胶州湾沉积物中硫酸盐还原和铁异化还原的影响因素研究

发布时间：2018-01-08 23:14

本文关键词：胶州湾沉积物中硫酸盐还原和铁异化还原的影响因素研究　出处：《中国海洋大学》2014年硕士论文　论文类型：学位论文

【摘要】：硫酸盐还原和铁异化还原是近海沉积物中有机质矿化的主要路径，对C、S、Fe、P以及微量元素的生物地球化学循环产生重要影响。本研究选取胶州湾沉积物为研究对象，对于揭示半封闭的富营养化海湾沉积物中硫酸盐还原和铁异化之间的关系具有重要价值。本文通过向沉积物中添加葡萄糖、活性铁(III)氧化物或钼酸盐，改变活性有机质（即电子供体）含量、活性铁(III)氧化物（即电子受体）含量以及对硫酸盐还原（竞争电子受体）的抑制，并避光厌氧培养63天，测定沉积物固相和孔隙水中Fe（II）、Fe(III)、酸挥发性硫化物（AVS）、黄铁矿硫（Spy）含量，定量评价对胶州湾沉积物中硫酸盐还原和铁异化还原的相对重要性以及活性有机质含量和活性铁氧化物含量对其相对重要性的影响。主要研究结果如下：（1）改变沉积物中活性铁氧化物含量进行培养实验发现，沉积物中活性铁氧化物含量越高，AVS和Spy的积累量越小，Fe（II）的积累量和Fe（III）的消耗量就越大。增加沉积物中活性铁氧化物含量，沉积物中AVS积累量可减少30%，黄铁矿积累量可减少10%，Fe(III)消耗量可增加6.5倍。表明在厌氧沉积环境中，较多的活性铁氧化物可促进铁异化还原作用，抑制硫酸盐还原，且铁含量越高，抑制作用更明显。（2）改变沉积物中活性有机质含量进行培养实验发现，增加沉积物中活性有机质含量，沉积物中AVS积累量可提高89%，，黄铁矿积累量可提高66%，Fe(III)消耗量可提高22%。表明在厌氧沉积环境中，活性有机质含量越高，越有利于硫酸盐还原和铁还原，从而促进黄铁矿的形成，且对硫酸盐还原的促进作用更为明显。进而推测在有机质含量丰富的近海陆架和初级生产力旺盛的低纬度海域厌氧沉积环境中，较高的活性有机质含量可能导致硫化氢大量积累，对海洋沉积生态环境产生毒害作用。（3）改变沉积物中活性铁氧化物或活性有机质含量进行培养实验发现，在富含活性有机质的沉积物中，活性铁氧化物含量增加1倍，Fe（III）还原量可以提高1.4倍，黄铁矿积累量下降28%。说明富含有机质的沉积物中活性铁含量的增加可以抑制硫酸盐还原，不利于FeS向黄铁矿的转化。进而推测在海水养殖区以及水体富营养化等有机质含量丰富的海洋沉积物中，增加活性铁氧化物含量有利于Fe（II）和毒性元素的活化和迁移，能够有效降低硫化物在水体中的积累，防止其对生物的毒害作用。（4）改变沉积物中活性有机质或活性铁氧化物含量进行培养实验发现，富含活性铁氧化物的沉积物中，活性有机质含量增加1倍，沉积物中AVS积累量可提高2.1倍，黄铁矿含量可提高77%，Fe（III）消耗量可提高18%，Fe（II）积累量减少24%。以此推测在盐沼、红树林、陆架海以及河口潮滩沉积物等典型的富铁自然沉积环境中，增加活性有机质含量会可能会促进硫酸盐还原和黄铁矿的形成与积累。（5）在硫酸盐还原受到抑制的条件下，活性有机质或活性铁氧化物含量提高均可促进铁的异化还原，且增加活性铁氧化物含量对铁异化还原的促进作用更加明显。表明胶州湾沉积物中活性铁还原主要以铁的异化还原为主，硫酸盐还原会受到一定程度的抑制，使沉积物中Fe（II）主要以非硫化溶解状态存在，并与释放的P和重金属向上扩散，提高水体富营养化水平和重金属的生物有效性。
[Abstract]:The reduction of sulfate reduction and iron alienation is the main path, mineralization of organic matter in marine sediment of C, S, Fe, P and trace elements have an important impact on the biogeochemical cycle. This study selected Jiaozhou Bay sediments as the research object, has important value to reveal the relationship between sulfate semi enclosed eutrophic Bay sediments iron reduction and alienation. In this paper, by adding glucose to the sediments, active iron (III) oxide or molybdate, change of labile organic matter (i.e. electron donor) content, the activity of iron (III) oxide (i.e. electronic receptor) content and on sulfate reduction (competitive electron acceptor) inhibition and light anaerobic culture the 63 day, Fe determination of solid phase and pore water sediment (II), Fe (III), acid volatile sulfide (AVS), sulfur (Spy) content, quantitative evaluation of sulfate reduction in the surface sediments of Jiaozhou Bay and dissimilatory iron reduction The relative importance and the effect of the content of active organic matter and the content of active iron oxide on its relative importance.
(1) training it is found that the content of active iron oxides in sediments, the higher the activity of iron oxide content in sediments, accumulation of AVS and Spy is small, Fe (II) accumulation and Fe (III) consumption amount is higher. Increase the content of active iron oxides in sediments, AVS accumulation can be 30% reduction in sediment accumulation, pyrite can be reduced to 10%, Fe (III) consumption can increase 6.5 times. That in the anaerobic sedimentary environment, the activity of iron oxide can promote more dissimilatory iron reduction, inhibiting sulfate reduction, and iron content is high, the inhibiting function is more obvious.
(2) training it is found that the content of active organic matter in the sediments, increase the content of labile organic matter in sediments, the accumulation of AVS can be increased by 89% in the sediments, pyrite accumulation can be increased by 66%, Fe (III) can improve the consumption of 22%. shows that in the anaerobic sedimentary environment, active organic matter content is higher, the more conducive to the reduction of sulfate and iron reduction, so as to promote the formation of pyrite, and to promote the role of sulfate reduction is more obvious. And that in the anaerobic sedimentary environment rich organic matter content of the offshore continental shelf and primary productivity of strong low latitude waters, activity of high organic matter content leads to the accumulation of a large number of hydrogen sulfide to produce toxic effects on the marine sedimentary environment.
(3) training was found that the change in sediment activity of iron oxide or active organic matter content in sediments rich in labile organic matter, active iron oxide content increased 1 times, Fe (III) reduction capacity can be increased by 1.4 times, indicating that the increase of pyrite decreased accumulation of 28%. active Fe content in organic rich sediments can inhibit sulfate reduction, is not conducive to the transformation. Then FeS pyrite speculated in the mariculture area and eutrophication rich in organic matter in marine sediments, and increase the activity of iron oxide content in favor of Fe (II) activation and migration and toxic elements, can effectively reduce the sulfide in the water to prevent the accumulation of the toxic effects on organisms.
(4) training was found that the change in sediment labile organic matter or active iron oxide content, the activity of iron oxide rich sediments, active organic matter content was increased by 1 times, the accumulation of AVS can be increased by 2.1 times in the sediment, pyrite content can be increased by 77%, Fe (III) consumption increased by 18%, Fe (II 24%.) accumulation reduced to speculate in the salt marsh, mangrove, iron rich natural sedimentary environment and Lu Jiahai estuary intertidal sediments typical, increased the content of active organic matter may promote the formation of sulfate reduction and pyrite and accumulation.
(5) in the sulfate reduction was inhibited under the condition of active organic matter or active iron oxide content can improve the promotion of iron and iron reduction, increase the activity of iron oxide was more pronounced on iron dissimilatory reduction role. That mainly in iron based iron reduction activity of the dissimilatory reduction of sulfate reduction in the sediments of Jiaozhou Bay, will be a certain degree of inhibition, Fe (II) in the sediment mainly exists in the non sulfide dissolved state, and with the P and release of heavy metals to improve the bioavailability of diffusion, eutrophication and heavy metals.

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P736.21

【参考文献】