Tipping point in the transcriptomic response of Crassostrea gigas to Ocean Acidification

Studies on the impact of ocean acidification involve exposing organisms to present and future acidification scenarios for oceanic waters based on IPCC scenario. However, pH variability in the coastal environment limits the relevance of applying such predictions and requires knowing reaction norms and identifying tipping points over wide range of pH variations. Reaction norms established so far relate to a few macro-physiological traits and provide a limited view of whole organism response. Here we established the reaction norm of juvenile oysters Crassostrea gigas over a wide range of pH and determine for the first time the presence of tipping point in overall gene expression. We therefore proprose a new method for the analysis and interpretation of transcriptomic data in global change research field and provide new insights about marine calcifiers response to ocean acidification.