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Investigation on the Growth Mechanism of the Toxic Cyanobacterium (Lyngbya majuscula) in Moreton Bay, Queensland, Austraria

澳大利亚昆士兰州莫顿湾有毒蓝藻（Lyngbya majuscula）生长机制的调查

基本信息

批准号：
16254001
负责人：
OMURA Tatsuo
金额：
$ 26.21万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

We have investigated on the behavior of iron in coastal waters and iron uptake mechanism of toxic cyanobacterium, Lyngba majuscula, and developed a numerical model to predict the dynamics of bioavailable iron in coastal waters. Follows are major outcomes from this study.1.Laboratory experiment and field work were conducted to understand forms of iron in coastal water and behavior of humic iron complex such as equilibrium and coagulation. It was found that ferric iron complexed by humic substances (HS) is predominant iron species in river water, however, 90 % of the complex dissociates in coastal water due to the competition with divalent seawater cations (i.e.,Ca^<2+> and Mg^<2+>). Chromatography analysis revealed that coagulation was least for HS which has low molecular weight and hydrophobicity, indicating that HS having these properties are the most important contributor to transport dissolved iron from river to coastal waters.2.The numerical model to predict behavior of humic iron … More complex was developed, considering the physicochemical behavior of humic iron complex such as equilibrium, coagulation and diffusion. The equilibrium model was developed on the basis of Debye-Huckel theory that is able to take account of the potential energy of iron around the surface of HS. The coagulation model was developed by involving hydrophobolic interaction, a strong attractive force working among HS molecules, into the well established DLVO theory. The equilibrium and coagulation model was then combined with diffusion model (Navier-Stokes and diffusion equations), allowing us to numerically calculate the spatial and temporal distributions of humic iron complex in coastal water.3.The kinetics of bioavailable iron production via superoxide-mediated reactions was investigated to develop a model for the iron uptake by L. majuscula. Although the rate of superoxide-mediated production of bioavailable Fe(II) (i.e., bioavailability of iron) varies due to the different origin of humic iron complex, the humic iron complex with higher content of acid functional groups generally shows lower bioavailability. By determining the kinetic rate constants involved in Fe(II) production, reaction scheme in terms of iron uptake was developed. The model calculated that the strong humic iron complex produces Fe(II) via non-dissociative reduction pathway in which the Fe(III) complexed by HS is reduced by superoxide prior to the complex dissociation. The results indicated that management and environment of catchments such as land use and vegetation (i.e.,origin of HS) significantly affect the bioavailability of iron in coastal waters..In summary, the numerical model which involves the equilibrium, coagulation, diffusion and bioavailability of humic iron complex was developed in this work. The model allows us to comprehensively assess and predict the process of iron uptake by L.majuscula in coastal waters. Less

本文研究了铁在近岸沃茨中的行为和大型蓝藻Lyngba majuscula对铁的吸收机制，并建立了一个预测近岸沃茨中生物可利用铁动态的数值模型。主要研究结果如下：1.通过室内实验和现场考察，研究了近岸水体中铁的存在形态以及腐殖酸铁络合物的平衡和混凝行为。研究发现，河流水体中主要以腐殖物质（HS）络合的三价铁为主，而在近岸水体中，由于与二价海水阳离子（即HS）的竞争，90%的络合物解离，Ca^<2+>和Mg^<2+>）。色谱分析表明，低分子量疏水性的HS对溶解态铁的絮凝作用最小，表明具有这些性质的HS是溶解态铁从河流向近岸水体迁移的最重要贡献者. 2.预测腐殖铁行为的数值模型 ...更多信息综合考虑腐殖酸铁络合物的平衡、凝聚和扩散等物理化学行为，开发了腐殖酸铁络合物。平衡模型是在Debye-Huckel理论的基础上发展起来的，该理论能够考虑HS表面周围铁的势能。通过将疏水相互作用（HS分子之间的强吸引力）纳入已建立的DLVO理论，开发了混凝模型。将平衡凝聚模型与扩散模型（Navier-Stokes方程和扩散方程）相结合，数值模拟了近岸水体中腐殖酸铁络合物的时空分布。majuscula。尽管超氧化物介导的生物可利用的Fe（II）的产生速率（即，铁的生物有效性）由于腐殖酸铁络合物的不同来源而不同，具有较高含量的酸性官能团的腐殖酸铁络合物通常显示出较低的生物有效性。通过确定的动力学速率常数参与Fe（II）的生产，铁的吸收方面的反应计划的开发。该模型计算出，强腐殖酸铁络合物通过非解离还原途径产生Fe（II），其中与HS络合的Fe（III）在络合物解离之前被超氧化物还原。结果表明，流域的管理和环境，如土地利用和植被（即，HS的来源）显著影响沿海沃茨中铁的生物利用度。综上所述，本文建立了一个包括腐殖酸铁络合物的平衡、凝聚、扩散和生物有效性的数值模型。该模型可以全面评估和预测沿海沃茨的大花石首鱼对铁的吸收过程。少

项目成果

期刊论文数量（13）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Equilibrium Model for Humic Iron Complex in Estuary

河口腐殖质铁络合物的平衡模型

DOI：
发表时间：
2005
期刊：
Environmental Engineering Research(in Japanese) Vol.42
影响因子：
0
作者：
Manabu Fujii;Tatsuo Omura
通讯作者：
Tatsuo Omura

Kinetics of Formation and Dissociation of Organically Complexed Iron in Coastal Waters : Relationship between Characteristics of Organic Ligand and Rate Constant

沿海水域中有机络合铁的形成和解离动力学：有机配体特性与速率常数之间的关系

DOI：
发表时间：
2007
期刊：
Journal of Japan Society on Water Environment(in Japanese) Vol.30(5)(in Press)
影响因子：
0
作者：
Manabu Fujii;Andrew L.Rose;T.David Waite;Tatsuo Omura
通讯作者：
Tatsuo Omura

競合リガンド法を用いた沿岸域における有機鉄錯体の解離速度の測定

竞争配体法测定沿海地区有机铁络合物解离速率