微生物及其碳酸酐酶对岩溶土壤系统钙镁元素淋失的影响

通过室内模拟土壤-灰岩岩溶系统,对不同微生物处理条件下的土柱进行降水淋滤,系统监测了淋出液的pH、电导率、Ca2+、Mg2+以及碳酸酐酶(CA)活性.结果表明,微生物对该模拟系统Ca、Mg元素迁移有较大促进作用.扫描电镜显示,埋入经微生物处理土柱的试片表面较对照(未埋入土柱和埋入灭菌土柱的试片)有明显侵蚀现象.另一方面,各处理的淋出液中均检测出不同程度的CA活性,说明土柱中的微生物产生了胞外CA并被淋出.相关分析表明淋出液中CA平均活性与Ca2+总淋失量之间存在较好的正相关关系,说明CA是影响Ca元素淋失的主要因素.对其进行深入研究将有助于解释生物岩溶的机理.

MICROBES AND ITS CARBONIC ANHYDRASE IMPACT ON THE LEACHING TO CALCIUM AND MAGNESIUM ELEMENTS IN CALCAREOUS SOIL SYSTEM

Dynamics of pH, electric conductivity, Ca~(2 ), Mg~(2 ) and carbonic anhydrase (CA) activity on the leaching process is investigated under different microbial treatment in calcareous soil systems. The results show that microorganisms are of promoting effects on calcium and magnesium elements migration in calcareous soil systems. Scanning electron microscopy analysis is performed on limestone cubes collected from the bottoms of soil columns at the end of the simulative experiment. The results show that the surface of limestone cubes which are put into soil columns with microbial action are corroded more significantly than on the surface which is put under sterilized soil column but not put under soil column. On the other hand, different CA activities are detected in the leachates collected from soil columns under different microbial treatments. This proves that the microbes in soil columns CA is produce and leached out. The correlation between average CA activity and total amount of Ca~(2 ) in leachates is analyzed, and the results show that they are positive correlated. This implies that CA is the major factor that influences the leaching of Ca~(2 ). Further research will be helpful to elucidate the mechanism of bio-karst.