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

9814584 Freeman最近的证据表明，C4植物生态系统在末次冰期（LGS）之后显著收缩，并表明全球变暖期间CO2的上升促进了C3植物的扩张。 然而，同样的模式可能是由于冰川期相对干燥的条件下水的可用性增加。 我们将测试的相对重要性，CO2与水availabiltiy更新世-全新世分布的陆地植物生态系统的核心样品从中美洲山区湖泊。 具体而言，我们将评估从湖泊沉积物中提取的陆地植物和藻类生物标志物的分子和同位素分布，这些湖泊在LGS期间经历了相对于今天的潮湿，干燥或类似条件。

9814584FreemanRecent 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.