| 摘要: |
| 采用氯化钠(NaCl)、氨水(NH3·H2O)、氢氧化钠(NaOH)、盐酸羟胺(NH2OH·HCl)溶液对渤海湾北部和西部海域表层沉积物中无机碳进行了连续浸取, 并将无机碳分为5 种赋存形态: 交换态(NaCl相)、弱碱结合态(NH3·H2O 相)、强碱结合态(NaOH 相)、弱酸结合态(NH2OH·HCl 相)和残渣态。同时, 结合沉积物其他地球化学参数, 对影响各形态无机碳含量变化的因素进行了讨论。结果表明: 研究区表层沉积物中NaCl 相、NH3·H2O 相、NaOH 相、NH2OH·HCl 相、残渣相无机碳的平均含量分别为0.66、0.86、0.23、2.56、0.46 mg/g。NaOH 相无机碳占总无机碳的比例最小, 约为5%; NH2OH·HCl相的比例最大, 在50%左右。无机碳的不同形态及沉积物地球化学参数之间的相关关系分析表明,NH3·H2O 相受沉积物含水率、总氮(TN)、总有机碳(TOC)和沉积物细组分的影响极为显著, NaOH 相受沉积物TN 和TOC 的影响极为显著, 残渣相受含水率的影响较为显著, 其余2 相受各因素的影响较弱; 在沉积物早期成岩过程中, NaCl 相和残渣相无机碳之间可能存在一定相互转化关系。 |
| 关键词: 渤海湾 沉积物 连续浸取 无机碳形态 |
| DOI： |
| 分类号: |
| 基金项目:中国科学院知识创新工程重要方向项目(KZCX1-YW-06-02,KZCX2-YW-Q07-03, KZCX2-YW-JC203) |
|
| Fractionation of inorganic carbon in the surface sediments of northern and western Bohai Bay |
|
|
| Abstract: |
| Fractionation of inorganic carbon (IC) in the surface sediments of northern and western Bohai Bay was extracted sequentially with solutions of sodium chloride (NaCl), ammonia (NH3·H2O), sodium hydroxide (NaOH), hydroxylamine hydrochloride (NH2OH·HCl), resulting in five fractions: the exchangeable fraction (NaCl fraction), weak alkali extractable fraction (NH3·H2O fraction), strong alkali extractable fraction (NaOH fraction), weak acid extractable fraction (NH2OH·HCl fraction), and residual fraction. Combined with other sediment geochemical parameters, the factors which affected the IC content were discussed. The results showed that in the surface sediments of the study area, the average contents of IC in different fractions, i.e. NaCl fraction, NH3·H2O fraction, NaOH fraction, NH2OH·HCl fraction and Residual fraction, were 0.66, 0.86, 0.23, 2.56 and 0.46 mg/g, respectively. The NaOH fraction accounted for the smallest proportion (about 5%) of the TIC. The NH2OH·HCl fraction ration was the largest, in the vicinity of 50%. Correlation analysis among different IC fractions and geochemical parameters indicated that the sediment moisture content, total nitrogen (TN), total organic carbon (TOC) and sediment fine fraction had a highly significant effect on the NH3·H2O fraction of IC; TN and TOC had a significant effect on the NaOH fraction IC; sediment moisture content had a significant effect on residual fraction IC; and there was no significant correlation between various sediment geochemical factors and the other two fractions. During early digenesis, there might be a certain transformation between the NaCl and the residual fractions of IC. |
| Key words: Bohai Bay sediment sequential extraction fractionation of inorganic carbon |
