Long‐range atmospheric transport of terrestrial biomarkers to the western North Atlantic

Abstract

We analyzed terrestrial plant‐derived leaf wax biomarkers in aerosols collected at Bermuda over a 2.5 years time series. Leaf waxes comprised 60–70% of extractable lipids and 0.5–1.0% of total organic carbon. Biomarker concentrations in biweekly integrated samples varied by over an order of magnitude and indicate that long‐range atmospheric transport is highly episodic. Results indicate that North America is the main source of terrestrial organic carbon in the western North Atlantic and that terrestrial carbon advected from Africa originates mainly in tropical C3 forests to the south of Saharan dust‐source regions. Terrestrial biomarker concentrations were poorly correlated with organic carbon concentrations, which suggest significant source differences. Variations in relative abundance of the major wax compound classes and in their carbon isotopic composition indicate that waxes in aerosols are mainly derived from ablation off living vegetation and reveal a large‐scale seasonal cycle in terrestrial biosphere emissions of wax biomarkers.