POST-GLACIAL FIRE AND CLIMATE HISTORY OF SOUTHERN NEW ENGLAND

Sedimentary archives document a significant link between fire and climate in western North America; however, records of fire in post-glacial ecosystems of northeastern U.S. are sparse. Connecticut’s Echo Lake is a kettle pond providing continuous deposition of sediments since >16,000 Cal yr BP, reflecting post-glacial retreat and the landscape evolution of Southern New England – this provides an excellent archive of climate and fire activity as reflected by organic matter preserved in the lacustrine sediments. Molecular distributions of terrestrial leaf waxes (n-alkanes) yield insight into vegetation, climate, and hydrological shifts through time, while polycyclic aromatic hydrocarbons (PAHs) generated during combustion of organic material afford insight into fire activity. Molecular fire markers indicate that southern New England was characterized by more frequent and larger fires in the early post-glacial period, followed by a reduction in fire as ecosystems transitioned from spruce/pine to northern hardwood forests. In agreement with other studies, shifts in average chain length (ACL) of n-alkanes primarily reflect a temperature increase beginning early in the post-glacial, followed by muted variability before cooling until modern day. Throughout the period of record, steadily increasing concentrations of PAHs reflect more frequent forest fires throughout the Holocene which may reflect local changes to the forest environment or anthropogenic impacts. In the youngest samples, the effects of European colonization and industrialization are observed in highly elevated concentrations of PAHs and molecular diagnostic ratios characteristic of petroleum combustion.