I am interested in freshwater microbial ecology. In particular, my current attention is paid to the microbial community inhabiting the oxygenated hypolimnion of deep lakes. By taking samples from multiple lakes, I am trying to reveal their ecology in terms of the following topics: I. Phylogenetic diversity (Who are they?) There is a growing number of evidences that support the existence of the bacterial lineages specific to the oxygenated hypolimnion of freshwater lakes. The members are often affiliated with phyla that are not common to the epilimnion. I am trying to reveal the diversity and distribution of these hypolimnion specialists.
II. Eco-physiological characteristics (What are they doing?) In deep freshwater lakes, the hypolimnion accounts for a large part of the lake in volume. To reveal the eco-physiology of the hypolimnion-specialists will facilitate our better understanding on the lake ecosystem. Since most of them are yet uncultivated, I am taking various isolation-free approaches to study this topic.
III. Phylogeography (Why are they there?) It is enigmatic that the same bacterial lineage inhabit the deep waters of different lakes, despite there is no direct water connection between the habitats. To reveal evolutional background behind them, micro-diversification of the hypolimnion-specific lineages between different lakes are investigated by comparing the sequences of multiple gene loci.
Microbial ecosystem in oxygenated hypolimnion is still largely overlooked. The relatively stable and predictable microbial dynamics and its individuality between lakes are good subjects to study in many aspects. I hope that studies in oxygenated hypolimnion will provide important findings not only for aquatic microbial ecology, but also for diverse aspects of ecology and microbiology.