Multi-proxy Record Of Water Level Variability From Three High-altitude Peatlands In Changbai Mountains

Peatl-based paleoclimate reconstruction is an important part of past global change. Correct comprehension of palaeo-environmental evolving history provides the theoretic foundation for understanding the changes of current climate and predicting the future climate direction. This paper selects Yuanchi, Chichi and Laobaishan peat bogs that all come from Changbai Mountain in northeast China as research subjects, through 137 Cs and AMS14 C isotope dating techniques to build time series, and analyses proxies such as humification, plant macrofossils, testate amoebae in order to reconstruct the change of mires surface wetness in Changbai Mountain area in recent 50 years. This paper will also do a comparative analysis between reconstruction of the water level and meteorological data, trying to find the driving factors of water level changes in the peatlands.Plant macrofossil analysis use QLCMA(Quadrat and Leaf Count Macrofossil Analyses) method. Based on the identification and statistics of plant macrofossils, environmental gradient are extracted. The results show that the species have obvious moisture gradient on DCA axis 1 ranking, Humidity is the most important environmental factor affecting the distribution of plants.Dividing testate amoebae species reference Charman's identification method, and then the relationships between amoebae and water level gradient are got by testate amoebae-water transfer function which was built by Hongkai Li in rioja software.The method applied in ACCROTELM plan in 2003 is used to measuring the peat humification, in this way Na OH's absorbance values stands for the degree of decomposition of peat when the wavelength is 540 nm in this method.Comparing plant macrofossils, testate amoebae and humification in Laobaishan peat bogs, the three proxy records indicate similar dry and wet change and all of them shows that mires surface wetness are down from the surface with the increase of the depth of the surface humidity get wet. In the same way, Yuanchi mire is similar with Chichi mire. And the change trends of three locations mire surface humidity are the same. The similarity of three locations' mires surface wetness which use multi-proxy record indicates that the changes of mire surface wetness in this area are influenced by the same factors.Contrasting the history of surface wetness rebuilt by proxy indicators in Laobaishan mire over the past 50 years and meteorological data of Dunhua station, the results show that the change of water tables is consistent with the changes of the recorded temperature in the meteorological station, the wetter years recorded by three indicators are also in good agreement with the increase of summer precipitation. Therefore, it can be inferred that the change of surface wetness in peatland controlled by the change of summer.However,the fluctuation of water table is mainly influnced by the precipitation.