１９９９年ラニーニャ時の西部太平洋赤道海域における珪藻フラックス変動

• 高橋 孝三

• 小林 扶美子

• 小野 逸郎

書誌事項

タイトル別名

• Seasonal fluxes of diatoms in the western equatorial Pacific during the 1999 La Nina conditions.
• 1999ネン ラニーニャジ ノ セイブ タイヘイヨウ セキドウ カイイキ ニ オケル ケイソウ フラックス ヘンドウ

抄録

Time-series sediment traps were deployed at two water depths, about 1, 000m and 3, 000m, in the western equatorial Pacific during 1999, which revealed seasonal changes of diatom fluxes. Two types of oceanographic conditions were investigated : Sites MT1, MT2 and MT3 were located in the Western Pacific Warm Pool (WPWP) ; and Site MT5 was located in the Equatorial Up-welling Region (EUR). Annual mean fluxes of total diatoms were high at Sites MT1 and MT5, and the lowest at Site MT2. The taxonomic composition of the diatoms was different between the two regions (the WPWP and the EUR). Pennate diatoms dominated the assemblages at Sites MT1, MT2 and MT3 in the WPWP. However, at Site MT5 in the EUR, the average percent occurrence of pennate diatoms was lower than that in the WPWP and the contribution of centric diatoms was higher than the latter. Nitzschia bicapitata was the dominant species in the WPWP, while Rhizosolenia bergonii was the dominant species in the EUR. Such a different composition of the diatom taxa is attributed to difference in environmental conditions, especially nutritional conditions between the WPWP and the EUR. At all sites, the flux levels of diatom taxa showed distinct seasonal patterns, while the relative abundances of the diatom assemblages did not show such a seasonality. Thus, the taxonomic composition of the equatorial diatom assemblages are considered to be stable with changes of source of nutrient supply. In the western equatorial Pacific, the seasonal changes of diatom fluxes reflect the seasonal change of nutrient concentrations, while the relative abundances of the diatom assemblages reflect the hydrographic and nutritional conditions of the surface waters.

収録刊行物

• 地質学雑誌

  地質学雑誌 108 (11), 721-732, 2002

  一般社団法人 日本地質学会

キーワード

• seasonal change

詳細情報

• CRID: 1390001206233596544
• NII論文ID: 110003009736
• NII書誌ID: AN00141768
• DOI: 10.5575/geosoc.108.11_721
• ISSN: 13499963
• ISSN: 00167630
• NDL書誌ID: 6368519
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I6368519
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可