Micro Plastics, Massive Problem

Sifting, sorting, finding and thinking: An insight into research on microplastics in the marine environment

We’ve all seen those iconic images of plastic trash draped over reefs, or photos of dead or injured marine animals entangled or struggling in carelessly discarded debris. And who can forget the viral video of mantas swimming through a sea of floating plastic trash? You don’t need to be a genius to see that plastic is having a massive effect on our reefs and marine life.

However, the invasion of microplastics in our ocean, tiny plastic particles smaller than five millimetres, is much harder to see.

It’s also hard to trace where these microplastics come from and where they end up, and the impacts these are having on our reefs and oceans.

Nevertheless, microplastics are the focus of a group of dedicated researchers at James Cook University (JCU) and the Australian Institute of Marine Science (AIMS), and microplastic research is more difficult than it sounds.

THE CHALLENGE

Microplastics can be really hard to accurately isolate and count. If you’re looking for them in the environment, you need to strain seawater, sift through sediment, or look inside animals to find these tiny particles and fibres. Imagine a bucket of beach sand, or the slimy, partially digested contents of a fish or turtle’s stomach. How do you properly separate out all the tiny plastic fragments from these contents?

Well, JCU and AIMS researchers have developed new techniques of chemically digesting, separating, and identifying microplastics from difficult

materials such as turtle stomachs.

The process includes using infrared spectroscopy, a tricky technique where samples are blasted with infrared light. The researchers then interpret the resulting absorption, emission and reflection spectra to work out what type of plastic it is.

SENSING THE SCALE

Testing the protocol on turtles, the research team found paint chips and synthetic fabric particles in turtle stomachs1. It’s a big problem. Another research team that included JCU scientists found plastics in the stomachs of every single one of 102 turtles examined, the most common being fibres from clothing, tyres, cigarette filters, and maritime equipment such as ropes and fishing nets2. While small amounts of microplastics may not be enough to block the digestive system, they could be leaching toxic chemicals into the animals that ingest them, an issue that needs to be studied.

And it’s not just turtles: Even fish such as the iconic coral trout

(Plectropomus spp) have been found to have plastic in their guts3. It’s not just divers and conservationists who are worried about this; fishing industry representatives have called for more research on the effects ingested plastics could have on fish health and reproduction.

The team found paint chips and synthetic fabric particles in turtle stomachs

CONSIDER THE CORALS

While microplastics may not be big enough to block a sea turtle’s gut, they can be big trouble for corals. Researchers running lab experiments at JCU have found that some corals eat microplastics almost as readily as they eat plankton, and these ingested particles became wrapped in digestive tissue and can potentially disrupt the polyp’s ability to digest food4. And it’s not just microplastics; larger plastic debris hurts corals, too.

Researchers surveyed 159 reefs from Thailand to Australia between 2011 and 2014, and estimated that

11.1 billion items of plastic are entangled on reefs across the Asia-Pacific. Apart from mechanical damage, entangled plastic can greatly increase a coral’s chances of becoming diseased5. With the amount of plastic items entangled on reefs projected to increase by 40 percent by 2025, this is a major problem.

When you consider the scale and magnitude of the plastic problem, it’s easy to get caught up in the doom and gloom. However, this new research is shedding light on all the different ways plastic pollution is affecting the marine environment, information that can be used to drive change.

And things are changing. Single-use plastic bags are being increasingly banned around the world, and public awareness of the issue appears to be exploding. As ocean users and advocates, we need to do our part in preventing plastic pollution. We’ve heard it all before – refuse, reduce, reuse, recycle – but this mantra for responsibility isn’t any less true just because it’s becoming mainstream. And as far as impact goes, while reducing individual waste may not seem like much, there are an awful lot of us on this planet.

As the saying goes “‘It’s just one straw,’ said billions of people.” Think about it.