Biologically versus inorganically mediated weathering reactions: Relationships between minerals and extracellular microbial polymers in lithobiontic communities
Biologically versus inorganically mediated weathering reactions: Relationships between minerals and extracellular microbial polymers in lithobiontic communities
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DOI：
10.1016/s0009-2541(96)00041-1
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发表时间：
1996-10-30
期刊：
影响因子：
3.9
通讯作者：
Banfield, JF
中科院分区：
文献类型：
--
作者：
Barker, WW;Banfield, JF
利用HRTEM、WDS、LM和XRD研究了与威斯康星州沃索附近的Stettin杂岩体有关的角闪石正长岩的生物物理和地球化学风化作用。岩石由微纹长石、铁闪石、石英和铁闪石组成。壳状石生地衣、Rupecarpon nutrients和Porpidea albocaerulescens，穿透岩石表面至10 mm的深度。在完整的岩石中，角闪石表面沿着菌丝填充的裂缝被高度腐蚀。真菌菌丝利用晶界、解理和裂缝进入矿物表面，导致解理结合的矿物碎片在下部叶状体内积累，小至5 μ m。细菌小菌落是常见的，所有矿物表面都被真菌和细菌来源的胞外酸性粘多糖完全覆盖。在角闪石、石英和长石的情况下，溶解似乎并不涉及普遍的沥滤，因为即使是最小的矿物碎片也保留了它们的化学和结构特征。与地衣叶状体直接接触的黑云母被沿沿着（001）解理生长的真菌菌丝紧密地相互渗透，并部分转化为蛭石。未发现硅质残渣。生物介导的风化涉及在覆盖所有矿物表面的酸性细胞外凝胶内发生的复杂溶解/选择性运输/重结晶机制。每个矿物颗粒周围的特殊风化微环境最初产生微小的页硅酸盐微晶。在溶解的母相周围形成一层粘土矿物，最终形成大量直径为5-10 μ m的聚合物结合的、成分均匀的面对面定向的粘土矿物聚集体。铁铁矿的物理化学风化作用产生了拓扑定向的蒙皂石和针铁矿。裂解控制反应既不是等化学反应，也不是等体积反应。
Biophysical and biogeochemical weathering of amphibole syenite associated with the Stettin complex near Wausau, Wisconsin, has been examined by HRTEM, WDS, LM, and XRD. The rock consists of microperthitic feldspar, ferriannite, quartz, and ferrohastingsite. Crustose saxicolous Iichens, Rhizocarpon grande and Porpidea albocaerulescens, penetrate the rock surface to a depth of 10 mm. Within the intact rock, amphibole surfaces along hyphae-filled cracks are highly corroded. Fungal hyphae exploit grain boundaries, cleavages, and cracks to gain access to mineral surfaces, resulting in accumulations of cleavage-bound mineral fragments as small as 5 mu m within the lower thallus. Bacterial microcolonies are common and all mineral surfaces are completely coated in extracellular acidic mucopolysaccharides from fungal and bacterial sources. In the cases of amphibole, quartz, and feldspar, dissolution does not appear to involve pervasive leaching, for even the smallest mineral fragments retain their chemical and structural identity. Biotite directly in contact with the lichen thallus is intimately interpenetrated by fungal hyphae growing along (001) cleavages and is partially converted to vermiculite. No siliceous relies have been identified. Biologically mediated weathering involves a complex dissolution/selective transport/recrystallization mechanism occurring within the acidic extracellular gels coating all mineral surfaces. A specialized weathering microenvironment around each mineral grain initially produces minute phyllosilicate crystallites. A rind of clay minerals forms around the dissolving parent phase, eventually culminating in abundant 5-10 mu m diameter polymer-bound aggregates of face-to-face oriented clay minerals of homogeneous composition.Physiochemical weathering of ferrohastingsite produces topotactically oriented smectite and goethite. The cleavage-controlled reaction is neither isochemical nor isovolumetric.