The National Field Station of Freshwater Ecosystem of Liangzi Lake, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
The National Field Station of Freshwater Ecosystem of Liangzi Lake, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
Environ Pollut. 2022 Sep 1;308:119650. doi: 10.1016/j.envpol.2022.119650. Epub 2022 Jun 17.
Phosphorus (P) is an essential element in the ecosystem and the cause of the eutrophication of rivers and lakes. The river-lake ecotone is the ecological buffer zone between rivers and lakes, which can transfer energy and material between terrestrial and aquatic ecosystems. Vegetation restoration of degraded river-lake ecotone can improve the interception capacity of P pollution. However, the effects of different vegetation restoration types on sediment P cycling and its mechanism remain unclear. Therefore, we seasonally measured the P fractions and physicochemical properties of sediments from different restored vegetation (three native species and one invasive species). The results found that vegetation restoration significantly increased the sediment total P and bioavailable P content, which increased the sediment tolerance to P pollution in river-lake ecotone. In addition, the total P content in sediments was highest in summer and autumn, but lower in spring and winter. The total P and bioavailable P contents in surface sediments were the highest. They decreased with increasing depth, suggesting that sediment P assimilation by vegetation restoration and the resulting litter leads to redistribution of P in different seasons and sediment depths. Microbial biomass-P (MBP), total nitrogen (TN), and sediment organic matter (SOM) are the main factors affecting the change of sediment phosphorus fractions. All four plants' maximum biomass and P storage appeared in the autumn. Although the biomass and P storage of the invasive species Alternanthera philoxeroides were lower, the higher bioavailable P content and MBP values of the surface sediments indicated the utilization efficiency of sediment resources. These results suggest that vegetation restoration affects the distribution and circulation of P in river and lake ecosystems, which further enhances the ecological function of the river-lake ecotone and prevents the eutrophication and erosion of water and sediment in the river-lake ecotone.
磷（P）是生态系统中的一种必需元素，也是河流和湖泊富营养化的原因。河流-湖泊交错带是河流和湖泊之间的生态缓冲区，可以在陆地和水生生态系统之间传递能量和物质。退化的河流-湖泊交错带的植被恢复可以提高 P 污染的截留能力。然而，不同植被恢复类型对沉积物 P 循环的影响及其机制仍不清楚。因此，我们季节性地测量了不同恢复植被（三种本地物种和一种入侵物种）的沉积物 P 形态和理化性质。结果发现，植被恢复显著增加了沉积物总 P 和生物可利用 P 的含量，从而提高了河流-湖泊交错带对 P 污染的沉积物容忍度。此外，沉积物总 P 含量在夏季和秋季最高，而在春季和冬季较低。表层沉积物的总 P 和生物可利用 P 含量最高，随着深度的增加而降低，这表明植被恢复对 P 的吸收以及由此产生的凋落物导致 P 在不同季节和不同沉积物深度的再分布。微生物生物量 P（MBP）、总氮（TN）和沉积物有机质（SOM）是影响沉积物磷形态变化的主要因素。所有四种植物的最大生物量和 P 储存都出现在秋季。尽管入侵物种空心莲子草的生物量和 P 储存较低，但表层沉积物中较高的生物可利用 P 含量和 MBP 值表明其对沉积物资源的利用效率较高。这些结果表明，植被恢复影响了河流和湖泊生态系统中 P 的分布和循环，从而进一步增强了河流-湖泊交错带的生态功能，防止了河流-湖泊交错带的水和沉积物富营养化和侵蚀。
