气候变化对氨氧化菌群落结构与功能影响研究

Climate change is perhaps the biggest challenge that humanity has ever faced. It is projected that as global warming worsens, the world is likely to experience more frequent extreme weather, such as heat waves and severe drought. How these extreme weather conditions will impact on the soil microbial community is unknown. Soil ammonia oxidizing bacteria (AOB) and archaea (AOA) are responsible for an important step of the nitrogen cycle, the first step of the nitrification process, ammonia oxidation. Nitrification produces nitrate which is a water contaminant, and leads to the production of nitrous oxide which is a potent greenhouse gas. Here we will conduct field and laboratory incubation experiments to study the impacts of extreme weather conditions (high temperatures and drought) on soil ammonia oxidizing bacteria and ammonia oxidizing archaea community structure and functioning, and the associated changes in nitrification rate and nitrous oxide emissions. The microbial communities will be studied using soil molecular biology techniques, such as real-time PCR, and the next generation sequencing (NGS). The results will help to understand possible impacts of extreme weather conditions on soil ammonia oxidizer communitiy structure and functioning and associated effects on nitrogen cycling. This is important for developing appropriate nutrient management systems to sustain agricultural production under the conditions of climate change.

气候变化是人类所面临的最大挑战之一。随着气候变化的加剧，预测今后极端天气，如高温、干旱等会更加频繁。这些极端天气将如何影响土壤微生物群落结构、功能和养分循环尚不清楚。土壤氨氧化细菌和古菌对土壤中氮循环，特别是硝化反应的第一步， 氨氧化反应，起着重要作用。其反应产物硝酸盐是重要水体污染物，而所产生氧化亚氮是重要温室气体。本课题将动过野外和室内培养实验，运用分子生物学的手段， 如PCR、基因测序（NGS），研究极端天气（高温和干旱）条件对土壤中氨氧化细菌和古菌群落结构和功能的影响。同时也研究氨氧化菌结构变化和硝化反应速率及氧化亚氮释放的关系。所得结果会帮助阐明气候变化对土壤氨氧化菌群落结构和功能的影响，帮助预测随之引发的氮循环变化，对理解气候变化对农业生产的影响以及制定长远的应对措施意义重大。

气候变化是人类所面临的最大挑战之一。随着气候变化的加剧，预测今后极端天气，如高温、干旱等会更加频繁。这些极端天气将如何影响土壤微生物群落结构、功能和养分循环尚不清楚。土壤氨氧化细菌和古菌对土壤中氮循环，特别是硝化反应的第一步， 氨氧化反应，起着重要作用。其反应产物硝酸盐是重要水体污染物，而所产生氧化亚氮是重要温室气体。本课题通过野外和室内培养实验，运用分子生物学的手段， 如定量PCR、高通量测序等手段，研究了极端天气（高温和干旱）条件对土壤中氨氧化细菌和古菌群落结构和功能的影响。同时也研究氨氧化菌群落的变化和硝化反应速率及氧化亚氮释放的关系。通过野外大田试验研究发现高温和干旱的综合作用减少了尿素处理中氧化亚氮的释放，并且水分的减少是主要原因。相对于氨氧化古菌，氨氧化细菌对气候的变化更为敏感，群落反应更为迅速。高温和干旱条件移除后仍会对氧化亚氮的释放起到刺激的作用，并刺激氨氧化细菌和古菌的增长与群落结构的改变。通过室内试验研究发现随着温度的升高，氧化亚氮的释放量随之增加。氨氧化细菌和古菌均不适应高于30℃的环境。以上所得结果会帮助阐明气候变化对土壤氨氧化菌群落结构和功能的影响，帮助预测随之引发的氮循环变化，对理解气候变化对农业生产的影响以及制定长远的应对措施意义重大。

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