Su Yaling, Ma Jingjing, Wu Zhaoshi, Guan Baohua, Li Kuanyi
Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China.
Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, 210008, China; Chongqing Three Gorges University, Chongqing, 404100, China.
J Environ Manage. 2024 Dec;372:123355. doi: 10.1016/j.jenvman.2024.123355. Epub 2024 Nov 16.
The ecological restoration of eutrophic lakes significantly influences the food composition of zooplankton. Zooplankton serve as the principal trophic link, transferring energy from phytoplankton to fish. Understanding the alterations in zooplankton carbon source compositions following ecological restoration and the seasonal variations in this relationship is crucial. This study employs stable carbon isotope (δC) and fatty acid (FA) analyses to investigate the seasonal changes in carbon source contributions to zooplankton between the restored and unrestored segments of Lake Xuanwu. Results from FA analysis reveal higher proportions of algal dietary markers in zooplankton FAs in both segments during spring and autumn. Summer exhibits a shift with zooplankton utilizing more bacterial FAs in the restored part and more algal FAs in the unrestored part. While approaching winter, zooplankton in the restored part consume more algal FAs but less in the unrestored part. Zooplankton FAs enriched in δC are associated with assimilation of more terrestrial carbon, contrasting with depleted δC when zooplankton relies more on phytoplankton. Isotope mixing models indicate a substantial contribution of terrestrial carbon to zooplankton carbon sources, especially in autumn (42.3% unrestored, 51.2% restored) and winter (41.4% unrestored, 36.8% restored), while phytoplankton has a higher contribution in summer (34.5% restored, 46.9% unrestored). These findings contribute to a comprehensive understanding of carbon cycling variations in food webs between eutrophic lakes and ecologically restored lakes.
富营养化湖泊的生态修复对浮游动物的食物组成有显著影响。浮游动物是主要的营养纽带，将能量从浮游植物传递给鱼类。了解生态修复后浮游动物碳源组成的变化以及这种关系的季节变化至关重要。本研究采用稳定碳同位素（δC）和脂肪酸（FA）分析方法，研究玄武湖修复区和未修复区浮游动物碳源贡献的季节变化。脂肪酸分析结果显示，在春季和秋季，两个区域浮游动物脂肪酸中的藻类食物标志物比例都较高。夏季出现了变化，修复区的浮游动物利用更多的细菌脂肪酸，而未修复区的浮游动物利用更多的藻类脂肪酸。接近冬季时，修复区的浮游动物消耗更多的藻类脂肪酸，而未修复区则较少。富含δC的浮游动物脂肪酸与更多陆地碳的同化有关，而当浮游动物更多地依赖浮游植物时，δC则会减少。同位素混合模型表明，陆地碳对浮游动物碳源有很大贡献，尤其是在秋季（未修复区为42.3%，修复区为51.2%）和冬季（未修复区为41.4%，修复区为36.8%），而浮游植物在夏季的贡献更高（修复区为34.5%，未修复区为46.9%）。这些发现有助于全面了解富营养化湖泊和生态修复湖泊食物网中碳循环的变化。
