Biodiversity of planktonic foraminifers and their contribution to the carbon cycle

浮游有孔虫壳的稳定碳同位素可能是重建过去碳循环的有用指标。本研究揭示了浮游有孔虫的多样性、生态学及其与光共生体的关系，以了解其在钙化过程中的重要作用。对世界海洋浮游有孔虫的系统地理分析表明，它们的遗传和表型变异与两大环境因子（洋流和水温）有显著的关系。时间序列观测表明，各浮游有孔虫遗传类型的频率随季节变化而变化，但不受任何环境因子（温度和叶绿素密度）的影响。光共生体的遗传类型频率与寄主的遗传类型频率表现出独立的季节性。这可能说明光共生体的种类组成反映了寄主的生态环境。

The stable carbon isotope of planktonic foraminiferal shells is potentially a useful indicator to reconstruct the past carbon cycle. This study has unveiled the diversity and ecology of planktonic foraminifers and their association with photosymbionts, to understand the vital effect during calcification process. Phylogeographic analyses of planktonic foraminifers in the world oceans showed significant relationships of their genetic and phenotypic variations to two major environment factors (ocean current and water temperature). The time-series observation showed that the frequency of each planktonic foraminiferal genetic type was seasonally changed, but not attribute to any environmental factors (temperature and chlorophyll density). The frequency of genetic types of photosymbionts showed independent seasonality from those of the hosts. This may suggest that species composition of photosymbionts is reflected to ecology of the host.