Removing marine microplastics with mussel power is a one-year feasibility study funded by Waitrose Plan Plastic to develop an ecological solution to microplastic pollution.
Microplastics are a persistent and widespread pollutant, which can be detrimental to the health of sensitive marine species. Mussels, however, are very robust and can thrive in polluted waters. They act as natural biofilters, efficiently filtering out particles from seawater which are then removed in their faeces or pseudofaeces (a bit like their spit). Just one square metre of mussel bed can filter an enormous 150,000 litres of water per day. This project will investigate whether the immense filtering power of mussels can be harnessed to remove microplastic pollution from estuarine and coastal waters using beds or "bioreefs" of mussels.
The study will begin with experiments where mussels are exposed to microplastics under laboratory conditions. The levels of microplastics will be as close to environmental levels as feasible and mussel health will be monitored throughout the experiment. This will enable us to determine exactly how much microplastic can be removed by these bioreefs in flowing water and from different depths. We will then investigate what happens to the microplastics after they’ve been filtered out of the water.
In the second phase of the project we will adapt a computer model of the marine environment to map and predict the distribution of microplastics without bioreefs and use our experimental data to enhance a computer model of shellfish biology (ShellSIM). These two models will then be combined to predict what the abundance and distribution of microplastics would look like if bioreefs were installed in different geographical locations.
The bioreefs are intended to be sited in areas of high microplastic pollution and are not intended for human consumption. Mussels that are farmed for food are usually sited in less polluted areas and will undergo a process called depuration where they are flushed with clean water to remove any toxins prior to harvesting. It may even be possible to site bioreefs upstream of aquacultures sites to reduce the amount of pollutants affecting fish and shellfish stocks.
Throughout the project we will work with stakeholders including experts in shellfish farming and local authorities to identify the risks and benefits of real-world deployment and to optimise bioreef design.
By the end of the project we aim to have robust scientific evidence to show how mussel bioreefs can be used to remove microplastics from estuarine and coastal waters. This will be used to create an evidence-based forward plan for implementation of the concept.
Funding permitting, we then plan to move on to a pilot study where bioreefs will be deployed at polluted sites so that we can test the feasibility of using this approach in the natural environment.
It is our vision that bioreefs can be deployed across the globe, reducing the flow of microplastic pollution into the oceans and improving water quality.
Funder: Waitrose Plan Plastic
Project start date: July 2019
Project end date: July 2020
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Dr Pennie Lindeque, Dr Ricardo Torres, Dr Tom Vance, Dr Yuri Artioli