Plastic Podcast Episode 22: Ocean Hotspots - Macro and Macro Plastics

In this science-focused episode of Plastic Podcast, host Clark Marchese takes listeners on a deep dive into the world of ocean garbage patches and microplastic hotspots. Joined by Dr. Annika Jahnke and PhD candidate Robbie Rynek, the episode explores a groundbreaking research expedition across the Pacific Ocean, from Vancouver to Singapore. The team discusses the surprising findings, including high concentrations of microplastics in unexpected areas, and the challenges of mapping plastic pollution in the vast oceans. Learn about the critical intersections of plastic and marine life, the implications for environmental policy, and the ongoing efforts to combat this growing issue. Tune in for a fascinating journey into the heart of one of our planet's most pressing environmental concerns.

Episode Guests:  Dr. Annika Jahnke and Robby Rynek

Find a link to Dr. Annika Jahnke and Robby Rynek’s project here

Find a link to Dr. Annika Jahnke and Robby Rynek’s article here

More information about the episode and the Plastic Podcast

Episode Transcript  and more information on the Pine Forest Media Website

Follow Pine Forest Media on Instagram @pineforestmedia

Hosted, produced, and edited by Clark Marchese 

Cover art and PFM logo by Laurel Wong. 

Theme music by Tadeo Cabellos 

Transcript:
[00:00:09.880] - Clark

Hello, and welcome back to another episode of Plastic Podcast, the show that tells the science and the story of our relationship with plastic. I am your host, Clark Marchese, and today we are talking about ocean garbage patches, microplastic hotspots in the sea, and an ocean expedition across the Pacific Ocean from Vancouver to Singapore. Before we get started, I just want to say thank you to all of you who have been listening to the series so far and to tell you that this is another science heavy episode. So if you enjoy these ones, and if you want to support science communication like this and help it reach more people, I will ask all of you who feel called to leave a one tap for five star review wherever you are listening to this now. Now, you've probably heard of the five major ocean garbage patches, and if not, we will cover them today. But in any case, there are five massive floating piles of plastic debris and other garbage in the oceans of the world. And knowing where these patches are gives us a pretty good understanding of where a lot of the ocean plastics will end up.

[00:01:14.990] - Clark

But these are macroplastics, ones that we can see with our eyes. What about the smaller ones? Are there separate hotspots of microplastics that we can't see? Do they exist in the same places? We're going to talk to two scientists today that are trying to figure that out. They worked together on a project called hotspots of floating plastic particles in the North Pacific Ocean, and they're going to tell us all about it. First up, we have Doctor Annika Jahnke, an environmental chemist from the Herman Center for Environmental Research in Leipzig, Germany. Doctor Jahnke's research spans bioaccumulation of organic contaminants in top predators and the weathering impacts of plastics in the environment. We also have Robbie Rynek, who has a master's degree with a focus in analytical chemistry, and he is currently working on a PhD investigating the distribution of microplastics in the Pacific Ocean. Without further ado, let's go ahead and get started. All right. Hello and welcome both of you, to the show. Since we have two guests today, I guess I'll start by asking each of you to introduce yourselves and tell us a bit about your research.

[00:02:31.180] - Robby Rynek

Okay, so I will start. My name is Robbie Rynek. I have a master's degree in chemistry with a focus on analytical chemistry. And in my PhD project, I work with the topic of microplastics distribution in the Pacific Ocean.

[00:02:47.160] - Dr. Annika Jahnke

And I'm Annika Jahnke. I'm an environmental chemist. I work also, like Robbie, at the Hermol center for Environmental Research UFZ in Leipzig in Germany. And I have two research foci. One is on bioaccumulation of organic contaminants in top predators, including humans. And my other research topic focuses on weathering impacts on the fate of plastics and associated chemicals in the environment.

[00:03:12.730] - Clark

Okay, wonderful. Well, it's great to meet you, and I want to thank both of you for coming on the show. It's interesting. We actually do end up talking quite a bit about bioaccumulation and biomagnification on the show, perhaps for obvious reasons. But the project that I would like to speak with both of you about today is a large research project you both worked on titled the Hotspots of floating plastic particles in the North Pacific Ocean. So maybe can you just give us an understanding of what this project set out to understand?

[00:03:39.760] - Dr. Annika Jahnke

Yes. So the title that you mentioned is the title of a recent paper that we published as an outcome of a large project. And this project was called Microfate, and it focused on the occurrence, on the fate and potential impacts of plastics and associated chemicals and hotspots, and also in more remote regions in the north Pacific Ocean, which we crossed on board of a german research vessel called Sonnet. There we took a lot of samples, both at the ocean surface, but also from the water column and from the seabed, which we then investigated for plastics, amongst others.

[00:04:16.140] - Clark

What else were you looking for besides plastics?

[00:04:19.020] - Dr. Annika Jahnke

Yeah, we really focused on the plastic, but on the one hand, we described its occurrence in these different areas and regions, and also in different layers of the Pacific Ocean. But part of the research also focused on the chemicals that, on the one hand, can be leached into the environment, but also those that can be taken up into the plastics that can work as a passive sampling device. And a group of researchers focused also on the plastispeare. So the biofilms and all kinds of organisms that grow on the plastic surface.

[00:04:50.160] - Clark

Okay. Yes. We learned before on the show how plastics can sort of soak up other chemicals that they encounter in the ocean. So then I'm wondering, is there a definition of what constitutes a hotspot of plastic in the ocean?

[00:05:02.610] - Robby Rynek

I don't know if there is really a fixed definition for this, but what we saw is that it's kind of an area that has elevated concentration of plastic compared to the surrounding waters. So, for example, if you just have a local maximum of plastic concentration or a global one, like this great Pacific garbage patch and so on.

[00:05:22.240] - Clark

So then I guess it's probably maybe impossible to know exactly how many hotspots there are, but we do know of some very, very large ones. I think many people have heard of the large ocean garbage patches, or gyres. But just in case, can you tell us what these are?

[00:05:37.220] - Robby Rynek

Well, there are, like, five large areas in the ocean. Like, one is in the North Pacific, one in the South Pacific, north south Atlantic, and in the Indian Ocean, which are somehow surrounded by large ocean currents. So when particles or like plastic items enter these areas, they are somehow trapped because all these currents are going around this area. So this basically leads to an ever increasing concentration if it's not really removed from there. And the largest one, or supposed to be largest one, is the so called great Pacific garbage patch in the North Pacific Ocean, somewhere between California and Hawaii.

[00:06:17.680] - Clark

Yeah. So there's five of these large ocean gyres. They were discovered first by Captain Charles Moore in 1997. So about 25 years ago. The largest one I was reading is larger than two Texas put together, or about the size of France, Germany, and Spain combined, which is a little scary because I remember when I was in high school, and I think I was just discovering about these large patches, I remember reading that it was just the size of one Texas. So they are growing. In fact, in an upcoming episode, we're going to be talking about the new stonic life or organisms that live on and around these garbage patches. And if you didn't know what new stonic means, that was a new word for me as well, and we will learn all about it very soon. So another thing that we've heard on the show about a million times is that plastics break down into smaller plastics, and these large gyres are microplastic gyres. But I assume there's also lots of microplastics there. So my next question is, how do we identify concentrations or hotspots of microplastics? Or was that what your research was trying to find out?

[00:07:19.490] - Robby Rynek

That's what we were basically doing. So it's really hard to see them because of their size. So large things like these ghost nets and so on, they are easily visible either if you are on the ship or if you do some remote sensing or stuff like this. But the smaller the particles get, the harder it is to really detect them. So that's what we wanted to see, or we wanted to hunt for these small particles.

[00:07:45.020] - Clark

Got it. So one of the goals then was to try and compare the microplastic concentrations that you got from sampling different areas and different levels of the water column with the visual observations. I'm curious, though, what's the process of doing that research look like, how large would a hotspot have to be, or how visible would it have to be in order for it to be counted?

[00:08:06.820] - Dr. Annika Jahnke

Yeah. The visual observations that we made on board were done in so called litter survey, in which groups of two scientists spent shifts of 1 hour each, where they were standing on the helicopter deck and they were monitoring a certain area next to the bow of the ship. So this focused on plastic items that were about 5 cm or bigger, and they were visualized or sighted from about 20 or 22 meters above the sea. It was always the same corridor that was monitored, and this was done while the ship was steaming. So one scientist would count and describe the item and the other scientists would take notes on the size, for example, if it's overgrown by biofilms and so on. And this was also gps tracked, so we can later on go back to this data. And this was done, as I said, when the ship was steaming and the other type of samples were taken at the station. So when the ship stopped for collecting the samples, because we had so many scientists who participate in that, we could cover a really big area entirely, crossing the North Pacific Ocean, or almost during hours of daylight.

[00:09:21.960] - Dr. Annika Jahnke

Of course, that's a precondition for this part, but it was a nice complementation of the station work with the small plastics. And also the patterns that we saw were relatively similar, so they could confirm each other.

[00:09:33.740] - Clark

Okay, that sounds like kind of an intense job, but also could be really fun and cool. So while you were traversing the ocean, you chose one particular pathway, which is from Vancouver all the way to Singapore. So basically across the entire Pacific Ocean, why was it that you chose this pathway?

[00:09:50.130] - Robby Rynek

Well, we basically crossed one of the hotspots, like this great Pacific garbage patch. And since in the north Pacific, the area around 30 degrees north is kind of surrounded by these ocean currents, we expected some concentrations of plastic in the whole area. But in the open ocean, we expected definitely less than in this one already known hotspot.

[00:10:19.320] - Clark

Yeah.

[00:10:19.720] - Dr. Annika Jahnke

This was partly given because the cruise or the transit was advertised as such, because the ship had to pass over to go for repair, and also for another research area that it was going to work on the. So for us, it was really an ideal case because we could make use of the time that the ship spent when crossing the ocean. And also we had some seven or eight days for station work. So it's the track, the cruise, and the distance that the ship has to make during a certain time. But we also had a bit more than one week to stop and to really go down, because the Pacific is sometimes several kilometers deep. In our area, it was always five, six, 7 km deep, and it simply takes time to lower down the instruments and to take up the samples.

[00:11:07.790] - Clark

Okay, wow. So you took samples from that far below the surface of the ocean, several kilometers, yes.

[00:11:13.990] - Dr. Annika Jahnke

So all the samples from the sediment from the seabed, they were about 6 km deep.

[00:11:19.660] - Clark

Okay, so then was the data able to confirm the hypotheses?

[00:11:24.180] - Robby Rynek

Basically, yes. So we were able to detect this great Pacific garbage patch with our visual observations and also with the net sample that we got that we had quite high concentrations for both in this area. So when we went in, the concentrations were getting higher, and when we went out of this area, it got lower. But the shocking, or somehow sad result that we had from our observations was that in the area of a marine national monument in the north of Hawaii, we were also able to detect large numbers of particles which was comparable to the numbers that we had found in the great Pacific garbage patch. But there, it was kind of interesting that we found lots of, lots of really, really small, like for our method, small particles in this sample compared to the other one.

[00:12:15.210] - Clark

Would you say that the data is able to establish a direct relationship between the level of visible plastics and the level of microplastics, or could there be some variance in that regard?

[00:12:25.390] - Robby Rynek

There could be some variance, definitely, because we have, like, in total ten samples that we were able to compare these somehow hundreds of visual observations. So we have a good coverage for these visual observations, but for these samples, we have just like small points on the ocean. But what we saw was that at these stations, where we found lots of small microplastics in our net, we also had increasing concentrations of visible floating debris in the area around it.

[00:12:54.430] - Clark

So it must be a lot easier to collect data based off of visual observation than it is to lower an instrument kilometers under the surface of the sea. But does this suggest that this method of visual observation, collection of plastics, is effective in estimating the microplastic concentrations in the surrounding waters? Or do you think that we still need to continue doing this type of research that you have been doing, taking samples from different levels of the sea?

[00:13:18.560] - Robby Rynek

I would say that both is somehow needed because the sampling takes quite some time and also the work afterhand. So if you just collect the sample, you have to get rid of all the biogenic material inside of it. You have to extract the microplastic particles from it, then you have to analyze them somehow, which takes quite a lot of time and quite some effort. So the visual observations at this point are quite nice tool. Yeah, good tool to have a general overview and to detect or maybe detect also area where these small microplastics are there in a high number. But there's still some work to do and to basically confirm what we found.

[00:14:02.210] - Clark

Right. I think as far as awareness of plastic issues goes, people are probably most familiar with plastic in the ocean. That's probably the most famous plastic issue in the media at least. So I'm wondering, since we already know that there's plastic there and there's not much hope of removing at all, can you help us understand why it's important to keep learning where these both micro and macro plastic hotspots are forming?

[00:14:27.740] - Robby Rynek

On the one hand, it's good to know where all this plastic ends up because also the big particles that are easily tracked by visual observations and also by remote sensing and by models and so on. But it's also interesting to know where all this small stuff is going because this is the stuff that has, or these are the particles that have maybe a greater influence on the wildlife there because it's in the size that a range of marine animals can somehow ingest and then are affected by it.

[00:14:58.250] - Dr. Annika Jahnke

Yes, maybe I can add quickly to this. During our expedition, we had different areas. I mean, the one that was between California and Hawaii was relatively well researched, so there was quite dense information about plastics in this area, whereas towards the second half of our expedition, there were very few data points. And of course, at this stage, we have some global models that predict where the plastics accumulate. And these were super helpful in planning the expedition and also in selecting where to stay and where to take the samples. But of course, these can always be improved because they contain a lot of extrapolation. So for this, I think it's always still valid, but we still don't know well enough how this extrapolates from the larger particles to the really small ones. And those are the ones that are responsible for impacts on biotas. So both are still valid, I think.

[00:15:51.610] - Clark

Is there any way that this data can help inform any cleanup efforts? Or is that something we should be exploring, or is the problem just too large?

[00:16:01.930] - Dr. Annika Jahnke

The oceans are just so vast. So a lot of these areas are not within reach even for weeks of going on the ship. And also what we saw in our net samples is that quite a lot of biota was sampled because it's an important habitat in the global oceans. So whenever you go and try to fish out the plastics, you will also collect organisms that live in this area and that of course, get into hazard here.

[00:16:32.830] - Robby Rynek

The basic problem is that if you want to get rid of these small plastic particles, you will interfere with the biota there. So if you want to filter it out, you will also filter out all these small marine life forms that are living there. And I think that this will cause more harm than it, than it helps at this point.

[00:16:53.110] - Clark

Yes. As I mentioned, the marine life that lives on and around these plastic hotspots is the main topic of an upcoming episode, so stay tuned for that.

[00:17:00.970] - Dr. Annika Jahnke

It's also a matter of the accessibility, as I said before, like, it's just too far away. And also the past has shown this, that these end of the pipe approaches don't really solve the problem. So we need certainly action on many different areas. It's not just a waste problem.

[00:17:19.100] - Clark

In what ways do you hope that understanding where concentrations of microplastics in the ocean will influence either further research or policy?

[00:17:27.730] - Dr. Annika Jahnke

I think it's important to show that we have these plastic particles in the remotest areas of the world, including our work here, but also on mountaintops and the arctic sea ice, in the deepest areas of the global oceans, because we know that they can't be removed and simply they should not be there. They don't belong there. So I think it gives a lot of incentive for people to see the problem. And this is also positive, I think, because the public is well aware of the problem and there's a lot of public pressure also towards policymakers.

[00:18:04.530] - Clark

Okay, so then my last question about this research has to do with future research questions. We know the ocean is huge and the time and resources that it would take to map exactly where these micro and microplastic hot spots are across the whole ocean would be, you know, quite an undertaking. So I'm wondering, where do you think we should start? What do you think are the most burning research questions in this field that you'd like to see addressed and answered in the near future?

[00:18:29.190] - Dr. Annika Jahnke

My focus here is really on the chemical side, which kind of additives and other compounds are put into the polymers because we have them in use for a while, at least. So I would like to see a lot of simplification on that level, focusing on polymers that we know are less harmful and also bring the chemicals to those that are known to be less hazardous. Of course, this needs to be updated always as the state of research progresses. But this would be my personal focus and wish.

[00:19:00.290] - Clark

Yes, we have a lot of work ahead of us still, but in order to do that, I think we need to be empowered and enthusiastic. But I know that there's a lot of good work being done and a lot of people working really hard, and therefore some moments for us to find that optimism. So I'm going to ask if there's maybe one piece of good news that either of you can share with us or a note of optimism we can end on.

[00:19:21.920] - Dr. Annika Jahnke

Yeah. Something I would like to highlight is a great group of scientists that work in a very multidisciplinary context. It's called the Scientist Coalition for an effective plastics treaty, where we have at present about 350 scientists worldwide at all different levels of experience, who work on very different aspects related to plastics. Because it's such a multidimensional and disciplinary problem. We have all kinds of expertise here, and these people are really committed to working towards getting this global plastics treaty as effective as it can be.

[00:20:00.450] - Clark

Yes, this comes up on the show quite a lot. I'm really happy to have been following the work of these scientists. And in fact, the next international round of negotiations for this treaty is coming up in just a few short weeks. And in fact, we will have an episode coming up that both discusses the previous rounds of negotiations and what we can expect and hope for in the upcoming one. So make sure you subscribe to the show so you don't miss that. All right, well, then, the last question I have for the two of you is, where can people find you and follow your work?

[00:20:26.390] - Dr. Annika Jahnke

Yes, for the project that we talked about. You can find it on our website. It's called the three w u z de slash micro minus fate. Here you will find the project and also the link to the publication.

[00:20:40.560] - Clark

Okay, perfect. I will make sure to put links to all of that in the episode description so people can find it easily. This is the part where I say thank you so much for coming on the show today. Thank you both so much for sharing your work with us and also for conducting this very important research.

[00:20:56.200] - Dr. Annika Jahnke

Thank you for your interest. Now the best to you.

[00:20:59.060] - Robby Rynek

Thanks.

[00:21:09.370] - Clark

You've been listening to plastic podcast. You can find more information about this week's guest and links to their work in the episode description. Cover art for the show was done by Laurel Wong, and the music you're listening to was done by Tadeo Cabellos. I am your host, Clark Marchese, and this episode was produced and engineered by me. So if you loved it, share it with someone who might find it interesting. Plastic Podcast is part of a larger network of sciency podcasts called Pine Forest Media. We have one on Antarctica, we have one on drinking water. And you can find more information about us in the episode description or on our website@pineforestpods.com. dot we also have some exciting new podcasts coming out towards the end of this year, and a one tap, five star rating across platforms and a review on Apple Podcasts is one of the best things you can do to help this entire network grow. All right, that's all I have for you today. Thank you so much for listening, and I will chat to all of you soon.