This course is part of a partnership with the Semester in Environmental Science (SES) Program of Marine Biological Laboratories (MBL). This program is open to students who have completed courses in chemistry, biology, and mathematics. Students accepted to this program will spend the fall semester at the Marine Biological Laboratory (MBL) in Woods Hole, MA. Please see here for more information on the SES program: https://www.mbl.edu/education/undergraduate-programs/semester-environmental-science. Prior to submitting your application to MBL’s Semester in Environmental Science program, you must meet with the Chair of the Natural Sciences and Mathematics department to discuss your interest and get permission to apply to this program. Since applications to the MBL SES program are due mid-March, you must meet with the Chair in the Fall semester or by the first week in February. Once you have received approval from the Chair you must submit an application to MBL’s Semester in Environmental Science program. In this course, we will present the scientific rationale behind a number of methods suitable for determining the role of microbes in ecosystems. The methods will be described and students will carry out the procedures in a series of hands-on laboratories. One theme will be choosing methods and temporal and spatial scales appropriate to the question being asked. Lectures will describe the biology and logic that underlie the various methods used by microbial ecologists. In the laboratory, students will work with the latest techniques to measure microbial biomass, activity, extracellular enzymes, biogeochemistry and species diversity. These include epifluorescence microscopy, radioisotopic tracers for bacterial production, fluorescent substrates, hydrogen sulfide and methane production, and molecular probes for classes of bacteria. Students will be required to turn in answers and calculations to problem sets that are associated with each lab topic. These problem sets will form the basis of the grade. In addition, students will be asked to present their laboratory results and participate in group discussions on the findings by the entire class. Students will be encouraged to use the methods developed in this course for their individual research projects associated with the SES course. This course satisfies the Intermediate Level Course requirements for the Interdisciplinary Science Major. Permission required to register for this course.