胶州湾李村河口沉积物中硫化物形成的控制因素

在胶州湾李村河口，对多个短柱状岩芯沉积物中的有机质（有机碳和有机氮）、酸可挥发性硫化物（AVS）、黄铁矿及活性铁等进行了分析。结果表明，样品的有机质含量较高，有机碳含量为0．16％～3．21％，有机氮含量为0．002％-0．2％；6个短柱状样的AVS含量变化较大：198．4—0．4umol／g，平均35．6umol／g；活性铁含量为47．5～169．3umol／g，平均91．4umol／g；黄铁矿含量为14．8～41．0umol／g，平均28．7umol／g。通过计算沉积物中活性铁的黄铁矿化度（DOP）与硫化度（DOS）指标，及分析各参数间相关性，发现以下现象：（1）胶州湾李村河口沉积物中的活性铁被转化为硫化物的程度较高，被转化为黄铁矿的程度较低，沉积物中的黄铁矿得到了较好保存。DOP不适宜用作河口区氧化还原状态的判断指标，DOS对氧化还原状态的响应更加灵敏；（2）距河口较近的区域，受李村河河水的影响较大，易分解有机质供应充足，AVS大量形成，其向黄铁矿的转化并不充分，活性铁成为硫化物形成的控制因素。距河口较远的站位，活性铁含量相对充足，有机质含量相对不足，因此有机质含量成为硫化物形成的控制因素，AVS向黄铁矿的转化比较充分；（3）有机质尤其是易分解有机质含量是李村河口硫化物形成、活性铁富集及其黄铁矿化度的主要控制因素。AVS的形成主要受到有机氮的限制，而黄铁矿的形成主要受到有机碳的限制。因此，河流输入物质对河口区沉积物中C、S和Fe的循环具有显著的影响。

Restriction factors to sulfide formation in estuarine sediments of Licun River of Jiaozhou Bay

The reactive iron, pyrite, acid volatile sulfide （AVS）, and organic carbon, etc, were analyzed for 6 short column sediment cores from Licun estuary in Jiaozhou Bay. The results show that the organic material contents are relative high ranging from 0. 16% -3.21% organic carbon and 0. 002% -0. 2% organic nitrogen. The AVS varies in a broad range of 198.4 - 0.4 umol/g, with an average value of 35.6 umol/g. The reactive iron content varies from 47.5 umol/g to 169.3 umol/g, with an average value of 91.4 umol/g. The pyrite content varies from 14.8 to 41.0 umol/g, with an average value of 28.7 umol/g. Degree of pyritization （DOP） and degree of sulfidation （DOS） of reactive iron were calculated, and relativity between those parameters were analyzed. Several conclusions were inferred： （1） the reactive iron in sediments from Licun fiver estuary was mostly transformed into sulfide minerals other than pyrite. Pyrite was well preserved in the sediment. At the estuary environment, DOS is more feasible to be an index of sediment redox condition than DOP. （2） Near the estuary area, the sediment was obviously influenced by Licun River. A large number of AVS formed on the basis of plentiful supply of metabolizable organic material, and the degree of AVS transform into pyrite was relative low. The supply of reactive iron is the limiting factor of sulfide formation. In the sediment far away from the estuary area, AVS transferred into pyrite in a relative high degree. The organic material concentration became the limiting factor because of the lack of the metabolizable organic material, while the reactive iron supply is relative abundant. （3） The organic material content, especially the metabolizable organic material content, is the mainly limiting factor of sulfide formation, reactive iron enrichment, and the DOP. Formation of AVS is mainly restricted by total organic nitrogen, while formation of pyrite is mainly restricted by total organic carbon. So, material inputted from river have remarkable influence