Collaborative Research: Influence of phosphorus deficiency on enigmatic biological methane production in oxic freshwater lakes

合作研究：缺磷对含氧淡水湖神秘生物甲烷生产的影响

• 批准号: 1951002
• 负责人: Matthew Church
• 金额: $ 48.59万
• 依托单位: University of Montana
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951002&HistoricalAwards=false
• 关键词: Collaborative; Research; Influence; phosphorus; deficiency

Atmospheric levels of methane have risen 150% since the Industrial Revolution, and continue to increase. Although energy sector and agricultural sources are major contributors, natural microbiological sources account for roughly half of total global methane emissions. Microbial methane production has long been assumed to be an anoxic process, carried out only under conditions of extremely low to zero oxygen. Recent research has demonstrated the potential for microbial methane production to occur in oxygenated upper waters of lakes and oceans through a previously unappreciated metabolic pathway present in microorganisms. Under conditions of phosphorus deficiency, certain bacteria can utilize otherwise unreactive organic molecules known as methylphosphonates to meet their phosphorus requirements, releasing methane in the process. The extent to which this mechanism supports the out-gassing of methane from lakes to the atmosphere is unknown, as are the consequences of changing environmental conditions upon it. This project will address this knowledge gap by investigating the distributions, rates of and controls on aerobic methane production in Flathead Lake and 18 other Montana lakes of varying phosphorus deficiency status. Because atmospheric deposition of pollutant nitrogen and deliberate measures to curtail phosphorus inputs to lakes can both lead to phosphorus deficiency, it is crucial that we know whether these factors may have the unexpected consequence of enhancing methane emissions. This research will also directly support the education, field and laboratory experiences of graduate and undergraduate students and will provide training to local high school teachers from Native American (Kootenai and Salish) tribal lands.This project will evaluate temporal and spatial variability in microbially-mediated, oxic methane production across lakes with varying phosphorus availability in western Montana. It is guided by the overarching hypothesis: diffusive effluxes of methane from oxic freshwater lakes are directly influenced by the nature and severity of ecosystem nutrient (nitrogen, phosphorus) deficiencies. A combination of observational and experimental approaches employing chemical, stable isotopic, metagenomic and PCR-based gene analyses will be used to examine: 1) time and space variability in the concentration, stable isotope composition, and net production of methane in freshwater lakes in Montana, focusing on Flathead Lake; 2) The extent to which microbial methylphosphonate degradation results in net production of methane in these lakes; 3) The functional diversity, abundances, and transcriptional activities of microorganisms involved in both phosphonate and methane cycling; and 4) How the stoichiometry (specifically nitrogen:phosphorus ratios) of aquatic nutrient (inorganic and total) pools influences oxic methane production and expression of methane cycling functional genes. The study will provide a systematic evaluation of microbial methane sources and the potential contribution of methylphosphonate degradation as a source of methane in oxic freshwater lakes. Results from this project will provide new insights and advance current understanding of coupled interactions between carbon and phosphorus cycling in freshwater lake habitats.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

自工业革命以来，甲烷的大气水平已上升150％，并继续增加。 尽管能源部门和农业来源是主要贡献者，但自然微生物来源大约占全球甲烷排放总数的一半。 长期以来，微生物甲烷的产生是一种缺氧过程，仅在极低至零氧的条件下进行。最近的研究表明，微生物甲烷产生的可能性通过微生物中存在的先前未经批准的代谢途径在湖泊和海洋的上层水中发生。 在磷缺乏症的条件下，某些细菌可以利用否则未反应的有机分子称为甲基膦酸酯，以满足其磷的需求，从而在此过程中释放甲烷。 这种机制在多大程度上支持从湖泊到大气的甲烷对大气的渗透，以及改变环境条件的后果也是如此。 该项目将通过研究Flathead Lake的有氧甲烷生产的分布，控制率和控制率，以及其他18个不同磷缺乏症状态的蒙大拿州湖泊，来解决这一知识差距。 由于污染物氮的大气沉积和故意削减磷投入到湖泊的措施都可以导致磷缺乏症，因此至关重要的是，我们知道这些因素是否可能具有增强甲烷排放的意外后果。 这项研究还将直接支持研究生和本科生的教育，现场和实验室经验，并将为来自美洲原住民（Kootenai和Salish）部落土地的当地高中教师提供培训。本项目将评估微生物介导的甲烷生产的较小磷酸磷酸化磷酸化磷酸磷酸磷酸化的时间和空间变异性。它以总体假设为指导：甲烷从疾病的淡水湖中的扩散排出直接受到生态系统养分（氮，磷）缺陷的性质和严重程度的影响。使用化学，稳定的同位素，核基因组和基于PCR的基因分析的观察和实验方法的结合将用于检查：1）浓度的时间和空间变异性，稳定的同位素组成以及蒙大拿州淡水湖中甲烷的净产生净产量，集中在Flathead湖上； 2）微生物甲磷酸降解导致这些湖中甲烷的净产生的程度； 3）与磷酸和甲烷循环有关的微生物的功能多样性，丰富性和转录活性； 4）水生养分（无机和总池）如何影响甲烷循环功能基因的氧化甲烷产生和表达。这项研究将对微生物甲烷源进行系统评估，并提供甲基膦酸酯降解作为毒性淡水湖中甲烷源的潜在贡献。该项目的结果将提供新的见解，并在淡水湖栖息地中对碳和磷自行车之间的耦合相互作用进行当前的了解。该奖项反映了NSF的法定任务，并被认为值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来进行评估。

项目成果

Productivity and photophysiology in a large, oligotrophic lake

大型贫营养湖的生产力和光生理学

• 发表时间: 2023
• 期刊: Association for the Sciences of Limnology and Oceanography
• 作者: Evans, Kate A.;Tappenbeck, Tyler;Peoples, Logan;Church, Matthew
• 通讯作者: Church, Matthew

Mixing‐driven changes in distributions and abundances of planktonic microorganisms in a large, oligotrophic lake

混合驱动大型贫营养湖中浮游微生物分布和丰度的变化

• DOI: 10.1002/lno.12509
• 发表时间: 2024
• 期刊: Limnology and Oceanography
• 影响因子: 4.5
• 作者: Evans, Kate A.;Peoples, Logan M.;Ranieri, John R.;Wear, Emma K.;Church, Matthew J.
• 通讯作者: Church, Matthew J.