COLLABORATIVE RESEARCH: Carbon-Limitation in Pleistocene Tropical Ecosystems: A Test of the Roles of CO2 and Aridity Using Molecular and Isotopic Proxies

9903473Eglinton最近的证据表明，C4植物生态系统在末次冰期(LGS)后显著收缩，并表明全球变暖期间二氧化碳增加促进了C3植物的扩张。然而，同样的模式可能是由于冰川阶段相对干燥的条件增加了水的可获得性。我们将使用中美洲山地湖泊的岩心样本来测试二氧化碳和水的可用性在更新世-全新世陆地植物生态系统分布上的相对重要性。具体地说，我们将评估从湖泊沉积物中提取的陆地植物和藻类的分子和同位素分布，这些湖泊在LGS期间经历了比今天更潮湿、更干燥或类似的条件。

9903473EglintonRecent evidence indicates C4 plant ecosystems contracted significantly following the Last Glacial Stage (LGS) and suggest rising CO2 during the global warming facilitated the expansion of C3 plants. However, the same pattern could result from an increase in water availability from the relatively dry conditions during the glacial stage. We will test the relative importance of CO2 versus water availabiltiy on the Pleistocene-Holocene distributions of terrestrial plant ecosystems using core samples from Mesoamerican mountain lakes. Specifically, we will evaluate molecular and isotopic distributions of biomarkers for land plants and algae extracted from sediments in lakes that experienced wetter, drier or similar conditions during the LGS relative to today.