杏MAP导航

By Federico Citterich 

Sunday, 2 February, marked World Wetlands Day. The theme chosen for 2025 is 鈥淧rotecting Wetlands for Our Common Future鈥� which highlights the vital role wetlands play in our ecosystem 鈥� and the growing threats they face, including plastic pollution. Wetlands in fact, provide extremely sensitive ecosystems, yet they are often understudied, particularly in the context of plastic pollution.

鈥淐urrently, there isn鈥檛 a global solution to plastic pollution鈥�, said Davide Taurozzi, a PhD candidate at Roma Tre鈥檚 Science Department. 鈥淐onsidering this, it is also important to recognise its few positive aspects鈥�.

Amongst these, a recent study suggests that plastic materials deposited in coastal wetlands may facilitate the colonisation of primary producers and consumers, life forms at the foundation of the food chain that can, in turn, support the proliferation of higher organisms.

鈥淥ur starting point was to investigate whether macroplastics 鈥� plastic items larger than 5 cm in size 鈥� in coastal wetlands could serve as an additional substrate for colonisation by small invertebrates鈥�, explained Taurozzi, first author of the study.

To do this, the researchers placed previously unexposed polystyrene and polyethylene terephthalate (PET) components on the surface and at a depth of up to two meters in a wetland at Torre Flavia, near Rome, and found that small invertebrates actively colonised all the samples.

鈥淏y active colonisation, we mean that the organisms reached the plastic sites by swimming towards them, rather than being transported by atmospheric agents such as winds鈥�, highlighted Taurozzi. 鈥淭his suggests that the organisms specifically selected the plastic as a substrate, indicating a preference for it over other available surfaces鈥�.

All that glitters is not gold

鈥淥bviously, this does not mean that from now on we have to purposely release plastics in wetlands鈥�, said Taurozzi. 鈥淲e always have to remember that plastic pollution creates colossal problems鈥�.

Among these, the authors mentioned the release of additives in the environment, plastic entanglement, and plastic ingestion.

鈥淚n addition, macroplastics can serve as a surface onto which not only small invertebrates but also microorganisms can grow and develop鈥�, explained Taurozzi. 鈥淭hey become functional plastic-based micro-ecosystems, known as plastispheres鈥�.

Among the microorganisms found on macroplastics, viruses and bacteria are the most concerning.

"Winds and currents can carry macroplastics across vast distances, potentially introducing pathogens to areas where they were previously absent鈥�, said Taurozzi. "This could lead to detrimental effects, as some species 鈥� having never been exposed to those pathogens 鈥� may lack the immune defences necessary to combat them鈥�.

Furthermore, macroplastic transfer can transport invasive species into new ecosystems. Invasive species are introduced organisms that ecologically harm their new environments, having negative effects on local organisms.

Macro- and microplastics

Macroplastics can also break down into smaller fragments. When these fragments become smaller than 5 mm, they are known as microplastics.

鈥淒ue to their extremely small size and our current limitations in engineering and ecological knowledge, removing microplastics from the environment is 鈥� at present 鈥� impossible鈥�, warned Taurozzi.

However, even when removal is theoretically possible 鈥� as in the case of macroplastics 鈥� the enormous quantities of these materials in the environment make their extraction unachievable.

Future perspectives

鈥淥ur study is the first of its kind鈥�, highlighted Taurozzi. 鈥淚t鈥檚 the first time anyone has investigated virgin macroplastic colonisation in a wetland鈥�.

鈥淗ence, it is essential to further assess how small invertebrates colonise not only plastic materials but also natural substrates such as wood or plant matter鈥�, he explained. In addition, the authors believe it would be useful to compare their results to similar studies carried out in different environments.

"We present what can be considered positive results, but the goal is always to prevent and avoid pollution", concluded Taurozzi. 鈥淭his is particularly true for sensitive ecosystems such as wetlands鈥�.