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更新世晚期以來熱帶太平洋與印度洋之 海洋初級生產力記錄

更新世晚期以來熱帶太平洋與印度洋之 海洋初級生產力記錄 Oceanic Primary Production in the Tropical Pacific and Indian Oceans During the Late Pleistocene 言婉婷 Wan-Ting YEN 國立台灣海洋大學 應用地球科學研究所. Introduction.

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更新世晚期以來熱帶太平洋與印度洋之 海洋初級生產力記錄

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  1. 更新世晚期以來熱帶太平洋與印度洋之 海洋初級生產力記錄 Oceanic Primary Production in the Tropical Pacific and Indian Oceans During the Late Pleistocene 言婉婷 Wan-Ting YEN 國立台灣海洋大學 應用地球科學研究所

  2. Introduction • Reconstructing past variations of primary production during Pleistocene climatic cycles is an important requirement for estimating the effects of the ocean’s biological pump on the atmospheric CO2 concentration through time. • Paleoproductivity reconstructions should also provide information about climate dynamics.

  3. Discussion ENSO

  4. Material 20°N 0° 20°S 30°E 60°E 90°E 120°E 150°E 180° 150°W 120°W 90°W • Analyzed the coccolithophore community preserved in • eleven deep-sea cores taken from the tropical Indian • and Pacific oceans. • By tuning oxygen isotope records from foraminifera • in most of the cores to the SPECMAP stacked record • ,sampling achieves a temporal resolution of 910000 • years.

  5. Methods • The coccolithophore Florisphaera profunda lives in the deep-photic zone. • As productivity increases, the relative abundance of F. profunda decreases.

  6. Methods Methods 衛星估計的pp Core top的F. profunda Beaufort et al,(1997) • Using the least squares method tested different types of equations to determine the best fit for the distribution of Fp versus PP. • PP = 617- [279x log(Fp+ 3)] • Fp is highly correlated with primary production estimated from satellite information.

  7. Methods Beaufort et al,(1997) • Paleoproductivity estimated from independent indicators is in very good agreement with the productivity deduced from the abundance of F. profunda.

  8. Methods The ePP records show large amplitude variability with regional similarities and contrasts that are explored using empirical orthogonal functions (EOFs). 0 50 100 128 150 primary production (g C m-2yr-1 ) Beaufort et al,(2001) Age(kyr)

  9. Methods Two significant EOF series (EOF-1 and EOF-2) have been extracted for the last 180 ky from the eight cores. 0 50 100 128 150 Beaufort et al,(2001) Age(kyr)

  10. Results 20°N 0° 20°S 30°E 60°E 90°E 120°E 150°E 180° 150°W 120°W 90°W Beaufort et al,(2001) • It gives a much clearer picture of the opposition in dynamic between the western and eastern Pacific ePPs . • This cyclic opposition can also be seen when comparing basin average regional records.

  11. Results 冰期 間冰期 間冰期 冰期 Beaufort et al,(2001)

  12. Results Beaufort et al,(2001)

  13. Results • A 30-ky period has been found in series from the tropical and tropical Indian oceans. • the 30-ky component that occurs in EOF-1 as • well as in most of the ePP series corresponds to a cyclic phase shift of the precession parameter. 30kyr 30kyr 30kyr 30kyr 30kyr 30kyr Beaufort et al,(2001)

  14. Discussion • Variations in equatorial productivity are primarily caused by glacial-interglacial variability and by precession-controlled changes in the east-west thermocline slope of the Indo-Pacific. • The precession-controlled variations in productivity are linked to processes similar to the Southern • Oscillation phenomenon, and they precede changes in the oxygen isotopic ratio, which indicates that they are not the result of ice sheet fluctuations.

  15. ( purple)：The three filtered series were then added together. At the bottom positive part of 30-ky Gaussian filters (centered on 0.034 ky 21 with a band width of 0.004 with cutting at period of 26.6 and 34.3 ky) of EOF. (green) ： 23-ky sine-wave frequency modulated by 100- and 40-ky cycle from SPECMAP. (orange) ： –CO2 from Vostok. Discussion Beaufort et al,(2001)

  16. Conclusions • The 30,000-year spectral peak in the tropical Indo-Pacific Ocean productivity records is also present in the Antarctica atmospheric CO2 record, suggesting an important role for equatorial biological productivity in modifying atmospheric CO2. • The 23-ky ENSO-like cycle is likely to have played a significant role in global climate dynamics.

  17. Conclusions Two independent forcings responsible for the long-term equatorial Indo-Pacific productivity dynamics. The depth of the equatorial thermocline to global climatic variations. Equatorial east-west thermocline tilt and is linked to the 23-ky period of Earth’s precession.

  18. 未來工作 嘗試利用衛星遙測所得之生產力資料與現有的岩心頂樣資料推估出一浮游有孔蟲之初級生產力經驗方程。 所利用衛星資料：SeaWiFS 區域：30°N~65°S，20°E~180°E Monthly Net Primary Production: February , 2005

  19. 參考文獻 • Luc Beaufort, Yves Lancelot Pierre Camberlin, Olivia Cayre, Edith Vincent, Franck Bassinot, Layrent Labeyrie ,Science 278, 1451-1454(1997) , Insolation Cycles as a Major Control of Equatorial Indian Ocean Primary Production. • Luc Beaufort, Thibault de Garidel-Thoron, Alan C.Mix , Nicklas • G.Pisias, Science 293, 2440-2444(2001), ENSO-like Forcing on • Oceanic Primary Production During the Late Pleistocene. • Luc Beaufort, T. de Garidel-Thoron, B. Linsley, D. Oppo, N. buchet, Science201, 53-65(2003), Biomass burning and oceanic primary production estimates in the Sulu Sea area over the last 380 kyr and the East Asian monsoon dynamics.

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