Adaptive preservation of artificial waterside along the mast of urban area-changes of the ecosystem of salt marshes in accompanied with the construction of sluice pipes-

对大阪南湖鸟类保护区的南北池塘进行了实地考察，以明确绿藻的分布和变迁。还进行了室内实验，以检查对空气和低盐度暴露的耐受性。北池有丰富的绿藻Pertusa，而毛藻则有较多。在大阪南科鸟类保护区南池塘人口稠密。孔石榴与毛藻的共存除了两个池塘的小范围外，没有观察到。这些现象的部分原因可以解释为两个池塘暴露在空气中的时间的差异，以及Pertusa对干燥条件的高耐受性。在大阪-南科樱岛运河，在晚春，底层水的溶解氧浓度超过了表层水。这种现象是绿藻毛藻光合作用活跃的结果。在底部的沉积物上。在水深3m以下，在运河的一个闸门附近观察到营养物质浓度显著下降。结果表明，降低运河水位、加深闸口、加强水交换是改善运河水质、抑制赤潮的有效措施。对大阪湾及其附近滩涂和盐沼底栖生物的氮素收支和现存量进行了比较。结果是，由于幼年人工潮滩底栖生物的大量繁殖，在建造后的2到3年内，氮的净交换显著地从源变成了汇。与人工滩涂相比，半自然滩涂养殖的双壳类数量较多，氮平衡状况良好。

Field studies were carried out at the north and south ponds of Osaka Nanko Bird Sanctuary to clarify the distribution and transition of Chlorophycean seaweeds. Indoor experiments were also conducted to examine the tolerance to exposure to the air and low salinity. A green alga Ulva pertusa was abundant at the north pond, while Chaetomorpha sp. was densely populated at the south pond of Osaka Nanko Bird Sanctuary. Coexistences of Ulva pertusa and Chaetomorpha sp. were not observed except for small areas of the two ponds. These phenomena could partly be explained by the difference of exposure time to the air between the two ponds, along with a high tolerance to dry conditions in Ulva pertusa compared to Chaetomorpha sp.At Osaka-Nanko Sakishima Canal, bottom waters exceeded surface ones in the concentration of dissolved oxygen in late spring. This phenomenon results from the active photosynthesis of a green alga, Chaetomorpha sp. on the bottom sediment. A marked decline in nutrient concentration was observed below 3m in depth near a sluice gate of the canal. The facts obtained here suggest that decreased water level of the canal, deepened mouth of the sluice gate, together with enhancement of water exchange are effective for the improvement of water quality and depression of algal blooms at the canal.Nitrogen budgets and standing crops of the benthic organism at tidal flats and .salt marshes in and near Osaka Bay were compared. As the result, the net exchange of nitrogen markedly changed from a source to a sink within 2 or 3 years of construction due to the massive reproduction of benthic organisms at the young artificial tidal flat. The semi-natural tidal flat yielded a large quantity of bivalves and its nitrogen budget was well balanced compared to the artificial ones.