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Biological and chemical estimation for environments of the sea bed of Ariake Sea and its activation

有明海海底环境的生物化学评价及其活化

基本信息

批准号：
15360268
负责人：
MATSUNAGA Nobuhiro
金额：
$ 9.02万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Field observations were made in September 22 to 13, 2002 in order to investigate the formation mechanism of oxygen-deficient water mass in the western area of Ariake Sea in Kyushu Island of Japan. A high turbidity layer was formed near the bottom by strong tidal currents. When the concentration of dissolved oxygen (DO) was kept enough high over the whole depth, a good negative high correlation was seen between the turbidity and the DO concentration near the bottom. Therefore, the oxygen consumption seems to be closely related to the formation of a high turbidity layer. It is found through the laboratory experiments that the oxygen consumption rate due to suspended solids (SS) takes 13 times the value of sediment oxygen demand (SOD). It suggests that the oxygen consumption due to SS is important for the formation of oxygen-deficient water mass in the western area of Ariake Sea.The seabed environments were investigated at 20 stations located in the northern area of Ariake Sea in July 200 … More 4. The spatial distributions of sediment characteristics and nutrients in porewater were obtained. It is found that the area where the acid volatile sulfides (AVS) content exceeds 0.2mg/gdry spreads along the west coast, and the seabed conditions in the area are bad. The concentrations of dissolved inorganic nitrogen (DIN) in porewater increase from the southwest to the northeast, and the concentration of phosphate (PO_4-P) takes the reverse distribution. The spatial distributions of nutrients seem to depend strongly on the process of adsorption and desorption of PO_4-P and the process of nitrification and denitrification of DIN.On the basis of the idea the low release of ammonium (NH_4-N) observed in the seabed surface off Takesaki of Ariake Sea may be caused by the nutrient adsorption due to the bed materials, mud cores were sampled off Takesaki and the quantities of water were investigated through laboratory experiments. The oxygen consumption and the concentrations of NH_4-N and phosphate PO_4-P measured through the experiments of mud resuspension. Though the concentrations of NH_4-N and (PO_4-P) were also increased with the depth from the surface of the mud core, they began to decrease after taking maximum values at some depths. The vertical profiles were very different from those seen in ordinary mud. The experiments of mud resuspension showed that the concentrations of NH_4-N and PO_4-P were kept constant though DO was consumed. These experimental results support the possibility that the high nutrient adsorption by the bottom mud occurs off Takesaki of Ariake Sea. Less

2002年9月22 ~ 13日在日本九州岛有明海西部海域进行了现场观测，以探讨缺氧水团的形成机制。强潮流作用在近底处形成高浊度层。当溶解氧（DO）浓度在整个深度保持足够高的，浊度和溶解氧浓度之间的良好的负相关关系被视为近底部。因此，耗氧量似乎与高浊度层的形成密切相关。通过室内实验发现，悬浮物（SS）的耗氧速率是底泥需氧量（SOD）的13倍。2000年7月在有明海北方海域20个站位进行了海底环境调查，结果表明，SS的耗氧作用对有明海西部海域缺氧水团的形成具有重要意义 ...更多信息 4.得到了沉积物特性和间隙水中营养盐的空间分布。结果表明，酸性挥发性硫化物（AVS）含量超过0.2mg/g干重的区域沿着西海岸分布，海底条件较差。溶解无机氮（DIN）浓度从西南向东北逐渐增加，磷酸盐（PO_4-P）浓度则呈相反的分布。营养盐的空间分布似乎强烈地依赖于PO_4-P的吸附-解吸过程和DIN的硝化-反硝化过程，有明海竹崎附近海底表层NH_4-N释放量低可能是由于床料对营养盐的吸附作用所致。在竹崎附近取泥芯，通过室内实验研究了含水量。通过泥浆再悬浮实验测定了耗氧量、NH_4-N和PO_4-P浓度。NH_4-N和（PO_4-P）的浓度随深度的增加而增加，但在一定深度达到最大值后又开始下降。垂直剖面与普通泥浆中的剖面有很大不同。污泥再悬浮实验表明，溶解氧消耗后，NH_4-N和PO_4-P浓度基本保持不变。这些实验结果支持了有明海竹崎附近海域底泥对营养盐的高吸附的可能性。少