桂林典型岩溶区土壤CO2通量及其δ13CCO2季节性特征

通过选用静态暗箱/气相色谱法，探讨桂林毛村典型岩溶区土壤CO2通量及其δ13C CO2的季节性演变规律，旨在揭示野外条件下土壤CO2及其δ13CCO2对环境因子变化的影响机制。同时野外原位监测大气温度、压强、土壤温度等环境参数来明确环境因子对土壤CO2的影响过程。结果表明:岩溶区土壤CO2通量及其δ13C CO2在季节时间尺度上呈现出相似的季节性变化规律，夏季土壤CO2通量较高，土壤δ13C CO2偏轻，且土壤CO2通量与土壤温度呈显著正相关关系。此外，夏季10 cm处土壤CO2通量明显高于0 cm，且该处δ13C CO2也偏轻于0 cm；冬季10 cm处土壤CO2通量与0 cm相差并不明显，而该处δ13C CO2却仍是偏轻于0 cm。在日时间尺度上10 cm土壤δ13C CO2明显偏轻于0 cm。 

Seasonal variation characteristics of soil respiration release and its isotopic composition in typical karst area, Guilin

It is of great value to understand the variation amplitude and temporal dynamics of soil respiration on a global scale so as to accurately predict the change of soil respiration under future climate scenarios， and to evaluate the carbon neutrality goals and technical approaches. In this study，the static chamber/gas chromatography were used to establish soil CO2 flux and δ13C CO2seasonal variation in the typical karst area of Maocun village.This study mainly aims to reveal the influence mechanism of soil CO2 and δ13C CO2 on environmental factors under field conditions Guilin.The influence of environmental factors on soil CO2 flux and δ13C CO2 were determined by monitoring atmospheric temperature， pressure， soil temperature and other environmental parameters. The monitoring results showed that the seasonal variation of soil CO2 flux in the study area was obviously high in summer and low in winter， and the soil CO2 flux at 10 cm in summer was significantly higher than that at 0 cm in the surface layer， while there was no significant difference in winter. Moreover， the soil Q10 value increased from 1.90 to 2.39 when the depth varies from 0 cm to 10 cm， indicating that the soil respiration mainly came from this depth range. Soil temperature is the main environmental factor affecting the change of soil CO2 flux， and the two show an obvious positive correlation. Copmared with 10 cm，the CO2 at 0 cm surface layer was also affected by the dilution of diffusion. Because the diffusion coefficient of 12CO2 is greater than 13CO2， the soil δ13C CO2 is lighter than the atmospheric δ13C during the monitoring period， which has obvious seasonal characteristics of being lighter in summer and heavier in winter， and the δ13C CO2 at 10 cm is significantly lighter than that at 0 cm.