Microplastics may affect how Arctic sea ice forms and melts

Nicolas-xavier Geilfus Research Associate, University of Manitoba

Plastic pollution in the oceans has become an important societal problem, as plastics are the most common and persistent pollutants in oceans and beaches worldwide. In the common imagination, plastic waste is often associated with bottles drifting in the ocean, fishing gear washing up on beaches or plastic bags that turtles mistake for jellyfish and eat.

But those larger particles are just the tip of the iceberg. Smaller particles are also an important part of the problem. Plastic particles smaller than five millimetres are called microplastics. They may originate from deliberate design (such as cleaning agents or personal care products), breakdown of larger pieces of plastic or microfibers from textiles.

Arctic impact

If people assume the Arctic environment is unaffected by what humans discard into the oceans, they are wrong. The pristine waters of the Arctic Ocean are under silent threat by those particles as they drift along with the ocean currents over long distances.

Microplastic concentrations in the Arctic are expected to increase rapidly due to increasing freshwater input and the intensification of shipping traffic and resource development activities. Given the exceptional vulnerability of Arctic marine ecosystems, there is an urgent need to assess the distribution, pathways and fate of microplastics in the Arctic.

In a recent paper published in Marine Pollution Bulletin, we studied whether and how microplastics could be incorporated within the sea ice structure. Microplastics within sea ice could impact the absorption of incident solar radiation. This affects sea ice albedo — how the ice reflects solar energy — one of the key properties of sea ice in terms of regulation of the heat exchange between the ocean and the atmosphere.

Measuring albedo

Changes in sea ice albedo would have strong consequences on the annual cycle of sea ice growth and melt. To test our hypothesis, we set up a microcosm study at the [Sea-ice Environmental Research Facility at the University of Manitoba], an outdoor pool where we can grow sea ice.

Two sets of 12 microcosms, measuring one cubic metre, were made using galvanized aluminium pipes as frames and cotton bed sheets as walls. The first set was used to measuring light levels, while the second set was used to collect sea ice samples. We manually added microplastic particles to monitor their incorporation into the sea ice as it grew. We used four different concentrations: control (no particles added), low, medium and high (about 120, 380 and 1,200 particles per litre, respectively).

We used a dye called Nile red to follow the microplastics as the ice froze. Under a fluorescent light, dye caused microplastics to glow, allowing us to see how sea ice concentrates microplastics within its structure and, once incorporated, how those particles remain in the ice matrix.

We found high concentrations of particles at the sea ice surface, due to the particles’ buoyancy and to the rapid formation of ice crystals, trapping the particles as ice coalesces into a firm ice layer. Although microplastics did not affect the sea ice growth rates, distinct changes in sea ice albedo in response to medium and high concentrations of microplastics microcosms.

To determine the real-world impact of our observations, we also measured microplastic concentrations from various sea ice samples collected in the Gulf of Bothnia (Baltic Sea). We observed microplastic concentrations similar to what is observed in the Arctic Ocean (8 to 41 particles per litre), but much lower than the concentration in our microcosms experiment. At those concentrations, we do not expect microplastic incorporation to have any impact on sea ice albedo.

For regions with higher microplastic concentrations, or should microplastic concentration increase, we expect seaice properties might change. These changes would affect most notably albedo, but also photochemical and photo-biological processes occurring in sea ice, such as light availability for algae living at the bottom of the ice cover, with potential impacts on the base of the Arctic food web. DEAR EDITOR, Disclosure statement

Nicolas-xavier Geilfus receives funding from the Swedish Postcode Foundation supported by International Union for Conservation of Nature, with additional financial support from the Canada Research Chairs program and the Canada Foundation Innovation

As a supporter of the CAQ education plan, allow me a word on Peter Black's editorial: "CAQ looking at compromise on elected anglo school boards" (Sept. 23, The Record)

The editorialist makes reference to three individuals of the English speaking community: former Liberal MNA Geoff Kelley, and present Liberal MNAS David Birnbaum and Jennifer Maccarone.

Now, let's reel back about three / four years ago when the Quebec Liberal Party created draft Bill 86 which called for the ditching of elected boards (same idea as the CAQ plan now).

MNA Geoff Kelley supported the draft bill and MNA David Birnbaum felt so strongly about the bill, the Montreal Gazette published his opinion piece : "Bill 86's school board reforms are no threat to the anglophone community." (Dec. 16, 2015)

Meanwhile, Jennifer Maccarone, head of the Quebec English School Boards Association fought against the bill and won and the bill collapsed.

No wonder the Liberal Party appears to be in a state of disarray concerning our public school system.

On the other hand, the CAQ has remained constant , since 2011, regarding school board governance: school boards will become service centres to better serve our kids.

Lastly, contrary to the thought expressed in the last paragraph of Mr. Black's editorial : the CAQ will not use the "notwithstanding clause" against "its own anglophone minority to make changes to school board governance."

It is not allowed.

CHRIS EUSTACE PIERREFONDS, QC

The informative September 23rd editorial “CAQ looking at compromise on elected anglo school boards” by Peter Black contained a factual error regarding the possible use of the so-called notwithstanding clause.

The English-speaking community’s right to control and manage our education system derives from jurisprudence on section 23 of the Canadian Charter of Rights and Freedoms. Happily, section 23 of the Charter is not subject to the notwithstanding clause, which applies only to sections 2, and 7 to 15 of the Charter.

The CAQ Government cannot use the notwithstanding clause to override our right to control and management of our school system even if they wanted to.

SINCERELY, R COPEMAN EXECUTIVE DIRECTOR - QESBA