The Effects of Animal-Sediment Interaction on Geochemical Processes Near the Sediment-Water Interface

动物-沉积物相互作用对沉积物-水界面附近地球化学过程的影响

• 批准号: 9314132
• 负责人: Robert Aller
• 金额: $ 37.5万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-02-15 至 1998-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9314132&HistoricalAwards=false
• 关键词: Effects; Animal; Sediment; Interaction; Geochemical

9314132 ALLER The activities of marine bottom-dwelling animals dramatically alter material transport and reaction distributions in surface sediments over much of the modern seafloor. It is the purpose of this research to continue to quantitatively examine and conceptualize the effect of these activities on the rates of diagenetic reactions, sediment-water solute exchange, and storage of organic or mineral phases in sedimentary deposits. A variety of field and laboratory observations demonstrate that particle reworking and irrigation activities of benthic fauna promote the remineralization of organic matter. Of the many simultaneous factors involved, two may be particularly important: (1) repetitive oscillation of redox conditions in the bioturbated zone, and (2) low metabolite build- up. Both factors likely decrease eventual storage of organic matter, or specific groups of organic compounds, in marine sediments. Experimental diffusion cells which mimic redox and diffusive transport conditions in the bioturbated zone will be used to further investigate these processes and test conceptual models of remineralization in surface sediments. Macrobenthic bioturbation also enhances the importance of secndary oxidants sucha s MN O2 and controls relative rates of coupled redox reactions in surface sediments. These cycles couple strongly with other elements, such as a variety of trace metals. Detailed experimental measures of Mn oxidation and reduction rates will be used simultaneously with measures of particle reworking, net fluxes, and solute profiles to develop a model of Mn cycling and associated redox balances in bioturbated deposits. The potential semipermeability of biogenic structures to components of the dissolved organic carbon pool (DOC) has major implications for models of sedimentary DOC distributions, microbial activity, and net sediment-water fluxes. Diffusion cell measurements will be performed to examine possible DOC fractionation across tube and b urrow walls. The long term goals of this research are a quantitative description (model) of the types of transport and reaction balances during early diagenesis and the exploration of the corresponding geochemical and ecological implications.

小行星9314132 海洋底栖动物的活动极大地改变了现代海底大部分表层沉积物中的物质输运和反应分布。本研究的目的是继续定量地检查和概念化这些活动对成岩反应速率、沉积物-水溶质交换和沉积矿床中有机相或矿物相的储存的影响。 各种实地和实验室观察表明，底栖动物的颗粒改造和灌溉活动促进了有机物的矿化。 在涉及的许多同时发生的因素中，有两个可能特别重要：（1）生物扰动区氧化还原条件的重复振荡，以及（2）低代谢物积累。这两个因素都可能减少海洋沉积物中有机物或特定有机化合物的最终储存。 模拟氧化还原和扩散运输条件下的生物扰动区的实验扩散细胞将被用来进一步研究这些过程和测试概念模型的表层沉积物中的矿化。 大型底栖生物扰动也提高了次级氧化剂的重要性，如苏查的MN O2和控制耦合的氧化还原反应在表层沉积物的相对速率。这些循环与其他元素强烈耦合，例如各种痕量金属。 详细的实验措施锰氧化和还原速率将同时使用的颗粒改造，净通量和溶质配置文件的措施，开发一个模型的锰循环和相关的氧化还原平衡生物扰动矿床。 潜在的半渗透性的生物结构的溶解有机碳库（DOC）的组件有重大影响的沉积DOC分布，微生物活性和净沉积物-水通量的模型。 将进行扩散池测量，以检查跨管壁和B管壁的可能DOC分级。 本研究的长期目标是定量描述早期成岩作用过程中的迁移和反应平衡类型（模型），并探索相应的地球化学和生态学意义。