Bioplastics on marine sandy shores: Effects on the key species Talitrus saltator (Montagu, 1808)

Talitrid amphipods are an important component of detritus web, playing a key role in the fragmentation of organic matters of marine and terrestrial origin, and it is well known that sandhoppers ingest microplastics. To assess the effective consumption of bioplastics and their effects on survival rate and on pollutants transfer (i.e. phthalates) on supralittoral arthropods, laboratory experiments were conducted by feeding adult T. saltator with two different types of bioplastic commonly used in the production of shopping bags. Groups of about 20 individuals were fed with 10 × 10 cm sample sheets of the two types of bioplastic for four weeks. The results show that amphipods ingest bioplastics even in the absence of microbial film and that ingestion of bioplastic can have effects on talitrid amphipods. Microtomographic analyses of faecal pellets seem consistent with this finding. The high phthalate concentrations in freshly collected individuals suggest the presence in the environment of these compounds, and the ability of amphipods to assimilate them, while the decrease in phthalate concentrations in bioplastic-fed individuals could be attributed to the scavenging effect of virgin plastic, as already observed in a previous study. In summary, the results indicate that different bioplastics may have effects on T. saltator (i.e. survival rate and faecal pellets structure) and confirm a potential role of amphipods in the degradation of bioplastics in supralittoral zone of marine sandy beaches, even when bioplastics are not colonized by bacterial biofilm that seems to improve palatability.