There are many problems facing the Mediterranean Sea. We have all heard of the issues with overfishing, warming water temperatures, invasive species, and plastic pollution. But how much do we know? And what is being done about it?

Archipelagos is a Greek non-profit organisation founded in 1998, focused on conservation and research in the Aegean Sea. Many of the most biodiverse areas of the world are also some of the most remote; an on-the-ground organisation is necessary to protect these remote areas from further degradation and to communicate the urgency of the local issues more broadly across a region.

I am Alex Merkle-Raymond and for my project here in Archipelagos Institute, I focused on the ‘Comparison of Microplastic Accumulation in Native and Invasive Sea Urchins of the Aegean Sea’. A study conducted in the Gulf of Naples deemed sea urchins as a suitable model organism for the examination of microplastics because of their critical role in the ecosystem (Murano et al., 2020). As a keystone species, they have a disproportionately large effect on the other organisms in their environment (Elmasry et al., 2013).

Two different sea urchin species were collected and their digestive contents examined for microplastic contaminants. Microplastics are small, ubiquitous plastic pollutants less than 5 mm in size (National Geographic Society, 2019). Estimates suggest that the Mediterranean basin contains between 21 to 54 percent of microplastic particles worldwide (Care and Blazquez, 2017). A wide range of marine organisms have been shown to ingest microplastics as they are often less than 1 mm in size. This negatively affects some biological processes, such as feeding, energy reserves, and reproduction (Murano et al., 2020).

My research project not only looks at the increasing abundance of microplastics but also looks at another major threat to the Mediterranean Sea: invasive species. Invasive species are a growing threat: more than five percent of the marine species in the Mediterranean are now considered non-native species. Alarmingly, over 986 alien species live in the Mediterranean, 78 percent which were found specifically in the eastern Mediterranean where my research was conducted. (One study (Zenetos, 2010) indicates that nearly 1,000 species have already been introduced in the Mediterranean Sea, which is equivalent to a rate of introduction of one species every nine days.

Based on the published literature, this is the first study that looks at the microplastic abundance in a comparative lens through native and invasive species of sea urchins.

We, the members of Archipelagos’ research teams, will better understand the population structure of the waters surrounding Lipsi Island and the relationship between native and invasive sea urchins and their relative uptake of microplastics. If the native sea urchin accumulates fewer microplastics than invasive, then we can conclude that they are that much more important to the ecosystem and that invasive species further endanger the existence of native ones. However, native species could potentially be less impacted by microplastics due to their prevalence in the environment for a longer period.

This project has the potential to be continued yearly to compare microplastic trends in native and invasive sea urchin species over time. Because the Mediterranean Sea is a biodiversity hotspot (Llorca et al., 2020), the anthropogenic threat of microplastics in this region could pose a higher risk to the marine species that inhabit it (Murano et al., 2020)

This project is a unique opportunity to do hands-on research in the Mediterranean Sea where you can be the first person to study microplastics in invasive and native sea urchins. The results can be used to create a similar study in another area of the Mediterranean Sea or be replicated by another student in the future. The impacts of invasive species and plastics are still being studied and this project is an excellent opportunity to get a chance to work in both expanding fields. Looking at microplastic research at Archipelagos has allowed me to combine my passion for conservation with new research on a local and international scale.

Stats so far: 3,332 total pieces of microplastics in the 180 collected sea urchins have been found. There have been 2,677 fibres (fibres often tend to be from textiles or fishing lines) and 29 fragments.

Informational Sources:

Care, M., & Blazquez, P. (2017). A Mediterranean full of plastic. Retrieved from GreenPeace Spain.

Cózar A, Sanz-Martín M, Martí E, González-Gordillo JI, Ubeda B, Gálvez JÁ, et al. (2015) Plastic Accumulation in the Mediterranean Sea. PLoS ONE 10(4): e0121762.

Elmasry, E., Omar, H., Razek, F., El-Magd, M. (2013). Preliminary studies on habitat and diversity of some sea urchin species (Echinodermata: Echinoidea) on the southern Levantine basin of Egypt. Egyptian Journal of Aquatic Research. 39, 303–311.

Llorca, M., Álvarez-Muñoz, D., Ábalos, M., Rodríguez-Mozaz, S., Santos, L., León, V., Campillo, J., Martínez-Gómez, C., Abad, E., Farré, M. (2020). Microplastics in Mediterranean coastal area: toxicity and impact for the environment and human health, Trends in Environmental Analytical Chemistry, Volume 27.

Murano, C., Agnisola, C., Caramiello, D., Castellano, I., Casotti, R., Corsi, I., Palumbo, A. (2020, April 26). How sea urchins face microplastics: Uptake, tissue distribution and immune system response. Environmental Pollution 264:114685

National Geographic Society (2019, June 28). Microplastics. National Geographic Society.

Zenetos, 2010 “Trend in aliens species in the Mediterranean. An answer to Galil”, 2009 «Taking stock: inventory of alien species in the Mediterranean Sea» Biological Invasions, 12 (2010), pp. 3379-3381

Alex Merkle-Raymond

Northeastern University | 2019

Université Côte d’Azur | 2022