Annual Review 2020: Marine

Groundbreaking research into microplastics and microfibres

In a year when the University’s 20-year expertise in marine plastics and litter was recognised with a third prestigious Queen’s Anniversary Prize for Higher and Further Education, its scientists unveiled several groundbreaking new studies. Among them were the findings of a major government-funded project detailing how particles released from vehicle tyres could be a significant and previously largely unrecorded source of microplastics in the marine environment. The research showed that tyre particles can be transported directly to the ocean through the atmosphere, or carried by rainwater into rivers and sewers, where they can pass through the water treatment process. Researchers estimate this could place around 100 million m² of the UK’s river network – and more than 50 million m² of estuarine and coastal waters – at risk of contamination by tyre particles. The project, undertaken for Defra, will be used to guide ongoing and future research into the impact of human activities on the marine environment, as the government continues in its fight against plastics pollution.

The University also published first-of-its kind research revealing that wearing clothes can release even greater quantities of microfibres to the environment than washing them. Working with scientists from the Institute for Polymers, Composites and Biomaterials of the National Research Council of Italy (IPCB-CNR), the team discovered that up to 4,000 fibres per gram of fabric could be released during a conventional wash, while up to 400 fibres per gram of fabric could be shed by items of clothing during just 20 minutes of normal activity. Scaled up, the results indicate that one person could release almost 300 million polyester microfibres per year to the environment by washing their clothes, and more than 900 million to the air by simply wearing the garments. The research, published in Environmental Science & Technology, found that there were significant differences depending on how the garments were made, meaning that clothing design and manufacturers have a major role to play in preventing microfibres from being emitted into the environment. A further study, published at the end of the year, went on to show that some commercially available washing machine filters may capture up to 80% of these fibres.

The key story here is that the emission of fibres while wearing clothes is likely of a similar order of magnitude as that from washing them. That constitutes a substantial and previously unquantified direct release to the environment. The results also show textile design can strongly influence both release to the air and release due to laundering; that is a crucial message highlighting the importance of sustainable design for the fashion industry. Indeed, many of the current issues associated with the environmental impacts of plastic items stem from a lack of holistic thinking at the design stage.

Professor Richard Thompson OBE FRS, Director of the Marine Institute, and Head of the International Marine Litter Research Unit.

 

<p>Mussels clumped together on rocks at Whitsand Bay in Cornwall (Credit University of Plymouth)<br></p>
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Plastic marine litter

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Mussel reefs heighten microplastic risk

Commercially important seafood species are at greater risk of microplastic contamination depending upon how they clump together in the marine environment. This was the finding of a first-of-its-type study in which scientists from the University used a series of experiments to assess whether the reefs formed by blue mussels (Mytilus edulis) affected their exposure to, and consumption of, tiny microplastic particles. Writing in Environmental Research Letters, the team, led by graduate Hyee Shynn Lim and Dr Antony Knights, evidenced how the arrangement and surface roughness of natural reef structures – such as that constructed by mussel populations – create conditions that make them natural sinks for plastics and other forms of human pollution. They also believe species like the blue mussel that are important for human consumption, but susceptible to microplastic pollution, may be useful indicators of the problem and its potentially harmful biological impacts.

Often we look to protect reef forming species based on what they are. However, we are not aware of any research that has shown that the physical structure of the reef itself might also inadvertently increase species’ exposure to pollutants like microplastics. With no means of addressing this issue, due to our increasing awareness of the quantity of microplastic in the marine environment, this study offers the first evidence that forming a reef is a double-edged sword for individuals.

Dr Antony Knights, Associate Professor in Marine Ecology, School of Biological and Marine Sciences.


The enduring LEGO brick

<p>LEGO</p>
<p>Detailed analysis has estimated a LEGO brick could survive in the ocean for as many as 1,300 years (Credit Andrew Turner, University of Plymouth)<br></p>

“The pieces we tested were smoothed and discoloured, with some of the structures having fractured and fragmented, suggesting that as well as pieces remaining intact they might also break down into microplastics. It once again emphasises the importance of people disposing of used items properly to ensure they do not pose potential problems for the environment.

Dr Andrew Turner, Associate Professor (Reader) in Environmental Sciences, School of Geography, Earth and Environmental Sciences.

 


 A new study has found that a LEGO brick can weather the effects of the marine environment for anywhere between 100 and 1,300 years. By measuring the mass of individual bricks found on beaches against equivalent unused pieces, researchers were able to calculate the length of time it would take for them to completely disintegrate. Published in Environmental Pollution, the study focused on 50 bricks recovered from beaches in the South West and analysed using an X-ray fluorescence (XRF) spectrometer.

Charting plankton decline in the atlantic ocean

Research led by the University has shown that a shortage of summer nutrients resulting from the changing climate has contributed to a 50% decline in important North-East Atlantic plankton over the past 60 years. The study, published in Global Change Biology, reveals that larger, nutritious plankton – vital to supporting fish, seabirds and marine mammals – are being replaced by tiny, primary producers that are of poorer food quality owing to decreasing amounts of iron and nutrients in surface waters. 

The study was led by scientists in the School of Geography, Earth and Environmental Sciences (funded through the Natural Environment Research Council’s [NERC] Shelf Sea Biogeochemistry Programme), working with colleagues from Plymouth Marine Laboratory, the Marine Biological Association and the University of Southampton. With picoplankton replacing nutritious phytoplankton – a vital primary producer of omega-3 – the scientists say that competition for scarce summer nutrients could become a key force in structuring shelf seafood webs, where 80% of the world’s wildcaptured seafood originates.


Zooplankton such as copepods are considered beacons of climate change, and the ~50% decline in their abundance over the last six decades is worrying. Our study is the first to provide a mechanism for such a widespread decline, and this understanding is essential for projecting future responses to climate change.

Dr Katrin Schmidt, plankton ecologist, School of Geography, Earth and Environmental Sciences.


 

Artificial night sky poses serious threat to coastal species to coastal species

A NERC-funded project led by marine biologists revealed that artificial lighting lining the world’s coastlines could be having a significant impact on species that rely on the moon and stars to find food. According to the Artificial Light Impacts on Coastal Ecosystems (ALICE) project, creatures such as the sand hopper (Talitrus saltator) orientate their nightly migrations based on the moon’s position and brightness of the natural night sky. But researchers found that lighting can disrupt this lunar compass and cause species to venture away from their natural feeding grounds, even impacting the ecosystem.

Through the ALICE project, we are finding increasing evidence that light pollution from coastal cities can influence marine species
inhabiting nearby beaches, rocky shores and even the seafloor. These results highlight how pervasive city lighting could be in shaping the ecology of coastlines kilometres distant from their nearest urban centres.

Dr Thomas Davies, Lecturer in Marine Conservation, School
of Biological and Marine Sciences.


 

Warmer and acidified oceans can lead to ‘hidden’ changes in species behaviour

A study conducted by researchers at Ghent University (Belgium), the University of Plymouth and the University of South Carolina (USA) has shown that ocean warming and acidification impact not only the behaviour of individual species but also the wider marine ecosystems which are influenced by them. Published in Nature Climate Change, the report shows that in warmer seawater with lower pH, a common clam – the peppery furrow shell (Scrobicularia plana) – makes considerable changes to its feeding habits.

Instead of relying predominantly on food from within the water column, it can adapt its behaviour to use its tube-like feeding siphon to scrape more of its food from the seafloor. This in turn can lead to surface-dwelling invertebrates showing greater tolerance to warming and acidification, most likely owing to the stimulatory effect of the clam’s altered feeding on their microalgal food resources.

 

This shows how unexpected the effects of human impacts on our environment can be. If the behaviour of a given species changes because of ocean acidification and warming, what are the implications for other components of that community? Our study illustrates the
importance of investigating the consequences of human impacts on the environment at multiple levels, including how this affects
the way animals behave..

Mark Briffa, Professor of Animal Behaviour, School of Biological and Marine Sciences.


Sea level rise might not result in ‘island drowning’

Coral reef islands across the world could naturally adapt to survive the impact of rising sea levels, according to new research led by the University of Plymouth in conjunction with the University of Auckland (New Zealand) and Simon Fraser University (Canada). The increased flooding caused by the changing global climate has been predicted to render such communities – where sandy or gravel islands sit on top of coral reef platforms – uninhabitable within decades.

However, in the study, published in Science Advances, the academics say this is far from a foregone conclusion. Using numerical modelling of island morphology alongside physical model experiments, the team were able to show that islands composed of gravel material can respond and in relation to overtopping waves, with sediment from the beach face being transferred to the island’s surface.

 

It is important to realise that these coral reef islands have developed over hundreds to thousands of years as a result of energetic wave conditions removing material from the reef structure and depositing the material towards the back of reef platforms, thereby creating
islands. The height of their surface is actually determined by the most energetic wave conditions; therefore, overtopping, flooding and island
inundation are necessary – albeit inconvenient and sometimes hazardous – processes required for island maintenance.

Gerd Masselink, Professor of Coastal Geomorphology, and Head of the Coastal Processes Research Group, School of Biological and Marine Sciences.


 

Research and Enterprise

The University has a proud reputation for conducting world-leading, impactful research across a broad range of fields. From health technologies to heritage; marine sciences to medicine; psychology to sustainability. And alongside these sustained peaks of excellence, the University is fast developing a critical mass of expertise in emerging, exciting areas such as agritechnology, antimicrobial resistance, cybersecurity and creative economies.

Our University draws upon its location to maximise these research strengths. Across marine sciences and maritime, we’re able to take advantage of the breathtaking natural environment of Plymouth Sound (the first National Marine Park), as well as the many marine-related companies that are based here. To this natural laboratory we have added a waterfront Marine Station, home to our expanding fleet of research and teaching vessels, and a nationally leading Marine Building, with its wave tanks and navigation centre, and we are developing a cutting-edge Cyber-SHIP Lab to tackle the issue of cybersecurity in the maritime sector.

In health and care research, we take advantage of our co-location and partnership with the University Hospitals Plymouth NHS Trust. Our Derriford Research Facility, located adjacent to the hospital, is home to medical and biomedical experts conducting research into areas such as infection and immunity, neurodegenerative diseases, brain tumours and antimicrobial resistance.

We are leading the development of potentially the first new antibiotic in 30 years and the first vaccines for the animal population against COVID-19. And adding to our first-class facilities, a new Brain Research and Imaging Centre is due to open, which will include the most advanced MRI scanner in the region.

Finally, our Sustainable Earth Institute (SEI) – our third overarching strategic research institute – continues to build innovative partnerships with industry and government, not just here in the South West, but also overseas. Operating from the new Sustainability Hub on campus, the SEI acts as a catalyst whereby University expertise can be applied to a range of challenges, from the low carbon agenda to water quality and food security in the developing world. Over the following pages, we present some of the developments and successes that have defined the year, including the publication of groundbreaking work in high-impact journals, the winning of major funding grants, our partnerships with industry, and the recognition of our staff in identifying and solving problems of global significance. The University’s research community is flourishing, ready to respond to global challenges and opportunities.



Professor Jerry Roberts
Deputy Vice-Chancellor – Research and Enterprise