Black Smoker Hydrothermal Vent (IMAGE) Penn State Caption Eggs of deep-sea skates have been discovered near the hottest type of hydrothermal vents, where super-heated water emerges out of the sea floor. These vents, called black smokers, emit dark, sulphurous plumes. Credit Ocean Exploration Trust Usage Restrictions Image credit must be published alongside the image. 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.