基于稳定同位素技术的保安湖食物网结构特征研究

FOOD WEB STRUCTURE OF THE BAO’AN LAKE BASED ON STABLE CARBON AND NITROGEN ISOTOPES ANALYSIS

文章利用碳、氮稳定同位素技术对江湖阻隔典型湖泊-保安湖的食物网结构进行了研究。结果表明保安湖中鱼类消费者的主要营养级范围为2.1—3.3,在调查到的16种鱼类中,顶级肉食性鱼类种类很少,杂食性鱼类的种类最多。保安湖食物网主要由两条营养传递途径构成,即由POM、浮游植物为主要食物源的浮游牧食链与沉积物为主要食物源的底栖食物链。POM、浮游植物、浮游动物和底栖动物是保安湖水域食物网中鱼类的主要食物来源,其次是沉积物中的碎屑和水生植物等。此外,从基于理论食性数据的食物网与BIMM模型预测的食物网结构可以看出,从POM、浮游植物、浮游动物到杂食性鱼类的浮游牧食链在整个食物网中具有主导性,而从水生植物、沉积物和底栖动物到杂食性鱼类的底栖食物链相对重要性较低。

The food web is a network that describes the complex nutritional interactions between different organisms in a biological community and reveals the substance circulation and energy flow in the ecosystem.Stable isotope analysis is one of the effective technology for studying the substance circulation and energy flow.This research applied carbon and nitrogen stable isotope analysis combined with theoretical fish diet and model prediction to construct the food web structure and quantify the energy transfer in Bao’an Lake.Our results showed that the main trophic level of fish species ranged from 2.1 to 3.3.Among the 16 fish species,the carnivorous fish species were the less and the omnivorous fish species were the most.The food web of Bao’an Lake mainly composed of two nutrient transmission pathways,the planktonic food chain with POM and phytoplankton as the main food sources and the benthic food chain with sediment as the main food source.POM,phytoplankton,zooplankton,and zoobenthos were the main food sources of fish in Bao’an Lake,followed by sediments and macrophyte,etc.In addition,the theoretical food web based on dietary data and the food web structure predicted by the BIMM indicated that the planktonic food chain was the dominant in the food web,and the importance of the benthic food chain in food web was low.Therefore,the food web regulation recommendations for Bao’an Lake to reduce the risk of algae bloom are:(1)Increase the number of filter-feeding fish,and use its active filter feeding habit to directly reduce phytoplankton;(2)Increase the number of carnivorous fish to reduce the omnivorous fish,and increase the volume of zooplankton;(3)Increase the number of large filter-feeding zoobenthos,and use their passive filter feeding habit to filter and reduce the volume of phytoplankton.