Giusto Lo Bue1, Nicoletta Mancin1, Agnese Marchini1, Maria Pia Riccardi1, Maya Musa1, Stanislas F. Dubois2, Stefania Lisco3, Massimo Moretti3, Alessia De Luca3
1University of Pavia, Italy - 2Ifremer, France - 3University of Bari Aldo Moro, Italy
Coastal environments represent the main entry point for most pollutants into the sea. Microplastics (MPs) are a growing threat, especially for the Mediterranean basin characterized by densely populated coasts and a semi-enclosed morphology (Suaria et al., 2016). Recent studies have highlighted the increasing concern over MP pollution in the bio-engineered structures created by marine worms, such as the reef-building polychaete Sabellaria (Lo Bue et al., 2023; Mancin et al., 2022) growing in the littoral environment. This work focuses on MPs accumulated in a unique and functionally important coastal habitat, i.e. within the largest reef of the Mediterranean area (Torre Mileto, Southern Adriatic Sea) built by the gregarious honeycomb worm Sabellaria spinulosa (Leuckart, 1849) (Lisco et al., 2017). We quantified MP absolute abundance in samples from both the reef and the surrounding shoreface sediments using a stereomicroscope equipped with a UV light and micro-Raman spectroscopy. Patterns of MP accumulation were investigated according to three main environmental factors: type of substrate (reef vs. sediment), development of the reef structure (hummock vs. platform morphology) and MP supply by the longshore littoral drift (west side vs. east side of the study site). Results showed a significantly higher MP abundance in both reef and sediment samples from the western side of the site, indicating a likely direct effect of longshore drift on MPs supply. No significant differences were observed between substrates (reefs vs. surrounding sediments) and reef morphologies (hummock vs. platform), indicating no direct control of reef-building activity or different reef developmental stages on MPs accumulating. Micro-Raman spectroscopy analysis, revealed polyethylene terephthalate as the dominant polymer and fibers as the most abundant morphology. The collected data prove that polychaete reefs act as a temporary sedimentary trap for these pollutants. The passive accumulation mechanism highlights the global risk to these engineered habitats.
Biography
Giusto Lo Bue is a PhD student at the Department of Earth and Environmental Sciences of Pavia University (Italy). He studies the effects of microplastic pollution on biogenic reefs built by sabellariid polychaetes. His work combines controlled laboratory experiments with field quantification and identification of pollutants in reef structures, assessing both accumulation patterns and biological impacts.