2002 Fiscal Year Annual Research Report

西太平洋暖水魂の挙動変化に伴う石灰質ナノプランクトン群集と炭酸塩フラックスの変化

Research Project

Project/Area Number	11304032
Research Institution	HOKKAIDO UNIVERSITY
Principal Investigator	岡田尚武北海道大学, 大学院・理学研究科, 教授 (80111334)
Co-Investigator(Kenkyū-buntansha)	JORDAN Richard 山形大学, 理学部, 助教授 (90260455)
Keywords	西太平洋暖水塊 / 石灰質ナノプランクトン / ココリス / 炭酸塩フラックス / 水塊 / ENSO
Research Abstract	西熱帯太平洋における石灰質ナノプランクトンの3次元的群集分布を研究し,高温海域,温暖富栄養海域,温暖貧栄養海域では,サーモクラインの上下で海域ごとに異なる群集が存在するが,温帯混合水域では水深による群集変化が存在しないことを明らかにした。また,米国ラモント・ドハティ地球観測所が採取した351点を含む熱帯-亜熱帯太平洋の表層試料485点について石灰質ナノプランクトンの生息数と種組成を研究し,表層水の栄養度レベルに対応した7種類の群集を識別した。これらの群集分布は表層水の東西方向栄養度レベル変化と明確に対応しており,外洋における石灰質ナノプランクトンの地理分布が,緯度方向にも変化することを世界で初めて見いだした。また,熱帯上昇流域では,他のどの海域にもみられない超小型のプラコリスが豊富に産出することを報告し,古海洋学解析の新たな手段を提供した。研究船「みらい」を用いた5年間のセディメントトラップ研究では,最終年度の試料が今年2月に回収されたばかりで研究を継続中であるが,エルニーニョからラニーニャへの変化に伴う,石灰質ナノプランクトン群集組成とココリスのフラックス変化を西太平洋暖水塊(WPWP>から混合域までの5地点で計測した。この結果,古海洋学研究に有効なモデルとされるMolfino and McIntyre(1991)モデルは,栄養躍層(nutricline)の深い熱帯太平洋では成立しないことを見いだした。このほか,堆積物中の石灰質ナノ化石含有数測定の新手法を開発し,西太平洋暖水塊を含む西太平洋と熱帯東インド洋からのピストンコア3本について石灰質ナノ化石を精密解析して,第四紀後期における古海洋学的変化を明らかにした。

Research Products
(18 results)

All Other

All Publications (18 results)

[Publications] Aizawa, C., Komuro, C., Katsurada, Y., Jordan, R.W.: "Some observations on small, marine centric diatoms, particularly Minidiscus spp. From the Indian Ocean and North Pacific"Diatom Research. (in press). (2003)
[Publications] Tanimoto, M., Aizawa, C., Jordan, R.W.: "Assemblages of living microplankton from the North Pacific Ocean and Bering Sea during July-August 1999"Courier Forschungsinstitut Senckenberg. (in press). (2003)
[Publications] Kleijne.A., Jordan.R.W., Heimdal.B.R., Samtleben.C., Chamberlain, A.H.L, Cros.L.: "Five new species of the coccolithophorid genus Alisphaera (Haptophyta) with notes on their distribution, coccolith structure and taxonomy"Phycologia. 40. 583-601 (2002)
[Publications] Hagino, K., Okada.H.: "Morphological observations of living Gephyrocapsa crassipons"Journal of Nannoplankton Rescarch. 23(1). 3-7 (2001)
[Publications] Takahashi, K., Okada, H.: "Paleoceanography for the last 195,000 years in the Solomon Sea(ODP Site 1109)by means of calcareous nannofossils"Marine Micoropaleontology. 42. 45-59 (2001)
[Publications] Ishiwatari, R., Houtatsu, M., Okada, H.: "Alkenone-sea surface temperature in the Japan Sea over the past 36 kyr : warm temperatures at the last glacial maximum"Organic Geochemistry. 32. 57-67 (2001)
[Publications] Takayama, H., Tada, R., Matsui, T., Iturralde-Vinent, M.A., Oji, T., Tajika, E., Kiyokawa, S., Garcia, D., Okada, H., Hasegawa, T., Toyoda, K.: "Origin of the Penalver Formation in northwestern Cuba and its relation to K/T boundary impact event"Sedimentary Geology. 135. 295-320 (2000)
[Publications] Okada, H.: "An improved filtering technique for calculation of calcareous nannofossil accumulation rates"Journal of Nannoplankton Research. 22(3). 203-204 (2000)
[Publications] Hagino, K., Okada, H., Matsuoka, H.: "Spatial dynamics of coccolithophore assemblage in the Equatorial Western-Central Pacific Ocean"Marine Micropaleontology. 39. 53-72 (2000)
[Publications] Takahashi, K., Okada, H.: "Environmental control on the biogeography of modern coccolithophores in the southeastern Indian Ocean off the coast of western Australia"Marine Micropaleontology. 39. 73-86 (2000)
[Publications] Okada, H: "Neogene and Quaternary calcareous nannofossils from the Blake Ridge, Sites 994,995 and 997"Proceedings of the ODP, Science Results. 164. 331-341 (2000)
[Publications] Nishi, H., Norris, R.D., Okada, H.: "Paleoceanographic changes in the dynamics of subtropical Atlantic surface conditions at Site 997A"Proceedings of the ODP, Science Results. 164. 343-363 (2000)
[Publications] Oba, T., Shikama, A., Okada, H.: "Data Report : Oxygen isotopic record of the last 0.8 m.y. at the Blake Ridge, Hole 994C"Proceedings of the ODP, Science Results. 164. 173-175 (2000)
[Publications] Ikeda, A., Okada, H., Koizumi, I.: "Data Report : Late Miocene to Pleistocene diatom from the Blake Ridge, Site 997"Proceedings of the ODP, Science Results. 164. 365-376 (2000)
[Publications] Jordan, R.W., Broerse, S., Hagino, K., Kinkel, H., Sprengel, C., Takahashi, K., Young, J.R.: "Taxon lists for studies of modern nannoplankton"Marine Micropaleontology. 39. 309-314 (2000)
[Publications] Jordan, R.W., Winter, A.: "Assemblages of coccolithophorids and other living microplankton off the coast of Puerto Rico during January-May 1995"Marine Micropaleontology. 39. 113-130 (2000)
[Publications] Ohkouchi, N., Kawamura, K., Kawahata, H., Okada, H.: "Alkenones in surface sediments from the Central Pacific Ocean"Global Biogechem. Cycles. 13. 695-704 (1999)
[Publications] Siesser, W.G., Jordan, R.W.: "Calcareous Nannofossils"Columbia University Press(in press). (2003)

2002 Fiscal Year Annual Research Report

西太平洋暖水魂の挙動変化に伴う石灰質ナノプランクトン群集と炭酸塩フラックスの変化

Principal Investigator

岡田 尚武 北海道大学, 大学院・理学研究科, 教授 (80111334)

Research Products

[Publications] Aizawa, C., Komuro, C., Katsurada, Y., Jordan, R.W.: "Some observations on small, marine centric diatoms, particularly Minidiscus spp. From the Indian Ocean and North Pacific"Diatom Research. (in press). (2003)

[Publications] Tanimoto, M., Aizawa, C., Jordan, R.W.: "Assemblages of living microplankton from the North Pacific Ocean and Bering Sea during July-August 1999"Courier Forschungsinstitut Senckenberg. (in press). (2003)

[Publications] Kleijne.A., Jordan.R.W., Heimdal.B.R., Samtleben.C., Chamberlain, A.H.L, Cros.L.: "Five new species of the coccolithophorid genus Alisphaera (Haptophyta) with notes on their distribution, coccolith structure and taxonomy"Phycologia. 40. 583-601 (2002)

[Publications] Hagino, K., Okada.H.: "Morphological observations of living Gephyrocapsa crassipons"Journal of Nannoplankton Rescarch. 23(1). 3-7 (2001)

[Publications] Takahashi, K., Okada, H.: "Paleoceanography for the last 195,000 years in the Solomon Sea(ODP Site 1109)by means of calcareous nannofossils"Marine Micoropaleontology. 42. 45-59 (2001)

[Publications] Ishiwatari, R., Houtatsu, M., Okada, H.: "Alkenone-sea surface temperature in the Japan Sea over the past 36 kyr : warm temperatures at the last glacial maximum"Organic Geochemistry. 32. 57-67 (2001)

[Publications] Okada, H.: "An improved filtering technique for calculation of calcareous nannofossil accumulation rates"Journal of Nannoplankton Research. 22(3). 203-204 (2000)

[Publications] Hagino, K., Okada, H., Matsuoka, H.: "Spatial dynamics of coccolithophore assemblage in the Equatorial Western-Central Pacific Ocean"Marine Micropaleontology. 39. 53-72 (2000)

[Publications] Takahashi, K., Okada, H.: "Environmental control on the biogeography of modern coccolithophores in the southeastern Indian Ocean off the coast of western Australia"Marine Micropaleontology. 39. 73-86 (2000)

[Publications] Okada, H: "Neogene and Quaternary calcareous nannofossils from the Blake Ridge, Sites 994,995 and 997"Proceedings of the ODP, Science Results. 164. 331-341 (2000)

[Publications] Nishi, H., Norris, R.D., Okada, H.: "Paleoceanographic changes in the dynamics of subtropical Atlantic surface conditions at Site 997A"Proceedings of the ODP, Science Results. 164. 343-363 (2000)

[Publications] Oba, T., Shikama, A., Okada, H.: "Data Report : Oxygen isotopic record of the last 0.8 m.y. at the Blake Ridge, Hole 994C"Proceedings of the ODP, Science Results. 164. 173-175 (2000)

[Publications] Ikeda, A., Okada, H., Koizumi, I.: "Data Report : Late Miocene to Pleistocene diatom from the Blake Ridge, Site 997"Proceedings of the ODP, Science Results. 164. 365-376 (2000)

[Publications] Jordan, R.W., Broerse, S., Hagino, K., Kinkel, H., Sprengel, C., Takahashi, K., Young, J.R.: "Taxon lists for studies of modern nannoplankton"Marine Micropaleontology. 39. 309-314 (2000)

[Publications] Jordan, R.W., Winter, A.: "Assemblages of coccolithophorids and other living microplankton off the coast of Puerto Rico during January-May 1995"Marine Micropaleontology. 39. 113-130 (2000)

[Publications] Ohkouchi, N., Kawamura, K., Kawahata, H., Okada, H.: "Alkenones in surface sediments from the Central Pacific Ocean"Global Biogechem. Cycles. 13. 695-704 (1999)

[Publications] Siesser, W.G., Jordan, R.W.: "Calcareous Nannofossils"Columbia University Press(in press). (2003)

岡田尚武北海道大学, 大学院・理学研究科, 教授 (80111334)