Supplemental Material: EFFECTS OF INCREASED pCO2 AND GEOGRAPHIC ORIGIN ON PURPLE SEA URCHIN (STRONGYLOCENTROTUS PURPURATUS) CALCITE ELEMENTAL COMPOSITION

• Main Authors: Michèle Lavigne, Tessa M. Hill, Eric Sanford, Brian Gaylord, Ann D. Russell, Elizabeth A, Jessica D. Hosfelt, Megan K. Young
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Planktonic foraminifera
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.422.6473; http://www.biogeosciences-discuss.net/9/17939/2012/bgd-9-17939-2012-supplement.pdf

We cleaned S. purpuratus test, spine, and newly settled metamorph calcite prior to dissolution for ICP-OES analysis in order to remove Mg and Sr associated with non-skeletally bound organic matter. Perioxide (H2O2) based methods have been utilized for cleaning live foraminiferal calcite and surface coral aragonite for to Mg/Ca and Sr/Ca analysis, respectively (e.g. Pak et al., 2004; Shen and Boyle, 1988). Prior to adopting the H2O2 method for preparing our samples, however, we compared several methods for chemically cleaning S. purpuratus test calcite powders (similar to the methods tested by Pak et al., 2004 for cleaning live planktonic foraminifera). Because our cultured urchin metamorph samples had been heated in a muffle furnace for ash free dry weight analysis prior to elemental analysis (Sanford et al., in prep), we also tested whether this heating affected S. purpuratus calcite Mg/Ca and Sr/Ca. Cleaning Treatments following Pak et al., 2004: Several calcium carbonate plates from an adult sea urchin test collected from Bodega Marine Reserve were homogenized to a coarse powder with an acid-cleaned ceramic mortar and pestle. Approximately 100 mg of homogenized calcite powder was transferred to two aluminum weigh boats and heated in a muffle furnace for 4 hours at 500°C. The remainder of the homogenized