| 引用本文: | 马静静,李廷真,李宽意,苏雅玲,刘正文.基于脂肪酸生物标志物分析南京市及其周边不同营养水平湖库的浮游动物碳源.湖泊科学,2022,34(2):590-600. DOI:10.18307/2022.0219 |
| Ma Jingjing,Li Tingzhen,Li Kuanyi,Su Yaling,Liu Zhengwen.Identification of zooplankton carbon sources using fatty acid biomarkers in lakes and reservoirs at different trophic states in Nanjing and surrounding areas. J. Lake Sci.2022,34(2):590-600. DOI:10.18307/2022.0219 |
|
| 摘要: |
| 脂肪酸在生物的摄食活动中相对稳定，可用于辨别消费者的食物来源.不同营养水平的湖泊与水库中浮游动物的碳源组成有差异，因而可能具有不同的脂肪酸组成特征.本研究对南京市及其周边21个湖库的颗粒有机物（POM）、浮游动物的脂肪酸组成进行了对比分析.结果表明，南京市及其周边湖库21个湖库由中营养、轻富营养、中富营养、重富营养共4个营养水平组成.中营养湖库总氮（TN）、总磷（TP）、叶绿素a（Chl.a）、浮游植物生物量均低于富营养湖库，透明度（SD）则相反.中营养湖库中POM脂肪酸的必需脂肪酸（EFA）平均浓度低于富营养湖库；而细菌特征脂肪酸∑C15+∑C17含量高于富营养湖库.随着湖库富营养化，POM中多不饱和脂肪酸（PUFA）浓度逐渐增大，单不饱和脂肪酸（MUFA）浓度则逐渐减少.中营养湖库中浮游动物PUFA浓度普遍低于富营养湖库，∑C15+∑C17含量高于富营养湖库；且浮游动物体内主要来源于藻类的必需脂肪酸EFA/C16：0比值与细菌源脂肪酸（∑C15+∑C17）/C16：0比值均大于其他湖库，表明中营养湖库中浮游动物摄食了较多细菌.随着湖库营养水平升高，浮游动物饱和脂肪酸（SFA）逐渐增多，MUFA浓度逐渐减少，EFA浓度增多，表明浮游动物主要摄食藻类，而外源碳对浮游动物的碳源贡献较小.冗余分析（RDA）结果显示，EFA/C16：0、（∑C15+∑C17）/C16：0与透明度呈正相关，与Chl.a、总磷、磷酸盐呈高度负相关，表明透明度较高、营养水平相对较低的湖库中，浮游动物可能利用较多的藻类与细菌碳；此外，陆源碳转化指标∑C24/C16：0与TN、硝态氮呈正相关性，表明随着营养水平升高，陆源碳对浮游动物碳源贡献呈增加趋势.总体而言，浮游动物更倾向于利用高质量的内源碳，但在内源碳不足以供给水生生物生长需求的中营养水体中，外源碳对生态系统的物质循环和能量流动会产生重要作用. |
| 关键词: 脂肪酸 营养水平 浮游动物 碳源 湖库 |
| DOI：10.18307/2022.0219 |
| 分类号: |
| 基金项目:国家自然科学基金项目（31971475）和国家重点研发计划项目（2017YFA0605201）联合资助. |
|
| Identification of zooplankton carbon sources using fatty acid biomarkers in lakes and reservoirs at different trophic states in Nanjing and surrounding areas |
|
Ma Jingjing1,2, Li Tingzhen1, Li Kuanyi2, Su Yaling2, Liu Zhengwen2
|
|
1.Chongqing Three Gorges University, Chongqing Key Laboratory of Water Environment Evolution and Pollution Control in the Three Gorges Reservoir Area, Chongqing 404100, P. R. China;2.Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China
|
| Abstract: |
| Fatty acids are relatively stable in the feeding activities of organisms and can be used to identify consumers' food sources. The carbon source composition of zooplankton in lakes and reservoirs with different nutrient levels is different, so they may have different fatty acid composition characteristics. This study compared the fatty acid composition of POM (particulate organic matter) and zooplankton in 21 lakes and reservoirs in Nanjing and its surrounding areas. The results show that the 21 lakes and reservoirs are composed of four nutritional levels:medium nutrition, light eutrophication, medium eutrophication, and heavy eutrophication. The total nitrogen (TN), total phosphorus (TP), chlorophyll-a (Chl.a), and phytoplankton biomass of mesotrophic lakes and reservoirs are lower than those of eutrophic lakes and reservoirs, while the transparency (SD) is the opposite. The average concentration of essential fatty acids (EFA) of POM fatty acids in mesotrophic lakes was lower than that of eutrophic lakes, while the content of bacterial characteristic fatty acids ∑C15+∑C17 was higher than that of eutrophic lakes. With nutrient increase, the concentration of polyunsaturated fatty acids (PUFA) in POM gradually increases, while the concentration of monounsaturated fatty acids (MUFA) gradually decreases. The PUFA of zooplankton in mesotrophic lakes and reservoirs is generally lower than that of eutrophic lakes and reservoirs, and the content of ∑C15+∑C17 is higher than that of eutrophic lakes and reservoirs; and the ratio of essential fatty acids EFA/C16:0, which are mainly derived from algae, and bacterial fatty acids in zooplankton (The ratio of ∑C15+∑C17)/C16:0 is larger than that of other lakes and reservoirs, indicating that zooplankton in the middle-nutrition lakes and reservoirs ingested more bacteria. As nutrient increases, zooplankton saturated fatty acids (SFA) gradually increase, MUFA gradually decreases, and EFA content increases, indicating that zooplankton mainly feeds on algae, while exogenous carbon contributes little to the carbon source of zooplankton. Redundancy analysis (RDA) show that EFA/C16:0, (∑C15+∑C17)/C16:0 are positively correlated with SD, and highly negatively correlated with Chl.a, TP, and phosphate, suggesting that zooplankton consumed more algal and bacterial carbon; and ∑C24/C16:0 is positively correlated with TN, nitrate nitrogen, indicating that zooplankton utilized more terrestrial carbon. In general, zooplankton is more inclined to use high-quality endogenous carbon, but in mesotrophic water bodies where endogenous carbon is not sufficient to supply the growing needs of aquatic organisms. Exogenous carbon plays an important role in the material circulation and energy flow of the ecosystem. |
| Key words: Fatty acid nutrient level zooplankton carbon source lakes and reservoirs |
