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Investigations of the Depletion of Ozone and Mercury over the Arctic Ocean (OASIS-CANADA) Brochure

Every year when the sun rises in the Arctic spring, the potent greenhouse gas, ozone and the toxic chemical, mercury disappear from the air near the ground along the coast of the frozen ocean. It is thought that this is caused by a combination of sunlight, snow and ice, and the low temperature over the frozen ocean.  With the OASIS project we hope to learn what truly causes the disappearing act” of these two polluting chemicals, and whether the disappearing mercury ends up in the marine food chain.

OASIS is an international research program that studies how chemicals move between the Ocean, the Atmosphere, the Sea Ice and the Snow pack. OASIS-Canada is the Canadian part of OASIS-international.

OASIS Ocean Atmosphere Sea Ice Snowpack:


OASIS Canada location of research sites | Photo: ECAnyone who looks at a map of the world can easily see that the Arctic is located far away from the pollution created by cities, factories and farms. It is therefore often assumed that the Arctic is a pristine environment free from pollutants. In reality we now know that this is not the case. any harmful chemicals that are foreign to the natural environment are found in the Arctic. We need to know from where these chemicals come, how they find their way to the Arctic and if the Arctic environment will tolerate these chemicals. Moreover, the effects of climate change in the Arctic are no longer theoretical, changes are happening today and these changes will also affect how these polluting chemicals travel around the Arctic and where they end up. The goal of the OASIS scientific research program is part of this enterprise. In particular, such questions will be addressed as how chemicals like ozone and mercury in the air behave over the frozen Arctic Ocean, and what the resulting impact on the Arctic will be.

OASIS is an international research program that studies how chemicals move between the Ocean, the Atmosphere, the Sea Ice and the Snow pack. OASIS-CANADA is the Canadian part of OASIS-international.


Every year when the sun comes up in the Arctic spring, the potent greenhouse gas OZONE and the toxic chemical MERCURY disappear from the air near the ground along the coast of the frozen ocean. It is thought that this is caused by a combination of sunlight, snow and ice, and the low temperature over the frozen ocean. With this project we hope to learn what truly causes the "disappearing act" of these two polluting chemicals, and whether the disappearing mercury ends up in the animals living in the marine world. Moreover, we hear yearly that the ice cover over the Arctic Ocean is decreasing, and we don't know what this will mean for this disappearing act. We can not answer that question until we know how it happens.

Until now all studies were taking place at the coast by the Ocean. The project will take these studies over the ocean onto the ice.

Our planned research will take place in the following areas:

  • On the Beaufort Sea on the icebreaker CCGS Amundsen
  • On the Beaufort Sea and Hudson Bay using special ocean buoys left out on the ice to travel by themselves
  • Over most of the Arctic Ocean on a drifting French sailboat named TARA
  • Over the Arctic Ocean at an ice camp near Barrow, Alaska
  • On Hudson Bay, accessed from Kuujjuarapik/Whapmagoostui, Quebec


Our plan is to take samples of air from the research sites during the activities described under (Field Research Studies for OASIS-CANADA) and use the results from these samples to findout what causes ozone and mercury to disappear from the surface air.


Once we understand what makes the ozone and mercury disappear we can, with the help from other scientists, answer these broader questions:

  • Does the mercury that disappears from the air end up in the Arctic food chain?
  • There is pollution in the Arctic spring coming from down south. What will happen to this pollution if there is less ozone in the air?
  • What will happen to the ozone and mercury if the ice goes away with global warming? Will this make things better or worse?


Circumpolar Flaw Lead Study (CFL)

The Canadian Research Icebreaker CCGS Amundsen | Photo: Environment CanadaWe are participating in the CFL study on board the Canadian Amundsen ice breaker so we can collect air samples to measure mercury and ozone right on the Beaufort Sea. There will be many scientists on this ship collecting other types of samples and we will work with them to meet our common objectives.

OOTI (Out On The Ice)

The OOTI (Out On The Ice) sled and instruments to measure chemicals in air, ice and snow on the Arctic Ocean| Photo: Environment CanadaAn Arctic sled has been outfitted with sophisticated hi-tech equipment to measure how fast chemicals move between the air, and the snow and ice. This sled will sit right on the ice and samples will be collected and analyzed on the spot. To make this possible all the instruments on the OOTI sled are battery operated and samples can be taken when nobody is present. To
help us keeping an eye out on what is going on, the instruments are supervised via a Web camera. These pictures, and the analysis results are sent directly by long range radio contact to a building at the coast, or to the icebreaker. The sled will be moved from one spot to the next close to open water and measure for a day or two at a time.

Ozone-buoys or (O-buoys)

Schematic diagram of the O-buoy, an ocean buoy that will  be deployed in the frozen ocean to measure concentrations of ozone, carbon dioxide and other chemicals in the air over periods of up to one year over the ice in Hudson Bay and the Beaufort Sea | Photo: D. Perovich, CRREL, (O-buoy consortium)We will design and construct ocean buoys that house instruments to measure year-long concentrations of ozone, carbon dioxide and other chemicals. These
O-buoys will be released into the ocean at several spots and left to collect air samples as they travel with the sea ice and ocean currents. The data will be retrieved via satellites and the instruments will be powered with solar panels and batteries.

COBRA (Combined iodine and bromine release on the arctic atmosphere)Drilling into sea ice in Hudson Bay near Kuujjuarapik/Whapmagoostui, Quebec for COBRA(combined iodine and bromine release to the atmosphere) | Photo: L., Carpenter, University of York, UK

COBRA is a research project led by British scientists at Kuujjuarapik/Whapmagoostui, Quebec and we will join them on this study. The goal of this project is to understand how chemicals in sea salts (iodine and bromine) from the water in the Hudson Bay affect the disappearance of chemicals like ozone and mercury from the air. Moreover, scientists from Montreal plan to determine what happens with mercury once it has disappeared from the air.


The French sailboat Tara drifting in the Arctic Ocean since 2006 to sample ozone in the air | Photo: G. Redvers, TARAWe are sampling ozone in the air from the French sailboat TARA, which has been drifting in the frozen Arctic Ocean since September 2006. We will also collaborate with many other OASIS scientists in a study called "OASIS-09" which will take place at Barrow Alaska, and the nearby US Navy Ice camp. Other venues in the planning stage include participation on the cruise of the Swedish Icebreaker Oden (summer 2008), and the North Pole Environmental Observatory (NPEO - spring 2009).

Download this brochure as PDF: (Download free reader)

OASIS International website

BACKGROUNDER - Environment Canada-led Arctic Ocean research expedition to study air pollutants

GATINEAU, February 26, 2009 – Environment Canada is leading an expedition of 10 Canadian scientists onto the frozen Arctic Ocean to learn more about how pollutants move from the air, to the ice and ultimately into the northern ecosystem. 

The research is taking place near Barrow, Alaska, as part of one of the last major expeditions during the International Polar Year (IPY).  The Canadian component of this international expedition, OASIS-Canada (Ocean-Atmosphere-Sea Ice-Snowpack), will focus on mercury, a chemical affecting the health of northern residents. It will also focus on ground-level ozone, which is both a smog pollutant and a greenhouse gas. 

“We’re trying to find out how these chemicals get there, how the Arctic tolerates their intrusion and what possible impacts there will be to the ecosystem should the Arctic Ocean melt,” says Jan Bottenheim, Senior Research Scientist with Environment Canada and lead on the OASIS-Canada project.

In the late 1980s, Environment Canada scientists were the first to discover that unusual chemical reactions take place on the surface of the Arctic ice and snow during the early spring sunrise in the Polar Regions.  These reactions remove all of the ground-level ozone and most of the mercury from the air.  This seems to speed up the movement of mercury and other air pollutants from the air into the snowpack and the ocean, where they can readily enter the ecosystem, and eventually the human population.  The impacts of this process on the Arctic ecosystem are unknown, however recent evidence indicates that climate change is already having a significant effect.

In Alaska, the Canadian scientists will use a small, sophisticated, fully-automated chemical laboratory, developed by Environment Canada researchers, which can operate in the extreme Arctic conditions, where temperatures can plunge below - 40° C.   The “Out On The Ice” lab or OOTI, consists of several sensitive measuring instruments, mounted on a specially-built sled.  The sled will be drawn onto the frozen ocean by snowmobile where it will record detailed information about the movement of air pollutants and other chemicals from the air into the Arctic ice and snow. 

“While the conditions are tough to work under, the environment is breathtaking,” says Sandy Steffen, Environment Canada Research Chemist. “The air is dry and crisp and when the sun is out it reflects brightly on all the ice and snow across the frozen Arctic Ocean,” she added.

The Canadian study, funded by the Canadian IPY Federal Program Office, is part of an international research campaign organized by the OASIS program.  The Canadian effort includes scientists from Environment Canada, York University, the University of Toronto, and McGill University.   The study also includes researchers from American and European universities and from the National Center for Atmospheric Research in Boulder, Colorado. 


Project lead : Dr. Jan Bottenheim, senior research scientist, Environment Canada

Websites : 

OASIS - CANADA 2009 Video

International Oasis Project


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