Biogeochemical Cycling of Heavy Metals in Lake Coeur d'Alene Sediments: The Role of Indigenous Microbial Communities

科达伦湖沉积物中重金属的生物地球化学循环：本土微生物群落的作用

• 批准号: 0420374
• 负责人: Brent Peyton
• 金额: --
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-15 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0420374&HistoricalAwards=false
• 关键词: Biogeochemical; Cycling; Heavy; Metals; Lake

0420374PeytonHeavy metals are highly toxic in the environment and their presence in sediments of Lake Coeur d'Alene (LCdA) in Idaho is mainly the result of historical mining in the mountains upstream. The objectives of this project are to 1) characterize the diversity of microorganisms in LCdA sediments using modern molecular biology techniques, 2) quantify the role of individual members of the microbial community in biogeochemical cycling of metals (Cu, Pb, and Zn), and 3) develop a dynamic numeric biogeochemical model of heavy metal cycling in sediment systems, calibrated to the unique environments of LCdA. These objectives will be met while testing the following overall hypothesis:A complex and dynamic community of phylogenetically distinct and previously uncharacterized microorganisms is present in the historically metal-contaminated sediments of Lake Coeur d'Alene. In response to a toxic metal stress, metal-tolerant species will dominate metal-sensitive species present in the sediments, with temporal and spatial microbial distribution and diversity dependant on the metal type and concentration. Dynamic biogeochemical models that incorporate chemical transport and reaction with novel microbial stress/response relationships and community dynamics can be used to 1) integrate complex microbial and geochemical observations across spatial and temporal scales, and 2) better predict broad community level response and influence on toxic metal cycling.Intellectual merit of the proposed activity: This project will significantly improve the quantitative understanding of interaction and response of a sediment microbial community subjected to severe heavy metal stress. Project objectives will be achieved by sampling LCdA sediments and identifying microbial diversity based on both 16S rDNA and rpoB gene sequences. These molecular techniques greatly facilitate the study of microbes in their natural environments and will provide a rational platform to base observations of community response to toxic metal additions. Shifts in microbial populations after being subjected to metal-stress will be quantified using terminal-restriction fragment length polymorphism (T-RFLP). Focused laboratory studies will be used to quantify the effects of toxic metals on microbial growth and inhibition for incorporation into the predictive model. The modeling effort will integrate for the first time to our knowledge, syntrophic consortium biotransformation dynamics, dose-dependent inhibition, and spatial and temporal dynamics of redox front formation under a diffusive transport regime. Broader impacts resulting from the proposed activity: While the research is focused on microbial communities in historically metal contaminated LCdA sediment, with increased industrialization worldwide, interactions of the environment and human contaminants have become more important issues, scientifically and socially, to the U.S. and internationally. The project integrates research mentoring and training of graduates, postdoctoral associate, and a research faculty. A supplemental grant for research experiences for undergraduates will be used to integrate undergraduate students into the research. The results will be published in a number of quality peer reviewed journal articles and will be conveyed to the public through presentations at local regulatory and public meetings, and at national and international conferences. An internet web site written for both scientists and non-technical readers will be developed. When complete, this research will significantly expand the fundamental and quantitative understanding of key biogeochemical processes for metals. The project has the potential to suggest fundamental improvements in metals-bioremediation technologies, since results will be broadly applicable in supporting innovative biological strategies to reduce human health risks and environmental damage from metal contaminated sites

0420374Peyton 重金属在环境中具有剧毒，它们在爱达荷州科达伦湖 (LCdA) 沉积物中的存在主要是上游山区历史上采矿的结果。 该项目的目标是 1) 使用现代分子生物学技术表征 LCdA 沉积物中微生物的多样性，2) 量化微生物群落单个成员在金属（铜、铅和锌）生物地球化学循环中的作用，以及3) 开发沉积物系统中重金属循环的动态数值生物地球化学模型，并根据 LCdA 的独特环境进行校准。 这些目标将在测试以下总体假设时得到实现：科达伦湖历史上受金属污染的沉积物中存在一个由系统发育上独特且以前未表征的微生物组成的复杂而动态的群落。 为了应对有毒金属胁迫，耐金属物种将主导沉积物中存在的金属敏感物种，微生物的时空分布和多样性取决于金属类型和浓度。 将化学运输和反应与新型微生物应激/响应关系和群落动态相结合的动态生物地球化学模型可用于 1) 整合跨空间和时间尺度的复杂微生物和地球化学观测结果，2) 更好地预测广泛的群落水平响应和对有毒物质的影响拟议活动的智力价值：该项目将显着提高对遭受严重重金属胁迫的沉积物微生物群落的相互作用和响应的定量理解。 项目目标将通过对 LCdA 沉积物进行采样并根据 16S rDNA 和 rpoB 基因序列识别微生物多样性来实现。 这些分子技术极大地促进了对自然环境中微生物的研究，并将提供一个合理的平台来观察群落对有毒金属添加物的反应。 受到金属胁迫后微生物种群的变化将使用末端限制性片段长度多态性 (T-RFLP) 进行量化。 重点实验室研究将用于量化有毒金属对微生物生长和抑制的影响，以便纳入预测模型。建模工作将首次整合我们的知识、互养联合体生物转化动力学、剂量依赖性抑制以及扩散传输机制下氧化还原前沿形成的空间和时间动力学。 拟议活动产生的更广泛影响：虽然该研究的重点是历史上受金属污染的 LCdA 沉积物中的微生物群落，但随着全球工业化程度的提高，环境和人类污染物的相互作用已成为美国和国际上更重要的科学和社会问题。 该项目整合了研究生、博士后助理和研究人员的研究指导和培训。 本科生研究经历的补充补助金将用于让本科生融入研究。 研究结果将发表在许多高质量的同行评审期刊文章中，并将通过在当地监管和公众会议以及国家和国际会议上的演示向公众传达。 将开发一个为科学家和非技术读者编写的互联网网站。 完成后，这项研究将显着扩展对金属关键生物地球化学过程的基本和定量理解。 该项目有可能对金属生物修复技术提出根本性改进，因为其结果将广泛应用于支持创新生物战略，以减少金属污染场地造成的人类健康风险和环境破坏