Two Postdoctoral Scholars, Microbial and Ecosystem Ecology Unit

Successful candidates are required to engage in one of the projects listed below.

Project 1. Urban areas have expanded worldwide over the past few decades and are predicted to continue growing in the coming years. Urban trees play vital roles in urban ecosystems, such as absorbing pollution, cooling the atmosphere, reducing energy use, and providing habitats for animals. However, urban trees face high mortality rates, and their soils are heavily disturbed: they are hot, dry, and subject to high chemical deposition and pathogen loads, which require trees to employ unique strategies for survival, such as utilizing stress tolerance and pathogen protection functions through symbiotic microbial communities. It is unclear how these trees distribute carbon and nutrient resources—which are generally higher than those in natural forest trees—towards both their own functions and those of microbial communities. At the same time, managing tree functional types and landscape design effectively has great potential to maximize the benefits of green space in urban systems, such as carbon sequestration, mitigating greenhouse gas emissions, and suppressing pathogen levels, although no established protocol currently exists for this. Furthermore, the dynamics of symbionts and pathogens within urban environments are not well understood. Isolated trees in cities may have difficulty finding ideal symbionts, while amplified pathogens in urban terrestrial ecosystems could spread to rivers and oceans. This project will broadly investigate microbial and ecosystem ecology in urban systems by employing amplicon sequencing, meta-transcriptomic, metabolomic, and stable isotope probing analysis techniques using various environmental samples, including soil, roots, leaves, wood, and air.

Project 2. Tropical forests are crucial for sequestering large amounts of carbon in terrestrial ecosystems, thanks to their high plant productivity. However, these forests are under significant threat from climate change and land-use changes, such as logging and deforestation, emphasizing the need to understand the mechanisms driving tropical forest dynamics to support conservation and recovery efforts. Tropical trees heavily rely on mycorrhizal symbionts for nutrient acquisition, particularly phosphorus (P) and nitrogen (N), which are often scarce in these ecosystems. Despite this, research on tropical ectomycorrhizal (ECM) associations has historically been limited. It is now recognized that many tropical species, particularly in Asia, are associated with ECM fungi, including canopy-dominant trees in the Dipterocarpaceae family, which are known for their high dominance and diversity in the region. The dominance of these families is thought to be driven by the strong ability of ECM fungi to exclusively utilize soil P and N sources, but this hypothesis has not yet been tested. There are also exceptions, where other ECM-associated trees do not exhibit such dominance. Additionally, the functional diversity and uniquely evolved traits of these fungi, which help them adapt to tropical ecosystems, are also worth exploring. This project aims to investigate tropical tree-ectomycorrhizal interactions through amplicon sequencing, meta-transcriptomic, and genomic analysis, as well as biogeochemical analysis.