EFFECTS OF SOIL ORGANIC FRACTIONS ON IRON OXIDE BIODISSOLUTION UNDER ANAEROBIC CONDITIONS
EFFECTS OF SOIL ORGANIC FRACTIONS ON IRON OXIDE BIODISSOLUTION UNDER ANAEROBIC CONDITIONS
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DOI：
10.1097/00010694-200502000-00003
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发表时间：
2005-02
期刊：
影响因子：
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通讯作者：
L. Petruzzelli;L. Celi;F. Ajmone-Marsan
中科院分区：
文献类型：
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作者：
L. Petruzzelli;L. Celi;F. Ajmone-Marsan
土壤氧化铁难溶；然而，它们的溶解不仅有利于有效铁量的增加，而且有利于吸附或封闭在FeIII氧化物上的阴离子和阳离子的释放，这可能对环境质量产生很大影响。本研究以不同土壤腐殖质组分为电子供体，评价了微生物对氧化铁的还原性生物溶解作用。从厌氧泥浆中提取的混合微生物群在厌氧条件下，在水合铁或针铁矿存在的情况下孵育15天，然后添加溶解的有机物（DOM）、黄腐酸（FA）、腐植酸（HA）或醋酸盐作为电子供体。在规定的时间间隔内测量Eh、pH、溶解FeII和溶液中溶解有机物的浓度。氧化还原电位（Eh）在培养的第一天迅速下降，水合铁比针铁矿下降得更多，然后恢复到初始值，具体值有所不同，取决于有机组分。淹水15 d后，水合铁中FeII的释放量最大，为11.0 μg Fe mL−1，针铁矿中FeII的释放量为7.5 μg Fe mL−1。水合铁具有较高的比表面积和较低的结晶度，释放出较多的FeII。DOM和FA组分对铁的还原效果最好，同时也是细菌的C源，这表明微生物既可以利用DOM供应N，也可以利用DOM供应C，选择富含单糖、氨基酸和羧酸的组分。
Soil iron oxides are poorly soluble; however, their dissolution may favor not only an increase in the amount of available iron but also the release of anions and cations, adsorbed or occluded on FeIII oxides, which may have a great impact on environmental quality. In this study, the reductive biodissolution of iron oxides by microorganisms was evaluated using different soil humic fractions as electron donors. A mixed population of microorganisms extracted from an anaerobic mud was incubated for 15 days under anaerobic conditions in the presence of ferrihydrite or goethite, after adding, as electron donors, dissolved organic matter (DOM), fulvic acids (FA), humic acids (HA) or, for comparison, acetate. At regular time intervals Eh, pH, dissolved FeII and the concentration of dissolved organic compounds that remained in solution were measured. The redox potential (Eh) decreased rapidly in the first days of incubation, more with ferrihydrite than with goethite, and then returned to the initial values with some differences in specific values, depending on the organic fraction. The amounts of FeII released from ferrihydrite reached a maximum of 11.0 μg Fe mL−1 after 15 days of waterlogging compared with 7.5 μg Fe mL−1 released from goethite. Ferrihydrite released more FeII because of its higher specific surface area and its low crystallinity. DOM and FA fractions were the most effective in Fe reduction and as a C source for bacteria, suggesting that microorganisms can also use DOM for N supply as well as for C, selecting fractions rich in monosaccharides, amino acids, and carboxyl acids.