Supplement to: LaVigne, M; Hill, Tessa M; Sanford, E; Gaylord, B; Russell, Ann D; Lenz, E A; Hosfelt, J D; Young, M K (2013): The elemental composition of purple sea urchin (Strongylocentrotus purpuratus) calcite and potential effects of pCO2 during early life stages. Biogeosciences, 10(6), 3465-3477, https://doi.org/10.5194/bg-10-3465-2013