Stoichiometric characteristics of carbon, nitrogen and phosphorus in surface sediments of different plant communities in Lake Baiyangdian wetland

Abstract

白洋淀是雄安新区的核心生态功能区.为探究白洋淀不同植物群落区表层沉积物碳（C）氮（N）磷（P）化学计量特征，采集了96组表层沉积物样品开展对比分析.研究表明：白洋淀湿地表层沉积物总有机碳（TOC）含量均值为39.64 g/kg，范围为14.4~136.82 g/kg，总氮（TN）和总磷（TP）均值分别为2.62和0.75 g/kg，范围分别为0.72~10.57和0.46~1.38 g/kg；不同植物群落区表层沉积物C、N、P化学计量特征存在显著差异，挺水植物分布区表层沉积物TOC和TN含量高于其他区，水田区沉积物TP含量最高；表层沉积物C：N：P比例平均值为141：8：1，C：N比值相对稳定，C：P和N：P比值空间分异性较大；不同水生植物群落区沉积物C、N、P化学计量特征存在差异，挺水植物区沉积物C：P和N：P比值显著高于其他各分区，沉水植物区表层沉积物C：N最大，挺水植物区和沉水植物区C：N：P比例平均值分别为222：13：1和129：6.5：1；白洋淀表层沉积物C、N、P化学计量特征受植物群落生物量、磷氮磷化学计量特征、枯落物分解速率以及人类活动等多个因素影响；与我国东部主要湖泊相比，白洋淀表层沉积物C、N、P含量均处于较高水平，建议在水生植物生长末期收割打捞运出淀外，减少淀内N、P营养盐累积，减缓白洋淀富营养化和沼泽化进程.;Lake Baiyangdian is the main ecological function area of Xiong'an New Area. To explore the stoichiometric characteristics of carbon, nitrogen and phosphorus in surface sediments of different plant communities in Lake Baiyangdian, 96 samples of surface sediment were collected for comparative analysis. Results showed that the average total organic carbon (TOC) contents of the surface sediments were 39.64 g/kg, ranging from 14.4 to 136.82 g/kg, while the average total nitrogen (TN) and total phosphorus (TP) contents were 2.62 and 0.75 g/kg, ranging from 0.72 to 10.57 and 0.46 to 1.38 g/kg, respectively. There were significant differences in carbon and phosphorus stoichiometric characteristics of surface sediments in different plant community regions. TOC and TN contents in surface sediment of emerged aquatic plant areas were higher than those in other areas, and TP contents in surface sediment of paddy fields were the highest. The mean value of the C:N:P ratio in surface sediments was 141:8:1, the C:N ratio was relatively stable, and the C:P and N:P ratios were highly variable. There were significant differences in carbon, nitrogen and phosphorus stoichiometry in sediments of different aquatic plant communities. The ratios of C:P and N:P in surface sediments of emerged aquatic plant areas were significantly higher than those of other regions. The mean C:N:P ratios of emerged aquatic plant area and submerged plants area were 222:13:1 and 129:6.5:1, respectively. The stoichiometric characteristics of carbon, nitrogen and phosphorus in surface sediments of Lake Baiyangdian were affected by many factors, such as plant community biomass, stoichiometric characteristics, decomposition rate and human activities. Compared with the main lakes in eastern China, the contents of carbon, nitrogen and phosphorus in the surface sediments of Lake Baiyangdian were at a higher level. It is suggested to harvest, salvage and transport the aquatic plants out of the lake at the end of the growth period to reduce the accumulation of nitrogen and phosphorus nutrients in the lake and slow down the process of eutrophication and swamping of Lake Baiyangdian.