Climate Change Threats (image) Virginia Institute of Marine Science Share Print E-Mail Caption Drops in pH signal more acidic waters, which can hinder a coral's ability to build its skeleton, while extreme warmth can make it expel the photosynthetic algae that provide much of its food energy. Credit © Emily Rivest. Usage Restrictions One-time use only. 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.