There May Be A Million Times More Microplastics In The Oceans Than Previously Estimated


Tom Hale

Senior Journalist

clockDec 5 2019, 14:26 UTC


The world has become increasingly aware of our planet’s plastic problem over the past decade. Research has consistently shown that plastic can be found in every part of the environment, from the deepest parts of the ocean to the Arctic snow and the tops of mountains.

However, it's now looking like the problem could actually be far worse than previously thought. 


New research from the Scripps Institution of Oceanography at UC San Diego has found there could be up to a million times more pieces of plastic in the ocean than previously estimated.

As reported in the journal Limnology and Oceanography Letters, the researchers estimate the ocean is contaminated by 8.3 million pieces of microplastics per cubic meter of water, while previous studies have detected just 10 pieces per cubic meter. 

Jennifer Brandon from the Scripps Collections measured quantities of microplastics found in the bodies of salps. UC San Diego

That's quite a jump. So, what accounts for this huge difference? This new estimate was reached through a novel method that can pick up on smaller pieces of plastic than before. Some previous surveys – such as the global inventory of microplastics from 2015 – have sampled water using nets, which only captures plastics as small as 333 micrometers (one-third of a millimeter). Using a newly refined approach, this recent research was able to collect plastic as small as 10 micrometers. 


“For years we’ve been doing microplastics studies the same way [by] using a net to collect samples. But anything smaller than that net mesh has been escaping,” Jennifer Brandon, biological oceanographer and study author, explained in a statement.

To detect smaller pieces, the researchers employed the help of salps, strange jelly-like creatures that live in the upper layers of the marine environment. Salps eat microscopic phytoplankton by straining water through their internal feeding filters as they propel themselves through the water. Unfortunately, this also means they ingest tiny microplastics, which end up in their bodies. Combined with seawater samples from the California Current, the new study dissected salps (also taken from the same area) in order to predict levels of microplastics in the environment. 

The consequences of these findings remain unclear, simply because the wider effect of microplastics on human health is uncertain.


Earlier this year, the World Health Organization (WHO) suggested the effects of microplastics on our bodies probably aren’t too severe. However, increasing evidence is suggesting that microplastic contamination does harm some aquatic and terrestrial animals.

Despite the WHO's somewhat muted response to microplastics, they have called for further investigation into microplastics in the environment and their potential impacts on human health. More research is certainly needed, but it's fair to guess that the presence of microplastic is unlikely to be good news for our planet or its inhabitants. 

  • tag
  • pollution,

  • marine life,

  • plastic,

  • environment,

  • microplastic,

  • salp,

  • marine environment