Impact of human disturbance on temporal partitioning within carnivore communities

• Published in: Global Change Biology
• Main Authors: Nava, Veronica, Matías, Miguel G., Castillo-Escrivà, Andreu, Messyasz, Beata, Leoni, Barbara
• Other Authors: European Commission, Ministerio de Economía y Competitividad (España), Università degli Studi di Milano-Bicocca
• Format: Article in Journal/Newspaper
• Language: English
• Published: John Wiley & Sons 2022
• Subjects: Biofouling; Epiplastic community; Periphyton; Phytobenthos; Plastic colonization; Plastisphere; Arctic
• Online Access: http://hdl.handle.net/10261/267536; https://doi.org/10.1111/gcb.15989

A variety of organisms can colonize microplastic surfaces through biofouling processes. Heterotrophic bacteria tend to be the focus of plastisphere research; however, the presence of epiplastic microalgae within the biofilm has been repeatedly documented. Despite the relevance of biofouling in determining the fate and effects of microplastics in aquatic systems, data about this process are still scarce, especially for freshwater ecosystems. Here, our goal was to evaluate the biomass develop-ment and species composition of biofilms on different plastic polymers and to in-vestigate whether plastic substrates exert a strong enough selection to drive species sorting, overcoming other niche-defining factors. We added microplastic pellets of high- density polyethylene (HDPE), polyethylene terephthalate (PET), and a mix of the two polymers in 15 lentic mesocosms in five different locations of the Iberian Peninsula, and after one month, we evaluated species composition and biomass of microalgae developed on plastic surfaces. Our results, based on 45 samples, showed that colonization of plastic surfaces occurred in a range of lentic ecosystems covering a wide geographical gradient and different environmental conditions (e.g., nutrient concentration, conductivity, macrophyte coverage). We highlighted that total bio-mass differed based on the polymer considered, with higher biomass developed on PET substrate compared to HDPE. Microplastics supported the growth of a rich and diversified community of microalgae (242 species), with some cosmopolite species. However, we did not observe species-specificity in the colonization of the different plastic polymers. Local species pool and nutrient concentration rather than polymeric composition seemed to be the determinant factor defying the community diversity. Regardless of specific environmental conditions, we showed that many species could coexist on the surface of relatively small plastic items, highlighting how microplastics may have considerable carrying capacity, with possible consequences on the wider ecological context. This work was supported by EU H2020-INFRAIA-project No 731065 “AQUACOSM: Network of Leading European AQUAtic MesoCOSM Facilities Connecting Mountains to Oceans from the Arctic to the Mediterranean”. MGM was funded by grant RyC-2016-19348 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future.” Raman facilities were provided by the Department of Earth and Environmental Sciences (DISAT, University of Milano- Bicocca, Italy, Peer reviewed