Porphyra (image) Carnegie Institution for Science Share Print E-Mail Caption Porphyra clinging to rocks in Germany's Heligoland. It thrives in the harsh habitat of the intertidal zone, where it is exposed to fluctuating temperatures, high UV radiation, severe salt stress, and desiccation. Credit By Gabriele Kothe-Heinrich Usage Restrictions With 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.