Ninety-Nine Percent Of The Waste We Dump In The Sea Is Missing But This Is Not A Good Thing
Stories about the large amounts of plastic polluting the surface of the ocean—millions of tons, according to estimates, have repeatedly hit the headlines over recent years.
But when a 400-strong team set out to comprehensively measure the amount of human-produced waste they found a relatively paltry 40,000 tons. This doesn’t mean that the initial figures were wrong; it means that “99 percent of the plastic that we have in the ocean” is missing. And the theories as to where it has gone are troubling.
Spending nine months dredging nets across the Indian, Pacific and Atlantic oceans, the Malaspina Circumnavigation Expedition took almost 200,000 samples from 313 sites (at depths of up to 6,000 meters) and found that while there are five large areas of plastic waste—such as the Great Pacific Garbage Patch—much of it is breaking up into smaller pieces and being disseminated widely across the world’s oceans.
“Ocean currents carry plastic objects, which split into smaller and smaller fragments due to solar radiation,” said Andrés Cózar, a researcher from Spain’s University of Cadiz and one of the team’s leaders. “Those little pieces of plastic, known as microplastics, can last hundreds of years and were detected in 88 percent of the ocean surface sampled.”
According to the report published by Proceedings of the National Academy of Sciences website, plastic pollution found on the ocean surface is dominated by particles smaller than 1 cm in diameter, commonly referred to as microplastics. Exposure of plastic objects on the surface waters to solar radiation results in their photodegradation, embrittlement, and fragmentation by wave action. However, plastic fragments are considered to be quite stable and highly durable, potentially lasting hundreds to thousands of years. Persistent nano-scale particles may be generated during the weathering of plastic debris, although their abundance has not been quantified in ocean waters.
These findings worry the researchers, who say that marine animals are most likely eating the plastic fragments. This is problematic for two reasons: There is the possibility that toxic ocean pollutants are attaching themselves to the plastic, which fish then eat and passed up the food chain (e.g., your latest sushi dinner); and vast amounts of plastic, via fish feces, are being deposited on the ocean floor and causing damage to the ecosystem.
The pathway and ultimate fate of the missing plastic are as yet unknown. Further, the abundance of nano-scale plastic particles has still not been quantified in the ocean, and the measurements of microplastic in deep ocean are very scarce, although available observations point to a significant abundance of microplastic particles in deep sediments, which invokes a mechanism for the vertical transport of plastic particles, such as biofouling or ingestion.
The report warns:
Because plastic inputs into the ocean will probably continue, and even increase, resolving the ultimate pathways and fate of these debris is a matter of urgency.
Source: Vocativ / Plastic Oceans / YouTube