Nodule in the lab (IMAGE) Northwestern University Caption Polymetallic nodules, collected from the ocean floor, sit in simulated seawater in chemist Franz Geiger's laboratory at Northwestern University. Credit Franz Geiger/Northwestern University Usage Restrictions add credit License Original 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.