Trash litter levels on the Arctic ocean floor are rising fast, with concentrations at one deep-sea station rising 20-fold in just a decade, according to new research from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research.
The research was performed by observing the ocean floor using the towed camera system known as the OFOS (Ocean Floor Observation System) at depths of around 2,500 meters. As such, the approach can by nature only be limited in scope. After 12 years of data gathering, the researchers “extrapolated the litter density to a larger area.”
To start things off with their actual observations — 89 pieces of litter were seen in a total of 7,058 photographs taken over the 12-year time period. What’s “impressive,” though, isn’t the total figure but rather the speed at which litter levels in the region have been increasing.
“The result: an average of 3,485 pieces of litter per square kilometre in the monitoring period (2002 to 2014). Further, there has been a clearly recognizable increase in the past few years: when the team calculated a contamination level of 4,959 pieces of litter per square kilometre for 2011 in an earlier study, they hoped it was a statistical outlier. But the levels have continued to rise since, reaching a new peak of 6,333 pieces of litter per square kilometre in 2014,” the press release notes. “The situation is particularly dramatic at the network’s northern station, called N3.”
At N3, “the amount of litter rose more than 20-fold between 2004 and 2014,” commented Tekman. “If we consider the findings for the northern research area in the marginal ice zone, the data for 2004 indicated 346 pieces of litter per square kilometre. Ten years later, the number had risen to 8,082. The level of contamination is similar to one of the highest litter densities ever reported from the deep seafloor, in Cap de Creus Canyon off the eastern coast of the Iberian Peninsula.”
In general, most of the litter observed was either plastic or glass. While the plastic litter could have originated almost anywhere, the glass litter very likely originated from nearby — since glass litter generally sinks immediately rather than drifting. What that means is, as indicated by other sources as well, increasing ship traffic in the region (as the ice cover extent diminishes) is resulting in increased litter levels.
The situation with the plastic litter is potentially more complicated, though. Here’s more on that:
“Still, it is extremely difficult to draw any firm conclusions on the origin of the plastic litter, since it often covers a considerable distance before reaching the seafloor. In most cases, the scientists can’t determine the origin on the basis of photographs alone. While it is clear that the Gulf Stream transports plastic litter into the Arctic with the Atlantic water masses, the authors also have a new theory as to why litter is accumulating in the Fram Strait: their results indicate a positive relationship between litter density and the summertime expansion of sea ice.
“If we’re right, sea ice could entrain floating litter during ice formation. During warmer periods, the ice breaks up and is transported to the south into the Fram Strait with the Transpolar Drift, releasing entrained litter into the survey area when it melts,” explained deep-sea biologist Dr Melanie Bergmann, a co-author on the study. “To date we’ve assumed just the opposite, since we viewed the ice as a barrier to litter contamination.”
Something that remains an unknown with regard to the plastic litter, though, is what is “breaking down” some of the litter. There aren’t notable levels of UV light making it to the floor of the Arctic Ocean, and the low temperatures there aren’t supportive of disintegration, yet the researchers have still observed “more and more small bits of plastic” over recent years, so the situation is somewhat opaque.
Clearly, some (or a lot?) of the plastic pollution isn’t breaking down, though, as the researchers actually “rediscovered” a piece of plastic in 2016 that they had first seen in 2014. And it was barely changed.
Bergmann: “Running into this same piece of plastic twice with hardly any changes to it is a vivid reminder that the depths of the Arctic are at risk of becoming a depot for plastic litter. The well-hidden accumulation of litter on the deep ocean floor could also explain why we still don’t know where 99% of the marine plastic litter ends up.”
If you’ve actually read through this whole article, you might be wondering right now why I covered this for CleanTechnica. I think that the reason should be obvious, though — whether the ~7.5 billion people in the world right now use electric cars or not, the current way of life is an arrangement without a future. It’s a way of life that is rapidly invalidating itself. The news above is just one amongst countless ways that the shortsightedness of modern life is being demonstrated.
Images via AWI
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