XANES spectra across the Ag L2,3 edge from a sea urchin exposed to AgNPs at a concentration of 0.3 mg/L after 51 h of growth (bottom), compared with spectra of AgCl, Ag foil, AgNO3, Ag2O, AgO and Ag2S (The Ag2S spectrum was taken from Yin et al. (2011)).