2004-05年夏季のオングル海峡定着氷下における植物プランクトンと栄養塩の時系列変化  [in Japanese] Temporal changes of phytoplankton and nutrients under the fast ice in the Ongul Strait during the austral summer of 2004/05  [in Japanese]

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Author(s)

    • 大槻 晃久 Otsuki Akihisa S.
    • 情報・システム研究機構国立極地研究所 National Institute of Polar Research, Research Organization of Information and Systems
    • 小達 恒夫 Odate Tsuneo
    • 情報・システム研究機構国立極地研究所 National Institute of Polar Research, Research Organization of Information and Systems
    • 工藤 栄 [他] Kudoh Sakae
    • 情報・システム研究機構国立極地研究所 National Institute of Polar Research, Research Organization of Information and Systems
    • 福地 光男 Fukuchi Mitsuo
    • 情報・システム研究機構国立極地研究所 National Institute of Polar Research, Research Organization of Information and Systems

Abstract

弱光環境の定着氷下で高濃度のクロロフィルaが存在する要因を明らかにするため,2004-05年夏季にオングル海峡にて海洋観測を行った. 観測されたクロロフィルa濃度は,これまで報告された値より小さく,最大で7.6 mg/m3であった.しかし,観測期間中の表層の硝酸塩,リン酸塩の減少量は大きく,定着氷下の一次生産は活発であったと考えられる.一方,定着氷下の流向及び流速は,概ね北向きに平均4.4 cm/sの流れが存在した.それゆえオングル海峡の定着氷下の水塊は,8日間前には約30 km南方の海域に存在したと考えられる.リュツォ・ホルム湾宗谷海岸の定着氷は,オングル海峡周辺より融解が早く,海中光量が増加して植物プランクトンの増殖できる環境が早く整う. したがってオングル海峡の定着氷下で観測される多量の植物プランクトンは,宗谷海岸沖の開水面域・薄氷域で増殖し,海流に乗って輸送され存在する可能性が考えられる.

Time series oceanographic observation was carried out in Ongul Strait during the austral summer of 2004/05 in order to clarify the reason why dense chlorophyll a can exist under fast ice where the light condition is unfavorable for ordinary phytoplankton. Chlorophyll a concentration observed in this study was smaller than that previously reported, and the maximum was 7.6 mg/m3. However, the decrease of nitrate and phosphate concentration in surface water during the observation period was large, and primary production under the fast ice seemed to be active. At the same time, a northward surface current of 4.4 cm/s was observed under the fast ice. Therefore, the water mass in Ongul Strait is believed to have been about 30 km south of the strait 8 days earlier. The fast ice in the Sôya coastal area in southeastern Lützow-Holm Bay melts earlier than that around Ongul Strait. Underwater light intensity increases and a favorable condition for multiplication of phytoplankton exists in early summer. Consequently, it is believed that the high biomass of phytoplankton observed under fast ice in the Ongul Strait increased in open water and under thin ice in the southern area (off the Sôya Coast area) and was transported northward by the current.

Journal

  • Antarctic record

    Antarctic record 50(3), 231-250, 2006-11

    National Institute of Polar Research

Keywords

Codes

  • NII Article ID (NAID)
    110004860890
  • NII NACSIS-CAT ID (NCID)
    AN00181831
  • Text Lang
    JPN
  • ISSN
    00857289
  • NDL Article ID
    8630899
  • NDL Source Classification
    ZM1(科学技術--科学技術一般)
  • NDL Call No.
    Z14-316
  • Data Source
    NDL  NII-ELS 
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