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| Main Authors: | , , , , , |
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| Format: | Recurso digital |
| Language: | |
| Published: |
Zenodo
2025
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| Online Access: | https://doi.org/10.5281/zenodo.17882580 |
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Table of Contents:
- <p><strong><span lang="EN-GB"> </span></strong></p> <p><span lang="EN-GB">The rapid rise of biodegradable plastics, particularly starch-based polymers like Mater-Bi, is often promoted as a sustainable solution to global plastic pollution. However, their biogeochemical and ecological impacts in freshwater ecosystems, key pathways for terrestrial waste, remain poorly understood. We conducted a full-factorial microcosm experiment (3 treatments × 2 temperatures × 6 sampling times × triplicate) using natural riverine microbial communities exposed to Mater-Bi at 20 °C and 30 °C over 20 days. The system employed dechlorinated tap water to simulate nutrient-limited conditions and isolate the bioplastic’s role as an external nutrient source. Mater-Bi exhibited significant degradation (4–8% weight loss; p < 0.001), enhanced at 30 °C (F = 5.11, p < 0.05), leading to an eightfold increase in dissolved organic carbon (DOC). Microbial communities acted as active carbon sinks, with greater DOC consumption in combined treatments, especially at 30 °C (net uptake = 15.13 mg L</span><span lang="EN-GB">⁻</span><span lang="EN-GB">¹; p = 0.029). This carbon release induced strong functional shifts: bacterial density and β-glucosidase activity increased, while algal biomass declined 25–40% (p < 0.001), likely due to nitrogen limitation rather than toxicity, as photosystem II efficiency remained stable. Multivariate analysis (PERMANOVA, R² = 32.9; p < 0.001) identified Mater-Bi as the dominant factor structuring communities, with temperature amplifying its effects. Overall, Mater-Bi acts as a bioactive carbon source, promoting heterotrophy through stoichiometric imbalance. These results suggest that warming may intensify the ecological footprint of biodegradable plastics, potentially shifting riverine benthic communities from net producers to net consumers of energy. Incorporating these biogeochemical effects into environmental risk assessments is urgently needed.</span></p>