Animals don’t just eat microplastic, they inhale it too!

In my last post I discussed the range of different species that ingest microplastics, and the potential consequences of this ingestion.

Last week (27/7/14), a new study was published in Environmental Science and Technology on the route of microplastics uptake in crabs, which discusses a new mechanisms for uptake.  You can find a link to the paper here. (You will need access to ES&T though).

The team of researchers at the University of Exeter (funded through the CleanSea* research project)  have been looking at the mechanisms of microplastic uptake and retention in the common shore crab, Carcinus maenas.  Their aim was to test the hypothesis that shore crabs can uptake microplastics across the gill surface during inspiration as well as ingestion from pre-exposed food (in this case, the common mussel, Mytilus edulis). They found that polystyrene microspheres (8-10µm) were retained in the body tissues of crabs, both following ingestion and inspiration. Interestingly they observed significantly higher uptake in the posterior gills than the anterior gills, the Watts et al. suggest that:

Crabs appear to uptake microspheres in two ways:

  • Ventilation:  a masked breathing study found microplastics were uptaken from the water column. All exposed crabs had plastic on their gills.
  • Ingestion of prey: dietary exposure also resulted in crabs having microspheres in their stomach. This suggests that trophic transfer of microspheres is possible within the marine food chain, especially at the lower levels.

  What happened with the microspheres:

  • They were NOT translocated to the haemolymph system.
  • They were excreted  in the form of faecel pellets.
  • Microspheres take over 6 times longer to leave the body compared to the average excretory phase for food waste.

Now the study of microplastic ingestion by wild and laboratory exposed animals is not uncommon (previous post), what makes this research different is that it looks at the mechanism behind the uptake of microplastics, going beyond the usual ingestion studies.

What are the consequences of this form of microplastic uptake

The mechanism of uptake may play a role in which organisms are more susceptible to microplastic pollution. In the case of the shore crab its  ventilation rate is less than that of the common mussel. Watts et al. discuss this in much more detail, but in summary, they suggest that in reference to ventilation rates alone,  mussels may be more susceptible to higher levels of pollutants. further research is required on levels of ingestion via feeding and predation

 *CleanSea is a multidisciplinary and collaborative research project addressing marine litter from different perspectives. It aims at providing Member States and other stakeholders with improved knowledge, methods and tools to be able to better define, monitor and achieve a marine environment free of harmful litter levels by 2020 (Good Environmental Status -GES- as required by the Marine Strategy Framework Directive -MSFD). In doing so, it will deliver a set of integrated results that will provide transparent and useful guidance to policy makers and stakeholders dealing with marine litter mitigation.   ——————————————————————————————————————————————————————————– Paper title: Uptake and retention of microplastics by the shore crab Carcinus maenas Authors: Andrew  Watts, Ceri Lewis, Rhys Goodhead, Stephen Beckett, Julian Moger, Charles Tyler, and Tamara Galloway

Abstract: Microplastics, plastics particles <5mm in length, are a widespread pollutant of the marine environment. Oral ingestion of microplastics has been reported for a wide range of marine biota,  but uptake into the body by other routes has received less attention. Here, we test the hypothesis that the shore crab (Carcinus maenas) can take up microplastics through inspiration across the gills as well as ingestion of pre-exposed food (common mussel Mytilus edulis). We used fluorescently labelled polystyrene microspheres (8-10 µm) to show that ingested microspheres were retained within the body tissues of the crabs for up to 14 days following ingestion and up to 21 days following inspiration across the gill, with uptake significantly higher into the posterior versus anterior gills. Multi-photon imaging suggested that most microspheres were retained in the foregut after dietary exposure due to adherence to the hair like setae and were found on the external surface of gills following aqueous exposures. Results were used to construct a simple conceptual model of particle flow for the gills and the gut. These results identify ventilation as a route of uptake of microplastics into a common marine non-filter feeding species.

 DOI: 10.1021/es501090e     Published by Amy Lusher


About beach clean up efforts in Norway

While in Tromso, after coming back from the Arctic cruise, I had the pleasure of meeting with Bo Eide. Bo is a forest engineer who took interest in marine debris for a while now. By his own initiative, he started drawing attention to the problem of marine debris, in the form of beach litter in Norway by organizing beach clean ups. Although Norway is a fairly clean country and there are fines and regulation for littering, its coastal shape is likely to retain impressive amounts of litter.

Bo depends on volunteers to help with beach clean ups as well as some funding to dispose of the collected debris. In some European countries, you cannot show up to a waste deposit with enormous amounts of litter for disposal without paying any fees. So Bo explained to me that all of the funding goes to be able to actually get rid of the collected litter. Once again, in my humble opinion, if you are cleaning a national patrimony without getting paid for it and cleaning it from trash that does not belong to you, there should be something to support you on that.

Another way Bo has been able to raise awareness on the marine litter issue in Norway is through a video he and some of his colleagues put together. The video points out the marine debris subject in Norwegian beaches and invites the common citizen to not only mind their own litter, but to spare an afternoon and volunteer to help. The movie was nominated for a Panda award, which is like the Oscars for Environmental Movies! 🙂 Very impressive! I would like to pay my respects to Bo for his brilliant work and for raising the marine debris flag in Norway.

Below, you can find the video and some quite impressive, as well as depressing, pictures of the beach clean ups in Tromso.

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All images by Bo Eide

Published by Heidi Acampora

Microplastic Ingestion

For those of you who are currently sitting at a desk chewing on their plastic  pen (or other plastic object). Stop. Think carefully about what you are doing (I have to remind myself about this on a daily basis). You are currently/potentially breaking off teeny tiny pieces of plastics which, if you are unlucky, will find their way into your mouth, and end up in your stomach. You know the old fable that if you swallow chewing gum it will say in your stomach for several years (It’s a myth). Well the same could be said about plastic. In fact it will more than likely exit your body given a day or two. Lets face it, gum and plastic pieces are small, your body cant dissolve or utilize  it, so it will try to get rid of it. However, what if the plastic gets stuck, or you eat enough plastic that it has a nasty effect on your body?


This is the basis for theory behind microplastic ingestion in the wild. In most cases ingestion is accidental and plastic is mistaken for food, although some studies have found that plastics can be targeted specifically by animals (more about this later). In some extremely polluted areas, the numbers of microplastic may outweigh natural prey items.

There are so many studies which look at microplastics ingestion in the wild. Most studies of microplastic come from the analysis of stomach contents. Below I am going to discuss are a few highlights, once you start getting into the material you will see that there are several other studies, these are some of the more recent ones. Some of the links you have to have access to journals, although most are available free online. I might be biasing your reading a little with two of them….

So we cut up all of these organisms (normally by-catch species, or those washed up on beaches), and find microplastic in their stomachs but what does this mean? The more species we look at, the more we find ingestion plastic. Is this a case of seek and you shall find? On a positive note: in all of the papers I have mentioned above, microplastics are not the cause of death.

Were the organisms feeding directly on microplastics?

This is often hard to determine from wild studies, in the case of the Humbolt squid (Dosidicus gigas) plastic pellets were found in their stomachs (Braid et al. 2012). However they are a predatory species which feeds at depths >200 m. The route of ingestion is unknown, they could have been feeding directly on pellets that had sunk, or they ate organisms that had already eaten pellets.

What’s great about laboratory studies is you can control for the plastics you are looking for and directly expose organisms. However sometimes the levels of exposure are greater than the  microplastic level in the wild. Laboratory studies have shown ingestion in marine species. For example:

Cole, Matthew, et al. "Microplastic ingestion by zooplankton." Environmental science & technology 47.12 (2013): 6646-6655.

Cole, Matthew, et al. “Microplastic ingestion by zooplankton.” Environmental science & technology 47.12 (2013): 6646-6655.

So why is the study of microplastic uptake important? 

Microplastic exposure doesn’t just stop at the individual that has eaten the microplastics. There have been a number of studies addressing the fate of ingested microplastics, and research is still continuing. Below are a quick run down of the fate of microplastics.

1) The first option for microplastics is to pass directly out of the organism, either by excretion or the production of pseudofaeces (think of it like the animals make themselves sick). If this happens then it can be assumed that microplastics are not having any long-lasting effect on the individual.

2) Microplastics might stay within the animal and transfer between tissues, as Browne et al (2008) and von Moos et al (2012) found in mussels. Further work is required in this area.

3) Micropalstics might have negative effects on organisms. Adverse effects of microplastic ingestion have been noticed in laboratory studies. Microplastics can reduce feeding activity and compromise the fitness of a invertebrates. Stephanie Wright’s PhD research has been based around this topic. Her paper on laboratory exposure of worms to microplastic is extremely interesting.

3) Animals with microplastics inside them, may subsequently be eaten by animals from higher in the food chain. Microplastics can therefore pass to other animals.



Microplastics moving in the food chain.From: Ivar do Sul, J. A., & Costa, M. F. (2014). The present and future of microplastic pollution in the marine environment. Environmental Pollution, 185, 352-364. DOI: 10.1016/j.envpol.2013.10.036


A question for you:

If microplastics are ingested by fish and bivalves  that we, as humans, consume on a regular basis….does this mean microplastics could end up inside us? From here on in:  what I say needs to be taken lightly, until we can provide results.

– The answer is technically, Yes. However this is assuming that microplastics are present in the tissue of individuals that we eat. In the case of most fish species, we gut them before eating. The risk is practically non-existent.  Although there are some species of fish and mollusc that we eat whole (mussels, pilchard etc). Microplastics might be in there tissues. The word MIGHT is important, because for all we know microplastics may have been egested (as laboratory studies have already shown), and the presence of microplastics will be related to how recently the individual has fed. Gut passage time for fish is relatively fast, and the likelihood of plastics hanging around in the gut of healthy fish is minimum. Furthermore, most shellfish are depurated before sold to the consumer, depuration would in theory allow for microplastics to be passed out of individuals.

-But what if the microplastics have transferred into tissues that we do eat, like skin….well currently there are no conclusive reports in this respect. It is more than likely the plastics will pass through our digestive system in the same way as the chewing gum and plastic example I gave earlier. So there is no need to worry ………. YET.

…..I will come back to the issue of chemicals associated with plastics in another post.



Published by Amy Lusher

About the Arctic and fulmars and litter

As a sea bird enthusiast and researcher, I was more than treated during our vessel trip to the Arctic. We saw hundreds of sea birds and could observe their behaviour at sea, in their real environment. Pelagic birds (sea birds that spend their life off shore, far from coastal areas) are an amazing thing to watch. Fulmars (Fulmarus glacialis) have a beautiful flight, more than occasionally shearing the water, as if to show off a little bit. And by watching the birds, I was impressed by the number of northern fulmars around.

Fulmars in the North Sea are indicators of good environmental state, as one of the OSPAR objectives to monitor marine litter (Ecological Quality Objectives for the North Sea (EcoQOs’)). Fulmars are part of the order Procellariiformes. Birds from this order, which include petrels, albatrosses and shearwaters have a very reduced ability to regurgitate hard/non-digestible material as the connection between the proventriculus (aka “chemical stomach”) and the gizzard (aka “mechanical stomach”) is very narrow. Thus, the amount of plastics found in their stomachs can be considered a true indicator of the amount of plastics in the sea. Therefore, I am so used to all these fulmars ingesting loads of plastics and ending up dead on beaches that seeing so many fulmars alive altogether was a bit overwhelming to me! How twisted is that it has become abnormal to see animals possibly healthy in their natural environment?

North Sea EcoQO: There should be less than 10% of northern fulmars having more than 0.1 g of plastic particles in the stomach in samples of 50 to 100 beach-washed fulmars found from each of four to five areas of the North Sea over a period of at least five years. Quality Status Report 2010, OSPAR Commission

All areas seem to extrapolate the amount of litter considered acceptable in a fulmar stomach. Quality Status Report, OSPAr: 2010.

All areas seem to exceed the amount of litter considered acceptable in a fulmar stomach. Quality Status Report, OSPAR: 2010.

Fulmars in the Arctic had darker plumage than the ones I had seen before and according to experts (aka Jan van Franeker), it is quite common that the birds from far north have a darker brown/grey plumage, instead of the white/light grey we are more used to seeing. As stated in the Save the North Sea Fulmar Dissection Manual, the plumage colour can therefore be an indicator of the origin of the bird.

Plumage patterns. Alterra rapport 672, Wageningen: 2004.

Plumage patterns. Save the North Sea Fulmar Dissection Manual, Wageningen: 2004.


By seeing so many fulmars (they follow ships, so they were a constant on our trip), I wondered if any similar work to the one for the OSPAR objectives was actually done on fulmars or other seabirds, in Norway and Svalbard. I found very little on the subject, so I suppose it might not be a big thing as of yet. I was told to contact the “seabird person” for Norway, but he hadn’t gotten back to me until the closing of this post :). From all the latest conferences I’ve been to and papers I have read, the scientific community claims for the standardization of methodologies when looking at marine debris/plastics in order to be able to compare data and come up with concrete results and possible solutions. Using sea birds (especially fulmars) as a sentinel species to monitor marine litter has proved to be effective and in my humble opinion should be expanded to wherever possible, obviously adjusting to regional differences.

If you wish to know more about the 2010 Quality Status Report by the OSPAR Commission, click here. As of the 2010 report, the Arctic Sea lacks information on marine litter. As for us, the Celtic Seas however, amount of litter is of concern, but pressure is unknown (we are working on getting more data, people!).

Lack of data for the Arctic Sea. Quality Status Report, OSPAR: 2010.

Lack of data for the Arctic Sea. Quality Status Report, OSPAR: 2010.

Here are some brilliant pictures taken by brilliant researchers (Sam Fredriksson & Ardo Robijn) using brilliant cameras during our Arctic cruise.

Image by Ardo Robijn

Image by Ardo Robijn

Image by Ardo Robijn

Image by Ardo Robijn

Image by Sam Fredriksson

Image by Sam Fredriksson


 Published by Heidi Acampora