底栖动物扰动功能群组合对沉积物-水界面厌氧氨氧化过程的影响机制

The microbial anaerobic ammonia oxidation processes (Anammox) at the sediment-water interface are important for mitigating aquatic eutrophication. However, the existing research mainly focuses on the physico-chemical environmental influencing factors, ignoring the bioturbation effects of benthic animals which are widely distributed at this interface, especially the combined effects of different functional groups coexisting. Benthic macroinvertebrates with different perturbation functional groups will differentially modify the physical and chemical conditions of the interface; the combined bioturbation gourps may create more diverse micro-habitats based on complementary effects, increase the diversity of anaerobic ammonium oxidizing bacteria, thereby promoting the function of Anammox. This project intends to select the dominant benthic species that are widely co-existent in eutrophic water bodies as representatives of different macro-invertebrate functional groups. Under the driving effect of the combination of benthic bioturbation functional groups, the changes of physio-chemical environment characteristics of sediment-water interface and the response characteristics of Anammox bacteria were established , “the characteristics of benthic functional group combination-physical and environmental characteristics- Anammox bacterial community characteristics-Anammox rate" relationship model was built, the mechanism of interaction of benthic functional groups on the Anammox process was clarified. This project provides a theoretical basis for the formulation of nitrogen pollution control strategies and has important scientific significance for the protection and restoration of aquatic ecosystems.

沉积物-水界面的微生物厌氧氨氧化过程对缓解水体富营养化具有重要意义。但现有研究主要关注其理化环境影响因素，通常忽略了栖息在此界面的底栖动物的扰动作用，特别是不同扰动功能群共存时的组合效应。不同底栖动物会以其独特的扰动功能对此界面的理化条件进行差异性改造；其扰动功能群的组合可能会基于互补效应进一步营造出更加多样化的微生境，提高厌氧氨氧化细菌的多样性，促进其生长和代谢，进而对厌氧氨氧化功能产生正面影响。本项目拟选取富营养化水体中三种常见共存的优势底栖动物作为不同扰动功能群的代表，研究不同底栖动物功能群组合扰动下，沉积物-水界面理化环境特征的变化规律及厌氧氨氧化细菌对其的响应特征，建立“底栖动物扰动功能群组合-理化环境特征-厌氧氨氧化细菌群落特征-厌氧氨氧化速率”关系模式，阐明底栖动物扰动功能群组合对微生物厌氧氨氧化过程的影响机制。本项目可为氮污染控制策略的制定、水生生态系统的修复提供理论依据。

深入研究微生物厌氧氨氧化过程的影响机制对富营养化水体氮素污染的缓解、水生态环境的保护和修复具有重要的现实意义和紧迫性。但现有研究主要关注其理化环境影响因素，通常忽略了栖息在此界面的底栖动物的扰动作用，特别是不同扰动功能群共存时的组合效应。本项目以重庆市典型富营养化水体清水溪为研究地，选取三种常见共存的优势底栖动物（苏氏尾鳃蚓、摇蚊幼虫、椭圆萝卜螺）作为不同扰动功能群的代表，通过室内微宇宙系统实验, 利用微电极、同位素示踪、分子生物学等技术手段, 进行了底栖动物扰动对关键理化因子的影响研究，完成了对沉积物中微生物和Anammox功能菌的多样性和丰度的分析，发现摇蚊和螺增加了沉积物Anammox菌丰度，增加了沉积物Anammox菌所属的浮霉菌门（Planctomycetota）相对丰度；摇蚊幼虫、尾鳃蚓、螺均增大了Anammox速率，其组合扰动的沉积物Anammox速率（7.52-9.23 nmol N/（gh））比物种在单种时其速率叠加后的平均值更高（DT>0），其中摇蚊+螺组合沉积物Anammox速率最高。本研究建立了沉积物-水界面“底栖动物扰动功能群组合-关键理化因子-Anammox功能菌群落结构-Anammox脱氮速率”关系模式，即底栖动物扰动通过增加反应底物（NH4+和NO2-）、改善 DO 微环境和扩大增殖、代谢场所等方面促进了Anammox功能菌和脱氮功能菌的生长，进而增大Anammox速率，促进了脱氮过程。本研究验证了底栖动物为影响Anammox过程中重要的生物要素，不同功能群组合可能存在的互补效应促进了沉积物的Anammox过程。本研究为制定氮污染控制和底栖动物多样性保护策略提供了理论依据，对水生态系统保护和修复具有重要科学意义。