Methane Bubbles on Lake Kariba, Africa (IMAGE) University of Minnesota Caption Methane bubbles to the surface Lake Kariba, Africa, of the world's largest man-made lake and reservoir by volume. Credit Credit: Christian Dinkel Usage Restrictions None 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.