- 著者
- Hiromi NAKANISHI Atsushi MORI Kouki TAKEDA Houdo TANAKA Natsuko KOBAYASHI Keitaro TANOI Takashi YAMAKAWA Satoshi MORI
- 出版者
- 日本学士院
- 雑誌
- Proceedings of the Japan Academy, Series B (ISSN:03862208)
- 巻号頁・発行日
- vol.91, no.4, pp.160-174, 2015-04-10 (Released:2015-04-10)
- 参考文献数
- 34
- 被引用文献数
- 3 14
Six months after the explosion of TEPCO’s Fukushima Dai-ichi nuclear power plant, radioactive silver (110mAg), was detected in concentrations of 3754 Bq/kg in Nephila clavata (the orb-web spider; Joro-gumo in Japanese) collected at Nimaibashi, Iitate village in Fukushima Prefecture, whereas 110mAg in the soil was 43.1 Bq/kg. A survey of 35 faunal species in the terrestrial environment during the 3.5 years after the accident showed that most of Anthropoda had two orders higher 110mAg in their tissues than soils, although silver is not an essential element for their life. However, tracing of the activity of 110mAg detected in spider Atypus karschi collected regularly at a fixed location showed that it declined much faster than the physical half-life. These results suggest that 110mAg was at once biologically concentrated by faunal species, especially Arthropoda, through food chain. The factors affecting the subsequent rapid decline of 110mAg concentration in faunal species are discussed.
- 著者
- HIROKAZU MATSUDA TAISUKE TAKENOUCHI TAKASHI YAMAKAWA
- 出版者
- The Japanese Society of Fisheries Science
- 雑誌
- Fisheries science (ISSN:09199268)
- 巻号頁・発行日
- vol.69, no.1, pp.124-130, 2003 (Released:2009-03-31)
- 参考文献数
- 23
- 被引用文献数
- 14
The timing of molting and metamorphosis was monitored for Panulirus japonicus phyllosoma larvae cultured in the laboratory. Larvae cultured under natural light-dark cycle molted synchronously within approximately 1.0 h before and after sunrise, except for a short period after hatching; the timing of molting changed with time of sunrise. When three artificial light-dark cycles were introduced, larvae molted around the start of lighting, irrespective of the light-dark cycles. In the event of a sudden change in the start or end of lighting, molting was regulated by an endogenous rhythm. The start of lighting had a greater impact on the timing of molting than the end of lighting, suggesting that sunrise is probably the critical signal for phase-setting in molting rhythm. Metamorphosis to the puerulus stage occurred within 0.4 h before and 1.2 h after sunset under a natural light-dark cycle, and the timing of metamorphosis was also changed artificially by regulating the end of lighting.