What the new study about ocean plastics tells us – Part 2 “Where is all the plastic gone?”

 

“Little is known about the transformations of plastics in seawater, including the time scales of degradation and its ultimate sinks. Weakened by UV radiation, chemical degradation, wave mechanics and grazing by marine life, plastics fragment into smaller and smaller pieces; …”

 

Global budgeting exercises find less plastic debris on the ocean surface than expected.

 

Any global estimate of total accumulated floating microplastic is only about 1% or less of the amount of plastic waste, which could potentially enter the ocean from land sources per year.

 

The decay could actually happen really fast. Plastic resins break down quite easily, they could even break into tiny, undetectable sizes. Through that they’ll loose their buoyancy and sink to the sea floor.

 

Another substantial part could have been actually ingested by sea birds. Digested and grinded, the particles either stay in their bodies or are deposited in even smaller particles.

fishplastic750_MEriksen
Credit: M Eriksen, 5 Gyres Institute

Same rule applies to Myctophid fish species, who account for as much as 65% of all deep-sea fish biomass). They are suspected to hold 12– 24 thousand metric tons of microplastic. Knowing this, the fear arises that all the fish combined could imply a reservoir comparable in size to the sea surface.

 

As much plastic in fish than on the sea surface?

 

Digest this and stay tuned for the next post!

 

Source: http://iopscience.iop.org/article/10.1088/1748-9326/10/12/124006/pdf

 

 

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