The course is designed for senior undergraduates and graduates interested in approaches and principles used to conduct studies and/or tackling problems in geomicrobiology. The course is mission-oriented and intensively lab-based. Two lectures at the beginning will be given to provide general concepts used to address the questions in geomicrobiology and to plan how the field work will be conducted. The students will be broken into different teams (with each team consisting of 2 students) and guided to conduct sample collection during a two-three day field trip to mud volcanoes in Taiwan. The collected materials will be processed in the field and lab, and used for analyses of abundances and isotopic compositions of porewater and gas, mineralogy, sediment geochemistry, community assemblage, cell abundance and microbial activity in the following weeks. Data analysis and compilation will be instructed during the last two lectures and the discussion will be held in the last lecture.