Podcast: How plastic pollution may harm marine life

Plastic rubbish on a beach

30 September 2014 by Richard Hollingham

This week in the Planet Earth podcast, Tamara Galloway, Matt Cole and Ceri Lewis of the University of Exeter talk about their research on the effects of fragments of plastics from food packaging, drinks bottles, and even facial scrubs, on marine wildlife.

To assist those who find text-based content more accessible than audio, a transcript of this recording is available below.

Richard Hollingham: This time in the Planet Earth podcast, fishing for plastics. I'm Richard Hollingham and with me here at their lab at the University of Exeter are Tamara Galloway and Matt Cole who are studying microplastics pollution at sea and we're going to hear Matt's audio diary from onboard ship or onboard yacht in just a moment but, Tamara, give us the background to what you are investigating. What are you looking at?

Tamara Galloway: Well, my research focuses on marine pollution and in terms of marine pollution you tend to think of the more obvious things like crude oil and oil spills on the beach, but another thing that you will always see if you go to the beach is plastic - plastic pollution on the beach, or plastic floating in the sea surface and our research is focusing on what harm that plastic might be doing to marine life.

Richard Hollingham: And talking about microplastics - you've got some examples here of various bits of plastic that end up in the ocean. Show us the sorts of things. Is this some stuff you have found in sands... was this just on a local beach?

Tamara Galloway: This is. This is from a beach at Whitsand near Plymouth and what you can see here is we've got small fragments of plastic that have broken down from larger items.

Richard Hollingham: They almost look like pebbles there. So what's that? That's a purply colour, what do you think that is?

Tamara Galloway: That's a red fragment. It looks like a piece of packaging material. So the majority of things when we actually try and track back where they've gone from they've come from packaging, food packaging or drinks bottles or other things that are used to transport things and released off into the environment and they start to break down.

Richard Hollingham: You've also got, curiously on here, a selection of shower gels and facial scrubs - let's not identify who they are made by - but here is a vivid pink one, a raspberry and blackberry facial scrub. What's the problem with this?

Tamara Galloway: Well the problem here is that many of the plastics that we find in our research are things that have actually been made to be of a small size. So this is a facial scrub and it's got tiny pieces of plastic in it to help with exfoliating your skin and when these are washed down the sink they go into the sewage system and then they end up in the sea, and that's where we can find them on the beach. This other piece of plastic you can see here is actually called a nurdle and-

Richard Hollingham: That's a lovely word isn't it? It's like a little pellet, a little bead.

Tamara Galloway: It's like a little bead and they are also most like little pearls and you will find these on many, many different beaches around the UK or around the world - just about any beach you look at you will find these little nurdles and this is the way that plastic is transported around the globe before it's used and produced into something else.

Richard Hollingham: So that would have got in the sea from, what, a container that had gone overboard or something like that.

Tamara Galloway: A container that had either gone overboard or it has been spilled while it was being filled up and these plastics because they are small and they float they are sorted out by the waves and they are washed back onto the beaches and that's where we find them.

Richard Hollingham: Now, Matt, you've been on expedition to gather plastics at sea, and this was somewhat unusual. It wasn't a big ship you went on, it was a small yacht and this was off the coast of Maine in the US.

Matt Cole: Yes that's right. We collaborated with a group called The Rozalia Project. They are a non-government organisation that have a mission to try and clear up and educate people about marine plastic litter. So we flew in a very small plane from Boston to Rockport in Maine and from there we boarded onto the American Promise which is their 60-foot yacht, so very different to your typical research vessel.

Richard Hollingham: Okay, so let's have a listen to how you and your colleagues got on.

Ceri Lewis: Okay, so are you two on the bow ready to deploy. Let's go ahead and drop them.

Hi, I'm Dr Ceri Lewis, I am a marine biology lecturer at Exeter University and I am out here on the Rozalia Project Cruise with Matt and Steph looking at the marine plastic debris in the Gulf of Maine.

This is actually quite a unique opportunity to do some science under sail. Most oceanographic data is collected from large research vessels with lots of equipment and lots of space to do the science. We are on a 60-foot yacht which is wonderful in that we're at the mercy and the tides and currents in much the same way as the plastics that we're trying to study are and so it makes us feel much more in tune with the environment that we're trying to study but it also comes with quite obvious challenges in that we have very limited space and not a lot of power to do the science that we need so we're having to be quite ingenious with some of the techniques that we're using. For example, we are having to use a small food dehydrator to dry out our samples rather than a nice big oven which is what we would have on a research cruise.

Matt Cole: I have just poured the contents of that trawl through a 200 micron mesh and what this has done has retained all the zooplankton and microplastics bigger than 200 micron in size on the mesh and I can see lots and lots of zooplankton here but also dotted in between little white bits of polystyrene and a tiny bit of monofilament line. So I'm just going to seal this up now using staples and we do this to stop contamination of our samples from clothing or airborne contamination and what I'm doing now is just popping it in the desiccator - so this is a good dehydrator - and we're going to be leaving these samples for about 24-hours until they are bone dry and then we will be sealing them up and not looking at them again until we are back in Exeter.

So we have just done our last sail of our trip and we're just heading into Portland Harbour now. We've had a really lucky day of seeing whales, storm petrels and we've just spotted an osprey so it's been an end to a really exciting trip where we've collected lots of samples both from the water column and the sediment. And what we're hoping to do is take those back to the lab now and very carefully go through each of our samples to try and identify where the micro plastics are found and in what numbers.

Richard Hollingham: Matt Cole at sea at the mercy of wind, tide and currents collecting micro plastics. So, you brought those samples back to the lab, so what did you do with them and what did you find?

Matt Cole: We took those samples and we had to be very careful how we treated them because we didn't want them to be contaminated from plastics in the air or from our clothing and what the main goal was to try and decipher how many plastics were in that sample. So to do that we removed the biological material and just had all the plastic material left which we could then look down under a microscope and start separating based on its size, shape and colour.

Richard Hollingham: Now you've got this plastic and you would think, yeah, plastics in the ocean not a good thing but surely the point of this is to really look at the biological impact of the plastic on the sea and the life in the sea.

Matt Cole: What's really interesting is that a whole array of different marine organisms can ingest or eat this microplastic litter and we've shown in the laboratory that animals such as zooplankton and worms, muscles and crabs are all able to eat this plastic. Now it's not necessarily clear whether that has an effect of them at this stage but certainly we're seeing that they are ingesting them and it looks like it might be impacting on how much normal food they are able to eat.

Richard Hollingham: So, Tamara, at this stage you know there is plastic there from quite large chunks as we have seen from these tiny, tiny beads and you know that the life in the ocean is ingesting these, so the next stage is to look at what biological effect it is having.

Tamara Galloway: That's right, yes, so we've seen many different marine creatures, especially at the base of the marine fob web ingesting plastic and what we want to determine is, well, does it matter, does it harm them in any way because if it doesn't should we be making a fuss about this. Many of our different experiments have involved chronic feeding studies where animals are living in environments where there is a lot of plastic and what we're finding is a common theme that they put on less weight. So they are spending too much time ingesting and processing and attempting to digest plastic and they are not ingesting healthy nutritious organic material.

Richard Hollingham: So we probably should be concerned but you don't know to what extent we should be worried?

Tamara Galloway: One of the reasons for combining laboratory studies with field studies is we can work out what happens in the laboratory but we need the field studies to tell us exactly how much plastic there is and where it is going. So the key areas that are of concern are areas where we've got a lot of wildlife, a lot of marine life but we've got a lot of plastic as well and this is where we think we might be seeing ecological effects.

Richard Hollingham: Are you shocked at just how much plastic you are finding even when you go to these remote parts of the world?

Tamara Galloway: Totally. Every single sample that we've looked at from all over the place, even from hundreds of miles out to sea, we're finding tiny bits of plastic. It's been quite extraordinary.

Richard Hollingham: And, Matt, you've just started this new project, so what's your next objective?

Matt Cole: We're taking the data that we've got from this trip and we're able to then work out the concentrations of plastic that are actually out there in the marine environment and we can then apply those concentrations in the laboratory and try and determine whether these plastics are effecting the reproduction or survival of these key animals such as zooplankton.

Richard Hollingham: So, ultimately, Tamara, you are looking for evidence that would then feed into policy of maybe doing something about it?

Tamara Galloway: It is such an easy problem to solve. All we need to do is stop throwing plastic into the sea and we won't have a problem anymore. Why do we not do that? Because we need the scientific evidence that it is causing harm. Just saying it doesn't look good isn't enough.

Richard Hollingham: Professor Tamara Galloway and Dr Matt Cole, thank you both very much. We will put some photos from the expedition on Planet Earth online's Facebook page so you can see the ship for yourself. We will also post some pictures on Facebook and Twitter of our recording here today. That's the Planet Earth podcast from the Natural Environment Research Council. I'm Richard Hollingham, thanks for listening.