MICROMÉGAS

Approximately 10 million tons of plastic are dumped into the oceans each year. And 200 million tons of these same plastics are already in the oceans.

Microplastic pollution of surface waters is only one aspect of a much larger phenomenon – ocean plastic pollution – affecting all of the world’s seas. The scientific community is just beginning to understand the extent of this problem and the associated challenges to maintaining the good ecological status of marine ecosystems.

In order to consider solutions to this multiform ecological disaster, reliable quantitative and qualitative data are still needed.

Acting at the source? Yes, but which source? Limiting losses along rivers, in cities? Changing our mentalities and our consumption patterns?

One thing is certain: the global production of plastic shows no sign of abating. To date, humans have generated more than 8 billion tons of plastic.

The Micromegas* program, in partnership with the Oceaneye association, aims to measure the concentrations of plastic pollution in a region of the world far from large urban centers but which is no less affected by this global scourge.

All along the tour of the Arctic, it consists in taking regular samples of surface water to evaluate the content of microplastic particles (from 0.3 to 5 mm in size) as well as meso plastic (greater than 5 mm).

The samples collected are sent to Oceaneye for analysis and exploitation of the results. The objective of Oceaneye is to map plastic pollution in different regions of the world.

* The name was inspired by Voltaire’s tale and refers to the idea of “micro-waste” carrying “mega stakes”.

Microplastics are all types of plastic fragments smaller than 5mm. These particles can be the result of a natural degradation process of a larger plastic debris (a drink bottle for example) or intentionally produced in this form. This is the case of microfibers found in modern clothing or microbeads widely used in the cosmetics and hygiene industry.

The most visible plastic pollution, in the form of macro-waste, is that which affects the coasts. The pollution of surface waters by micro-waste is beginning to be the subject of numerous field study campaigns such as the one conducted jointly by the Pacifique Foundation and the Oceaneye association around the world from 2015 to 2019 as part of The Ocean Mapping Expedition.

But field data remains patchy and highly disparate from ocean to ocean, and almost non-existent in the Arctic. Even less is known about the pollution of the ocean floor, where 60% of plastics are concentrated, particularly in the form of micro-particles resulting from the progressive fragmentation of macro-waste or originally produced in this form, as is the case of plastic microbeads widely used by the cosmetics industry.

Similarly, we still know little about the behavior of plastic and how certain particles aggregate chemical elements present in the oceans. With what consequences on the food chain?