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

为探讨日本九州岛有源海以西海域缺氧水团的形成机制，于2002年9月22日至13日进行了野外观测。强烈的潮流在底部附近形成了高浊度层。当溶解氧(DO)浓度在整个深度范围内保持足够高时，浊度与底层附近的DO浓度之间存在很好的负相关。因此，氧气的消耗似乎与高浊度层的形成密切相关。通过室内试验发现，悬浮物(SS)的耗氧率是底泥耗氧量(SOD)的13倍。结果表明，悬浮物的耗氧量是有源海西部缺氧水团形成的重要原因。于200年7月…，对有源海北部20个测站的海底环境进行了调查此外，还得到了孔隙水中沉积物特征和营养盐的空间分布。研究发现，酸性挥发性硫化物(AVS)含量超过0.2 mg/g的区域沿西海岸分布，海床条件较差。孔隙水中溶解无机氮(DIN)浓度从西南向东北逐渐增加，而磷酸盐(PO4-P)浓度呈相反分布。营养盐的空间分布似乎强烈地依赖于PO4-P的吸附和解吸过程以及DIN的硝化和反硝化过程。基于这一观点，在有宅海竹崎附近的海床表面观察到的低氨氮释放可能是由于底质对养分的吸附造成的，因此，在竹崎附近的泥岩岩芯上进行了采样，并通过实验室实验研究了水体的数量。通过泥浆再悬浮实验，测定了系统的耗氧量和氨氮、磷酸盐浓度。NH4-N和(PO4-P)浓度也随着泥芯表层深度的增加而增加，但在某些深度达到最大值后开始下降。垂直剖面与在普通泥浆中看到的非常不同。污泥再悬浮实验表明，在DO消耗的情况下，NH4-N和PO4-P的浓度保持不变。这些实验结果支持底泥对营养物质的高吸附可能发生在有莱克海的竹崎附近。较少

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