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

9814584

Freeman

Recent 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.