Interview with Matteo Galli

Matteo Galli, currently a PhD student involved in the Plastic Busters MPAs Project, has completed both a Bachelor’s degree and a Master’s degree focusing on marine pollution issues.


The young researcher describes his experience at the University of Siena investigating the impact of marine litter on Mediterranean ecosystems and marine biodiversity.

Is the presence of microplastics in biota a real problem?  

The number of species affected by plastic pollution has increased over the years, reaching over 100 species in the Mediterranean Sea in 2020. During the analysis performed within the Plastic Busters MPAs Project, we have isolated plastic particles from the gastro-intestinal tracts of several fish species and invertebrate organisms confirming that plastic ingestion represents a serious threat for the marine biota. Species’ ecological niches and feeding behaviours may affect plastic intake in different ways, stressing the need to select a suite of indicator organisms to evaluate the potential impact of microplastic on the marine ecosystems. Our preliminary results show how fishes such as Bogue (Boops boops) and European pilchard (Engraulis encrasicolus) are among the most affected fish species by particles ingestion, highlighting their important role as bioindicators in coastal and open waters, respectively. In turn, the ingestion of microplastic can cause physical harm in marine organisms, as well as other toxicological effects due to plastic additives or adsorbed compounds leaching out from particles. These latter aspects still need to be clearly investigated, which is something I have set out to do in the second part of my PhD project.  

In your experience, where do microplastics come from?  

Understanding the sources and fate of microplastics in different environments is essential in order to define exposure levels, as prerequisites for risk assessments, with the aim to mitigate the problem. The majority of microplastics found at sea originates from the degradation processes that affect larger size objects. Named as “secondary microplastics”, these particles are the most abundant in the Mediterranean waters and are mainly represented by hard plastic fragments and small pieces of bags and industrial packaging. This is what I have also experienced myself when analyzing several samples collected in different areas of the Mediterranean basin - within the Plastic Busters MPAs Project - and in the Atlantic Ocean, thus stressing the need for specific management strategies aimed at preventing and reducing the dispersion of plastic litter from land to the marine environment.  

The majority of microplastics found at sea originates from the degradation processes that affect larger size objects

Has the Plastic Busters MPAs project changed your approach to marine litter challenges?  

Despite the growing attention from the scientific community, the presence and the impact of plastic debris in Marine Protected Areas and on marine wildlife remain poorly understood. Bearing this in mind, the Plastic Busters MPAs project allowed me to gain information about the occurrence and the distribution of marine litter in areas of high biological value, and I am looking forward for the opportunity to contribute to researching how the presence of plastic litter can affect the whole marine ecosystem. Moreover, the project presented the unique opportunity to collaborate with partners from many Mediterranean countries and to share different expertise, techniques and approaches to the topic, thereby allowing for a better understanding of this issue and for progress to be made in addressing research questions and, then, elaborating effective mitigation actions. 

Matteo Galli, PhD student actually involved in the Plastic Busters MPAs Project, has carried out both the bachelor’s degree and master’s degree working on marine pollution issues. He has been working on the evaluation of plastic presence in the Mediterranean Sea waters and in gastro-intestinal tracts of different commercial fish species, turtles, and marine mammals in the context of Descriptor 10 of the European Marine Strategy Framework Directive. Moreover, he has focused his attention on the physical and toxicological effects that plastics additives (i.e. PAEs and PBDEs) leaching from plastic products may have on marine biota. Within the Plastic Busters MPAs project, he will have the great opportunity to improve his knowledge and his skills about the biological and ecological implications of marine litter, developing future collaborations and research involving the University of Siena and the other institutions worldwide to set-up a joint collaborative framework to study and tackle marine pollutions.