Increased sensitivity of sea urchin larvae to metal toxicity as a consequence of the past two decades of Climate Change and Ocean Acidification in the Mediterranean Sea.

The Mediterranean Sea represents a natural laboratory to infer the possible impacts of climate change and ocean acidification. In this article, we report the deteriorating ability of sea urchin larvae (Paracentrotus lividus) to cope with toxicity of a reference contaminant (Cu EC) over the past 20 years and assessed the influence of 5 environmental factors from satellite measurements. This timeframe was divided in before and after January 2016 (46.57 μg/L vs 28.56 μg/L respectively, p < 0.001). In the second subset of data, correlation of the biological variable with CO and pH strengthened compared to the first part (rCO-EC: -0.21 vs -0.83 and rpH-EC: 0.25 vs 0.87 respectively), with a causal link starting from one year and ending 4 months prior to EC measurements. Considering the continuous increase in CO concentrations recorded recently, this study could reveal a rapid deterioration of the health condition of this population of sea urchins in a coastal ecosystem.