河口陆基养虾塘沉积物铁的含量和形态

为研究河口陆基养殖塘底泥中铁的迁移和转化机制，本文测定了福建省3个河口养虾塘养殖期表层和亚表层底泥沉积物中活性铁含量及间隙水的常见组分.结果表明，不同站点间晶质Fe（III）、非硫Fe（II）、有机铁、铁硫化物含量存在显著差异.间隙水SO₄^2-和Cl^-可能是影响不同站点间Fe的形态和分布存在异质性的主要环境影响因子之一.盐度较高的养虾塘，铁的硫化物含量较高，有机铁和晶质Fe（III）含量较少.陆基养虾塘底泥沉积物中活性铁含量按固相Fe（III） > 铁硫化物 > 非硫Fe（II） > 有机铁的顺序排列.养虾塘亚表层沉积物铁硫化物（FeS和FeS₂）含量高于表层沉积物，而表层沉积物有机铁含量与间隙水SO₄^2-和NH₄⁺浓度高于亚表层沉积物.铁硫化物的生成一定程度上降低河口陆基养虾塘沉积物营养盐污染的潜在风险.

Abundance and speciation of sediment iron in the estuarine land-based shrimp ponds

To research the mechanisms of Fe transport and cycling in wetland-based aquaculture ponds. In this study, the abundance and speciation of reactive Fe in sediments of four wetland-based shrimp ponds in three estuaries of Fujian Province, southeast China, were investigated during the intensive culture period. Significant differences of crystalline Fe(III), non-sulfidic Fe(II), organic Fe-complex, and Fe sulfides were observed among the four shrimp ponds. Porewater Cl^- and SO₄^2- were key factors affecting the abundance and speciation of Fe among different shrimp ponds. Along with increasing salinity, the contents of Fe sulfides increased, whereas those of organic Fe-complexes and crystalline Fe(III) decreased. The contents of reactive Fe were in the following order:solid-phase Fe (III) > Fe sulfides > non-sulfidic Fe (II) > organic Fe complexes. The contents of FeS and FeS₂ were higher in the subsurface sediments of the shrimp ponds than those in the surface sediments.However,the contents of organic Fe complexes and concentrations of porewater SO₄^2- and NH₄⁺ were higher in the surface sediments than those in the subsurface sediments. The precipitation of Fe sulfides could partially reduce the potential risk of nutrient contamination in sediments of wetland-based shrimp ponds.