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-

城区桅杆人工水边的适应性保护——泄洪闸建设带来的盐沼生态系统变化——

基本信息

批准号：
18510014
负责人：
YAMOCHI Susumu
金额：
$ 1.41万
依托单位：
Osaka City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

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.

在大阪南港鸟类保护区的南北池塘进行了实地研究，以明确绿藻类海藻的分布和转变。还进行了室内实验来检查对暴露于空气和低盐度的耐受性。北池塘有丰富的绿藻 Ulva pertusa，而 Chaetomorpha sp。大阪南港鸟类保护区的南池，人口密集。石莼 (Ulva pertusa) 和 Chaetomorpha sp. 共存。除了两个池塘的小区域外，没有观察到。这些现象的部分原因是两个池塘暴露在空气中的时间不同，以及石莼 (Ulva pertusa) 与毛壳藻 (Chaetomorpha sp) 相比对干燥条件具有较高的耐受性。晚春溶解氧浓度。这种现象是由绿藻 Chaetomorpha sp 的活跃光合作用引起的。于底部沉积物上。运河闸门附近3m以下深度观察到养分浓度明显下降。本文得出的事实表明，降低运河水位、加深闸口以及加强水交换对于改善运河水质和抑制藻类繁殖是有效的。对大阪湾及其附近的潮滩和盐沼的底栖生物进行了比较。结果，由于年轻的人工滩涂底栖生物的大量繁殖，氮的净交换在建造后的两三年内就从源头显着变成了汇。半自然滩涂产生了大量的双壳类动物，与人工滩涂相比，其氮收支平衡良好。