Researcher Database

Keiichiro Sakaoka
School of Fisheries Sciences Training Ship “Oshoro-maru”
Associate Professor

Researcher Profile and Settings

Affiliation

  • School of Fisheries Sciences Training Ship “Oshoro-maru”

Job Title

  • Associate Professor

J-Global ID

Research Interests

  • 水産学一般   

Research Areas

  • Life sciences / Aquaculture

Academic & Professional Experience

  • 2007 - 2011 水産学部附属練習船おしょろ丸 助教
  • 2011 - 水産学部附属練習船おしょろ丸 准教授
  • 2000 - 2007 水産学部附属練習船おしょろ丸 助手
  • 2000 - 2007 Research Associate
  • 1997 - 2000 水産学部練習船北星丸 助手
  • 1997 - 2000 Research Associate
  • 1994 - 同助手(水産学部附属練習船おしょろ丸) 助手
  • 1994 - Research Associate
  • 1993 - 同助手(水産学部附属練習船北星丸) 助手
  • 1993 - Research Associate
  • 1992 - 北海道大学助手(水産学部附属練習船おしょろ丸) 助手
  • 1992 - Research Associate

Education

  •        - 1992  Hokkaido University
  •        - 1992  Hokkaido University  Graduate School, Division of Fisheries
  •        - 1991  Hokkaido University  School of Fisheries Sciences
  •        - 1991  Hokkaido University  Faculty of Fisheries
  •        - 1990  Hokkaido University  School of Fisheries Sciences
  •        - 1990  Hokkaido University  Faculty of Fisheries
  •        - 1989  Hokkaido University  School of Fisheries Sciences
  •        - 1989  Hokkaido University  Faculty of Fisheries

Research Activities

Published Papers

  • Uchida, R, K. Kuma, A. Omata, S. Ishikawa, N. Hioki, H. Ueno, Y. Isoda, K. Sakaoka, Y. Kamei, S. Takagi
    Journal of Geophysical Research 118 1 - 15 2013/03 [Refereed][Not invited]
  • Nishioka J, Ono T, Saito H, Sakaoka K, Yoshimura T
    Journal of Geophysical Research 116 (C2) C02021  0148-0227 2011 [Refereed][Not invited]
  • KITAYAMA Saori, KUMA Kenshi, MANABE Eri, SUGIE Koji, TAKATA Hyoe, ISODA Yutaka, TOYA Kenji, SAITOH Sei-ichi, TAKAGI Shohgo, KAMEI Yoshihiko, SAKAOKA Keiichiro
    Journal of Geophysical Research. Supplement 114 (C8) C08019  0148-0227 2009 [Refereed][Not invited]
  • 天皇海山列周辺における移行領域の海洋構造変化
    海の研究 15 (3) 267 - 281 2006 [Refereed][Not invited]
  • H Takata, K Kuma, Y Saitoh, M Chikira, S Saitoh, Y Isoda, S Takagi, K Sakaoka
    GEOPHYSICAL RESEARCH LETTERS 33 (2) L02613 - L02613 0094-8276 2006/01 [Refereed][Not invited]
     
    Labile dissolved Fe (< 0.22 mu m) in the western (165 degrees E) and eastern (165 degrees W) North Pacific Ocean had nutrient- and apparent oxygen utilization (AOU)- like profiles characterized by surface depletion and deep enrichment ( 5 - 3000 m depth). Dissolved Fe concentrations in the deep-water column at the mid-latitudes were approximately one-half lower in the eastern region (0.5 - 0.8 nM) than in the western region ( 0.8 - 1.3 nM) although the dissolved Fe concentrations in the surface mixed layer in both regions were extremely depleted to 0.1 - 0.2 nM. Surprisingly, the labile particulate Fe concentrations (<=similar to 0.1 nM, total dissolvable Fe minus labile dissolved Fe) throughout the water column at low latitudes in the eastern region were extremely lower than those (similar to 0.5 - 1 nM) in the western region. It is suggested that the low Fe levels in the eastern mid-latitude oceanic region are primarily due to the lower atmospheric Fe supply in the eastern region.
  • 橋本 洋平, 磯田 豊, 大西 広二, 坂岡 桂一郎
    海の研究 14 (4) 513 - 525 0916-8362 2005 [Refereed][Not invited]
  • H Takata, K Kuma, S Iwade, Y Yamajyoh, A Yamaguchi, S Takagi, K Sakaoka, Y Yamashita, E Tanoue, T Midorikawa, K Kimura, J Nishioka
    MARINE CHEMISTRY 86 (3-4) 139 - 157 0304-4203 2004/05 [Refereed][Not invited]
     
    Sources of natural Fe(III)-complexing organic ligands which control vertical distributions of Fe(III) hydroxide solubilities [Fe(III) solubility, < 0.025 mum] and labile dissolved Fe (< 0.22 mum) concentrations were studied at the subarctic and subtropical surface waters (5-300-m depth) in the northwestern North Pacific Ocean during June 2002. High Fe(III) solubility values (0.71.3 nM) were observed at the depth of high chlorophyll a (Chl a) concentrations in the surface mixed layer with no strong correlation between Fe(III) solubility and size-fractionated Chl a concentrations. However, a significant correlation was found between Fe(Ill) solubility values and heterotrophic bacteria abundance at 5 - 100-m depth in the subarctic coastal water. The high Fe(III) solubility observed in the surface mixed layer is probably due to the production of natural Fe(III)-complexing organic ligands, such as siderophores, which were possibly released by specific phytoplankton or bacteria species. Higher Fe(III) solubility values than the labile dissolved Fe concentrations in the surface waters indicate that natural Fe(III)-complexing organic ligands are in excess of labile dissolved Fe concentrations. The Fe(III) solubility levels appeared to increase with depth in mid-depth waters (100-300-m depth), especially in the subarctic waters, in association with higher iron levels (labile dissolved Fe and dissolvable Fe concentrations), nutrient concentrations and humic-type fluorescence intensity. The relatively strong linear correlations between labile dissolved Fe concentrations or Fe(III) solubility values and humic-type fluorescence intensity in mid-depth waters suggest that the labile dissolved Fe concentrations and Fe(III) solubility in mid-depth waters are primarily associated with humic-type fluorescent organic matter produced through the oxidative decomposition and transformation of sinking biogenic organic matter. Humic-type fluorescent organic matter (i.e., marine dissolved humic substances) may thus account for a significant fraction of the Fe(III)-complexing organic ligands, which control Fe(III) solubility and labile dissolved Fe concentrations in mid-depth waters. (C) 2004 Elsevier B.V. All rights reserved.
  • 天野 春菜, 深田 陽久, 藤田 敏明, 小林 直人, 坂岡 桂一郎, 原 彰彦
    水産増殖 52 (3) 293 - 300 0371-4217 2004 [Refereed][Not invited]
  • 高緯度海域におけるノルパックネット標準採集の特性-その2 荒天下に起こる過剰曳網とプランクトン現存量評価
    日本プランクトン学会報 46 (2) 134 - 142 1999 [Refereed][Not invited]

MISC

  • Results of 2009 Salmon Research Cruises of the Oshoro maru.
    North pacific Anadromouse Fish Commition Documents  (Doc.1226)  Doc.1226  2010  [Not refereed][Not invited]
  • 2008 T/V Oshoro-maru Salmon Research Cruises
    North pacific Anadromouse Fish Commition Documents  1158-  17  2009  [Not refereed][Not invited]
  • 2007 T/V Oshoro-maru Salmon Research Cruises
    North Pacific AnadromouseFish Commition Documents  1088-  25  2008  [Not refereed][Not invited]
  • Results of 2006 Salmon Research Cruise of the Oshoro maru
    North Pacific AnadromouseFish Commition Documents  1021-  16  2007  [Not refereed][Not invited]
  • Results of 2005 Salmon Research Cruise of the Oshoro Maru
    North Pacific Anadromous Fish Commission  940-  1  2006  [Not refereed][Not invited]
  • Results of 2004 Salmon Research Cruise of the Oshoro Maru
    North Pacific Anadromous Fish Commission  840-  1  2005  [Not refereed][Not invited]
  • 「2002・2003年における155°E線上の移行領域」
    北海道大学水産科学研究彙報  55-  23  -33  2004  [Not refereed][Not invited]
  • Results of 2003 Salmon Research Cruise of the Oshoro maru
    North Pacific Anadromous Fish Commission  748-  1  -15  2004  [Not refereed][Not invited]
  • Results of 2002 Salmon Research Cruise of the Oshoro Maru
    North Pacific Anadromous Fish Commission  663-  1  2003  [Not refereed][Not invited]
  • Wave fluctuation with the passage of a depression
    北海道大学水産科学研究彙報  53-  (1)  51  -55  2002  [Not refereed][Not invited]
  • The 2000 International cooperative Salmon research Cruse of The Oshoro Maru
    North Pacific Anadromous Fish Commission  547-  1  2001  [Not refereed][Not invited]
  • Stock Abundance and Fish Size of Pacific Salmon in the North Pacific Ocean, 1998
    North Pacific Anadromous Fish Commission.  323-  1  1998  [Not refereed][Not invited]
  • 北太平洋東経155度線における夏季と秋季の海洋構造と表層性魚類・イカ類の分布
    北海道大学水産学部研究彙報  48-  (1/2)  13  -28  1997  [Not refereed][Not invited]

Research Grants & Projects

  • 海洋の気体交換フィードバックシステムと生物生産応答に関する研究
    Date (from‐to) : 2009 -2012
  • プランクトンネット採集特性に及ぼす船舶操作に関する研究


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