Determination of thermal stability of specific biomarker lipids of the freshwater fern Azolla through hydrous pyrolysis

Enormous blooms of the free-floating freshwater fern Azolla occurred within the Arctic Basin during an extended period of ∼1.2 Ma during the middle Eocene (Brinkhuis et al. 2006; Speelman et al., GB, 2009). The sustained growth of Azolla, currently ranking among the fastest growing plants on Earth, in a major anoxic basin may have substantially contributed to decreasing atmospheric CO2 levels by burial of Azolla-derived organic matter. Speelman et al. (OG, 2009) reported biomarkers for Azolla (1,w20 C32 C36 diols, structurally related C29 20,21 diols, C29 1,20,21 triols, C29 dihydroxy fatty acids as well as a series of wax esters containing these monoand dihydroxy lipids), which can be used to reconstruct palaeo-environmental conditions. Here we assess the thermal stability of these compounds, to extend their biomarker potential.