COMPLETE OXIDATION OF SOLID-PHASE SULFIDES BY MANGANESE AND BACTERIA IN ANOXIC MARINE-SEDIMENTS
COMPLETE OXIDATION OF SOLID-PHASE SULFIDES BY MANGANESE AND BACTERIA IN ANOXIC MARINE-SEDIMENTS
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DOI：
10.1016/0016-7037(88)90335-3
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发表时间：
1988-03-01
影响因子：
5
通讯作者：
RUDE, PD
中科院分区：
文献类型：
--
作者：
ALLER, RC;RUDE, PD
在表层海洋沉积物的物理或生物改造过程中，金属氧化物经常与固体和溶解的硫化物接触。模拟这些混合过程的实验表明，在缺氧条件下，天然沉积物中的锰氧化物可以完全氧化固相硫化物为SO 4-。硫的主要来源可能是酸挥发性硫化物。含有Mn+4的矿物在驱动氧化方面明显比Mn+3更有效。在类似条件下，铁氧化物完全氧化硫化物的证据很少或没有。该反应被DNP（二硝基苯酚）和叠氮化物抑制，这意味着由一组化学无机营养细菌如硫杆菌的生物介导，具有组织良好的细胞色素系统，氧化磷酸化加上硫化物氧化，并可能自养CO2固定。缺乏对氯酸盐的敏感性表明，NO3-还原酶复合物不参与。由于金属还原和反应的总体化学计量，与O2氧化相比，这种硫化物氧化导致pH升高。碱度也同时被Mn、Ca碳酸盐沉淀耗尽。锰氧化物kutnahorite和managanoan方解石观察到形成迅速（天）在Mn还原。锰氧化物对硫化物的氧化作用可能很重要，但在富含有机物的陆架沉积物和热液喷口等环境中变化很大，在这些环境中，羽流与氧化金属接触。沉积硫化物的很大一部分可能会被氧化，锰减少这一途径，特别是在生物扰动沉积物。目前，海洋沉积物中石养（S）和异养（C）锰还原的相对作用尚不清楚。
During the physical or biological reworking of surficial marine sediments, metal oxides are often brought into contact with both solid and dissolved sulfides. Experiments simulating these mixing processes domonstrate that in natural sediments Mn-oxides can completely oxidize solid phase sulfides to SO4- under anoxic conditions. The major source of sulfur is probably acid volatile sulfide. Minerals containing Mn+4 are apparently more effective than Mn+3 in driving the oxidation. There is slight or no evidence for complete sulfide oxidation by Fe-oxides under similar conditions. The reaction is inhibited by DNP (dinitrophenol) and azide, implying biological mediation by a group of chemolithotrophic bacteria such as the thiobacilli, having a well-organized cytochrome system, oxidative phosphorylation coupled with sulfide oxidation, and possibly autotrophic CO2 fixation. Lack of sensitivity to chlorate suggests that a NO3- reductase complex is not involved. Because of metal reduction and the overall stoichiometry of reaction, this sulfide oxidation causes a rise in pH in contrast to oxidation by O2. Alkalinity is also simultaneously depleted by Mn, Ca carbonate precipitation. Both manganoan kutnahorite and managanoan calcite are observed to form rapidly (days) during Mn reduction. The oxidation of sulfides by Mn-oxides is likely to be important, but highly variable, in organic-rich shelf sediments and environments such as hydrothermal vents where plumes contact oxidized metals. A substantial proportion of sedimentary sulfide may be oxidized and Mn reduced by this pathway, particularly in bioturbated sediments. The relative roles of lithotrophic (S) and heterotrophic (C) Mn-reduction in marine sediments are presently unknown.