微生物对碳酸盐岩的风化作用

微生物-矿物相互作用可以促进许多表生生物地球化学反应过程,是表生地球化学研究的重要内容。通过综合岩石表面的微生物类群及其地质作用,分析碳酸盐岩微生物风化的各种现象,特别是微观尺度上的各种形态,阐述碳酸盐岩的微生物风化机制与风化产物,笔者提出微生物对碳酸盐岩风化的4种途径:(1)通过微生物在岩石表面和缝隙中生长,导致岩石表层发生生物溶蚀、生物磨蚀和生物钻孔作用,加速岩石风化进程;(2)微生物群体形成的钻孔网络可以增强岩石化学溶蚀的有效表面积并导致其表面强度减弱而促进机械侵蚀作用,微生物对周围岩石颗粒胶结结构的破坏、疏松作用也会导致岩石矿物颗粒的分解;(3)微生物的持水作用,微生物分泌的有机酸以及微生物呼吸所释放的CO2对岩表水分的酸化过程亦加速岩石矿物的分解;(4)微生物生长过程中从岩石内摄取营养元素和产生复杂的有机配体,能促进矿物元素的释放。文中提出在开展微生物对碳酸盐岩风化过程和机理研究的基础上,有必要引入微生物生物技术来综合开发本地低品位含钾磷矿产资源,加速岩溶地区山地土壤的形成与演化。

Progress in the study of the weathering of carbonate rock by microbes

The interaction between microorganisms and minerals can facilitate the process of exogenic biogeochemical reaction,which is one of the important research contents in exogenic geochemistry.Microbes and their geological effects were summarized,and a variety of microbial weathering phenomena toward carbonate rocks,especially on different microcosmic scales,were analyzed.The products and mechanisms of weathering of carbonate rocks by microbes were also expounded.The authors put forward four microbial weathering mechanisms of carbonate rocks:(1)microorganisms grow on rock surface or in crevices,which will result in bio-corrosion,bio-erosion,and boring,and will accelerate rock decomposition and weathering;(2)boring meshes produced by microbial colony could increase the efficient superficial area of chemical denudation of rocks,and could lead to the intensification of rock surface weathering to promote mechanical erosion,and the microbial destruction and loosing of cementation structure of rock particles would also accelerate the decomposition of mineral particles;(3)rock weathering can be intensified by the effects of microbial water-keeping,acidification of organic acids secreted by microorganisms and the release of CO2 induced by microbial respiration onto rock surface;(4)microorganisms uptake nutrition from rock surface to produce complicated organic ligands and promote the release of mineral elements in the growing process of microorganisms.Finally,how to carry on the studies of the microbial weathering of carbonate rocks was proposed.The authors suggest to comprehensively exploit local low-grade mineral resources which contain potassium and phosphate and to accelerate soil formation and evolution in karst regions by using microbial technology.