【作者】 牟德海；

【导师】 黄长江； 张春粦；

【作者基本信息】 暨南大学 ， 水生生物学， 2002， 博士

【摘要】 本文主要研究（1）大亚湾的沉积速率和沉积通量；（2）大亚湾沉积物中微量元素、游离氨基酸和水解氨基酸的垂直分布特征；（3）大亚湾核电站低放废液中主要放射性核素在大亚湾表层沉积物上的吸附行为；（4）海洋双壳贝类和浮游微藻对这些放射性核素的吸收和累积行为。1 用过剩²¹⁰Pb法研究了大亚湾沉积物的沉积年代以及沉积速率和沉积通量随年代的变化。结果表明：（1）W0、W2、W6和W9站位60cm深的柱状沉积物的年龄分别为124、109、109和101 yr；（2）沉积通量和沉积速率总体上均呈逐年升高的趋势；（3）从1998年起的过去10、20、50和100年间，大亚湾的平均沉积速率依次为1.28、1.15、0.92、和0.74cm yr^-1。2 用BCR 4步连续提取法研究了大亚湾柱状沉积物样品中Fe、Mn、Zn、Sr、Cu、Pb、Cd、As、Cr和Co共10种元素4种形态（酸可提取态、可还原态、可氧化态和残渣态）的垂直分布特征。在沉积物年代学结果的基础上，研究了这10种元素的沉积通量随时间的变化。结果表明：（1）在总量构成中占次要地位的形态（次要形态）随深度的显著变化可能完全被在总量构成中占优势的形态（主要形态）所淹没，而次要形态可能具有比主要形态更为重要的环境学、生态学和生物地球化学意义；（2）沉积物在埋藏过程中会发生形态之间的转化；（3）大亚湾外源性微量元素输入通量自上个世纪80年代以来发生了显著的变化。3 研究了大亚湾沉积物中12种游离氨基酸（FAA）和12种水解氨基酸（HAA）的垂直分布特征以及FAA和HAA之间的关系。结果表明：（1）12种FAA和HAA的含量均随深度而下降。沉积物中FAA总量和HAA总量随深度的变化可以分别用指数方程c_z=1.60e^-0.0122z（R=-0.97）和c_z=16.3e^-0.0047z（R=-0.90）来描述；（2）FAA的摩尔分数（x_F）和HAA的摩尔分数（x_H）随深度的变化的特点是：天冬氨酸和甘氨酸的x_F和x_H均随深度而上升；苏氨酸、缬氨酸、异亮氨酸和亮氨酸的x_F和x_H均随深度而下降；谷氨酸的x_F随深度而下降， 暨南大学博士论文 大亚湾放射生态学及沉积物的生物地球化学研究 牟德海XH随深度而上升；丝氨酸和丙氨酸的 XF随深度而上升，FH随深度而下降；（3）X。／X。与氨基酸的结构密切相关，结构相似的氨基酸具有相近的 Xr／X。。直链脂肪族氨基酸为 1．48；羟基氨基酸为1刀2；酸性氨基酸0．86；碱性氨基酸为0石7；支链脂肪族氨基酸0．50。国内外文献中未见相关研究和报道。 4用多核素示踪法研究了具有重要生态和环境意义的 10种人工放射性核素在大亚湾’表层沉积物上的吸附行为，获得了约30 s～ll3 d的吸附分配系数随时间的变化曲线。结果 闰表明：（）”‘Ru、”‘Ru、”Zr、”Nb在大亚湾沉积物上的分配系数随时间的变化曲线存在一个谷值；（2）经 113 d的吸附反应，”‘Ru、”‘Ru、”Zr、”Nb‘’Co‘’Z＊”’mAg”vCs”‘Sb和’、在大亚湾沉积物上的平均分配系数依次为 3．6X”、5．gX10’、1．SX旷、1．6x”、38X”、20X”、4．4X”、8．7X”、80和 70。 5 用多核素示踪法研究了 14天时间内放射性核素在僧帽牡顿（Saccostrea cucullata）、翡翠贻贝（Pernavirde）和马氏珠母贝（Pinctadamartensl体内的浓集因子随时间的变化及其组织分布。结果表明：（）”Zr、”＊b、”‘Rl和‘’C。在三种贝类体内的分布主要集中在外壳和足丝上；Q）三种贝类的软组织对’‘hAg和‘kn均有很高的浓集能力；N)’刃Cs、’油和l’‘Sb在外壳和软组织中的浓集因子都比较低；（4）三种贝类对l”Ru和”‘Ru的吸收和累积行为有很大的差异，”’Ru绝大部分在外壳上，而软组织对’吨ll的却具有很高的浓集能力。 6用多核素示踪法研究了扁藻（plQmpOn—euiptiC口）、小球藻（ChO。llQffiihUtiSSim。）和简单角毛藻（Chaetoceros guilts）对上述放射性核素的浓集动力学。结果表明这 3种微藻对’仍Ru’肠Ru 的Zr ”Nb、m、6’Zn、”MAg的累积速率快、浓集能力强。扁藻、’J’球藻和简单角毛藻对这 7种核素的累积在 48 h内即达到平衡，浓集因于为 10‘－10’。 (更多还原

【Abstract】 The paper studied on (1) Sedimentatary fluxes and rates of Daya Bay; (2) Vertical profiles of microelements and amino acids in sediment of Daya Bay; (3) Adsorption behaviors of artificial radionuclides on surface sediment of Daya Bay and (4) Uptake behaviors of the radionuclides by marine bivalves and phytoplankton algae.1 Four sediment cores of Daya Bay, the South China Sea, were dated by excess 2l癙b geochronology, and the variations of sedimentatary fluxes and rates with time were investigated. Results showed that (1) The ages of the 60-cm-length cores at station WO, W2, W6 and W9 were 124, 109, 109 and lOlyears respectively. (2) The sedimentatary fluxes and rates increased continually with years during the past 100 years before 1998. (3) The average sedimentatary rates during past 10, 20 50 and 100 years before 1998 were 1.28, 1.15, 0.92 and 0.74 cm yr"1 respectively.2 Fe, Mn, Zn, Sr, Cu, Pb, Cd, As, Cr and Co in four cores were partitioned into four operationally defined geochemical fractions (acid extractable, reducible, oxidizable and residual) by BCR four-step sequential extraction procedure. Variations of sedimentatary fluxes of the elements with time were studied based on geochronology of the cores. Results demonstrated that (1) The remarkable variations of subordinate fractions of an element with depth, which may be more environmentally, ecologically and biogeochemically important than dominating fractions, could be submerged completely by insignificant variation of dominating fractions of the element. (2) Elements in sediment could change from one fraction to another during burying. (3) Sedimentary flux of heavy metals to Daya Bay contributed by external input sources varied remarkably since 1980’s, the years of rapid industry developing of the area.3 Vertical profiles 12 free amino acids (FAA) and 12 hydrolysable amino acids (HAA) in the cores and the results showed that (1) Contents of FAA and HAA decreased with depth and the down-coretrends of total FAA and total HAA can be described by exponential equation of cz = 1.60 e~l22z and cz = 16.3 e-0.00472, with the correlation coefficient of-0.97 and -0.90, respectively. (2) The down-core trends of mole fractions of free (xr) and hydrolysable (XH) amino acids were: both XF and XH of aspartic acid and glycine increased with depth; both XF and XH of threonine, valine, isoleucine and leucine decreased with depth; XF decreased and XH increased with depth for glutamic acid; XF increased and XH decreased with depth for serine and alanine. (3) The ratios of xFio XH of amino acid heavily dependent on its’ structure and amino acids with similar structure had approximately the same ratio. The ratios of XF to XH for straight aliphatic, hydroxyl, acidic, basic and branched aliphatic amino acids were 1.48, 1.02, 0.86, 0.67 and 0.50 respectively. There were no relevant reports in literature.4 Adsorption behaviors of ten environmentally and ecologically important radionuclides on surface sediments of Daya Bay were studied and the results showed that (1) There was a valley in the kinetics curve of 103Ru, 106Ru, 95Zr and 95Nb. (2) Kds of 103Ru, I06Ru, 95Zr, 95Nb, 60Co, 65Zn, 110mAg) 137Cs, l24Sb and 85Sr were 3.6xl03,5.9xl03, 1.5*104, 1.6xl05, 3.8xl03, 2.0xl03, 4.4xl03, 8.7xl02, 80 and 70 respectively after 113 days adsorption.5 The behaviors of bioaccumulation and tissue distribution of the above radionuclides in marine bivalves (Saccostrea cucullata, Perna viridis, Pinctada martensi ) were investigated during an exposure time of 14 days. The results showed that (1 )The majority of 95Zr, 95Nb, 106Ru and60Co were distributed in the shells and byssl of bivalves. (2) Soft tissues of bivalves had high concentration factors for 110mAg and 65Zn. (3) Concentration factors of l37Cs, 85Sr and l24Sb in shell and soft tissue bivalves were low. (4) Uptake behaviors of 103Ru and 106Ru by bivalves were great differences: most of 103Ru uptake by the bivalves was in shells and 106Ru mainly distributed in soft tissues.6 The concentration biokinetics更多还原