MBARI researchers use benthic respirometers to measure how much oxygen is being consumed by organisms in deep-sea sediment. This provides an indication of how much food (organic matter) these organisms are consuming. Before sending a benthic respirometer system (BRS) thousands of meters below the ocean surface, MBARI engineers dunk it in a 10-meter-deep tank to make sure that it is properly weighted and nothing leaks. This photograph, taken from a window looking into the tank, shows the BRS just below the water's surface. At the top of the image is a upside-down reflection of the BRS and the tank windows. Image: Todd Walsh © 2010 MBARI