Effects of municipal wastewaters on aquatic-nearshore food webs

城市废水对水生近岸食物网的影响

• 批准号: RGPIN-2021-02704
• 负责人: Kidd, Karen
• 金额: $ 4.01万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745762
• 关键词: Effects; municipal; wastewaters; aquatic; nearshore

Terrestrial and aquatic ecosystems are tightly linked through the runoff of materials from land to water and the return of these materials via emergent aquatic insects to nearshore (riparian) predators. However, these energetic links can be disrupted by contaminants because they impact the abundance of aquatic insect larvae and subsequent prey available to riparian predators. Our understanding of how contaminants disrupt aquatic-riparian linkages is mainly limited to highly contaminated, industrial sites. Municipal wastewaters are the largest human inputs by volume to Canadian surface waters and contain excess nutrients and a wide range of contaminants including antimicrobials (antibiotics, disinfectants). Our previous work at wastewater-impacted sites revealed that fish, larval insects and riparian spiders have altered microbiomes but it is unclear whether these effects occur at other sites and the mechanisms behind these shifts (i.e., exposures to antimicrobials, shifts in dietary habits). Given that the microbiome is critical for energy provision, immune function, etc., in their hosts, changes in its diversity and composition may lead to adverse effects in individuals. In addition, the excess nutrients and contaminants may impact aquatic food web structure and aquatic-terrestrial linkages, which can be assessed because the unique isotopic values of nitrogen in these effluents are incorporated into the downstream food web. The long-term objective of my Discovery program is to understand the ecological risks posed directly or indirectly by contaminants in aquatic and riparian environments. This will be met through short-term objectives that determine how municipal wastewater effluents and the antimicrobials they contain affect: 1) microbiomes, tissue antimicrobials, and energy sources of diverse aquatic species; 2) water-land subsidies via emergent aquatic insects to riparian spiders and their microbiomes and antimicrobial levels; and 3) biofilms, leaf litter decomposition and macroinvertebrate microbiomes. For Obj. 1 and 2, food web sampling will be done upstream and downstream of effluent discharges to assess changes in its structure and reliance of macroinvertebrates, fish and spiders on wastewater-associated nutrients using stable C and N isotope ratios. Biological samples and surface water will be analyzed for antibiotics to assess their fate. Host microbiomes are characterized using the 16S rRNA gene of the V3-V4 region and Illumina sequencing and assessed for changes in diversity and relative abundance and the presence of wastewater-derived bacteria. Mesocosm experiments (Obj. 3) using mixtures of antimicrobials will determine effects on the microbiomes and growth of macroinvertebrates and ecosystem functions (e.g., decomposition). Overall, the program will address how these substantial discharges into Canadian surface waters are affecting key ecosystem processes and advance knowledge on the fate and effects of antimicrobials.

陆地和水生生态系统通过物质从陆地径流到水中以及这些物质通过新兴水生昆虫返回到近岸（河岸）捕食者而紧密相连。然而，这些充满活力的联系可能会被污染物破坏，因为它们会影响水生昆虫幼虫的丰度，并随后影响河岸捕食者的猎物。我们对污染物如何破坏水生-河岸联系的理解主要限于高度污染的工业场地。 城市废水沃茨是加拿大地表沃茨中最大的人类输入量，含有过量的营养物质和各种污染物，包括抗菌剂（抗生素、消毒剂）。我们以前在受废水影响的地点的工作表明，鱼类、幼虫昆虫和河岸蜘蛛改变了微生物组，但目前还不清楚这些影响是否发生在其他地点以及这些变化背后的机制（即，暴露于抗菌剂、饮食习惯改变）。鉴于微生物组对能量供应、免疫功能等至关重要，在其宿主中，其多样性和组成的变化可能导致对个体的不利影响。此外，过量的营养物质和污染物可能会影响水生食物网结构和水生-陆地联系，这是可以评估的，因为这些废水中氮的独特同位素值被纳入下游食物网。我的探索计划的长期目标是了解水生和河岸环境中污染物直接或间接造成的生态风险。这将通过短期目标来实现，这些目标确定城市污水及其所含的抗菌剂如何影响：1）微生物组，组织抗菌剂和各种水生物种的能源; 2）通过新兴水生昆虫对河岸蜘蛛及其微生物组和抗菌水平的水陆补贴; 3）生物膜，落叶分解和大型无脊椎动物微生物组。对于目标1和2，将在废水排放的上游和下游进行食物网取样，以评估其结构的变化以及大型无脊椎动物、鱼类和蜘蛛对废水相关营养物的依赖，使用稳定的C和N同位素比率。将对生物样本和地表水进行抗生素分析，以评估它们的命运。使用V3-V4区域的16 S rRNA基因和Illumina测序表征宿主微生物组，并评估多样性和相对丰度的变化以及废水衍生细菌的存在。使用抗菌剂混合物的围隔实验（目标3）将确定对微生物群落和大型无脊椎动物生长以及生态系统功能（例如，分解）。总的来说，该计划将解决这些大量排放到加拿大地表沃茨是如何影响关键的生态系统过程和先进的知识的命运和影响的抗菌剂。