共同研究報告書


研究区分 一般研究

研究課題

 アイス・バイオータ初期形成過程の実験的解明
研究代表者／所属 創価大学・工学部・環境共生工学科
研究代表者／職名 教授
研究代表者／氏名 田口哲

研究分担者／氏名／所属／職名
　
氏　　名
所　　属
職　　名

1

 濱崎恒二 広島大学 助教授

2

 服部寛 北海道東海大学 教授

3

 大井信明 創価大学 助手

4

 柴田晃 創価大学 助手

5

 多部田茂 東京大学 助教授

6

 白澤邦男 北大低温研

研究目的 The ice structure and ice biota change significantly during the initial sea ice formation. We had the experimental site in Saroma-ko Lagoon， Hokkaido. In situ incubation experiment was made for one week. Since we had our field trip in the first week of March 2005， we have not analyzed any samples yet. We report here results obtained in the previous fiscal year.
　　
研究内容・成果 Solar radiation， snow falls， and ice thickness were monitored. Temperature， salinity， nutrients， and ice biota in the newly formed sea ice (NFSI) and the unfrozen water in the incubation vessels (UFW) were determined. Nutrient concentrations in brine standardized to brine salinity were not much different between the brine in the NFSI and the UFW. Ice biota including bacteria， viruses and heterotrophic flagellates in addition to phytoplankton were incorporated into the NFSI. The former three groups reached a plateau level within one week but the latter group continued to grow even after the plateau of the former three groups. Those densities were not much different from those in the 36 days old ice core but the chlorophyll a concentration in the 36 days old ice was much higher than those at the end of the present incubation experiment. These observation may suggest that while all ice biota are initially incorporated into the NESI， their subsequent growth is some how balanced by the trophic relationship.

Publication:
Imai， A.， Takasuna， T.， Ohi， N.， Fukada， H.， Shibata， A.， and Taguchi， S. Microbial dynamics during the initial formation of sea ice in Saroma-ko Lagoon， Hokkaido， Japan. Submitted to Hyolrobiologiya.