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Effects of Bioturbation by Macrobenthos Living on the Tidal Flat on the Bottom-Mud Environment and Concentration Profiles of Nutrient Salts

滩涂大型底栖动物生物扰动对底泥环境及营养盐浓度分布的影响

基本信息

批准号：
10660233
负责人：
SEGUCHI Masahiro
金额：
$ 1.98万
依托单位：
Saga University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

The effects of bioturbation by macrobenthos living on the tidal flat on the environment in the bottom-mad and the concentration profiles of nutrient salts were investigated on the basis of field measured and analytical data. The results obtained by this research are summarized as follows :1. The species of macrobenthos and its number distribution in the study sites were grasped. Moreover, it was found that the number distributions of macrobenthos and its nesting holes on the tidal flat surface were strongly affected by air and mud temperature.2. The close relationships were observed between the redox potential (Eh) in the bottom-mud, and the number distributions of macrobenthos and its nesting hole. Therefore, it was assumed that the most important bioturbation that influenced on the environment in the bottom-mud was the nesting hole formation by macrobenthos.3. It was estimated that the vertical distributions of oxidized and reduced layers in the bottom-mud changed remarkably and periodically according to ebb and flood, and variation of bioturbation strength by macrobenthos.4. The close relationship was observed between the number distributions of macrobenthos and its nesting hole, and the vertical profiles of Eh in the bottom-mud and NH_4^+ and NO_3^- concentrations in the bottom-mud pore water.5. It was estimated that the decomposition and mineralization of organic matters, that is, the nutrient salts production processes by bacteria in the bottom-mud took place effectively under the environment variations that occurred according to ebb and flood, and nesting hole formation by macrobenthos in the bottom-mud.6. The resuspension mechanism of bottom-mud under the combined wave-current flows, which was one of physical action that affected on the concentration profiles of nutrient salts in the bottom-mud, was made clear theoretically and experimentally

根据实测和分析资料，研究了潮滩大型底栖动物生物扰动对潮滩底质环境和营养盐浓度剖面的影响。本研究取得的主要成果如下：1.掌握了调查点大型底栖动物的种类和数量分布。此外，还发现大型底栖动物及其巢穴在潮滩表面的数量分布受气温和泥温的强烈影响.底泥氧化还原电位（Eh）与大型底栖动物数量分布及巢穴分布有密切关系。因此，认为底栖动物对底泥环境影响最大的生物扰动是其筑巢洞的形成.底泥中氧化层和还原层的垂直分布随潮涨潮落和大型底栖生物扰动强度的变化而发生明显的周期性变化.大型底栖动物的数量分布与其筑巢孔的数量分布、底泥Eh的垂向分布以及底泥孔隙水NH_4^+和NO_3^-浓度的垂向分布关系密切.根据潮涨潮落和大型底栖动物在底泥中筑巢成洞的环境变化，推测底泥中有机质的分解和矿化，即细菌产生营养盐的过程是有效的。从理论和实验上阐明了波流共同作用下底泥的再悬浮机理，即影响底泥营养盐浓度分布的物理作用