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滨海潮滩沉积物铁异化还原过程对有机质代谢及生源要素(C、N、P、S、O等)生物地球化学循环具有深远的影响.本文以闽江河口鳝鱼滩潮滩湿地为研究对象,对高、中、低潮滩0~80 cm深度内与铁异化还原相关的不同形态铁的含量和空间分布进行分析.结果表明,无定形Fe(Ⅲ)((39.3±5.3)μmol·g~(-1))和晶质Fe(Ⅲ)((84.2±10.7)μmol·g~(-1))主要分布在高潮滩,并沿着向海方向减少;铁的硫化物FeS((15.3±2.8)μmol·g~(-1))和Fe S2((6.0±1.1)μmol·g~(-1))集中分布在中、低潮滩;非硫Fe(II)((111.7±12.8)μmol·g~(-1))富集在整个潮滩剖面上,且含量随着深度增加而增加.孔隙水Fe~(2+)((3.7±0.7)mmol·L~(-1))与Fe S2、SO_4~(2-)和pH相关,说明Fe~(2+)可能与黄铁矿的水解有关.不同形态铁在高、中、低潮滩表现出显著的空间分布异质性.高潮滩铁异化还原的强度大于硫酸盐异化还原,但沿着向海方向,硫酸盐异化还原的潜势逐渐增加.本研究证明了潮汐水文和高程对潮滩湿地铁的迁移和转化具有重要的意义.
The process of dissimilatory reduction of iron in coastal tidal flat sediments has a far-reaching impact on the biogeochemical cycling of organic matter metabolism and biogenic elements (C, N, P, S, O, etc.) .In this paper, (39.3 ± 5.3) μmol · g ~ (-1)) in different depths of 0 ~ 80 cm in high, medium and low tidal flats. The results showed that Fe (Ⅲ) (-1) and the crystalline Fe (Ⅲ) (84.2 ± 10.7) μmol · g -1 were mainly distributed in the high tide beach and decreased along the seaward direction. FeS (15.3 ± 2.8 μmol · g -1 and Fe 2 O 6.0 ± 1.1 μmol · g -1 were mainly distributed in the middle and low tide beach, and the concentrations of non-sulfur Fe (II) ((111.7 ± 12.8) μmol · G ~ (-1)) enriched in the whole tidal flat section, and the content increased with the increase of depth.The pore water Fe 2 + (3.7 ± 0.7) mmol·L -1) Fe S2, SO 4 2- and pH, indicating that Fe 2+ may be related to the pyrolysis of pyrite, and the different forms of Fe show remarkable spatial heterogeneity in high, medium and low tide beaches. Intensity of dissimilatory reduction of tundra is greater than that of sulfate dissimilatory reduction, but along the seaward direction, the potential of dissimilatory reduction of sulfate Gradually increase. This study demonstrated elevation and tidal hydrology has important implications for migration and transformation of tidal wetlands subway.