The promoting effect of soil carbonic anhydrase on the limestone dissolution rate in SW China.

To gain a better understanding of the biological effect on the water-gas-carbonate interaction, 15 sample plots from five ecotypes (grass land, ecological demonstration, artificial forest, tree-shrub, and forest community) in three experimental sites of SW China due to the absence of time-series succession ecotypes at the same karst site were selected to discuss the relationship between soil microbial populations, carbonic anhydrase (CA) and limestone dissolution rate. The results show that the soil microbial populations and soil CA activities within different ecotypes have the significantly positive correlation ( r = 0.968), which vary significantly and tend to decrease along the ecological succession process. In view of moist character and water-holding capacity in the evergreen forest, which can fleetly participate in water-gas-carbonate interaction, the limestone dissolution rate is not matching to the total microbial population and CA activity in forest community. If the ecotype for forest community was removed, the correlative coefficient between CA and the limestone dissolution rate is 0.950, the correlative coefficient between CA and total microbial population is 0.999 and the correlative coefficient between limestone dissolution rate and total microbial population is 0.952. It can be inferred that soil CA secreted by the soil microorganisms has the important role to promote the production of bicarbonate ions which affects limestone dissolution rate. [ABSTRACT FROM AUTHOR]