Visualizing Microbial Communities on Plastic Marine Debris: Identification, Interactions and Impacts

海洋塑料废弃物（PMD）是全球海洋中日益严重的人为污染物。已经报道了由于缠绕或缠绕对海洋动物的影响，然而，PMD对微生物的影响，例如形成食物网基础的细菌，古生菌或原生生物，知之甚少。由于PMD的特殊性质，它可以作为某些微生物的新栖息地，并且似乎能够长距离运输甚至有害的微生物并将其分布在外国海洋制度中。此外，PMD使微生物能够在近距离内长时间生存，这可能会影响不同化合物的途径。为了了解PMD相关微生物对海洋环境的影响，我们需要确定PMD上微生物群落的组成和相互作用以及它们在全球的分布情况。我将表征的多样性和空间分布的微生物群落居住在PMD已经收集从地理上不同的海洋区域（大西洋，太平洋，印度洋，地中海和加勒比海）。我的目标是：1）确定PMD上存在哪些微生物; 2）调查PMD和生物基塑料上存在的微生物群落的空间结构; 3）检查哪些微生物与塑料聚合物表面最密切相关; 4）调查不同海洋区域的PMD特征是否存在核心微生物组;以及5）在环境样品中和在使用天然组合物的培养实验中以及在已经被鉴定为推定的烃降解剂的微生物中，检查哪些微生物可以降解PMD。从这个项目中获得成功结果的机会很高，因为样品已经可以应用一种称为CLASIFISH（组合标记和光谱成像荧光原位杂交）的创新显微技术。这种技术可以在一块PMD上快速准确地识别数百种不同的微生物类群及其空间分布。CLASI-FISH是在我所在的机构开发的，我的东道主Amaral-Zettler教授将训练我设计适当的系统发育探针，并进行经典FISH实验和CLASI-FISH实验。当我熟练使用这些方法时，我将把它们应用于在大西洋和太平洋收集的不同样品，以及含有尚未确定的PMD潜在降解剂的天然样品。此外，我将在我的宿主实验室中使用Plastisphere细菌培养物进行孵育实验。这些实验将包括研究微生物组合如何随着时间的推移在生物基塑料上发展，以及这些微生物是否/如何降解塑料。在这些孵育实验中，我将应用FISH和CLASIFISH方法，以及扫描电子显微镜，宏基因组学和元转录组学方法，如果可行的话。

Plastic marine debris (PMD) is an increasing anthropogenic pollutant in the global ocean. The effects on marine animals due to entanglement or ingesting have been reported, however, the effect of PMD on microorganisms, such as bacteria, archaea or protists that form the base of the food web, is poorly known. Due to the special properties of PMD, it can serve as a new habitat for certain microbes and seems to be able to transport even harmful microbes over long distances and distribute them in foreign marine regimes. Moreover, PMD enables microbes to live for a long time in close proximity, which might influence the pathways of different chemical compounds. To understand the impact of PMD associated microbes on marine environments, we need to identify the composition and interactions of the microbial communities on PMD and how they are globally distributed. I will characterize the diversity and the spatial distribution of microbial communities residing on PMD already collected from biogeographically diverse marine regions (Atlantic, Pacific, Indian Ocean, Mediterranean and Caribbean Sea). I aim to: 1) identify which microbes are occurring on PMD; 2) investigate the spatial structure of the microbial communities residing on PMD and bio-based plastics; 3) examine which microbes are most closely associated with the plastic polymer surface; 4) investigate if there are core microbiomes on PMD characteristic for different oceanic regions; and, 5) examine which microbes can degrade PMD in environmental samples and in incubation experiments using natural assemblages and microbes already identified as putative hydrocarbon degraders. The chances of obtaining successful outcomes from this project are high, because samples are already available on which to apply an innovative microscopy technique called CLASIFISH (Combinatorial Labelling and Spectral Imaging Fluorescence In Situ Hybridization). This technique enables fast and precise identification of hundreds of different microbial taxa, and their spatial distribution, on a single piece of PMD. CLASI-FISH was developed at my host institution, and my host, Prof. Dr. Amaral-Zettler will train me to design appropriate phylogenetic probes and conduct classical FISH experiments, as well as CLASI-FISH experiments. When I am proficient with the methods, I will apply them to different samples collected in the Atlantic and Pacific Ocean and to natural samples containing potential degraders of PMD that have yet to be identified. Additionally, I will conduct incubation experiments with Plastisphere bacterial cultures maintained in my host laboratory. These experiments will include investigations of how microbial assemblages develop over time on bio-based plastics, and if/how these microbes degrade plastic. During these incubation experiments, I will apply FISH and CLASIFISH methods, as well as scanning electron microscopy, metagenomics and metatranscriptomic approaches, as feasible.