[If I interpret this press release correctly, I believe it claims: Ocean plastic pollution is less than 1% of what we’ve been screaming for decades, but is still as big a problem as ever! MAYBE EVEN BIGGER!~cr]
The missing plastic sink in the ocean: away from the rivers
The mysterious plastic tub in the ocean
UNIVERSITY OF BARCELONA
Research news
PICTURE: A MICROPLASTIC UNDER THE MICROSCOPE. View more CREDIT: CEFREM / UPVD
Plastics are a growing problem for natural ecosystems around the world, and especially for our marine and freshwater environments. Rivers are the main source of plastic pollution as they are estimated to bring millions of tons of plastic into our oceans annually through poor land-based waste management. The problem is that estimates of plastic flowing out of rivers are tens to hundreds of times higher than the amount of plastic floating on the ocean’s surface. So where does all this plastic from rivers actually go – is there a plastic sink missing somewhere in the ocean? Are the estimates correct?
In an article published today in Science, Dr. Lisa Weiss and her colleagues from the Center of Education and Research on Mediterranean Environments (CEFREM), a joint research laboratory between the University of Perpignan (UPVD) and the French National Center for Scientific Research (CNRS), and a team of researchers from a number of research institutions in France and from the University of Barcelona in Spain show that current river river ratings are overestimated by two to three orders of magnitude compared to previous estimates. This would explain why a large amount of microplastic appears to be disappearing into a mysterious “plastic sink” in the ocean.
However, these results do not suggest that plastics are less of a problem than previously thought. In fact, through their analyzes, the researchers found that plastics remain on the ocean surface much longer than previously thought – which further exacerbates the effects of plastic pollution on natural systems.
The mysterious plastic tub in the ocean
Rivers are the main source of plastic discharges into the oceans. According to current estimates, the floating stocks of microplastics on the ocean surface – from ten to one hundred tons – are only a small fraction of the millions of tons that are emitted by rivers every year. This imbalance has led to the “plastic sink” hypothesis, according to which the amount of microplastic in the “plastic sink” plus the plastic on the surface would be equivalent to the amount that is believed to be discharged from rivers into the sea.
According to the study’s lead author, Dr. Lisa Weiss from the CEFREM laboratory at the University of Perpignan: “The in-situ data we now have for microplastics in rivers, compared to early empirical model studies, enabled us to put together a robust database that we were then able to analyze, to get a more reliable estimate of the amount of microplastic discharged from rivers into the sea. This process has revealed several significant methodological errors in previous flow estimates. When we corrected these errors, we found that the estimates of global river flow are two to three orders of magnitude lower than previously thought. In addition, we found that the average retention time of microplastics on the surface of the oceans can actually be a few years instead of just a few days as previously estimated. “
According to the study’s lead author, Dr. Lisa Weiss from the CEFREM laboratory at the University of Perpignan: “The in-situ data we now have for microplastics in rivers, compared to early empirical model studies, enabled us to put together a robust database that we were then able to analyze, to get a more reliable estimate of the amount of microplastic discharged from rivers into the sea. This process has revealed several significant methodological errors in previous flow estimates. When we corrected these errors, we found that the estimates of global river flow are two to three orders of magnitude lower than previously thought. In addition, we found that the average retention time of microplastics on the surface of the oceans can actually be a few years instead of just a few days as previously estimated. “
“We can now confirm that the search for the missing ‘plastic sink’ is over as the missing plastics were found by correcting the river flow estimate,” says Professor Miquel Canals, head of the Consolidated Research Group on Marine Geosciences at the University of Barcelona and one of them of the study co-authors.
The new study identifies key methodological errors that have led to inaccurate assessments of rivers and the total mass of microplastics discharged from rivers into the sea on a global scale. In particular, errors were made due to a systematic overestimation of the average microplastic particle weight in river samples; from the integration of incompatible data obtained through various sampling methods; and from ratings based on the relationship between microplastic flows and the MPW (Missmanaged Plastic Waste) index
.A fight without borders to preserve the oceans of our planet
Marine litter knows no borders and has reached the remotest corners of our oceans and seas. According to Dr. Wolfgang Ludwig, director of the CEFREM laboratory and co-author of the study, “will only have a chance of winning the fight against microplastic pollution if we target the sources in which microplastic waste is produced”. . We have to act on a human level. We have to change our consumption habits, manage our waste better and do this on a global basis. “
“Our study shows that marine microplastic pollution is not only coming from developing countries – with little to no waste management, as one might think – but also from countries with well-established waste management systems. If we were to stop microplastics from entering the sea from rivers today, the amount of suspended particles and their harmful effects on marine ecosystems would last at least several years, ”said Dr. Ludwig.
Next Steps…
The impact of plastics on the marine environment is an emerging area of scientific research that has spawned a large number of scientific publications in recent years. Still, we are only just beginning to understand how plastics circulate in the oceans. There are many plastic size classes, oceanic compartments, and land-to-sea transfer processes that urgently require further research to properly assess inventory sizes and exchange flows between compartments. In the future, we will need the best science available if we are to have a chance to win the battle against plastic pollution. To do this, the scientific community must work together to overcome past inertia, correct mistakes, and work with common protocols and guidelines to provide the best possible decision-making support to protect our oceans and seas.
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From EurekAlert!
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