2 0 0 0 OA 北海道東部の海跡湖能取湖における海洋環境 -水温・塩分・溶存酸素・栄養塩の動態-
- 著者
- 西野 康人 佐藤 智希 谷口 旭
- 出版者
- 生態工学会
- 雑誌
- Eco-Engineering (ISSN:13470485)
- 巻号頁・発行日
- vol.26, no.1, pp.3-9, 2014-01-31 (Released:2014-02-06)
- 参考文献数
- 25
- 被引用文献数
- 3
Lagoon Notoro-ko is connected to the Okhotsk Sea by an artificial channel and the water mass of this lagoon is exchanged by a tidal movement and little river flows. Therefore, this lagoon is assumed a saltwater lagoon and a seasonal change of environmental conditions on this lagoon has been reflected one of the coastal waters on Okhotsk Sea. In order to investigate a property of the lower trophic levels in the Lagoon Notoro-ko, we monitored salinity, temperature, dissolved oxygen and nutrient concentrations in the water column vertically during April to December from 2007 to 2009 (non-iced season). Stratification of the water column was found to occur during June to August and oxygen-deficient water mass was generated in bottom water. Concentration of silicate, phosphate and ammonium were higher in the bottom water. The fundamental importance of these nutrients is that the rate at which they are supplied may determine the rate of primary production. Oxygen-deficient water mass is generally recognized to produce negative effects on fisheries, however, the results of this research showed that it may work to supply nutrients to primary production in Lagoon Notoro-ko.
1 0 0 0 OA 閉鎖循環式水槽におけるアマモZostera marinaの長期育成
- 著者
- 西野 康人 石川 義朗
- 出版者
- 生態工学会
- 雑誌
- Eco-Engineering (ISSN:13470485)
- 巻号頁・発行日
- vol.19, no.4, pp.247-253, 2007-10-31 (Released:2008-03-29)
- 参考文献数
- 26
We conducted the experimental long-term cultivation of eelgrass Zostera marina in closed aquarium systems using non-filter and non-exchanging seawater. Eelgrass was cultivated in two types of the closed aquarium systems (2 m3 and 20 m3). The conditions of the cultivation were as follows: water temperature: 15 °C; light source: halogen water lamp; photoperiod: 12-h dark and 12-h light; light intensity (photosynthetic photon flux density, PPFD): 125-200 μmol m-2 s-1 in the 2 m3 aquarium and 80-250 μmol m-2 s-1 in the 20 m3 aquarium. Dried eelgrass (457g dry weight m-2) was supplied as fertilizer into the bottom sediments before cultivation experiments. Nutrients seemed to be slowly supplied to eelgrass during the long-term experiment attributed to the slow decomposition of fertilized eelgrass. The growth of eelgrass in the 2 m3 aquarium continued for at least 458 days, a period longer than that of eelgrass in the 20 m3 aquarium (236 days). It indicated that the dry eelgrass buried in the sediment was effective as fertilizer. The experimental eelgrass utilized ammonia the most. Reproductive shoot in the experimental eelgrass appeared from approximately the third month after the transplant, and kept on increasing till the end of the experiment. It indicated that it is possible to conduct a long-term cultivation of eelgrass in a closed system. And the result may contribute to the elucidation of material circulation in seagrass bed.