Algae bloom. (IMAGE) University of Gothenburg Caption Algal blooms can become so dense that they discolour the water. However, most toxic algal blooms on the west coast of Sweden do not discolour the water. Credit Erik Selander Usage Restrictions None 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.