A PROCESS-BASED ECOSYSTEM MODEL (PALEO-BGC) TO SIMULATE THE DYNAMIC RESPONSE OF LATE CARBONIFEROUS PLANTS TO ELEVATED O-2 AND ARIDIFICATION

摘要

Ecosystem process models provide unique insight into terrestrial ecosystems by employing a modern understanding of ecophysiological processes within a dynamic environmental framework. We apply this framework to deep-time ecosystems made up of extinct plants by constructing plant functional types using fossil remains and simulating-as dose as possible-the in vivo response of extinct taxa to their paleoclimatic environment. To accomplish this, foliar characteristics including maximum stomatal conductance, distance from leaf vein to stomata, and cuticular carbon and nitrogen were input as model parameters derived from measurements of well-preserved Pennsylvanian-age fossil leaves. With these inputs, we modeled a terrestrial tropical forest ecosystem dominated by "iconic" plant types of the Pennsylvanian (similar to 323-299 Ma) including arborescent lycopsids, medullosans, cordaitaleans, and tree ferns using a modified version of the process model BIOME-BGC, which we refer to as Paleo-BGC. Modeled carbon and water-and, for the first time, nitrogen-budgets of a tropical ecosystem from Euramerica driven by daily meteorology are simulated using the Global Circulation Model GENESIS 3.0. Key findings are: