A student takes a core sample with a KB corer in the Cutler Reservoir wetland (Utah). The corer extracts a 30-50 cm (12-20 inch) sample of mud in a tube. The extruded mud can be sliced into layers. These can then be dated to determine the decade of deposition, and analyzed for a variety of physical, chemical and biological components to assess how water quality, climate and other driving factors have influenced aquatic and nearby terrestrial environments.