富营养化湖泊蓝藻—芦苇碎屑堆积分解过程及其潜在的共代谢效应

为探究富营养化浅水湖泊所富集的有机物对湖泊碳循环和水质的影响,本研究构建微宇宙系统,模拟蓝藻和芦苇碎屑单独分解及混合分解过程.通过测定各组上覆水营养盐浓度、有机质含量及结构的变化,揭示富营养化湖泊藻草残体混合分解过程中养分和有机碳的释放特征.结果 表明,在实验0～88 h内,在添加相同的碳源条件下,蓝藻和芦苇混合处理组...

Accumulation and decomposition of cyanobacteria and reed debris in eutrophic lakes and its potential co-metabolism effects

In order to explore the effect of enriched organic matter in eutrophic shallow lakes on water quality and carbon cycle, in this study, we constructed a microcosm system to simulate the separate decomposition and mixed decomposition of cyanobacteria and reed debris. The changes of nutrient concentration, organic matter content and structure of the overlying water in each treatment were determined to reveal the release characteristics of nutrients and organic carbon during the mixed decomposition process of cyanobacteria and reed debris in eutrophic lakes. The results showed that the total carbon (TC) release of the mixed treatment was significantly higher than the theoretical value within 0-88 hours of the experiment under the same carbon source addition, indicating that there is a co-metabolism effect during the mixed decomposition of cyanobacteria and reed debris. In the initial stage of the cultivation, sediments accelerated the release of total nitrogen (TN) and total phosphorus (TP) to the overlying water and caused a significant impact on the water quality via the co-metabolism effect. Compared with the reed treatment, the maximal release of TN and TP in the mixed treatment increased by 13.49% and 26.84%, respectively. The change of fluorescence intensity of fulvic acid characterized by the three-dimensional fluorescence spectroscopy (EEMs) also showed that the decomposition rate of reed was faster in the mixed treatment group. At the beginning of cultivation, each treatment quickly turned into anaerobic state, and the concentration of TC, TN and TP displayed a trend of dramatical increase and then gradually flattened, with a maximum of (372.4±2.98), (138.45±2.97), and (7.95±1.11) mg/L at 228, 108 and 324 hours, respectively. The variations of bacterial specific fatty acid showed that the input of Microcystis detritus into Phragmites detritus increased the abundance of decomposing bacteria in Phragmites detritus, and accelerated the decomposition rates, resulting in the co-metabolism of Microcystis and Phragmites carbon. Under the background of global warming, with the increasing frequency of algae outbreaks in eutrophic lakes, the co-metabolism effect may be further strengthened, and the water quality of eutrophic lakes will be affected continuously.