沖縄琉球石灰岩島の地下海水の取水・性状・養殖特性 [in Japanese] Well Seawater Obtained from Underground Limestone Layer in OKINAWA Islands, its Drawing Techniques, Physical, Chemical and Biological Characteristics and Performance of Shellfish (Abalone) Cultivation [in Japanese]
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Abstract
沖縄県竹富町黒島は, サンゴ礁島で地下は琉球石灰岩である. ここに井戸を約100m掘削し, 地下海水を揚水した. 深度59m～72m間は, 変成琉球石灰岩 (シルト岩) 層の堅牢な地層で, この下部から揚水した海水は, 周年恒温で表層海水と隔離され, 化学的に低酸素, 微生物学的には極めて清浄でバクテリア, ウイルス, 植物ピコプランクトンが, 表層外洋海水の数パーセント以下であった. この海水を用いアワビを試験飼育したところ, 放流養殖の2倍の成長を示し, 生残率は大略100%を示し有望な海水資源であることが認められた.
As an example of underground brackish-seawater, well seawater from coral limestone layers was high lighted as a new characteristic oceanographic resource, that is free of bacteria and also percolating microorganisms like viruses and pico-plankton. The well seawater was brought up from a 70m depth under a metamorphic Ryukyu limestone layer drilled by a diamond cutting boring machine. The well seawater has a constant temperature of 24°C over the year, the same salinity and density as natural seawater, but an extremely small amount of microorganism. A shellfish (Abalone) cultivation test using well seawater continued successively over the last 2 years, and as a result, a growth rate that is about 2 times higher than the growth of natural juveniles in the open sea and a survival ratio of about 100 % free of diseases and microorganisms was obtained.
Journal
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- Bulletin of the Society of Sea Water Science, Japan
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Bulletin of the Society of Sea Water Science, Japan 60(2), 119-124, 2006-04-01
The Society of Sea Water Science, Japan