State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
Water Res. 2021 Feb 15;190:116741. doi: 10.1016/j.watres.2020.116741. Epub 2020 Dec 10.
During decay, the sediment microenvironment and water quality are severely affected by excessive proliferation of harmful algae such as filamentous green algae (FGA). The frequency of this FGA is increased through global warming and water eutrophication. In the present study, the degradation processes of a common advantage FGA Cladophora oligoclora and its effect on nitrogen and phosphorus nutrient structure and bacterial community composition at the sediment-water interface were investigated by stable isotope labelling and high-throughput sequencing. The results showed that the decomposition process of C. oligoclona was fast, stable, and difficult to degrade. The changes in sediment δN values reached 66.68 ‰ on day 40, which indicated that some of the nitrogen had migrated to the sediment from C. oligoclona litter. TN and NH-N in the overlying water rapidly increased between days 0-10, NH-N rose to 78.21% of TN on day 40, resulting in severe pollution of ammonia in the overlying water. The nitrogen forms and contents in the sediment are mainly derived from the increasing ammonia nitrogen release. The TP and IP in the overlying water increased to the highest concentrations of 6.68±0.64, 6.59±0.79 mg·L during the decomposition process, respectively, resulting in the migration of phosphate to the sediments with increasing phosphorus content. The abundance of the main dominant bacterial communities, such as Acinetobacter (0.08%-62.48%) and Pseudomonas (0.13%-20.36%) in sediments and overlying water has changed significantly. The correlation analysis results suggested that the phosphorus was mainly related to the bacterial community in the overlying water, while the various forms of nitrogen demonstrated a high relevance with the bacterial community in the sediment. Our research results will be valuable in evaluating the potential ecological risk of FGA decomposition and provide scientific support for shallow lake management and submerged vegetation restoration.
在腐烂过程中，过度增殖的有害藻类（如丝状绿藻）会严重影响沉积物微环境和水质。全球变暖以及水体富营养化增加了这种丝状绿藻的发生频率。本研究采用稳定同位素示踪和高通量测序技术，研究了常见优势种绿藻聚球藻（Cladophora oligoclona）的降解过程及其对沉积物-水界面氮磷营养结构和细菌群落组成的影响。结果表明，C. oligoclona 的分解过程快速、稳定且难以降解。沉积物 δN 值在第 40 天变化达到 66.68‰，表明部分氮已经从 C. oligoclona 凋落物中迁移到沉积物中。上覆水中 TN 和 NH4+-N 在 0-10 天之间迅速增加，NH4+-N 在第 40 天上升到 TN 的 78.21%，导致上覆水中氨氮严重污染。沉积物中氮素形态和含量主要来源于不断增加的氨氮释放。上覆水中 TP 和 IP 在分解过程中分别增加到 6.68±0.64、6.59±0.79mg·L-1 的最高浓度，导致磷向沉积物中的迁移和磷含量的增加。沉积物和上覆水中的主要优势菌门，如不动杆菌（0.08%-62.48%）和假单胞菌（0.13%-20.36%）的丰度发生了显著变化。相关分析结果表明，磷主要与上覆水中的细菌群落有关，而各种形态的氮与沉积物中的细菌群落高度相关。我们的研究结果将有助于评估丝状绿藻分解的潜在生态风险，并为浅水湖泊管理和沉水植被恢复提供科学支持。
