Geomicrobial response to environmental stress-functional implications of identifying thresholds in anthropogenic gradients

地球微生物对环境胁迫的响应-识别人为梯度阈值的功能影响

• 批准号: RGPIN-2022-02939
• 负责人: Weisener, Christopher
• 金额: $ 2.19万
• 依托单位: University of Windsor
• 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=755167
• 关键词: Geomicrobial; response; environmental; stress; functional

Agricultural land and urban pressures on the terrestrial-freshwater interface can lead to increased stress on biota, poor water quality and can be an impediment to ecosystem health. A long-standing approach to ecosystem assessment uses biological integrity (BI) measures contrasting biological attributes of degraded environments to those of more desirable, minimally impacted ones. However, anthropogenic activity produces diverse materials that stress biota, salts, nutrients, hydrocarbons, metals, and xenobiotics. A critical knowledge gap is to identify measures of BI diagnostic of the key microbially-mediated transformations of those materials in sediment and water and determining whether how these processes can ameliorate the stress. The sediment/water interface plays an important role in biogeochemical cycles (e.g., P, N, S, C, Fe and Si) and water quality. Although this ecotone harbors a vast array of microbial taxa, their dominant functional characteristics and resilience to increasing environmental stress e.g., anthropogenic pressures, environmental extremes are largely unknown. For example, studies of eutrophication involving P and N sediment dynamics have focused on adsorption/desorption mechanisms associated with metal oxides and their redox transformations (e.g., nitrogen fixation, mineralization (decay), nitrification and denitrification). However, these measures can be system specific as the essential microbial component is a black box in modelling and conceptual characterization. Our approach to understanding microbial functional expression coupled with geochemical methods show clear connections between microbial community response to redox fluctuations and mineral dissolution in the presence of bacteria, which can lead to specific pathways of metal and nutrient release and explain how the bacteria benefit from this electron exchange metabolism. Using microbial and analytic techniques in laboratory and field-based programs, this hypothesis driven research program will expand our understanding of bacterial response to anthropogenic pressure in aquatic freshwater sediments. We will identify the mechanistic and functional roles of bacteria at the sediment water interface in transforming key materials of concern that characterize classes of stressed habitats. Results will be shared in a new omics database and used to refine models of biogeochemical cycling in stress impacted ecosystems and improve understanding of microbial heterotopic function. Maintaining sustainable freshwater resources is essential to Canada's socio-economic sustainability through agriculture, industry, people, and tourism. This program will document the critical role that bacteria play in controlling metal and nutrient dynamics in natural freshwater ecosystems subject to anthropogenic stress. By identifying key biomarkers of gene expression, we will advance the application of tool based open arrays for assessing contaminants in terrestrial and aquatic ecosystems.

农业用地和城市对陆地-淡水界面的压力可能导致对生物群的压力增加，水质变差，并可能阻碍生态系统的健康。一种长期存在的生态系统评估方法使用生物完整性(BI)措施，将退化环境的生物属性与更理想、受影响最小的环境的生物属性进行对比。然而，人类活动产生了各种各样的物质，这些物质对生物群、盐、营养物质、碳氢化合物、金属和外来生物构成了压力。一个关键的知识缺口是确定对这些物质在沉积物和水中的关键微生物介导的转化进行BI诊断的措施，并确定这些过程是否可以改善压力。沉积物/水界面在生物地球化学循环(如P、N、S、C、Fe和Si)和水质中起着重要作用。虽然这个交错带蕴藏着大量的微生物类群，但它们的主要功能特征和对日益增加的环境压力(如人为压力、环境极端情况)的适应能力在很大程度上是未知的。例如，涉及磷和氮沉积物动力学的富营养化研究侧重于与金属氧化物相关的吸附/解吸机制及其氧化还原转化(例如，固氮、矿化(腐烂)、硝化和反硝化)。然而，这些措施可以是系统特有的，因为基本的微生物成分在建模和概念描述中是一个黑匣子。我们了解微生物功能表达的方法结合地球化学方法表明，微生物群落对氧化还原波动的反应与细菌存在下的矿物溶解之间存在明显的联系，这可能导致金属和养分释放的特定途径，并解释细菌如何从这种电子交换代谢中受益。利用实验室和现场项目中的微生物和分析技术，这一假设驱动的研究项目将扩大我们对水生淡水沉积物中细菌对人为压力的响应的理解。我们将确定细菌在沉积物-水界面转化关键材料方面的机制和功能作用，这些材料是表征受压力的生境类别的特征。结果将在一个新的组学数据库中共享，并用于改进受压力影响的生态系统中的生物地球化学循环模型，并提高对微生物异位功能的理解。通过农业、工业、人口和旅游业，维持可持续的淡水资源对加拿大的社会经济可持续性至关重要。该计划将记录细菌在自然淡水生态系统中控制金属和营养动态的关键作用，这些生态系统受到人为压力的影响。通过识别基因表达的关键生物标记物，我们将推动基于工具的开放阵列的应用，以评估陆地和水生态系统中的污染物。