Heliocidaris population in Sydney (IMAGE) The University of Hong Kong Caption Heliocidaris population in Sydney, Australia. Sea urchins play a key role in maintaining the function of ecosystems, but the fate of future populations is under threat due to increases in the occurrence of marine heatwaves. Credit Dr Maria Byrne Usage Restrictions N/A 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.