Investigation Into the Plio-Pleistocene Development of Pacific-Caribbean Environmental Differences Using Mollusc Stable Isotope Profiles

中美洲地峡(约3.5 Ma)的出现为检验海洋生物进化变化速率和机制的因果基础提供了一个理想的自然实验。这一事件隔离了东太平洋和加勒比以前毗连的人口，并在屏障的两侧启动了不同的选择性制度的发展。软体动物的稳定同位素图谱可以很好地记录周围环境条件。特别是，软体动物的同位素剖面记录了温度、盐度和上升流的季节性变化的对比模式，这些模式是今天东太平洋和加勒比海西南部的特征。将对中美洲地峡两侧广泛且年代准确的上更新世剖面中精选的软体动物贝壳进行稳定同位素分析。这些分析的目的是：1)跟踪东太平洋和加勒比环境之间差异的发展，以及2)为未来海洋无脊椎动物类群的进化研究提供古环境背景。

The emergence of the Central American isthmus (approximately 3.5 Ma) presents an ideal natural experiment for testing the causal basis of the rates and mechanisms of evolutionary change of marine organisms. This event isolated previously contiguous populations in the eastern Pacific and Caribbean, and initiated the development of different selective regimes on opposing sides of the barrier. Molluscan stable isotopic profiles can provide an excellent record of ambient environmental conditions. In particular, molluscan isotopic profiles record the contrasting patterns of seasonal change in temperature, salinity, and upwelling that characterize the eastern Pacific and southwestern Caribbean today. Stable isotopic analyses will be conducted for selected mollusc shells from extensive and well-dated Plio-Pleistocene sections on either side of the Central American isthmus. The purpose of these analyses is to: 1) track the development of the differences between eastern Pacific and Caribbean environments, and 2) provide a paleoenvironmental context for future evolutionary studies of marine invertebrate taxa.