Blue-green Alga (image) Forschungsverbund Berlin Share Print E-Mail Caption Microscope image of the nitrogen-fixing blue-green alga Anabaena crassa from the lake Müggelsee. Credit Image: IGB Usage Restrictions This image may only be used in the context of this press release with appropriate caption or credit. 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.