Application Of Carbon And Nitrogen Isotopes To Explore The Relationship Between Aquatic Food Chain And Trophic Level In Guizhou Plateau Reservoirs

The health of the aquatic ecosystem affects the national economy and people's livelihood.The ecological health of the reservoir is closely related to the flow of energy.Stable isotope technology is an important method to study the structure of the food chain and the relationship between nutrients in the ecosystem and its dynamic changes.This paper first summarizes the processing,storage,analysis and data interpretation of stable isotope samples of carbon and nitrogen in the study of reservoir aquatic ecosystems.At the same time,this article also reported the application of carbon and nitrogen stable isotope technology in Hongfeng Reservoir,Baihua Reservoir,and Aha Reservoir in lake-related ecological problems,including the temporal and spatial changes of stable isotope of primary producers and consumers in lakes,and food chain structure.The trophic level relationship,the research results and conclusions are as follows:1.During the sampling survey,the main environmental factors affecting TLI changes in Hongfeng Reservoir,Baihua Reservoir and Aha Reservoir were nitrogen,phosphorus,and chlorophyll,and TLI was the largest during the wet season(July and August).2.The abundance of phytoplankton and zooplankton in Hongfeng Reservoir,Baihua Reservoir,and Aha Reservoir in high water period is higher than that in normal water period(September and October),including Pseudanabaena sp.,acuminata,and small ring Cyclotella sp.,Synedra sp.,Achnanthes sp.and Cryptomonas sp.are the common dominant species of the three reservoirs,Keratella cochlearis,Keratella valga,Asplanchna priodonia,Polyarthra remata,Cyclopoidea,Nauplius and Bosmina longirostris is the common dominant species of the three reservoirs.The diversity indexes of the three reservoirs all change with the change of the water regime.3.The ratio of stable isotope of each trophic level is different in reservoirs and points,but the trend of change is as follows:?¹³C(fish)>?¹³C(plankton)>?¹³C(phytoplankton)>?¹³C(benthos),?¹⁵N(Benthos)>?¹⁵N(fish)>?¹⁵N(plankton)>?¹⁵N(phytoplankton).4.The trophic level of the three reservoirs are all 3.Phytoplankton is the producer,among the consumers,zooplankton is the primary consumer,benthic animal is the secondary consumer,and fish is the tertiary consumer.5.It can be seen from the aquatic food chain that the two main energy flow pathways are phytoplankton?zooplankton?fish,phytoplankton?zooplankton?benthos.