Sclerosponges as a new potential recorder of environmental changes: Lead in Ceratoporella nicholsoni

Lead concentrations have been analyzed on a 223 yr profile through the arag onitic skeleton of the reef-building Caribbean sclerosponge Ceratoporella n icholsoni by using laser-ablation inductively coupled plasma-mass spectrome try. A parallel study of the delta(13)C distribution in the skeleton valida tes the previously established mean annual growth rate of 230 mu m/yr, at l east for long-term important environmental changes. The Pb trend in the spe cimen displays a general increase from 0.30 ppm ca. A.D. 1760 to 2.15 ppm c a. A.D. 1984; a major threefold increase occurred after 1930. This Pb profi le is analogous to results acquired from ice or coral cores and clearly hig hlights the potential of sclerosponges as a new proxy of environmental chan ges for time series extending over several centuries.