Faculty and research guide

Laboratory of Environmental Microbiology (Sameshima)

Reiko Sameshima-Saito

Soil contains more than 100 million microorganisms per gram, with thousands or tens of thousands of varieties. In this laboratory, we aim to contribute to the resolution of environmental puzzles, by clarifying the functions and ecology of these microorganisms. We are therefore pursuing the following challenging research and analysis.

「Ecology and control of nitrifying and denitrifying microorganisms that are important to the nitrogen cycle」
Nitrogen is one of the major elements that constitutes the living things. Enormous amounts of nitrogen are dumped on farmland to improve crop yields and quality. As a result, the nitrifying and denitrifying microorganisms in the soil are activated, and producing the nitrous oxide (N2O) gas that is thought to contribute to the greenhouse effect and destruction of the ozone layer. Nitrifying microbes also produce nitrate, and contaminate the groundwater. To solve these global and regional environmental problems, we are researching diversity and ecology of nitrifying- and denitrifying-microorganisms, that inhabit in tea field soils (Fig. 1) that are receiving excessive amount of nitrogen fertilizer, with the aim of developing the controlling methods.

Fig. 1 Distinctive features of tea field soil appear especially in furrow soil. High carbon input by trimming tea tree, and high nitrogen input by frequent fertilization from spring to autumn are the conventional management of tea field.