Plastic Soup a Hard Meal to Swallow

This is a guest post by Nicole Mertens. 

A few weeks ago, I was walking down a beach on the Mornington Peninsula. It has been many years since I visited this beach, but having recently made the move back to Melbourne it was a pleasant and nostalgic experience. Strolling past colourful bathing boxes, occasionally dipping my feet into the crystal blue water, enjoying the sunshine… it was perfect, but for one little thing. Well, lots and lots of little things.

I’m talking about plastic debris.

As we walked I couldn’t help but pick out colourful shards of plastic amongst the sand. The little lids from sushi sauce bottles and flashes of silver film from chip packets long dead. At first glance this beach was pristine; white sand littered only with colourful shells for as far as the eye could see. But up close was a different story, and it’s one shared by most urban beaches in our country and across the world.

Chances are you already know about coastal and marine debris, and in particular the impact plastic litter has on our marine life. Recently, news that a beached whale in Norway had over 30 plastic bags in its stomach reached outlets worldwide. Scientists concluded that the animal was starving as it simply could not eat any real food, and speculated that the bags may have been mistaken for squid. Sadly, this is not an isolated incident. Aside from whales, many marine turtles unwittingly fill their stomachs with plastic bags, which also do a very good job of imitating jellyfish.

The green sea turtle is one marine species that fills their stomach with plastic bags resembling jellyfish. Image: Cathy Cavallo

The green sea turtle is one marine species that fills their stomach with plastic bags resembling jellyfish. Image: Cathy Cavallo

But plastic fragments and microplastics (pieces of plastic less than 5mm in size) are just as dangerous. Microplastics can be mistaken for scraps of algae or fish eggs. Apart from the risk of ingestion, many plastics can entangle marine life and can even release harmful chemical compounds (such as the endocrine disruptor BPA) into the surrounding waters (or intestines) as they start to degrade.

Conventional plastics are not biodegradable. That is, they are not broken down by living organisms; instead they photodegrade, slowly breaking down into their smaller, petrochemical-based components through exposure to light. Given that we have only been mass-manufacturing plastics for less than 200 years and that it is estimated it will take over 650 years for a plastic water bottle to break down in the environment, it is no wonder that our oceans are filling up with plastics.  A recent study estimated that there are 5.25 trillion particles of plastic floating on the world’s oceans, weighing a total of nearly 270, 000 tonnes. And that’s just at the surface.

If we want to stop plastic accumulating in our oceans we need to know where it’s all coming from. Marine debris surveys allow researchers and volunteers to sample the number, weight and types of debris along our coastlines. It shouldn’t shock you by now that plastics make up more than 80% (and over 90% in some cases) of all marine debris recovered from our beaches. According to the CSIRO, the vast majority of plastic on Australian beaches is derived from local sources, making its way out to sea via rivers, creeks and stormwater systems. This goes to show that it is we, the everyday consumers, who are having the biggest impact.

Once plastics and other litter enter the stormwater system, they are destined for the coast. Image: Nicole Mertens

Once plastics and other litter enter the stormwater system, they are destined for the coast. Image: Nicole Mertens

So, what can be done?

Well, ongoing monitoring is important, as it can help shape policy. Results comparing Australian states show that their cash for containers scheme is keeping plastic drink bottles out of South Australian waterways. If you want to help in a hands-on way, you should keep an eye out for calls for volunteers to conduct marine debris surveys with both government and non-government organisations and community groups. Otherwise, the Tangaroa Blue website allows you to register and enter your own data from your local beach (using their free survey resources) onto the Australian Marine Debris Database.

Scientists are trying to find solutions too. Like their first iterations, some consumer plastics are now made from cellulose (plant fibres) and are therefore actually biodegradable. Innovations such as this acknowledge our society’s reliance on the convenience of plastic, but also our responsibility to reduce its impact on our natural environment. As consumers, I think we can also find a middle ground - it may not be possible for a busy household to go zero waste, but we can all make small adjustments for the better.

Choose less plastic packaging where possible, reuse plastics where you can, and recycle what you can’t reuse. Reduce, reuse, recycle - and in that order (remember, recycling is more efficient than making things from scratch, but it does still use resources and create emissions). The last, simple request I can make is that when you walk past plastic rubbish on the footpath or in the gutter, pick it up. It might not be “your” mess, but it’s still you that has to deal with it further down the line, whether it’s through the sad reminder of our carelessness on an otherwise beautiful beach or the increasing impact on our marine life as plastic becomes harder and harder to avoid.  


Nicole Mertens

Nicole is a marine biologist who has spent the last five years engaging school children and community members in environmental education and conservation. She is interested in exploring how citizen science can be used as a tool to benefit both researchers and the broader public.


Banner image courtesy of NOAA.