Data from: Macrofouling communities and the degradation of plastic bags in the sea: an in situ experiment

The increasing amount of plastic littered into the sea may provide a new substratum for benthic organisms. These marine fouling communities on plastic have not received much scientific attention. We present, to our knowledge, the first comprehensive analysis of their macroscopic community composition, their primary production and the polymer degradation comparing conventional polyethylene (PE) and a biodegradable starch-based plastic blend in coastal benthic and pelagic habitats in the Mediterranean Sea. The biomass of the fouling layer increased significantly over time and all samples became heavy enough to sink to the seafloor. The fouling communities, consisting of 21 families, were distinct between habitats, but not between polymer types. Positive primary production was measured in the pelagic, but not in the benthic habitat, suggesting that large accumulations of floating plastic could pose a source of oxygen for local ecosystems, as well as a carbon sink. Contrary to PE, the biodegradable plastic showed a significant loss of tensile strength and disintegrated over time in both habitats. These results indicate that in the marine environment, biodegradable polymers may disintegrate at higher rates than conventional polymers. This should be considered for the development of new materials, environmental risk assessment and waste management strategies.越来越多被弃置于海洋的塑料垃圾，可为底栖生物（benthic organisms）提供全新的附着基底。然而，这类附着于塑料表面的海洋污损群落（marine fouling communities）尚未得到足够的科学关注。据我们所知，本研究首次针对地中海沿岸底栖生境与水层生境中，传统聚乙烯（PE）及可降解淀粉基塑料共混物上的大型群落组成、初级生产力与聚合物降解情况开展全面分析。 随时间推移，污损层的生物量显著增长，所有样本最终均达到足以沉至海底的重量。该污损群落共涵盖21个科，其群落组成在不同生境间存在显著差异，但在不同聚合物类型间并无明显区分。研究在水层生境中检测到正向初级生产力，而底栖生境中未检测到该现象，这表明大量漂浮塑料聚集体或可为当地生态系统提供氧气来源，同时亦可作为碳汇。 与PE不同，可降解淀粉基塑料在两种生境中均表现出拉伸强度的显著损失，并随时间发生降解破碎。上述结果表明，在海洋环境中，可降解聚合物的降解速率可能高于传统聚合物。这一点在新型材料开发、环境风险评估以及废弃物管理策略制定过程中均应予以充分考量。