Not So Unnatural (image) Brown University Share Print E-Mail Caption A new study suggests that most of the nitrogen deposited from the atmosphere into the open ocean comes from natural sources, not humans. The findings suggest humans aren't disrupting ocean biogeochemistry as much as some models might predict. Credit Hastings lab / Brown University Usage Restrictions None Share Print E-Mail 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.