42 Hours of Data (IMAGE) University of Washington Caption An echogram displays the relative density of aquatic organisms from the seafloor to the surface of Monterey Bay. Vertical movement of zooplankton and fish, usually deeper during day and dispersed in surface waters at night, are displayed over a 42-hour period. The seabottom is located at the top of the image and the ocean surface is at the bottom. Credit University of Washington Usage Restrictions Image credit required License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.