A strong temperature effect on U/Ca in planktonic foraminiferal carbonates

• Published in: Geochimica et Cosmochimica Acta
• Main Authors: Yu, J., Elderfield, H., Jin, Z., Booth, L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2008
• Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems; Neogloboquadrina pachyderma; North Atlantic
• Online Access: http://eprints.esc.cam.ac.uk/824/; http://eprints.esc.cam.ac.uk/824/1/Yu_Elderfield_Booth_GeoChim_Cosmo_Acta_72_2008.pdf; http://www.sciencedirect.com/science/article/B6V66-4T2S8V1-2/2/9ab52ff2ead2ff33c0fd3510b8d97767; https://doi.org/10.1016/j.gca.2008.07.011

Three planktonic foraminiferal species Globigerina bulloides, Neogloboquadrina pachyderma (d), and Globorotalia inflata collected from core-tops spanning 35° to 65°N in the North Atlantic were used for U/Ca and Mg/Ca and foraminiferal shell weight analyses. Except for U/Ca in G. bulloides calcified under warm conditions (>not, vert, similar13 °C), U/Ca ratios in all three studied species increase with decreasing latitude and show strong positive correlations with Mg/Ca ratios. A dissolution effect on planktonic U/Ca is suggested by decreased shell weight and U/Ca and Mg/Ca ratios for shells from very deep water depth (>4.4 km) along the latitudinal transect. G. bulloides from down core samples in the North Atlantic show low U/Ca ratios during the last glacial and high ratios during the Holocene, similar to the Mg/Ca evolution trend. In general, our data indicate that the U incorporation into planktonic foraminiferal carbonates is strongly influenced by calcification temperature, although U/Ca in G. bulloides may be affected by seawater carbonate ion concentration under warm conditions and/or other factors.