【摘要】 对珠江口淇澳岛海岸带3个站位(QA-11,QA-9和QA-14)的沉积物中不同形态的还原硫(酸可挥发性硫,黄铁矿和有机硫)、总有机碳(TOC)和孔隙水中SO42-,甲烷浓度进行了测定,并且利用稳态扩散模型计算其中2个站位(QA-9和QA-14)硫酸盐还原通量[1.74和1.14 mmol/(m2.d)]和甲烷厌氧氧化通量[0.34和0.29 mmol/(m2.d)]。研究结果表明由于潮间带沉积物受到SO42-供给的限制,因此位于潮间带的QA-11站位硫酸盐还原带较浅(约16 cm);在潮下带的QA-9和QA-14站位,随离海岸距离和水深的增加,硫酸盐还原通量呈现减小的趋势,并且硫酸还原逐渐受到可利用活性有机质的限制;甲烷厌氧氧化对硫酸盐还原的贡献表现出增加的趋势,由19.2%增加至25.5%。三个站位沉积物中按不同形态还原硫含量由大到小列出,它们是有机硫(OS)、黄铁矿(DS)、酸可挥发性硫(AVS)。沉积物中AVS的空间分布与硫酸盐还原通量有正相关性。QA-11和QA-14站位的黄铁矿与AVS硫的含量比值大于3,分别为7.9和3.6,表明两个站位的黄铁矿形成可能受硫酸盐还原作用的控制;QA-9站位黄铁矿与AVS硫的含量比值为2.2,暗示AVS向黄铁矿转化受到可利用活性铁的限制。更多还原

【Abstract】 The concentrations of methane and sulfate in pore-water and pools of reduced sulfur compounds(acid volatile sulfur,pyrite and organic sulfur) and total organic carbon in sediment were determined at three sites(QA-11,QA-9 and QA-14) in the shore sediments of Qi’ao Island in the Zhujiang Estuary.By using a steady state diffusive model,sulfate reduction and anaerobic oxidation methane fluxes were calculated from pore-water sulfate and methane profiles.The sulfate reduction flux equaled 1.74 and 1.14 mmol/(m2·d) at Sites QA-9 and QA-14,and the methane anaerobic flux equaled 0.34 and 0.29 mmol/(m2(d) respectively.Because the sulfate supply from overlying water is limited in intertidal sediment,the depth of sulfate reduction zone is shallow at Site QA-11.With the increasing of the distance from the coast and the seawater depth,the sulfate reduction flux gradually decreased from Sites QA-9 to QA-14 located in the subtidal zone,sulfate reduction might be controlled by the supply of organic matter in sediment,meanwhile the contribution of the anaerohic oxidation of methane to the sulfate reduction increased from 19.2% to 25.5%.The results show that according to the order of high to low content of reduced sulfur of different forms in sediment they are organic sulfur,pyrite,acid volatile sulfur.The concentration of AVS and the sulfate reduction flux showed obvious correlation in the sedimentary cores of three sites.The values of the sulfur content ratio of pyrite to AVS were 7.9 and 3.6 at Sites QA-11 and QA-14 respectively,suggesting that AVS could be transformed to pyrite efficiently and the sulfate reduction was likely to limit formation of pyrite in the sediments,and the sulfur content ratio of pyrite to AVS being less than 3,with value of 2.2,at Site QA-9 indicated that sulfide mineralization was limited by the availability of highly reactive iron.更多还原