility at U of T, which is funded by the university, the Canadian Foundation for Innovation and the Province of Ontario.

Climate change slows reduction of methylmercury levels in Arctic: U of T researchers

Christopher.Sorensen — Fri, 19 Feb 2021 18:31:22 +0000

Climate change slows reduction of methylmercury levels in Arctic: U of T researchers

Christopher.Sorensen Fri, 02/19/2021 - 13:31

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Igor Lehnherr, a researcher at U of T Mississauga, assessed the build-up of methylmercury, a dangerous neurotoxin, in Lake Hazen, one of Canada’s northernmost lakes (photo by Igor Lehnherr)

Topic

Climate change may be slowing the reduction of methylmercury – a dangerous organic neurotoxin created by microbes that metabolize mercury – in Arctic waters despite a global movement to reduce industrial mercury emissions.

That is among the findings of Igor Lehnherr and his research team at the ��Ƶ after assessing the build-up of methylmercury in Lake Hazen, one of Canada’s northernmost lakes.

The study is published in the journal Environmental Science & Technology.

“Mercury pollution has gone down in the atmosphere,” says Lehnherr, an assistant professor of geography at U of T Mississauga. “We’re doing things to tackle it, but climate change is throwing things for a loop [because] it can actually undo some of the benefits from emission reductions.”

Methylmercury levels rise only indirectly from human activity. Burning fossil fuels, mining and other industrial processes release unmethylated mercury into the atmosphere. As the mercury settles into aquatic ecosystems, certain types of microbes metabolize it to form the much more dangerous methylmercury.

A “persistent organic pollutant,” Methylmercury becomes more concentrated as it moves up the food chain – from bacteria to fish, predators and people. It affects the nervous system and can also cause cardiovascular damage. The toxin is especially dangerous for pregnant women and for fetuses, babies and young children whose nervous systems are still developing.

While the area where the U of T team collected samples is not close to any northern communities, Lehnherr says the work is relevant for Indigenous people who hunt and fish for food.

“What we’re learning is not constrained to that location,” he says. “We put a lot of import on understanding mechanisms that affect methylmercury, so we can apply what we learn in one place somewhere else.”

Igor Lehnherr, an assistant professor of geography at U of T Mississauga, says the field work for his latest study spanned several seasons and involved collaboration with other research teams in order to expand sampling (photo by Igor Lehnherr)

Arctic methylmercury levels depend on a complex mix of factors, including industrial emissions, precipitation patterns, microbial numbers and activity, as well as changes in seasonal sea ice. The complexity, along with the remoteness of northern ecosystems, make Lehnherr’s work particularly challenging.

“The field work spanned a few seasons,” he says of his latest study. “Some years we were there in the spring when it’s all snow and ice cover, some years in the summer, some years for both. By combining efforts with other teams, we expanded the sampling. Arctic research by nature is fairly collaborative – we share costs, time and ideas.”

Igor Lehnherr and his research team take water samples through the ice (photo by Igor Lehnherr)

In general, methylmercury-producing microbes are more active in warmer environments, implying a direct correlation between global warming and increased toxicity. But climate change also has many other effects that can exacerbate, mitigate and further complicate the situation.

“Temperature in the Arctic also controls permafrost thaw. It affects the amount of precipitation by controlling cloud cover, sea ice cover, rates of evaporation and these kinds of things,” Lehnherr says.

Changing weather patterns also affect how much methylmercury builds up in specific isolated areas and how efficiently it flows from one lake to the next, creating more widespread problems. In the short term, Lehnherr says it looks as though reduced emissions have not fully translated into cleaner Arctic ecosystems. However, Lehnherr says it should not necessarily be interpreted as a sign that efforts to reduce mercury aren’t worth it.

“I mostly think it validates the ongoing efforts to reduce anthropogenic mercury emissions,” he says. “Countries have shown this is something they’re willing to take on. These results allow us to have reasonable expectations about how long it will take for mercury levels to go down and stabilize.”

Lehnherr also wants to reassure people in northern communities who may be concerned about the safety of their food supply.

“Whenever I talk about the risks of mercury and negative health impacts, I always stress that the benefits of consuming traditional foods vastly outweigh the risks of contaminants. Locally caught Arctic char has better nutritional value than dried goods and flown-in goods,” he says.

Lehnherr plans to continue his study of methylmercury in the Arctic region to get a better sense of the long-term impacts of climate change.

Ice arches holding Arctic's ‘Last Ice Area’ in place are at risk, U of T researcher says

Christopher.Sorensen — Tue, 05 Jan 2021 14:21:49 +0000

Ice arches holding Arctic's ‘Last Ice Area’ in place are at risk, U of T researcher says

Christopher.Sorensen Tue, 01/05/2021 - 09:21

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Sea ice in the Nares Strait as seen from a NASA P-3B turboprop during a 2013 survey flight (photo by Christy Hansen/NASA)

Topic

Factor-Inwentash Faculty of Social Work

Snugged up against the upper edges of the Canadian Arctic Archipelago and Greenland lies the oldest and thickest sea ice in the world, covering hundreds of thousands of square kilometres of ocean. Arctic sea ice grows and shrinks with the seasons, but this ice has so far lasted even through the warmest summers on record.

Scientists call this region “The Last Ice Area.” They say it could endure even after the rest of the Arctic becomes ice-free in the warmer months, providing a vital refuge for polar bears, walruses and other species that rely on sea ice to survive.

But recent research at the ��Ƶ Mississauga suggests the Last Ice Area may be in more peril than previously thought. In a recent paper published in the journal Nature Communications, Professor Kent Moore and his co-authors describe how this multi-year ice is at risk not just of melting in place, but of floating southward into warmer regions. This, in turn, would create an “ice deficit” and hasten the disappearance of the Last Ice Area.

“This very old ice is what we’re concerned about,” says Moore, who is in U of T Mississauga’s department of chemical and physical sciences. “The hope is that this area will persist into the middle part of this century or even longer. And then, hopefully, we'll eventually be able to cool the planet down. The ice will start growing again, and then this area can act as a sort of seed,”

Using satellite data, Moore has been studying ice arches that form along Nares Strait, a 40-kilometre-wide, 600-kilometre-long channel that runs between Greenland and Ellesmere Island from the Arctic Ocean into Baffin Bay.

Moore had already observed warning trends in earlier research that indicated this ice is increasingly on the move.

“The Last Ice Area is losing ice mass at twice the rate of the entire Arctic,” Moore says. “We realized this area may not be as stable as people think.”

His most recent analysis of satellite data says the problem may be getting even worse. The arches along Nares Strait that historically have held the Last ice Area in place have become less stable, according the study.

“The ice arches that usually develop at the northern and southern ends of Nares Strait play an important role in modulating the export of Arctic Ocean multi-year sea ice,” he and his authors write.

“The duration of arch formation has decreased over the past 20 years, while the mass of ice exported through Nares Strait has increased.”

The ice arches form as the weather cools. Multiple ice floes converge as they funnel into the relatively narrow strait, forming huge structures that look like bridge supports turned on their sides. The arches span the full width of the passage, blocking the movement of multi-year ice from north to south.

“It's really quite profound to imagine a 100-kilometre-long barrier of ice that remains stationary for months at a time. That's more than twice as long as Louisiana’s Lake Pontchartrain Causeway – the world’s longest continuous bridge over water,” Moore says. “It speaks to the strength of ice.”

But that strength is diminishing. Ice arches only form for part of the year. When they break up in the spring, ice moves more freely down the Nares Strait. And that breakup is happening sooner than in the past.

“Every year, the reduction in duration is about one week,” Moore says. “They used to persist for about 200 days and now they’re persisting for about 150 days. There’s quite a remarkable reduction.

“We think that it’s related to the fact the ice is just thinner and thinner ice is less stable.”

The impact of losing the Last Ice Area would extend far beyond photogenic species like polar bears. Ice algae flourishes below the ice and in brine channels that run through its cracks and fissures, supplying carbon, oxygen and nutrients that underpin an elaborate but vulnerable ecosystem.

In 2019, the Canadian government designated a section of the Last Ice Area as the Tuvaijuittuq Marine Protected Area. Tuvaijuittuq is Inuktut for “the place where the ice never melts.”

Moore remains hopeful that his analysis of the Nares Strait ice arches will focus more attention on this important region of the Arctic. However, he says action targeted specifically at preserving the arches won’t be sufficient to solve the problem. A global solution is needed.

“The scale is so huge and the region is so remote,” he says. “The only thing we can do is cool the planet down. Then the arches will hopefully naturally form again.”

Inset: Images of the ice arch that formed at the southern end of Nares Strait in 2020. The upper image shows the arch holding back the ice while the lower image shows the ice streaming southwards after the arch collapses (Sentinel-2 satellite imagery courtesy of the European Space Agency)

Virginia Isaac, a U of T Social Work grad, is helping Nunavut residents quarantine during COVID-19

Christopher.Sorensen — Tue, 17 Nov 2020 14:31:58 +0000

Virginia Isaac, a U of T Social Work grad, is helping Nunavut residents quarantine during COVID-19

Christopher.Sorensen Tue, 11/17/2020 - 09:31

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Virginia Isaac, who is graduating with a master's degree in social work, is currently supporting Nunavut residents who must quarantine at an isolation centre in Ottawa before returning to the territory (photo by Dale Duncan)

Topic

Nunavut

Virginia Isaac, a community social worker with the Government of Nunavut, is working out of Ottawa these days as she supports returning residents who must complete a 14-day quarantine in the territory’s isolation hubs.

The isolation hubs, which also exist in Winnipeg, Edmonton and Yellowknife, serve as entry points to Nunavut and have played a key role in helping it avoid the first wave of COVID-19.

Yet, while the strategy has been successful – the territory’s first case was identified Nov. 6 – Isaac says the experience can take its toll on residents.

“My job is to welcome new guests to the hubs, help them with their adjustment to quarantine, and do whatever I can to ease their stress during their stay,” Isaac says. “Isolation can be difficult, whether you’re travelling alone or managing the pressures of having your spouse and children living together in one room.”

Isaac, who is graduating this fall from the ��Ƶ’s master of social work program in the Factor-Inwentash Faculty of Social Work, does daily check-ins to monitor guests’ needs, which include meals that cater to their cultural and dietary requirements, safety, support and mental health services. Guests at the isolation hubs are reminded to adhere to public heath regulations, which include wearing a mask, practising social distancing, staying in their bubble and washing their hands frequently.

“When people are struggling with the demands of quarantine, I remind them that they’re making a positive contribution to preventing the spread of the virus,” Isaac says. “Remembering the broader value and purpose of their sacrifice often helps.”

As for her own safety, Isaac also takes a big-picture perspective.

“I’m very proud to be among those making a difference in people’s lives during the pandemic,” she says.

Isaac says her education and experience have served her well in her current role. As an advanced standing student, she pursued the faculty’s social justice and diversity field of study.

“A central emphasis in the program is recognizing clients’ unique life experiences and treating them as equal partners,” she says. “This is the way I approach my relationship with every new guest at the hub.”

Isaac was a social worker with the Government of Nunavut for more than six years before studying for her master’s degree at U of T. When she arrived in the territory in 2012, it was her first time in Canada’s Arctic. “It was a bit shocking at first in terms of the vast and untamed landscape,” she says. “But I took the time to get to know the culture and traditions of the Inuit, and their close relationship to the land.”

She says she soon saw similarities with her own childhood on the Caribbean island of Saint Lucia, where people in her rural village also have strong ties to their surroundings.

Isaac was a teenager when she immigrated to Toronto, which she now considers home. But she spent several years in British Columbia studying, working and vounteering with an intercultural and immigrant aid society – work that inspired her to becoming a social worker. There, she forged strong connections with local Indigenous communities. Before moving to British Columbia, Isaac worked for several years in health care in Toronto.

“I’ve always had a strong interest in learning about and working with Indigenous Peoples in Canada,” she says. “My own experience as a Black woman and that of my ancestors is very parallel in terms of marginalization, poverty, discrimination and stigma.”

For her master of social work practicum, Isaac worked at a community organization serving the Black community in Toronto, where many of the clients were coping with such issues.

Isaac is not sure what she’ll do once the isolation hubs are no longer needed. But she says the uncertainty doesn’t bother her.

“My ambitions are many, but wherever I am and whoever I’m working with, I approach things with an open mind and a passion for helping people.”

U of T researchers, students travel to high Arctic to conduct atmospheric research

Christopher.Sorensen — Mon, 28 Sep 2020 15:46:58 +0000

U of T researchers, students travel to high Arctic to conduct atmospheric research

Christopher.Sorensen Mon, 09/28/2020 - 11:46

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The PEARL Ridge Lab is located on Ellesmere Island at Eureka, Nunavut, about 1,100 kilometres from the North Pole (photo by Ramina Alwarda)

Ellen Eckert

Topic

Faculty of Arts & Science

Arctic

Physics

Ellen Eckert is a post-doctoral researcher in the Faculty of Arts & Science’s department of physics and a member of the department’s Earth, atmospheric and planetary physics group. Below she shares a first-person account of what it was like to conduct research at the Polar Environment Atmospheric Research Laboratory (PEARL).

For just over two decades, students and post-doctoral researchers working with the ��Ƶ’s Kimberly Strong and Kaley Walker have traveled to Eureka, Nunavut, in the Canadian High Arctic each spring to make unique measurements of atmospheric trace gases.

Strong is chair of the department of physics and Walker is a professor in the department. Together with department colleagues and researchers from Dalhousie University and York University, the team had another extraordinary opportunity last winter to work at the Polar Environment Atmospheric Research Laboratory (PEARL).

The three-week campaign yielded valuable measurements obtained using a wide variety of instruments. The measurements are used to validate data gathered by satellites and to investigate a variety of atmospheric phenomena. This year, the team observed record low levels of Arctic ozone and is currently analyzing these results to understand why conditions were so different.

But why go to this remote location? At 80 degrees north, PEARL is 1,100 kilometres from the North Pole. And why at this time of the year when temperatures can plunge to -50 C before windchill?

At the 80 degrees north sign on the way from Eureka to PEARL (photo by Pierre Fogal)

PEARL is in a sweet spot for atmospheric research for several reasons: it is located in an area of the world that is crucial for understanding the global atmosphere; and there are no other stations anywhere nearby, meaning there’s a lack of data for polar regions.

Another reason is that satellites like the Canadian-led Atmospheric Chemistry Experiment frequently pass over this area, so data collected during these campaigns can be used to make sure the satellites are working properly.

Ice crystals in the atmosphere result in spots of light on either side of the sun, a phenomenon known as a sun dog (photo by Ellen Eckert)

Also, campaigns at this time of year coincide with the transition between the season in which the sun never rises to the season in which it never sets. This transition only takes about seven weeks at Eureka. Since some of the instruments operate at night and some need sunlight to operate, this time of year is ideal for comparisons between the different instruments to determine if there are biases between their measurements.

Team members joined PEARL site manager Pierre Fogal in the radio room (photo by Ramina Alwarda)

This year’s team included myself, graduate students Ramina Alwarda, Kristof Bognar, Beatriz Herrera Gutierrez and Tyler Wizenberg, as well as post-doctoral researcher Ali Jalali – all from the department of physics. They were joined by U of T senior research associate and PEARL site manager Pierre Fogal, operator John Gallagher, research associate Alexey Tikhomirov from Dalhousie and Professor Emeritus Tom McElroy from York University.

When the team arrived at Eureka this year, the sun was only above the horizon for about two hours. When they left, daylight hours had exceeded nine hours. The team lived at Environment and Climate Change Canada’s Eureka Weather Station, where they enjoyed the hospitality of the permanent staff, amazing food and recreational activities.

To do their research, the team drove about 20 to 25 minutes to the PEARL Ridge Laboratory each day, weather permitting, to take measurements. They also performed maintenance and repair tasks when necessary. This work can be interrupted by poor weather such as storms, so the team had to always be aware of the meteorological conditions.

Working in the high Arctic is challenging but very rewarding. Frigid temperatures mean that seemingly simple tasks such as tightening screws and adjusting components need to be done quickly and carefully, with fingers well protected.

The cold takes its toll on the instruments, but the lab is well stocked with tools and spare parts so things can often be fixed on site. On rare occasions, specific spare parts are shipped north and instruments are sometimes brought south for major repairs.

This year’s campaign was a success, as the team was able to get all the instruments running and to keep them collecting data that will provide insight into Arctic atmospheric phenomena. In addition to measuring ozone, the team also monitored atmospheric trace gases associated with ozone destruction, which allows them to better understand the chemical and dynamic processes behind the event.

The team encountered several members of the local wildlife community during this year’s trip (photos by Ellen Eckert, Guillaume Gamache and Ramina Alwarda)

Visiting Eureka is a unique and fantastic experience – not only for the scientific research, but also for the mind-blowing scenery and the wildlife. This year, the team was lucky to encounter a couple of foxes close to the Ridge Laboratory, a musk ox that had made itself comfortable around the Eureka weather station and even a pack of wolves that strolled by the station on the last day of the campaign.

Predator loss, climate change combine to devastate Alaskan reefs: U of T study

Christopher.Sorensen — Thu, 17 Sep 2020 15:40:39 +0000

Predator loss, climate change combine to devastate Alaskan reefs: U of T study

Christopher.Sorensen Thu, 09/17/2020 - 11:40

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Massive reefs, built slowly over centuries to millennia, are now rapidly eroding because of overgrazing by sea urchins amid predator loss and climate change (photo by J. Tomoleon)

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Alaska’s living reefs – which house an entire ecosystem – are collapsing thanks to climate change and the disappearance of sea otters, new research published in the journal Science reveals.

Weakened by warming waters and increased acidity, the centuries-old reefs are being ground down by sea urchins, whose population has exploded following the functional extinction of their predator, the Aleutian sea otter.

“It’s basically a top down relationship,” says Jochen Halfar, a paleoclimate and paleontology professor at the ��Ƶ Mississauga who studies sea floor algae and was one of the study’s authors.

He says that, with the loss of their original food source due to hunting, orcas now prey on sea otters, seals and other smaller marine animals. The adaptation has, in turn, led to the removal of sea otters from the system and their main food source – sea urchins – are now proliferating unchecked.

“It’s amazing the amount of sea urchins on the sea floor,” Halfar says, noting there were sometimes layers of urchins stacked on the seabed when he was diving. “I had to use knee pads to get down to the sea floor so the sea urchins wouldn’t puncture my dry suit.”

Bioeroded alga with numerous sea urchins of different sizes grazing on the dead tissue (photo by Jochen Halfar)

Sea urchins prefer to eat kelp, but with so many dining on the once-abundant underwater forests, they’ve had to turn to an alternate food source: the coralline algae that form the reef.

Attached to the sea floor, the algae grow over thousands of years, one calcified layer after another, much like tree rings, with the living tissue on the surface. Halfar says the massive reef-like structures cover the Aleutian sea floor at a depth of between 10 to 30 metres.

This isn’t the first time the sea otter population has plummeted and sea urchin numbers have spiked. Halfar explains that, during the fur trade in the late 1700s and early 1800s, sea otters were hunted almost to extinction. By 1840 the population had declined so much that hunting them was no longer economical.

Yet, the reefs were nevertheless able to hold their ground against the urchins.

What makes the loss of sea otters so devastating this time around are changes to water temperature and acidity.

Oceans are warming and, according to Halfar, the acidity is rising with increased concentrations of carbon dioxide from burning fossil fuels.

To test the impact of temperature and acidification, the researchers put live algae and urchins in controlled environments that replicated preindustrial and current seawater conditions, plus those expected at the end of the century. Halfar says they found that the density of the calcified algae skeleton decreased and the urchin bites were deeper with higher levels of C02 in the water.

“The sea urchins, which might not have been able to attack the algae so easily maybe 50 years ago when it was colder and less acidic, are now able to inflict deeper bites,” Halfar says.

Experiments were performed to test how climate change has altered the intensity of sea urchins grazing on algae (photo by D. Rasher)

He explains that algae are built for grazing. They are able to repair their wounds and regenerate tissue. But if the bites are deep, large or numerous, the algae can’t heal.

Researchers found that lethal grazing under current conditions was about 35 per cent to 60 per cent greater than in preindustrial conditions. The rates grew by an additional 20 per cent to 40 per cent under future conditions. The results confirm that climate change has recently allowed urchins to breach the algae’s defences, pushing the system beyond a critical tipping point.

“You get what’s called bioerosion,” Halfar explains. “The entire surface of the algae is eroded and the algae ultimately die.”

The coralline algae play a vital role in the Aleutian Islands’ marine ecosystem. Different species depend on the algae substrate to live in, find shelter and reproduce.

“These structures house millions of organisms. If these reefs disappear, we’re changing the entire ecosystem – bottom up,” Halfar says.

An end of whaling could see orca shift back to their original diet, leading to the return of sea otters, which would help reduce sea urchin populations and mitigate the bioerosion that’s taking place.

That, however, is only part of the puzzle.

“Obviously temperatures are going to keep increasing,” Halfar says. “And as long as we use fossil fuels, acidity is going to keep on increasing.”

The research was funded by the U.S. National Science Foundation and the Natural Sciences and Engineering Council of Canada.

The unexpected link between the ozone hole and Arctic warming: U of T expert

Christopher.Sorensen — Wed, 19 Feb 2020 14:59:47 +0000

The unexpected link between the ozone hole and Arctic warming: U of T expert

Christopher.Sorensen Wed, 02/19/2020 - 09:59

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Temperatures are warming faster in the Arctic than anywhere else in the world. Water and sewer pipes in Iqaluit, Nunavut, are cracking during the winter as the ground shifts (photo by Sean Kilpatrick/CP)

Karen Smith

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