Institute of Polar Sciences, National Research Council (CNR-ISP), Spianata S. Raineri 86, 98122 Messina, Italy.
Water Research Institute, National Research Council (CNR-IRSA), Via Salaria km 29.300 CP10, 00015 Monterotondo, Rome, Italy; National Biodiversity Future Center, Piazza Marina 61, 90133 Palermo, Italy.
Sci Total Environ. 2024 Sep 15;943:173773. doi: 10.1016/j.scitotenv.2024.173773. Epub 2024 Jun 5.
Microbial colonization on plastic polymers has been extensively explored, however the temporal dynamics of biofilm community in Antarctic environments are almost unknown. As a contribute to fill this knowledge gap, the structural characteristics and microbial diversity of the biofilm associated with polyvinyl chloride (PVC) and polyethylene (PE) panels submerged at 5 m of depth and collected after 3, 9 and 12 months were investigated in four coastal sites of the Ross Sea. Additional panels placed at 5 and 20 m were retrieved after 12 months. Chemical characterization was performed by FTIR-ATR and Raman (through Surface-Enhanced Raman Scattering, SERS) spectroscopy. Bacterial community composition was quantified at a single cell level by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) and Confocal Laser Scanning Microscopy (CLSM); microbial diversity was assessed by 16S rRNA gene sequencing. This multidisciplinary approach has provided new insights into microbial community dynamics during biofouling process, shedding light on the biofilm diversity and temporal succession on plastic substrates in the Ross Sea. Significant differences between free-living and microbial biofilm communities were found, with a more consolidated and structured community composition on PVC compared to PE. Spectral features ascribable to tyrosine, polysaccharides, nucleic acids and lipids characterized the PVC-associated biofilms. Pseudomonadota (among Gamma-proteobacteria) and Alpha-proteobacteria dominated the microbial biofilm community. Interestingly, in Road Bay, close to the Italian "Mario Zucchelli" research station, the biofilm growth - already observed during summer season, after 3 months of submersion - continued afterwards leading to a massive microbial abundance at the end of winter (after 12 months). After 3 months, higher percentages of Gamma-proteobacteria in Road Bay than in the not-impacted site were found. These observations lead us to hypothesize that in this site microbial fouling developed during the first 3 months could serve as a starter pioneering community stimulating the successive growth during winter.
微生物在塑料聚合物上的定殖已得到广泛研究，但南极环境中生物膜群落的时间动态几乎未知。为了填补这一知识空白，本研究调查了罗斯海四个沿海地点深度为 5 米处、收集时间分别为 3、9 和 12 个月的聚氯乙烯 (PVC) 和聚乙烯 (PE) 面板相关生物膜的结构特征和微生物多样性。另外，还在 5 和 20 米深度处放置了相同的面板，并在 12 个月后取回。通过傅里叶变换衰减全反射红外光谱 (FTIR-ATR) 和拉曼光谱（通过表面增强拉曼散射，SERS）进行化学特性分析。通过催化报告物沉积荧光原位杂交 (CARD-FISH) 和共聚焦激光扫描显微镜 (CLSM) 在单细胞水平上定量细菌群落组成；通过 16S rRNA 基因测序评估微生物多样性。这种多学科方法提供了生物膜形成过程中微生物群落动态的新见解，揭示了罗斯海塑料基质上生物膜多样性和时间演替。发现自由生活和微生物生物膜群落之间存在显著差异，与 PE 相比，PVC 上的生物膜群落组成更牢固和结构化。可归因于酪氨酸、多糖、核酸和脂质的光谱特征表征了与 PVC 相关的生物膜。变形菌门（包括γ-变形菌门）和α-变形菌门主导着微生物生物膜群落。有趣的是，在靠近意大利“马里奥·祖凯里”研究站的罗兹湾，生物膜生长 - 在浸入水中 3 个月后，已经在夏季观察到 - 之后继续生长，导致冬季末（12 个月后）微生物丰度大量增加。在罗兹湾，与未受影响的地点相比，3 个月后γ-变形菌门的比例更高。这些观察结果使我们假设，在这个地点，在前 3 个月内发展的微生物污垢可能充当先驱社区，刺激冬季的后续生长。
