Plastics and seagulls: How marine litter is affecting seabird fertility
MARE researchers Sara Veríssimo, Vítor Paiva, Lara Cerveira, Jorge Pereira, Jaime Ramos, Isabel dos Santos and Ana Cláudia Norte are co-authors of the article ‘Physiology and fertility of two gull species in relation to plastic additives’ exposure’ recently published in the scientific journal Science of the Total Environment. In the study, the researchers evaluate the effects of the absorption of plastic additives on Yellow-legged Gulls and Audouin's Gulls.
Plastic pollution in natural and urban environments has become a growing threat to the proper functioning of ecosystems, directly impacting biodiversity. This phenomenon is a particular concern for marine and coastal species, which, as well as being at risk of becoming trapped in plastic debris, frequently ingest this marine litter, often leading to the death of the animal. In addition, there is growing concern about the possible chemical contamination characteristic of plastic degradation.
The additives released, used to improve or give different properties to plastics, are usually not chemically bound to the polymer. This means that they can easily leach into the surrounding environment and accumulate in the tissues of different species, causing physiological problems.
Although polybrominated diphenyl ethers (PBDEs) are currently banned for causing endocrine problems, they are still present in the natural environment due to the leaching of plastic materials used decades before. More recently, methoxylated PBDEs (MeO-BDEs) have attracted the attention of researchers because they have been detected in different species, from low trophic positions to top predators, often in higher concentrations than PBDEs. Their potential for bioaccumulation and the fact that they share similar chemical structures to PBDEs indicate that these compounds can cause identical toxic effects in organisms.
As gulls are used as environmental indicators due to their large distribution area, trophic position and opportunistic behaviour, a team of researchers, including several members of MARE, assessed the absorption of PBDEs and MeO-BDEs in different tissues of Yellow-legged Gulls (Larus michahellis , YLG) and Audouin's Gulls ( Ichthyaetus audouinii , AG) and their effects on physiological and reproductive parameters.
The results of this study indicate that, in general, adult seagulls have an inhibited immune system and impaired neurofunction when they have high concentrations of these plastic additives in their tissues. Their chicks, on the other hand, showed inflammation and oxidative stress. In addition, there was a significant difference in sperm count, with implications for the fertility of these animals.
This study confirms the widespread presence of compounds associated with plastic and their harmful effects on gulls, particularly on neurofunction, the immune system, oxidative balance and fertility, especially due to the presence of MeO-BDEs. These results are an environmental and health concern for these animals and all elements of the trophic chain, and consequently also affect human health.
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