Discover More: Plastics in Nature
Plastics are everywhere. These (incredibly useful) human-made materials can now be found polluting ecosystems across the globe, and traces can also be found within the bodies of various organisms, including us. Discover more with Linnean Learning.
Published on 18th May 2022
The Discover More series is a collection of animations, blogs and interviews exploring a wide variety of topics to enrich your appreciation of the wonderful natural world that we are a part of. There are seven topics which will be released over several months, and the animations are best viewed via Instagram @LinneanLearning.
The first plastic was invented in the late 1800s, and in the 1900s a huge variety of other plastics came into being, becoming an essential material to our industrial societies. Plastics were, at first, considered a wonder material. Made by humans, the fact they could be easily manipulated gave them their name; plastic means “capable of being shaped or molded.”
These materials had many potential properties; they didn’t decay and were flexible, durable, easy to clean, lightweight, heat-resistant, and electricity-resistant. This meant they went on to replace naturally-sourced materials, and themselves created entirely new products which otherwise hadn’t been possible.
But what was once considered wonderful has now become one of the biggest ecological problems of this century. The fact that they are so durable and resistant to decay means truly getting rid of plastic has proved difficult, and when they do break down, they create microplastics and even nanoplastics which disappear into the environment. This pollution presents issues for organisms and ecosystems, the world over.
This week, as the UK completes its first Big Plastic Count, we are taking a closer look at plastics in nature. We’ll be sharing an interview with expert Alex McGoran, who looks at the effect of microplastics on different species of aquatic animals in the River Thames, in London. Read on for a couple of our examples of plastics in nature below, watch our short animations on Instagram, Twitter, or TikTok, and enjoy our interview with Alex on those platforms or as a transcript (see below).
Plastic everywhere! Microplastic pollution has been found in some of the most remote habitats on Earth. In 2009, scientists took ice cores from east Antarctica and, even there, where human habitation is minimal, microplastics from a number of different sources were identified. This means to some extent, microplastics are likely a part of almost every ecosystem on the planet. What long-term effects this might have, we do not yet know.
Plastic stressing you out? You aren’t alone! Nanoplastics can slip into cells, affecting their ability to function properly, and in the waterflea, Daphnia pulex, nanoplastics have been shown to affect their stress responses, growth, and reproduction! They’ve also been shown to stunt the growth of ryegrass and earthworms.
Trees: the environmental disaster of the past! When wood first evolved, it presented a similar problem that plastic does today - no organisms knew how to break it down. Plants first evolved the sturdy and waxy structures of wood so that they could grow tall and stable into trees. The rest of life didn’t quite know what to do with this new structure. Over millions of years, the emergence of trees would massively alter ecosystems, both by this new way of living, but also by their lack of decay - dead trees would collect without breaking down. This built up and fossilised over time, becoming compressed, and turning into what we know as coal. This period of 60 million years became known as the Carboniferous, or “coal-bearing,” period.
Eventually, mushroom fungi developed the enzymes needed to digest this material and break down dead trees, and thus the formation of coal decreased dramatically, once again shifting the ecosystem. In similar ways, a few organisms have found ways to break down plastics, but if we don’t do something about their relative abundance, it is likely that other many organisms will evolve ways to break plastics down.
Yum, plastic! We can already see evolution happening in response to the availability of plastic. Scientists recently discovered a bacteria that can eat plastic. In 2016, scientists in Japan tested different bacteria near a bottle recycling plant and found one that could digest particular kinds of plastic, like those used in single-use drinks bottles. The bacteria, Ideonella sakaiensis, did this by secreting a special enzyme, called PETase, which was able to break down the notoriously strong chemical bonds in polyethylene terephthalate (PET) plastics into simpler molecules, which the bacterium could then absorb.
Eat faster! Over several years, other scientists found they were able to engineer this enzyme with another bacterium, so that the reaction happens six times faster than it did in nature. This could represent a great tool in the arsenal in tackling plastic pollution. However, one thing to consider is the possibility that this or other bacteria may evolve and start consuming plastics that humans use in medical or infrastructural contexts; we are very reliant on plastics in many ways; how will we respond if the plastics we use throughout our societies start to break down more readily?
An interview to an expert in plastic ecology
We spoke with Alex McGoran from Royal Holloway and the Natural History Museum on the subject of plastics in the environment.
I'm a PhD student. I'm a researcher at the Natural History Museum and Royal Holloway University. I am looking at plastics, both macro plastics, the large pieces of litter you can recognise; your coffee cups and crisp packets - all the way down to micro plastics, which are these really small pieces of plastic, which are much easier to be eaten by the animals that live in the environment. And for me, that environment is specifically the Thames River, in London.
How did you first get interested in ecology or biology?
I've always liked animals, I've always been fascinated by them, and almost preferred animals to people in a way. When I was younger, I wanted to be a vet, until I worked out what vets do most of the time, which isn't just playing with the puppies. it's harder, and there's a lot more sad bits to that job. So that deterred me. But I stuck with animals from then on. So it was always sort of been in the back of my mind -- not that I necessarily thought I was going to go and be an ecologist -- I probably didn't know what ecologist was, you know, you get to university and suddenly go, “Oh, these are what they actually do. And these, you know, are the jobs I could take.” But for me, it was always a toss up between art, maths and science, and then science won out in the end.
Could you tell us a little bit about what an ecologist might do?
So it's quite a diverse range of jobs, because it's really looking at the environment and the interaction between all of the things in that environment. So you can be as specific or as broad as you like. For example, you could be looking at a field. One of the things that we had to do during training was you'd look at a field, it was a farmer’s field, and you had to look at the crops and think about how to make the farmer happy. But also to add in, you know, biodiversity corridors and things to keep nature happy. But you could also be very specifically looking at just one pond on that farm and all the little microorganisms and really small invertebrates that live in that pond. And then you could probably go even smaller and look at biofilms. So things like microbes living on the surface of the plants. So it's really all encompassing career where you can look at as big or small as takes your fancy, really.
It often seems plastics are fundamental to our day to day, they are everywhere, but you could maybe describe to us what a plastic actually is? And what a microplastic is specifically?
Plastics are a range of synthetic, so manmade, and semi synthetic, which is a sort of modified organic compound. And they can almost be anything, you know, they can be flexible, like a rubber piping, or they can be really rigid, like a plastic tub. And they make up as you say, so much of everything that we're using every day, you know, from coffee cups, to water bottles, and plates and tables, you know, there's all this plastic in so many different places. And it's one of these amazing materials that can be used for almost anything, and that's why it's great. But then microplastics are sort of why this product is also bad. So in the same way, it's good that it lasts a really long time, and it's really strong. Once it's in the environment, it lasts a really long time. And it's strong and it doesn't go away. So the same pro is also a con and really your plastic isn't bad, but how we use it and how we dispose of it is what it is bad.
So microplastics are either pieces of plastic made to be really small, or are fragments of these larger bits of plastic. So it could be a carrier bag that has broken up or it could be a microbead that used to be in cosmetics, for instance. And really the thing that sort of defines it as microplastics sort of slightly counterintuitive to the name micro is anything smaller than five millimetres in its longest dimension, which means you're anything smaller than a grain of rice. typically micro would mean less than one millimetre. So it's a little bit of an unusual name for the category of plastic we've chosen.
Could you talk a little bit about your own research?
I'm looking at mostly microplastics. But also large pieces of litter, as I said, things like coffee cups and crisp packets. So I look at the Thames. And the idea is to look at local plastic pollution. Rivers are a pathway to the ocean, so will end up in the ocean. But so much of the time we think of plastic pollution, we think of, you know, seals entangled in fishing nets, or turtles eating carrier bags, or having straws up their nose. And whilst those are really important, and charismatic animals that get the message across, it can often feel like, that's a problem that's too far away, or it can't be my fault, because it's all the way over there. Whereas looking at a river and going, “No, this is our back doorstep, this is how we treat our local environment.” And then that goes out there. It's not just somebody else's problem, because it's so far away. And so the idea is to have that outreach aspect to it, but also answer important scientific questions, which is to see how much plastic is eaten by different levels of the food web. So looking at shrimp, which are then eaten by fish, which are then eaten by seals or porpoises in the river, and seeing if you can look at the different levels, and whether there's a difference in the type of plastic or whether there's an accumulation.
So pesticides are a really good example of accumulation. So I think, DDT, I think they still teach it in schools, where it was sprayed on crops to get rid of insect pests, and the insects would eat it. But it would only be a really small dose, but then you'd have a small bird come along, that would eat the insects, but really several insects and get a slightly higher dose. And you ended up with a bird of prey eating that small bird and having a really high dose. And that having a really big impact on their reproductive success and their fitness. And plastics accumulate in a similar way, you could have one intention, eating one piece of plastic, and then 50% of fish eating three or four pieces of plastic, all the way up to seals, which could be having huge amounts of plastic in their stomach. And so that's where my project is looking at. Trying to address whether there is that difference in plastic, but also looking at macroplastic, because as sad as it is, if we go fishing with a net to catch the animals in the river, we can't not catch plastic. So all of that stuff is coming up in the net. So it's almost a sort of accidental project that side of it, because in an ideal world, I just get the 30 fish that I want to look at. But instead I'm there sifting through wet wipes and sanitary products and crisp packets, and... I make my job sound so glamorous!
What are you discovering in your research?
So rather unsurprisingly, at this point, we're finding that pretty much every animal we look at not necessarily every individual, but each group, each species will be ingesting plastic. So it's quite sad. But obviously at this point, with all we know about plastic, it'd be very surprising to have an animal that isn't encountering plastic in at least some part of its, yeah, every day life.
It seems more and more people are becoming ecologically aware, particularly young people at the moment. Is that also your feeling kind of on the ground?
Definitely. There's a lot more people now that are aware. I mean, as I said, you know, five years ago, nobody knew what microplastics were. And now everybody knows what microplastics are. And I think it's the good, the positive thing. Obviously, it sounds all doom and gloom, because there's people, you know, older than I am that like all that have never heard about the environment before. Why is it an issue now? Obviously, as we know, it's always been an issue. It's just people listening now or people are willing to speak up now. But it's so good to know that the next generation or the next couple of generations are really passionate, because then you know, you're at least leaving it in safe hands and that hopefully, there will be change because people want to make a change. So it's a nice rewarding feeling to have that many positive young people.
There are many positive moments where you see things are improving, where we're maybe getting to grips with the problem, because it can kind of it can sometimes, as awareness grows, so does the sense of scale of the problem. And it can, you can sometimes get into a defeatist mindset. Then there are a little moments where you're like, “Ah, yes, we're going somewhere, and we're doing something, and it's actually, there is kind of possibility and hope.”
Yeah. So I think, for all of this research, there's sort of lots of little positives. So one being that everybody is more engaged. Now, people are much more aware. And, you know, people come up and say, “How can I make a change? How can I make it better?” You know, and even if it's just a couple of people using a reusable water bottle, that will make a huge amount of difference for the number of water bottles they use in their entire lifetime, for instance. So it's, I guess, mainly look at the silver lining, like, okay, it feels like a small difference. But if you make that little change, actually, that'll be a huge change after one or two or three or four years, it builds up. And then once you've made that little change, what have you made another little change? And so, I mean, that's the one thing I'd always say is that it might feel like you can't make a difference. But really, you can, I guess that's the point of highlighting the local pollution is that if we stop it in the river, then it's not going out to sea. And then the other thing would be to just look at how much policy and industry has changed. Because we're more aware, and because of all that research, microbeads and plastic straws, and
you carrier bag levies and deposit return schemes for plastic bottles wouldn't be implemented if we hadn't done the research. And if people like David Attenborough and all of these young activists hadn't just made a lot of noise and said, “Look, this is wrong. Let's change it.” So it's also about you're using your voice and you're complaining and saying, like, “this is wrong, but here's what we could do to fix it, or here's a way to make it better."
Are you taking part in The Big Plastic Count? Find out more about how to get involved here.