Spatial Distribution Pattern And Influencing Factors Of Stable Carbon And Nitrogen Isotopes And Heavy Metal In Plants Around Qinghai Lake Region

We select typical plant samples around Qinghai Lake,the total organic carbon in plant samples（TOC）,total nitrogen（TN）,the ratio of total organic carbon and total nitrogen（TOC/TN）,stable carbon and nitrogen isotopes(delta ¹³C,delta ¹⁵N)and heavy metal and other biogeochemical indicators were measured in the study area to discover the characteristics of organic matter with plant composition and the distribution of heavy metals,reason the research and its influencing factors.The research is helpful to discover the factors that ring the ecological environment of the ring Qinghai Lake area,and provide scientific theoretical basis for the rational exploitation and protection of environmental resources around Qinghai Lake region.The main results were as follows:（1）The range of TOC value in the study area was 13.57%⁴4.11%,with an average value of 30.79%;The range of TN value was 0.90%³.04%,with an average value of 1.85%;TOC/TN value was 7.31⁴3.57,the average was 18.62;The content of delta ¹³C was-28.24‰^-21.54‰,the average was-25.57‰;The range of the delta¹⁵N value was-17.35‰⁰.07‰,and the average value was-4.66‰.Most of this study plants was C3 plant.（2）Plants with different landscape types have different TOC values,the TN value of plants is affected by vegetation type and altitude,the change range of plant carbon and nitrogen ratio is large,precipitation has a significant effect on the content of delta¹³C in plants.The value of plant Delta ¹⁵N may be affected by grazing,livestock and livestock activities,natural resources abuse or improper use of pesticides and fertilizers.（3）It is shown that the spatial distribution of stable carbon and nitrogen isotopes in the ring Qinghai Lake region is related to soil,temperature,altitude,precipitation,landscape category and plant category.（4）The average contents of the 7 heavy metals were Cr>As>Ni>Pb>Sb>Co>Cd.There are great differences in absorption and accumulation of different elements in different plants.The accumulation of heavy metals in plants is related to the background values of heavy metals in soil.With the increase of altitude,the contents of various elements showed a decreasing trend,indicating that heavy metal pollution was relatively low in high altitude area.（5）Elements As and Sb,Pb,Cd,Ni,Co,Sb and Pb,Cd,Co,Pb and Co,they all have a more obvious correlation,and they can interact with each other to promote the absorption and utilization of plants.One of the sources of heavy metals in plants is industrial and agricultural pollution.