Pumice and plastics: Techniques in volcanology applied to assessing the distribution of oceanic microplastics

The challenge

Microplastics are a globally inescapable contaminant with very few options available to determine their pervasiveness. The impact of microplastics on ecosystems and humans is being continually assessed, calling for a better understanding of how bad the situation actually is. 

What we're doing

This project aims to determine whether the volcanic ejecta, pumice, can be used as a proxy for microplastic distribution in surface waters. The benefit of using pumice is the ability to visually recognize presence or absence using satellite imaging, as opposed to microplastics, due to them being too small.

Pumice is one of very few naturally buoyant substances meaning that, similar to plastic, it may reside in surface waters for extended periods of time, up to many years. This project will determine the spatial relationship between microplastics and pumice – how they float, “floc” together, and break apart.

We will conduct analyses in the lab and use samples collected in the field to determine the real-world applicability of this approach. Comparisons and methodologies usually only conducted on geological samples will also be applied to standardised and sampled microplastics to help us better understand sinking rates of different types of plastics. 

How it helps

Combined, these techniques will aid in quantifying the relationship between microplastic and pumice, allowing microplastics to be more efficiently tracked in the ocean.

If successful, we aim to apply for further funding to model the dispersal and linkages of pumice and plastic, allowing satellite images to provide a method of determining microplastic distributions. 

Investigators

• Dr Lewis Alcott, School of Earth Sciences 
• Dr Samuel Mitchell, School of Earth Sciences 
• Prof Alison Rust, School of Earth Sciences 
• Chimnaz Emrah, School of Geographical Sciences