Sampling the Tree Phyllosphere
Tree canopies represent the interface to the atmosphere and are exposed to the input of energy, water and matter. Phyllosphere microbial communities in tree canopies perform central biogeochemical functions and interact with the host plant species in multiple ways.
Lateral view from a treetop to canopies of surrounding trees in a forest.
Temporal and spatial heterogeneity of phyllosphere microbiomes is strongly influenced by phenology-driven changes of host plant properties but also by the structural heterogeneity of the tree canopy. We leverage the Leipzig Canopy Crane Facility (https://www.idiv.de/en/research/platforms-and-networks/canopy-crane-facility.html) located in the Leipzig floodplain forest to disentangle the controls on canopy microbial diversity and functioning by analysing the relationship between microbial communities and microhabitat structure, and potential pathways of microbial distribution and nutrient supply within the canopy. Using amplicon sequencing, we assess microbial community composition in association with leave and bark surfaces, and in rain water that moves through the tree canopies.
Bottom-Up view along a latticed boom of a crane standing between tree canopies in a forest.
We hypothesize that vertical gradients of bacterial abundance and diversity across the canopy are tightly linked to throughfall-mediated vertical transfer of dust-, pollen- and leaf-derived carbon compounds and nutrients, and transport of microorganisms themselves. Further, we expect a strong correlation of temporal patterns of microbial communities and their predicted metabolic functions with phenology-driven changes of carbon compound and nutrient availability on leaf surfaces. In collaboration with iDiv researchers we integrate aspects of water and nutrient distributions within tree canopies as one key factor underlying spatial and temporal heterogeneity.