| Global Change Science began to rise in the1970s and is an emerging fields of science,its purpose is to describe and understand the operation mechanism of the Earth’s environmentby which human lived and its variation regularity and the impact of human activities on theEarth System, to improve the ability of prediction and assessment of environment change forhuman, with a clear record of the information carrier of the environmental change history,combined with historical documents, record the evolution of historical climate reconstructionto infer the response of ecosystems to climate change.Tarim Basin is located in China’s southern Xinjiang, the Altun Mountains, the Pamirs,Tianshan and Kunlun Mountains amidst it, China’s largest desert, the Taklimakan Desert islocated in its central area. The inner basin drought windy, precipitation mostly concentrated inthe summer and winter humidity, river recharge is dependent on glacier melt water of thesurrounding mountain ranges. The main vegetation including Tamarisk shrub, shrub andsucculent woody salt plant, the desert forest is located in a natural oasis, only Tamariskcoverage on the shifting sand dunes, due to the lack of water supply instability, rely oasis,relatively closed, independent fragile ecosystem is formed at the edge of the basin.Tamarix has a good ability to adapt to the arid desert areas, and has long life,heat-resistant, cold-resistant. Tamarix has ability to adventitious roots when its roots sufferedburied, branches grow upward at the same time. Fallen leaves are compacted to form the litterlayer containing sand substances, namely the annual layer. The thickness of the annualstratum mainly depends on the intensity of wind, the times of sandstorm and the amount ofgrowth of Tamarix in that year. Owing to the arid climate, the annual stratum can beconserved for a long time. Just like dendrochronology,"Annual layers" function per year andsave the environment information. The analysis on the compositions of Tamarix Cone can beutilized to research and restore the changes of climate and environment hundreds of years ago, and is one of the powerful tools for researching the changes of environment in the arid zone.So it has a very vital significance in the study of evolvement of ecological environment in ariddesert area.Selecting Tamarix Cones located in the Cele and Andier as the main object of the study,through the field investigation combined with laboratory analysis, this paper compares theTOC, TN and C/N data in the three samples, and binding studies of regional climate recorddata, explores the history of climate change, the conclusions are showed as following:(1) There is a significant correlation between TOC、TN and C/N of tamarisk defoliation.TN is to determine the main factors of the C/N change.(2) For nearly221years, TOC content increased significantly in the study sample, thelinear trend values were0.101%/10a,0.284%/10a and0.111%/10a; TN content in group Aand group B sample declining tendency values were-0.03%/10a and-0.012%/10a; samplesTN rising trend at a value of0.06%/10a in Group B; C/N was significantly higher in Group Aand group B; C/N clear downward trend, tendency value is-0.61/10a in Group B.(3) TOC, TN and C/N content were affected by regional temperature and precipitation.When TOC content increases, the temperature rises; when the TN content decreased, theregional climate into the dry period; when C/N rises, the regional climate is dry.(4) Based on this relationship, the division of the stage: Group A, Group B and Group Csample sites in which climate change in the past221years. Point A:1792~1873（cold andhumid）,1874~1958（warm and dry）,1959~2010（warm and dry）;Point B:1826~1886（coldand dry）,1887~1950（warm and humid）,1951s~2010（swarm and humid）;Point C:1790~1888（cold and humid）,1889~1955（warm and humid）,1956~2010（warm and dry）.(4) Correlation analysis between atmospheric CO2and the precipitation, temperature,and other al factors, we found temperature, precipitation and CO2have a high negative linearcorrelation. |
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