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・生物工学科
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

 大井信明 創価大学 助手

2

 服部寛 北海道東海大学 教授

3

 濱崎恒二 広島大学 助教授

4

 白澤邦男 北大低温研

研究目的 The microbial loops in ice algal community are dominated often by large cell diatoms. Based on our previous study， small cells in picoplankton size were abundant at the beginning of ice formation. This comparison strongly suggests the occurrence of species succession as sea ice grows. Our novel method to study the ice formation and incorporation of organisms into sea ice was applied to study on the species succession of ice algal community.
　　
研究内容・成果 In 2004 ice season of Saroma-ko Lagoon， the ice development was extremely poor and a heavy ice storm came just before our field experiment. We were forced to change our experiment on the sea ice. Therefore we could not conduct the field experiment as we planed in our proposal.
Ice core samples were collected at 25 stations within 2*2m to study the spatial heterogeneity in ice algal distribution. Then all samples were mixed to start the in situ experiment to study the xanthophyll cycle of dark adapted ice algae. In situ experiment was lasted for 24 hr， and subsamples were collected every half hour for 2 hours. Another set of ice core samples were collected for the incubation experiment of bacteria. All filtered samples were frozen and shipped to each university laboratory for later analysis.
From the analysis of ice core samples collected in 2003 ice season， the spatial distribution of ice algae was studied along the transect from the month of Saroma-betsu River towards the second channel of the Lagoon. Salinity and phosphate concentration decreased seaward.
Ice formation with different proportions of low salinits water due to discharge from Saroma-betsu River with sea water in the basin may affect heterogeneity in the distribution of salinity， chlorophyll a concentration， and ice algal species.