水华对沉积物中氮的转化和去除的影响

湖泊富营养化和水华暴发已经成为突出的环境问题之一,了解水华对湖泊氮素的转化和去除的影响,对于削减湖泊氮负荷至关重要.本文研究了水华对沉积物中氮转化和氮转化相关功能基因的影响,并采用结构方程模型分析了水华影响湖泊中氮转化和去除的途径.结果表明,与厌氧氨氧化相比,反硝化作用是太湖沉积物氮削减的主要途径,对沉积物中总溶解性氮去除率的解释度为42. 3%.水华可以直接造成沉积物中TDN和TOC量的增加,提高厌氧氨氧化菌、nir S和nir K的基因丰度,并且间接提高沉积物中氨氮和硝酸盐的浓度,通过增强厌氧氨氧化和反硝化过程加速沉积物中氮的去除.

Water Bloom Modified Sediment Nitrogen Transformation and Removal

Water bloom is a notorious and annual reoccurring problem in eutrophic lakes. Understanding the influence of water bloom on lacustrine nitrogen transformation and removal is crucial for predicting ecosystem functions and taking strategies to reduce in-lake nitrogen budgets. In this study, we investigated the impact of water bloom on the levels and transformation of nitrogen in sediments as well as the pathway to influence the nitrogen removal process. The results of structural equation model analysis showed that water bloom can directly elevate the sediment budget of total dissolved nitrogen (TDN) and total organic carbon (TOC), and the gene abundance of anaerobic ammonium oxidation (ANAMMOX), nirS, and nirK and can indirectly enhance sediment concentration of ammonia and nitrate as well as nitrogen removal. Moreover, compared with coupled nitrification-ANAMMOX in Lake Taihu sediment, denitrification was the main path of nitrogen removal, with 42.3% explanation of the total nitrogen removal in the sediments. Water bloom can accelerate nitrogen removal in sediment through enhancement of ANAMMOX and denitrification process.