渤海湾西北部沿岸主要入海河流表层沉积物中无机碳形态研究

摘要

【目的】调查渤海湾西北部沿岸河流表层沉积物中不同形态无机碳(IC)的分布和影响因素，阐明我国近岸不同环境沉积物中 IC 分布形态的异同和调控机制。【方法】采用连续浸取方法，根据 IC 在沉积物中的结合强度，将其分为交换态(氯化钠相)、弱碱结合态(氨水相)、强碱结合态(氢氧化钠相)、弱酸结合态(盐酸羟胺相)和残渣态，分析表层沉积物中不同形态的 IC 含量，并讨论其与各地球化学参数之间的关系。【结果】渤海湾西北部沿岸河流表层沉积物中总 IC 的平均含量为6.76 mg/g。沉积物中各相 IC 的平均含量为盐酸羟胺相(3.21 mg/g)>残渣相(1.92 mg/g)>氨水相(0.77 mg/g)>氯化钠相(0.64 mg/g)>氢氧化钠相(0.22 mg/g)。盐酸羟胺相是沉积物 IC 的主要形态。总有机碳(TOC)对各形态 IC 影响较强。氨水相 IC 与沉积物各参数间存在较为紧密的联系。【结论】研究区域沉积物中不同形态 IC 的组成和分布空间变化显著，不同地点样品中 IC 的活跃程度和可能的环境影响因子差异很大。%Objective]The environmental behavior and mobility of inorganic carbon (IC)de-pend strongly on their specific chemical forms and binding state.This study investigated the specific chemical forms of IC in the surface sediments collected from the coastal rivers along the Bohai Bay.[Methods]Sediment samples were extracted sequentially using solutions of so-dium chloride (NaCl),ammonia (NH 3 · H 2 O),sodium hydroxide (NaOH),hydroxylamine hydrochloride (NH 2 OH·HCl),resulting in five fractions:Exchangeable fraction (NaCl frac-along the Bohai Bay was 6.76 mg/g.The average content of IC in different fractions was NH 2 OH·HCl fraction (3.21 mg/g)>residual fraction (1.92 mg/g)>NH 3 ·H 2 O fraction (0.77 mg/g)>NaCl fraction (0.64 mg/g)>NaOH fraction (0.22 mg/g).NH 2 OH · HCl fraction was the main speciation of IC in sediments.Total organic carbon (TOC)had a strong impact on various IC fractions.The IC content extracted by NH 3 ·H 2 O was closely related to sediment parameters.[Conclusion]The composition and distribution of different forms of inorganic carbon in the surface sediments of the studied area exhibited a significant spatial variation.In addition,a significant difference was found in the mobility of IC and the possible environmental parameters in the sediments from different sampling site.