Sprecher
Beschreibung
Leaf decay processes are central to understanding plant taphonomy and the formation of fossil leaf compressions. Microbial biofilms and their extracellular polymeric substances (EPS) are increasingly being recognized as key mediators of early decay and preservation. Yet, the influence of leaf biological affinity on biofilm development remains poorly understood. In this experimental study, we investigate exopolysaccharide (EP) production, the principal component of EPS, and microbial community composition on the submerged leaves of three conifer genera—Araucaria, Podocarpus, and Metasequoia—after two weeks of immersion in a natural freshwater pond environment. EP concentrations were quantified at three time points, and associated biofilm microbial communities were characterized using molecular analyses.
Araucaria leaf biofilms produced significantly higher EP concentrations than those associated with Podocarpus and Metasequoia. In addition, distinct microbial taxa were positively correlated with elevated EP production, indicating that the biological affinity of leaves shapes microbial community structure and biofilm development. These results suggest that certain plant taxa, such as Araucaria araucana, may promote the formation of thicker, EPS-rich biofilms that reduce degradation efficiency, stabilize leaf tissues, and create microenvironments favorable for preservation.
Our findings provide experimental evidence that leaf–microbe interactions may directly influence fossilization potential, contribute to taxonomic biases, and possibly promote the preservation of araucarian foliage in the fossil record. More broadly, this study highlights microbial biofilms as active agents in plant taphonomy and suggests that biological controls on EPS production may play an underappreciated role in determining which leaves are preferentially preserved as fossil compressions.