HKU Marine Scientists Unveil Sea Urchin’s Secret to Surviving Marine Heatwaves

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Global ocean temperatures are increasing due to climate change, exposing ecosystems to extreme temperatures called marine heatwaves (MHWs), which can increase the temperature of marine waters by 5°C higher than normal in summer. 

Global ocean temperatures are increasing due to climate change, exposing ecosystems to extreme temperatures called marine heatwaves (MHWs), which can increase the temperature of marine waters by 5°C higher than normal in summer. MHWs can last several months and cause devastating effects on marine organisms.

Dr Bayden D. RUSSELL from The Swire Institute of Marine Science (SWIMS) and The School of Biological Sciences (SBS) at The University of Hong Kong (HKU), along with his research group, in collaboration with Dr Maria BYRNE, from the Sydney Institute of Marine Science, The University of Sydney (USyd), experimentally assessed whether adult sea urchins (Heliocidaris erythrogramma) that are exposed to marine heatwaves could pass beneficial protective mechanisms onto their offspring, thus ensuring the survival of the next generation. The findings indicated that adult sea urchins could pass on this heatwave resistance to the next generation. However, the study also identified that these carryover effects may not remain effective throughout the development and growth of juvenile urchins. The findings have been published in Global Change Biology.

Sea urchins are both economically and ecologically valuable. They maintain the structure and function of benthic marine ecosystems by eating algae that would otherwise take over these systems in the absence of urchins, making the ecosystem simpler and less biodiverse. This role is particularly important in ecosystems stressed by human activities like nutrient pollution or marine heatwaves, which benefit fast-growing algae that replace critical habitats like coral reefs or larger seaweed forests (e.g., kelp forests). Therefore, the continued survival of sea urchins under global heating is key to the continued function of many marine ecosystems.

Read more at The University of Hong Kong

Image: Heliocidaris juvenile under microscope. The ability of urchin parents to pass on benefits to their offspring after exposure to heatwaves is key to helping prepare and protect the next generation. (Credit: Dr Maria Byrne)