Climate change-driven extinction in planktonic foraminifera

生物多样性的持续下降要求对气候变化造成的灭绝风险进行准确的预测。对气候变化的进化反应的长期研究需要对化石记录进行调查，但很少有化石记录允许我们对进化进行高度确定的重建。浮游有孔虫是一种数量丰富、分布广泛的海洋浮游动物，其化石记录保存得非常完好，可以对不同环境和气候状态下的进化变化进行详细分析。浮游有孔虫的多样性在过去500万年中稳步下降[1,2]。在这段时间内，地球气候从温暖的明显单极（南极）冰川气候状态转变为足够寒冷，足以支持两个半球的大冰原；最初是在以~ 41000年为周期的冰期旋回期间，最终是在以~100千万年为周期的冰期旋回期间。人们普遍认为，气候在生物多样性的减少中起了作用，但个体灭绝的原因尚不清楚。该项目将研究过去500万年中所有46种浮游有孔虫物种的灭绝，以调查共同的驱动机制和早期预警信号。将使用多元统计技术[4]将灭绝和幸存物种的壳大小和形状的变化与当地环境变化记录进行比较，以测试对气候变化强迫的阈值响应行为。

Ongoing declines in biodiversity call for accurate predictions of extinction risk arising from climate change. Long-term studies of evolutionary response to climate change require investigation of the fossil record, but very few fossil records allow us to make highly resolved reconstructions of evolution. The exceptionally well-preserved fossil record of planktonic foraminifera, an abundant and wide-spread group of marine zooplankton, allows for detailed analyses of evolutionary change across diverse environmental settings and climate states. Planktonic foraminifera diversity has decreased steadily over the past 5 million years [1,2]. Over this interval Earth's climate transitioned from a warm distinctly unipolar (Antarctic) glacial climate state to become cold enough to support large ice polar sheets in both hemispheres; initially during ~41 thousand year (kyr)-paced glacial cycles, eventually during the large ~100 kyr-paced Ice Age cycles [3]. It is widely suggested that climate played a role in this decline in diversity, but the causes of individual extinctions remain unknown. This project will study all 46 extinctions of planktonic foraminifera species in the past 5 million years in order to investigate common driving mechanisms and early warning signals. Changes in shell size and shape of extinct-going and surviving species will be compared to local records of environmental change using multivariate statistical techniques [4] to test for threshold response behaviour to climate change-forcing.