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

我们研究了沿海水域中铁的行为和有毒蓝藻 Lyngba majuscula 的铁吸收机制，并开发了一个数值模型来预测沿海水域中生物可利用铁的动态。1.实验室实验。进行了现场工作，以了解沿海水中铁的形态以及腐殖质铁络合物的行为，例如平衡和凝结。结果发现，腐殖质（HS）络合的三价铁是主要的铁物种。然而，在河水中，90% 的复合物在沿海水中由于与二价海水阳离子（即 Ca^<2+> 和 Mg^<2+>）的竞争而解离。色谱分析表明，HS 的凝结最少。它具有低分子量和疏水性，表明具有这些特性的 H2S 是将溶解的铁从河流运输到沿海水域的最重要的贡献者。2.预测腐殖铁行为的数值模型……更复杂的是考虑到腐殖质铁络合物的物理化学行为，如平衡、凝结和扩散，平衡模型是在德拜-休克尔理论的基础上开发的，该理论能够考虑 H2S 表面周围铁的势能。模型通过疏水相互作用（HS 分子之间的强大吸引力）发展到完善的 DLVO 理论中，然后将平衡和凝固模型与扩散模型（纳维-斯托克斯和扩散方程）相结合，使我们能够对沿海水域中腐殖质铁复合物的空间和时间分布进行数值计算。3.研究了通过超氧化物介导的反应产生生物可利用铁的动力学，以开发 L. majuscula 的铁吸收率模型。超氧化物介导的生物可利用Fe(II)（即铁的生物利用度）的产生因腐殖铁络合物来源的不同而不同，酸官能团含量较高的腐殖铁络合物通常表现出较低的通过确定 Fe(II) 生成中涉及的动力学速率常数，开发了铁吸收方面的反应方案，计算出强腐殖质铁复合物通过非解离还原途径生成 Fe(II)。 (III) 与 H2S 络合的物质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 H2S 的来源）显着影响铁的生物利用度。总之，本工作建立了涉及腐殖质铁复合物的平衡、凝结、扩散和生物利用度的数值模型。该模型使我们能够全面评估和预测 L.majuscula 的铁吸收过程。沿海水域较少。

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