Abstract
Very early diagenetic processes of free, esterified and amide or glycosidically bound fatty acids and hydroxy fatty acids present in well documented samples of living and decomposing eelgrass (
Zostera marina L.) were investigated. Free and esterified fatty acids decreased significantly over a period of decay of 12.5 years, although their distribution patterns were largely unchanged. Amide or glycosidically bound α-hydroxy fatty acids and the newly recognized α,β-dihydroxy fatty acids were not degraded. Thus both, but in particular the α,β-dihydroxy fatty acids, may serve as potential biomarkers for the recognition of eelgrasses in palaeoenvironments. The increasing amounts of ω-hydroxy fatty acids and α,ω-dicarboxylic fatty acids upon decay indicate bacterial transformations of eelgrass lipids. This bacterial action was further demonstrated by a substantial increase of amide-bound β-hydroxy fatty acids derived from LPS of gram-negative bacteria.