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A three-dimensional reactive transport model for sediments, incorporating microniches.

Sochaczewski, Łukasz and Stockdale, Anthony and Davison, William and Tych, Wlodek and Zhang, Hao (2008) A three-dimensional reactive transport model for sediments, incorporating microniches. Environmental Chemistry, 5 (3). pp. 218-225. ISSN 1448-2517

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    Abstract

    Most reactive transport models have represented sediments as one-dimensional (1-D) systems and have solely considered the development of vertical concentration gradients. However, application of recently developed micro-scale and 2-D measurement techniques have demonstrated more complicated solute structures in some sediments, including discrete localized sites of depleted oxygen, and elevated trace metals and sulphide, referred to as microniches. A model of transport and reaction in sediments, that can simulate the dynamic development of concentration gradients occurring in 3-D, was developed. Its graphical user interface (GUI) allows easy input of user-specified reactions and provides flexible schemes that prioritise their execution. The 3-D capability was demonstrated by quantitative modelling of hypothetical solute behaviour at organic matter microniches covering a range of sizes. Significant effects of microniches on the profiles of oxygen and nitrate are demonstrated. Sulphide is shown to be readily generated in microniches within one centimetre of the sediment surface, provided the diameter of the reactive organic material is greater than one millimetre. These modelling results illustrate the geochemical complexities that arise when processes occur in 3-D and demonstrate the need for such a model. Future use of high-resolution measurement techniques should include the collection of data for relevant major components, such as reactive iron and manganese oxides, to allow full, multi-component modelling of microniche processes.

    Item Type: Article
    Journal or Publication Title: Environmental Chemistry
    Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
    Departments: Faculty of Science and Technology > Lancaster Environment Centre
    ID Code: 8964
    Deposited By: Dr Tony Stockdale
    Deposited On: 07 Jul 2008 09:59
    Refereed?: Yes
    Published?: Published
    Last Modified: 06 Sep 2013 21:14
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/8964

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