地衣和地衣酸与岩石矿物风化及其机制研究进展

岩石矿物风化是地球表面发生的最重要化学现象之一,其中生物风化备受关注。对地衣及地衣真菌分泌的地衣酸类物质(简称地衣酸)在岩石矿物风化中的作用及机制进行综合述评,从而为科学评价地衣和地衣酸在森林(特别是寒温带)生态系统中的作用提供理论依据。地衣通过物理和化学方式显著诱导并加速岩石矿物的风化进程,即同时具有生物物理风化和生物化学风化两方面作用,而后者更为重要。在地衣诱导的岩石矿物风化过程中,地衣依其共生真菌/藻类特异性分泌的地衣酸起主导作用,无论是在野外还是实验室条件下,地衣酸都是岩石矿物生物风化的主要作用力。地衣酸对岩石矿物的风化机制包括质子促进效应和络合促进效应两方面,特别是地衣酸能与岩石矿物中的盐基离子形成可溶性螯合物,从而引起岩石矿物的强烈溶蚀。

Research progress on lichens,lichenic acids,rock and mineral weathering and its mechanisms

Weathering of rock and minerals is one of the most important geochemical phenomena that occurs on the earth’s surface, among which biological weathering is considered to be important. The role of lichens and lichenic acids secreted from lichens on biological weathering of rock and minerals was summarized in this paper. We also discussed the mechanisms of weathering. Our objective was to provide the theoretical basis for the scientific evaluation of the important functions of lichens and lichenic acids in forest ecosystems(especially for the cold temperate). Lichens can significantly induce and accelerate the weathering process of rock and minerals through physical and chemical mechanisms; Biophysical and biochemical weathering occur at the same time, of which the latter is more important. During the course of lichen-induced rock and mineral weathering, lichenic acids are secreted by lichens specifically on their symbiotic fungi or algae; these acids are the main drivers behind rock and mineral weathering both in the field and in the laboratory. Their weathering mechanisms include proton promotion and complexation effects. Lichenic acids, especially, can form soluble chelates with the base ions in rock and minerals, thus leading to dissolution of rock and minerals.