Supplement to: Collard, Marie; Rastrick, S P S; Calosi, Piero; Demolder, Yoann; Dille, Jean; Findlay, Helen S; Hall-Spencer, Jason M; Milazzo, Marco; Moulin, Laure; Widdicombe, Steve; Dehairs, Frank; Dubois, Philippe (2015): The impact of ocean acidification and warming on the skeletal mechanical properties of the sea urchin Paracentrotus lividus from laboratory and field observations. ICES Journal of Marine Science, https://doi.org/10.1093/icesjms/fsv018