Students in a College of Natural Resources class (Utah State University) prepare a Van Dorn bottle to take a water sample through frozen Hyrum Reservoir, Utah. The bottle is lowered to the desired depth, and a steel messenger is then sent down the line to the trip mechanism which closes the plungers on the bottle. The water sample was then analyzed for chemical parameters (nutrients) and chlorophyll (as a measure of phytoplankton biomass).


Photo: 6 February 2009.