Quantifying the impact of anthropogenic nutrient imbalance on C flux from freshwater lakes: cellular mechanisms, community assembly and modelling

量化人为营养失衡对淡水湖泊碳通量的影响：细胞机制、群落组装和建模

• 批准号: NE/X005119/1
• 负责人: Deepak Kumaresan
• 金额: $ 61.53万
• 依托单位: Queen's University Belfast
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX005119%2F1
• 关键词: Quantifying; impact; anthropogenic; nutrient; imbalance

Freshwater lakes are amongst the largest ecosystems on Earth, and a major contributor to both carbon dioxide (CO2) and methane (CH4) emissions, two potent greenhouse gases. The use of nitrogen-rich fertilisers and their runoff into freshwater lakes as a result of human population growth are major contributors to the growing imbalance of nitrogen (N) and phosphorus (P), two key macronutrients limiting primary production and greenhouse gas release from this ecologically important ecosystem at a global scale. The much faster increase of anthropogenic nitrogen runoff has dwarfed the input of phosphorus and shifted the balance of the global N:P ratio from 19:1 to 30:1 in the past four decades, driving more and more lake ecosystems towards phosphorus limitation. Although this trend is likely to continue, our knowledge of how such an anthropogenically indued phosphorus limitation affects CO2 and CH4 flux in freshwater ecosystems remains uncertain. Capitalising on our recent discovery that P limitation appears to reduce the capacity of both cyanobacteria for CO2 fixation and methanotrophs for CH4 oxidation, we propose a multidisciplinary approach to uncover the response to N:P imbalance in freshwater microbial assemblages and subsequent impact on greenhouse gas emissions in freshwater lakes.

淡水湖是地球上最大的生态系统之一，也是二氧化碳(CO2)和甲烷(CH4)排放的主要贡献者，这两种温室气体是强有力的。由于人口增长，富氮化肥的使用及其对淡水湖的径流是氮(N)和磷(P)日益失衡的主要原因，这两种关键常量营养素在全球范围内限制了这个具有重要生态意义的生态系统的初级生产和温室气体排放。在过去的40年里，人为氮素径流的快速增加使磷的输入相形见绌，使全球氮磷比的平衡从19：1变为30：1，促使越来越多的湖泊生态系统走向磷限制。尽管这一趋势可能会继续下去，但我们对人类造成的这种磷限制如何影响淡水生态系统中的二氧化碳和甲烷通量的了解仍然不确定。基于我们最近的发现，磷限制似乎降低了蓝藻固定二氧化碳的能力和甲烷氧化菌的能力，我们提出了一个多学科的方法来揭示淡水微生物组合中N：P失衡的响应以及随后对淡水湖温室气体排放的影响。