The Oxygen Isotope Composition Of Modern Plants In Dajiuhu Peat Bog And Its Climate Significance

The organic matter oxygen isotope characteristics of peat sediment have been considered as one of the important methods to study the ancient climate changes,which many domestic and overseas scholars were used as the research object.They has achieved fruitful results about the use of peat cellulose δ¹⁸O on the inversion of climate change.Compared with different research areas,we have found peat cellulose delta δ¹⁸O in different research areas have different climate instruction significance.Peat in plant residues are mainly from terrestrial plant,and land plants are closely associated with climate change,therefore finding out the relationship between modern plant delta δ¹⁸O and climate factor is the basis of properly explain the climate significance of peat sediment in the delta δ¹⁸O and reconstruct the paleoclimate.In this paper,we analysis the oxygen isotope of peatland seasonal plant,atmospheric precipitation and swamp water in Dajiuhu,China.We discussed season scale change of climate elements such as temperature and humidity effects on,trying to reveal the relationship between the δ¹⁸O of plants as well as the swamp water and climate factor in a relatively short-time.The specific conclusions of the study are as follows:（1）The values of δ¹⁸O in different modern plants of the Dajiuhu Peat bog range from 19.29‰ to 30.65‰,with the average of 25.09‰.The Carex plants（vascular plants）have more enrichment of heavy oxygen isotopes than the moss plants（nonvascular plants）.The values of Dajiuhu δ¹⁸O is more dispersed with comparison of the values of δ¹⁸O in other modern peatland plants of areas in china.This is a clear demonstration of Dajiuhu Peat bog is in the stage of mesotrophic peat or eutrophic peat.（2）There are some differences in time series between δ¹⁸O of holocellulose andδ¹⁸O of a-cellulose.We found that δ¹⁸O of a-cellulose are more sensitive to the climatic conditions.Therefore,δ¹⁸O of a-cellulose are more suited to study the climate change.（3）The δ¹⁸O of dominant plants α-cellulose indicate the change of monthly mean temperature.This indicates that relative humidity is an important factor influencing the values of δ¹⁸O in plants of this area.The results are consistent with existed research about interpret the paleoclimate of this area with the value of δ¹⁸O.When remodelling the paleoclimate the bulking sample may be the better choices（4）The equation of local meteoric water line was δ¹⁸O and δD between precipitation and bog water,δD=8.128180+14.21;δD=10.5 δ¹⁸O+34.13.The value of d implied the main sources of water vapor is ocean.The Dajiuhu Basin,located in a typical East Asian monsoon region,is significantly affected by the monsoon.The negative correlation between δ¹⁸O and 5D with temperature about marsh water was discovered.From the modern process of peatlands,the relationship between the oxygen isotope in different modern plants of the investigated area and the climate factor is established,laying the foundations for remodelling the paleoclimate of this area with oxygen isotopes from the sedimentary peat plant residues.