Wildfire and Terrestrial Plant Biomarkers in Modern West African Margin Core Top Sediments
Abstract
Biomass burning has significant impacts on the global carbon system both through the release of CO2 and aerosols into the atmosphere and through complex feedbacks with terrestrial vegetation. Organic molecular indicators of combustion--fire biomarkers--have become an increasingly useful set of tools for reconstructing the history of biomass burning in order to better understand wildfire variability both in different regions and during varying climate conditions. Previous work has focused primarily on lacustrine archives, while marine sediments have received less attention. Here we demonstrate that two classes of fire biomarkers, pyrosugars and polycyclic aromatic hydrocarbons (PAHs), preserved in core top sediments along the West African Margin (15-38°N) faithfully record modern latitudinal gradients of biomass burning in western Europe and northwest Africa. By pairing isomeric ratios of the pyrosugar levoglucosan with terrestrial leaf wax concentrations and d13C, we show a transition from a C3 (30-38°N) to a C4 grass (20-30°N) vegetation and fuel source consistent with an increasingly C4-dominated landscape moving southward along the West African Margin. Fire biomarkers normalized to n-alcohol terrestrial plant waxes reveal higher instances of fire in grassier ecosystems consistent with modern studies which highlight the important ecological role fires play in maintaining savanna ecosystems in mesic environments by actively suppressing woody vegetation growth.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP23F1724O
- Keywords:
-
- 0424 Biosignatures and proxies;
- BIOGEOSCIENCES;
- 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCES;
- 1620 Climate dynamics;
- GLOBAL CHANGE;
- 4950 Paleoecology;
- PALEOCEANOGRAPHY