水华全生命周期的温室气体产汇和增温潜势研究

Algal blooms is a phenomenon that quick growth and aggregation of algae in freshwater. With the growing concern of global warming, the mutual feedbacks between algal bloom and global warming have become a hot topic. Current knowledge showed that global warming would promote the formation of blooms. However, the sources and sinks of greenhouse gases within life cycle of algal blooms and the feedback effects on global warming are still not well addressed. On general, formation of algal blooms require large amounts of CO2, while death and decomposition of tremendous algal biomass could release CH4, CO2 and N2O. As the warming effect of CH4 and N2O were 28 times and 265 times than that of CO2, it could be hypothesized that algal blooms will promote global warming. In the present study, Lake Taihu and tributaries of the Three Gorges Reservoir were selected to: 1. perform field surveys and determine the dynamic of production and sinks of greenhouse gas in blooms under natural state. 2. conduct in situ experiments to reveal the production and sinks of greenhouse gas in blooms under different levels of nutrition water, and 3. explore the dynamics mechanism on production and sinks of greenhouse gas in blooms by light, temperature and nutrient control experiments indoor. Finally, analysis the patterns of greenhouse gases in blooms process comprehensively and assess its global warming potential to verify its impact on global warming.

水华是淡水中藻类大量生长聚集的现象。随着全球变暖日益受到关注，水华现象同全球气候变暖的互馈效应亦成为研究热点。既有认识是全球升温将促进水华形成，但水华对全球气候变暖的反馈仍鲜有关注。通常，水华过程中藻类增殖需吸收大量的CO2，而水华末期藻类死亡分解，会释放CH4、CO2和N2O等温室气体。故本研究假设水华过程是CO2的汇、CH4和N2O的源。由于CH4和N2O的增温效应分别为CO2的28倍和265倍，故水华是促进增温的。为求解该假设，本研究分别选择太湖和三峡水库支流，进行水华过程温室气体源汇变化的野外调查，掌握自然状态下的水华温室气体产汇动态；通过原位实验揭示不同营养水平下水华温室气体的产汇规律，通过室内控制实验探索不同环境条件水华温室气体的光照、温度和营养盐动力学机制。最后综合分析揭示水华温室气体的产汇机制，建立水华全生命周期的增温潜势模型，求证其对全球气候变暖的影响。

本研究分别选择太湖和三峡水库支流，进行水华过程温室气体源汇变化的野外调查，掌握自然状 态下的水华温室气体产汇动态；通过原位实验揭示不同营养水平下水华温室气体的产汇规律， 通过室内控制实验探索不同环境条件水华温室气体的光照、温度和营养盐动力学机制。最后综合分析揭示水华温室气体的产汇机制，建立水华全生命周期的增温潜势模型，求证其对全球气候变暖的影响。. 该项目按计划顺利执行，资助发表论文8篇。其中SCI论文7篇，其中一区TOP SCI 3篇，二区SCI 2篇，中文核心1篇。申请专利5项，获授权4项（发明专利2项，实用新型2项）。 项目已经完成实验、野外调查、数据整理等工作，还有数据有待进一步深入分析，3篇论文在修改，将于近期投稿。项目资助了4位硕士研究生毕业，项目负责人和主要参与人鲁伦慧晋升了副研究员。