Comparative assessment of microplastic ingestion among deep sea decapods: Distribution analysis in Sardinian and Catalan waters
April 1, 2025 | ScienceDirect
Abstract
Microplastic (MP) pollution is a widespread and concerning environmental issue. The benthic layer is known as one of the major accumulation sinks, yet knowledge gaps still remain in describing the interactions of its biota with MPs. This work represents a comprehensive comparative analysis of MP ingestion in the four deep-sea crustacean decapods Aristeus antennatus (Risso, 1816), Aristaeomorpha foliacea (Risso, 1827), Nephrops norvegicus (Linnaeus, 1758) and Parapenaeus longirostris (Lucas, 1846) sampled from two distinct regions of the Mediterranean Sea in order to underscore the species-specific characteristics driving their MP ingestion variations.
Results show that 72.5% of the individuals had ingested MPs, with fibers being the most common shape (91.36%), followed by tangles (8.64%). Catalan specimens had significantly higher fiber loads (mean; 3.69 fibers ind−1) than Sardinian ones (mean; 1.62 fibers ind−1), and distinct patterns among species were observed within the two regions. A. antennatus showed the highest MP load in the Catalan area whereas N. norvegicus was the most contaminated decapod in Sardinia. The observed variations are likely the result of a combination of factors, ranging from potentially different environmental exposure levels among regions to differences in the uptake and retention of MPs due to each species feeding ecology and morphological features. Overall, the results underscore the relevance of comprehensive assessments to properly interpret the trends in MP ingestion in crustacean decapods.
Introduction
Plastic pollution is one of the most concerning contemporary threats for marine environments. About 250,000 Tons of plastic are globally floating at sea and no decrease is foreseen for the next future (Andrady, 2011; Eriksen et al., 2014). Among plastics, microplastics (MPs) have raised widespread interest as environmental pollutants. Defined as plastic pieces smaller than 5 mm, their origin may be both by intentional manufacture and by fragmentation of larger debris due to weathering and biological fragmentation processes, making them ubiquitous contaminants (Arthur et al., 2009; Boucher and Friot, 2017). The first evidences of MPs as marine pollutants date back to the early 1970s (Carpenter et al., 1972; Carpenter and Smith, 1972) but after twenty years of research, our understanding on the effects of this pollutant is far from conclusive, with important gaps not only on their effects but also on their pathways and sinks (Frias and Nash, 2019; GESAMP, 2021; Thompson et al., 2024).
Once dispersed in the marine environment, the combined action of both biological and physical factors change the physicochemical features of plastic items, eventually triggering their sinking to the seafloor (Andrady, 2011; Kaiser et al., 2017; Pinto et al., 2019; Latva et al., 2022; Wallbank et al., 2022; Li et al., 2016). This, together with the persistence of plastic, particularly in the deep-sea where weathering processes are slow, results in the progressive accumulation of MPs in these environments (Chamas et al., 2020; Zhang and Peng, 2022).
As a result, benthic ecosystems are considered the largest sink for plastic and MP contamination (Van Cauwenberghe et al., 2013; Haegerbaeumer et al., 2019; Pitacco et al., 2022) which inevitably leads to their potential interaction with the biota present. Numerous potential effects across all levels of the biological hierarchy could arise (Cau et al., 2024), ranging from the impairment of bacterial activities to plastic accidental ingestion, which has been widely demonstrated in species with different trophic levels (Savoca et al., 2021; Pitacco et al., 2022).
Within deep-sea benthic communities, decapod crustaceans have gathered great attention due to their great gastronomic value and ecological interest (Cau et al., 2023). In the Mediterranean in particular, Aristeus antennatus (Cau et al., 2018; Carreras-Colom et al., 2018, 2020) and Nephrops norvegicus (Carreras-Colom et al., 2022a, 2022b; Cau et al., 2020, 2023) have been thoroughly studied in the context of MP contamination, with more recent attention given to Aristaeomorpha foliacea and Parapenaeus longirostris (Bono et al., 2020; D'Iglio et al., 2022; Yücel, 2022; Leila et al., 2023; Ciaralli et al., 2024). Regardless of the methodological approach or sampling area, these studies have revealed significantly high levels of plastic ingestion in these species compared to other faunistic groups, such as fish (Marmara et al., 2023), underscoring the need for further research to fully understand the extent of this impact and identify which species may be most at risk.
Research in laboratory-controlled conditions has shown that MP ingestion may have several noxious repercussions on crustaceans, including loss of appetite, increased oxidative stress and gut microbiota alterations, among others (Timilsina et al., 2023, Welden and Cowie, 2016a). Naturally occurring strategies might be exploited to prevent total blockage: highly exposed species like decapods crustaceans have been suggested to be capable of getting rid of ingested MPs through ecdysis and regurgitation, in addition to egestion through feces (Welden and Cowie, 2016b; Carreras-Colom et al., 2018; Saborowski et al., 2019). In particular, ecdysis was suggested as one of the main potential drivers of the spatial patterns observed in A. antennatus in the NW Mediterranean Sea (Carreras-Colom et al., 2020). However, to our best knowledge, species-specific moulting rates throughout the year represent a relevant gap in knowledge that prevents a proper assessment of whether moulting could be a successful strategy among decapod crustaceans to cope with MPs ingestion.
Despite the progress made in understanding the topic of plastic ingestion in Mediterranean benthic decapods, most studies have focused on one or two species at a time hence limiting comparisons across species once the spatial and temporal differences are accounted. A further challenge in this field is the variety of methodologies employed by different authors, which hinders the comparison of studies (Monteiro and da Costa, 2022). Overall, while these studies provide valuable insights, they do not offer a comprehensive basis for analysing the biological and ecological factors that determine MP ingestion across decapod species.
The aim of the present study is to conduct a novel and comprehensive comparative assessment of MP ingestion in four ecologically and commercially significant decapod crustaceans (Aristeus antennatus, Nephrops norvegicus, Aristaeomorpha foliacea, and Parapenaeus longirostris) from two distinct areas in the western Mediterranean—the Sardinian and Catalan coasts. By employing a standardized and consistent methodology, this study seeks to uncover species-specific and spatial variations while identifying previously unrecognized drivers of MP ingestion, thereby advancing our understanding of the factors influencing microplastic accumulation in marine organisms.
