The carbon isotope fractionation in the atmosphere-soil-spring system associated with CO2-fixation bacteria at Yaji karst experimental site in Guilin, SW China
The carbon isotope fractionation in the atmosphere-soil-spring system associated with CO2-fixation bacteria at Yaji karst experimental site in Guilin, SW China
复制标题
桂林雅吉喀斯特试验场大气-土壤-泉水系统中与二氧化碳固定细菌相关的碳同位素分馏
DOI：
10.1007/s12665-015-4553-x
复制
发表时间：
2015
影响因子：
2.8
通讯作者：
Liu Chang
中科院分区：
文献类型：
--
作者：
Li Qiang;Wang Hua;Jin Zhenjiang;Xiong Wenbin;Wu Xia;Zhang Ying;Liu Chang
在表岩溶扩散入渗层中，水-碳酸盐岩-CO2气体在生物/非生物CO2的驱动下发生相互作用。因此，有必要研究岩溶系统中生物/非生物CO2的碳同位素组成变化。本文介绍了中国西南部丫吉岩溶试验区的一些水文地球化学和生物特征。水文地球化学研究发现，S31泉主要出露于1号漏斗，主要为HCO 3 −-Ca型，平均镁钙比仅为0.87%，计算出的S31泉的PCO 2与SIC之间存在正相关关系（R2= 0.9591），一般来源于复杂的水-碳酸盐岩-CO2气体相互作用。1号漏斗0 ~ −10 cm和−20 ~ −30 cm两层土壤CO2-δ 13 C差值为6.6 ‰，1号漏斗固定CO2细菌与土壤有机碳（SOC）呈显著正相关（P< 0.0003）。根据O 'Neil方程计算，S31的土壤CO2-δ 13 C与S31的δ 13 CDIC相差10.93，其中76%的CO2来自于土壤生物CO2。上述结果表明，大气CO2通过表溶扩散入渗层时，固碳菌优先吸收12 CO2，土壤CO2可能来源于土壤中的异养微生物呼吸作用。在固定CO2细菌的干预下，表溶扩散入渗层会产生“胎盘”作用，促使土壤CO2与泉水DIC之间的稳定同位素平衡分馏，在只有样品单方面结果的情况下，可用于预测土壤CO2-δ 13 C或δ 13 CDIC值，特别是用于洞穴滴水监测。此外，未来对CO2固定细菌同位素分馏的研究将为解释表溶扩散入渗层的功能提供更多令人惊讶的信息。
In the epikarst-diffusing infiltration layer, the water–carbonate rock–CO2gas interaction takes place under the driving force of biotic/abiotic CO2. Therefore, it is necessary to study the changes of carbon isotopic composition relating to biotic/abiotic CO2in the karst system. This paper presents some hydrogeochemical and biological characterization in the Yaji karst experimental site of SW China. Based on the hydrogeochemical studies, it was found that spring 31 (S31) mainly flowing out from doline 1, was primarily characterized as a HCO3−–Ca type, with a mean magnesium/calcium ratio of only 0.87 %, and a positive relationship (R2= 0.9591) existed between calculatedPCO2andSICin S31 which generally originates from the complex water–carbonate rock–CO2gas interactions. The difference of soil CO2–δ13C in two soil layers (0 to −10 and −20 to −30 cm) from doline 1 is 6.6 ‰ and the CO2-fixation bacteria has the significant positive correlation with soil organic carbon (SOC) in doline 1(P< 0.0003). Moreover, the difference between soil CO2–δ13C in doline 1 and δ13CDICin S31 is 10.93 and 76 % CO2in S31 comes from soil biotic CO2based on O’Neil equation. The above results indicate that when atmospheric CO2transfers through the epikarst-diffusing infiltration layer,12CO2will be requested by the CO2-fixation bacteria with high priority, and soil CO2probably originates from heterotrophic microbial respiration in the bulk soil. Then, under the intervention of CO2-fixation bacteria, the epikarst-diffusing infiltration layer will produce the “placenta” function to spur the stable isotopic equilibrium fractionation between soil CO2and spring DIC, which could be used to predict the value of soil CO2–δ13C or δ13CDICwhen we only have one aspect result of the samples, especially for monitoring drip water in the cave. Moreover, the future research on the isotopic fractionation of CO2-fixation bacteria could provide more surprising information to explain the function of epikarst-diffusing infiltration layer.