Calcareous nannoflora and carbonate flux variations associatd with the dynamic change of the Western Pacific Warm Pool

通过对赤道西太平洋钙质微型浮游生物三维空间分布的研究，发现：（1）在高温水、暖富营养水和暖贫营养水的温跃层上，钙质微型浮游生物的植物群存在差异;（2）在温带混合水的温跃层上，钙质微型浮游生物的植物群没有差异。通过分析485个热带和亚热带太平洋表层水样品，其中包括351个样品收集的拉蒙特-多尔蒂地球天文台，我们已经确定了7个不同的植物区系与不同的表面营养水平。这些植物群的分布格局清楚地对应于在表面营养水平的纵向梯度，是在远洋环境中的微型浮游植物群的纵向分布的第一个观察。我们还报道了在热带上升流沃茨中非常小的板状体的异常集中，并指出了这些非常小的类群的古海洋学用途。虽然最后一批样品刚刚回收，分析仍在继续，但我们现在可以肯定，在营养层相当深的热带太平洋，广泛用于古海洋学重建的Molfino和McIntyre（1991）模型不适用。本文提出了一种新的沉积物样品超微化石定量研究方法，并利用这一新技术分析了几个高分辨率古海洋学的样品。

We have studied the three dimensional distribution of calcareous nannoplankton in the Western equatorial Pacific and have identified, 1) the flora differs across the thermocline in the high-temperature water, warm eutrophic water and warm oligotrophic water regimes, but 2) no floral difference can be seen in the temperate mixed-water regime. By analyzing 485 tropical and subtropical Pacific surface-water samples including 351 samples collected by the Lamont-Doherty Earth Observatory, we have identified seven different floras correlating to different surface trophic levels. The distribution pattern of these floras clearly correspond to the longitudinal gradient in the surface nutrient level, and was the first observation of the longitudinal distribution in nannoplankton flora in a pelagic environment. We have also reported unusual concentration of very small placoliths in a tropical upwelling waters and have indicated paleoceanographic usefulness of these very small taxa.For the multi-year study of seasonal variations of calcareous nannoplankton in the tropical Pacific using the sediment-trap samples, we have obtained continuously the transition from La Nina to El Nino phases. Although the last batch of samples were just recovered and the analysis is continuing, we are now sure that the Molfino and Mclntyre (1991) Model that is widely used for paleoceanographic reconstructions does not work in the tropical Pacific where the nutricline is quite deep. A new methodology was proposed for a quantitative study of nannofossils in sediment samples, and by using this new technique we have analyzed several Quatemary cores for hgih-resolution paleoceanography.