PAthways of Chemcials Into Freshwaters and their ecological ImpaCts (PACIFIC)

人造化学品对维持公众健康、食品生产和生活质量至关重要，包括各种药品、杀虫剂和个人护理产品。这些化合物在整个社会的使用导致了环境中的浓度和化学多样性的增加。虽然人们把重点放在了解化学品对淡水生物多样性(特别是无脊椎动物和鱼类)的影响上，但我们对化学污染如何影响淡水微生物了解较少。这些微生物群落(“微生物群”)每毫升水或每克沉积物有数百万到数十亿个细胞，构成了淡水生态系统中生物多样性和功能最重要的组成部分。淡水微生物提供的生物地球化学和生态功能对更广泛的淡水生态系统健康至关重要。化学品进入淡水的途径及其生态影响(太平洋)项目将侧重于了解淡水生态系统中人为化学品的来源及其途径、命运和生态影响之间的联系，重点是淡水微生物生态系统及其发挥的功能。我们将研究泰晤士河和布里斯托尔埃文河流域的预测扩散和点源化学路径与水和沉积物中测量的化学浓度之间的关系，这两个流域被选为代表扩散污染源的梯度。这些地点的选择将与污水处理厂(WWTW)相吻合，以了解污水如何通过这些梯度对化学负荷造成影响。将使用液相色谱结合(高分辨率)串联质谱仪和QTOF(飞行时间四极杆)质谱仪，对已证实和怀疑会影响淡水生态的化学物质进行有针对性和无针对性的分析。我们还将在每个地点测量一系列微生物群落生态系统端点，以确定化学暴露的影响，包括通过DNA测序的细菌和真菌群落组成，营养循环和化学胁迫和抗性基因的表达，与生物地球化学循环有关的胞外酶的产生，以及整个微生物群落的功能基因库。我们将对淡水微生物群落进行实验微宇宙暴露，增加复杂性和现实性，部署高通量筛选，以确定具有重建这些群落能力的新的化学类群(及其结构特征)。将通过应用尖端分子技术来确定代表淡水微生物生态系统不同分类和功能方面的生态暴露阈值，对示范微生物群落修饰化学品进行更详细的研究。新的基于现场的中观系统将用于在更现实但可控的环境中探索废水暴露，使我们能够探索化学污染如何与其他生态驱动因素(如营养物质和温度)相互作用，以及微生物响应如何放大到更高的营养水平并改变生态系统功能。扩散和点源化学污染路径的空间和时间放大模型将与实验室和野外暴露开发的新阈值相结合，以确定对淡水微生物的化学威胁，支持开发工具更好地管理化学污染对淡水生态系统健康的风险。这些将与未来的水文、气候和社会经济情景结合起来，从我们实验中的反应中获得信息，并与项目合作者环境署共同制定，以探索未来对微生物淡水生态系统和更广泛的生态系统健康的威胁。

Manufactured chemicals are essential for the maintenance of public health, food production and quality of life, including a diverse range of pharmaceuticals, pesticides, and personal care products. The use of these compounds throughout society has led to increasing concentrations and chemodiversity in the environment. Whilst there has been focus on understanding the impacts of chemicals on a subset of freshwater biodiversity (particularly invertebrates and fish), we understand less about how chemical pollution impacts freshwater microbes. These microbial communities (the 'microbiome') number in the millions to billions of cells per millilitre of water or gram of sediment and form the most biodiverse and functionally important component of freshwater ecosystems. The biogeochemical and ecological functions delivered by freshwater microbes are essential to wider freshwater ecosystem health. The PAthways of Chemicals Into Freshwaters and their ecological ImpaCts (PACIFIC) project will focus on understanding the link between sources of anthropogenic chemicals and their pathways, fate and ecological impacts in freshwater ecosystems, with an emphasis on freshwater microbial ecosystems and the functions they perform. We will investigate the relationship between predicted diffuse and point source chemical pathways and measured chemical concentrations in water and sediments at locations across the Thames and Bristol Avon catchments, chosen to represent gradients of diffuse pollution sources. These locations will be chosen to coincide with Wastewater Treatment Works (WwTWs) to understand how sewage effluent contributes to chemical burden across these gradients. Liquid chromatography coupled with (high resolution) tandem mass spectrometry and QTOF (quadrupole Time-of-Flight) mass spectrometry will be used to perform targeted and untargeted profiling of chemical groups proven and suspected to impact freshwater ecology. A range of microbial community ecosystem endpoints will also be measured at each location to identify the impact of chemical exposure, including bacterial and fungal community composition via DNA sequencing, the expression of nutrient cycling and chemical stress and resistance genes, the production of extracellular enzymes involved with biogeochemical cycling, and the functional gene repertoire of whole microbial communities.We will perform experimental microcosm exposures on freshwater microbial communities, with increasing complexity and realism, deploying high-throughput screening to identify novel chemical groups (and their structural features) with the capacity to restructure these communities. Exemplar microbial community modifying chemicals will be investigated in more detail by applying cutting-edge molecular techniques to determine ecological exposure thresholds that represent different taxonomic and functional aspects of freshwater microbial ecosystems. Novel field based mesocosms will be used to explore wastewater exposures in more realistic, but controlled settings, allowing us to explore how chemical pollution may interact with other ecological drivers such as nutrients and temperature, and how microbial responses scale-up to higher trophic levels and alter ecosystem functioning.Spatially and temporally up-scaled models of diffuse and point source chemical pollution pathways will be combined with novel thresholds developed from the lab and field exposures, to determine chemical threats to freshwater microbes, supporting the development of tools for the better management of the risks of chemical pollution to freshwater ecosystem health. These will be combined with future hydrological, climate and socio-economic scenarios, informed by responses in our experiments, and co-developed with project collaborators, the Environment Agency, to explore future threats to microbial freshwater ecosystems and wider ecosystem health.