Marine pollution and, in particular, the presence of floating waste in seas and oceans poses a danger to the environment in general, with a consequence that until now is little known. Floating residual materials and objects are being used by various organisms as a support or method of transportation, so that they can reach new territories and become invasive species.
This sad reality has been pointed out in recent years by various studies and now has new evidence thanks to research in the waters of the southeastern coast of India with the participation of two researchers from the University of Barcelona and the Institute of Marine Sciences ( ICM-CSIC). The research, recently published in the journal Marine Pollution Bulletin, delves into the relationship between plastic pollution and the introduction of non-native organisms into Indian waters.
In recent years, increasing anthropogenic debris in the ocean has provided a wide range of substrates for the colonization of marine organisms. This accumulation of marine debris, which occurs especially near highly populated cities or tourist destinations, has inadvertently become a vector for the transport of fouling organisms, which can have far-reaching ecological and economic consequences.
To prepare the work, the research team, led by the Institut de Ciències del Mar (ICM-CSIC) and the Sathyabama Institute of Science and Technology, in collaboration with the University of Barcelona (UB), the Abdelmalek Essaadi University (UAE ) and the University of Oslo (UiO), carried out a comprehensive examination of organisms attached to various types of waste, whether plastic, glass, rubber, foam sponge, fabric, metal or wood. Their meticulous efforts revealed a surprising reality: a total of 3,130 specimens or colonies belonging to seven phyla and representing 17 species.
Specifically, the results reveal the presence, in abundance, of the invasive mussel Mytella strigata in fishing nets. “This finding highlights the important role of marine litter in facilitating the spread of invasive species, potentially disturbing the ecological balance of Indian waters,” explains Gunasekaran Kannan, the first author of the study.
“Litter items with high buoyancy, such as bottles, buoys and plastic bags, harbored abundant macroinvertebrate assemblages, suggesting their great potential for long-distance transport,” adds Kannan.
Among the most usual organisms associated with marine litter are the cosmopolitan bryozoans Jellyella tuberculata and J. eburnea, the percebes Lepas anserifera, Amphibalanus amphitrite and Amphibalanus sp., and the oysters Saccostrea cucullata and Magellan bilineata.
The team responsible highlights that this is the first research that identifies marine litter as a vector of species dispersal in India. “The results reveal the increasing risk of plastic colonization by invasive species along the southeast coast of India. This is especially worrying at a time when plastics are becoming an increasingly common substrate for marine organisms, especially in India, which is one of the countries that contributes the most to plastic pollution in the ocean,” explains Blanca Figuerola, member of the Medrecover Group and last author of the study, which calls for action. “to address plastic pollution and its related threats in India.”
“The predominance of plastic with attached organisms in marine litter is evident, since it represents 75.5% of the trash elements with embedded organisms found,” says Anna Sanchez-Vidal, associate professor at the Department of Earth Dynamics and Oceans of the UB, member of the Consolidated Research Group in Marine Geosciences of the UB and co-author of the study.
“Effective waste reduction and management campaigns, education and awareness are imperative to mitigate the introduction of invasive species through marine debris. Local and global stakeholders must come together to address this critical issue and protect fragile marine ecosystems from southeastern coast of India,” adds Sanchez-Vidal.
The team already warned in a recent study that plastic waste in the sea was contributing to the introduction and transport of non-native marine species on the Catalan coast. Given this scenario, they decided to expand the research in other regions in collaboration with other universities and research centers, which has allowed them to publish this latest work.
“These types of studies are also effective for the early detection of invasive species. However, it is essential to prioritize international cooperation to coordinate efforts aimed at reducing the proliferation of floating plastics and, ultimately, curbing the risk of transport of species invasive between oceans,” concludes Figuerola.
