Study On Terrestrial Food Chain Of Rana Chensinensis Basted On Stable Isotope

By using natural carbon and nitrogen stable isotopes, the source of organic matter, food composition of the consumer and the nutrient level of the organisms in the food web can be effectively revealed. In this paper, we selected Rana chensinensis which is the representative amphibian of river - forest wetlands system in mountainous area of eastern Jilin Province as the main research object; we studied the composition of terrestrial food chain of Rana chensinensis, and then determined the migration and transformation of heavy metal mercury along the food chain by using table isotope method. Near the gold mining area in Weisha river basin of the upper reaches of Songhua River, we collected water, sediments in the rivers, plants, insects and Rana samples along the rivers respectively in spring and autumn in 2009. Then the samples were pretreated correspondingly. The experiments included two parts: determination of terrestrial food chain of Rana chensinensis and correlation analysis of methylmercury and stable isotope. The conclusions are as follows:①δ13C andδ15N appeared enrichment with increasing of trophic level,δ15Nincreased 3.47‰on average from the producers (plants) to primary consumers (insects),δ13C increased 1.61‰on average from primary consumers (insects) to secondary consumers (Rana), this shows that the food chain structure of Rana terrestrial environment is plants - locust - Rana;②Methylmercury content in Samples of different sampling locations was positively correlated withδ13C, the correlation coefficient between the methylmercury content andδ13C in the sample of Wu Daogou is the maximum. This shows that methylmercury bioaccumulated with the food chain; mercury that local gold mining released transformed into methylmercury and entered the plant - locust - frog food chain structure.