Spanish researchers have shown for the first time thattemperature is the only environmental variable that controls the life cycle of Cotylorhiza tuberculata, a jellyfish that for the last 20 years has been dispersed in the Mediterranean basin, especially in the waters of the Mar Menor.
“It is easily identified by its flattened shape and because, seen from above, it looks like a fried egg. It is not very poisonous, and is also characterized by its eight arms with white or bluish button-shaped ends. This is how scientists from the Andalusian Institute of Marine Sciences (ICMA-CSIC) describe the jellyfishCotylorhiza tuberculata, a species that they have analyzed in the laboratory for three years to study how the presence of nutrients in water, salinity or the influence of light affects it.
Scientists have observed thatif winter is very cold, the mortality of polyps is very highand the number of jellyfish the following summer will be low. Changes in water temperature, therefore, condition the survival of polyps and their subsequent conversion to jellyfish.
? For the jellyfish to remain in the water during the summer, the polyps have to be stimulated by an increase in water temperature that occurs only in spring ,? explains Laura Prieto, researcher at the ICMA-CSIC and director of the study published in the next issue of the magazinePLOS One. Specific meteorological phenomena, such as the passing of a storm, are not enough for this transition to take place to a different life phase. What’s more,due to climate change, springs come early, so jellyfish have more time to grow.
