Correlation between DBC and He-3 (IMAGE) Hokkaido University Caption In the eastern South Pacific Ocean, excess DBC concentrations increase closer to the equator, and are correlated with helium-3 isotopes from hydrothermal vents. Hydrothermal vents are the primary source of excess DBC (Youhei Yamashita, Yutaro Mori, Hiroshi Ogawa. Science Advances. February 9, 2023). Credit Youhei Yamashita, Yutaro Mori, Hiroshi Ogawa. Science Advances. February 9, 2023 Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. License CC BY-NC 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.