CPD Climate of the Past Discussions CPD 1814-9359 Copernicus GmbH Göttingen, Germany 10.5194/cpd-6-2795-2010 Quantifying sea surface temperature ranges of the Arabian Sea for the past 20 000 years Ganssen G. 1 Peeters F. 1 Metcalfe B. 1 Anand P. 2 Jung S. 3 Kroon D. 3 Brummer G.-J. 4 Section Marine Biogeology, Institute of Earth Sciences, Faculty of Earth- and Life Sciences, VU University Amsterdam, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands Faculty of Science, Open University, Walton Hall, Milton Keynes, MK7 6AA, UK School of Geosciences, University of Edinburgh, Edinburgh, UK Royal NIOZ, Landsdiep 4, 1797 SZ't Horntje, Texel, The Netherlands 21 12 2010 6 6 2795 2814 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.clim-past-discuss.net/6/2795/2010/cpd-6-2795-2010.html The full text article is available as a PDF file from http://www.clim-past-discuss.net/6/2795/2010/cpd-6-2795-2010.pdf

The oxygen isotopic composition of planktonic foraminifera tests is one of the widest used geochemical tools to reconstruct past changes of physical parameters of the upper ocean. It is common practice to analyze multiple individuals from a mono-specific population and assume that the outcome reflects a mean value of the environmental conditions during calcification of the analyzed individuals. Here we present the oxygen isotope composition of individual specimens of the surface dwelling species <i>Globigerinoides ruber</i> and <i>Globigerina bulloides</i> from sediment cores in the Western Arabian Sea off Somalia inferred as indicators of past seasonal ranges in temperature. Combining the &delta;<sup>18</sup>O measurements of individual specimens to obtain temperature ranges with Mg/Ca based mean calcification temperatures allows us to reconstruct temperature extrema. Our results indicate that over the past 20 kyrs the seasonal temperature range has fluctuated from its present value of 16 °C (14 to 30 °C), to 11 °C (15 to 26 °C) during the LGM. The range during the LGM suggests that the maximum temperature was lower, whilst minimum temperature remained approximately constant.

 References Anand, P., Kroon, D., Singh, A. D., and Ganssen, G.: Coupled sea surface temperature-seawater $\delta^18$O reconstructions in the Arabian Sea at the millennial scale for the last 35 ka, Paleoceanography, 23(4), PA4207, doi:10.1029/2007PA001564, 2008. Bé, A. W. H., Hemleben, C., Anderson, O. R., Spindler, M., Hacunda, J., and Tuntivate-Choy, S.: Laboratory and field observations of living planktonic foraminifera, Micropaleontology, 23, 155–179, 1977. Bijma, J., Hemleben, C., and Wellnitz, K.: Lunar-influenced carbonate flux of the planktic foraminifer Globigerinoides sacculifer (Brady) from the central Red Sea, Deep-Sea Res. Pt I, 41(3), 511–530, 1994. Conan, S. M. H. and Brummer, G.-J.: Fluxes of planktic foraminifera in response to monsoonal upwelling on the Somalia Basin margin: Deep-Sea Res. Pt II, 47, 2207–2227, 2000. de Moel, H., Ganssen, G. M., Peeters, F. J. C., Jung, S. J. A., Kroon, D., Brummer, G. J. A., and Zeebe, R. E.: Planktic foraminiferal shell thinning in the Arabian Sea due to anthropogenic ocean acidification?, Biogeosciences, 6, 1917–1925, doi:10.5194/bg-6-1917-2009, 2009. Elderfield, H. and Ganssen, G.: Past temperature and $\delta^18$O of surface ocean waters inferred from foraminiferal Mg/Ca ratios, Nature, 405, 442–444, 2000. Emiliani, C.: Depth habitats of some species of pelagic foraminifera as indicated by oxygen isotope ratios, Am. J. Sci., 252, 149–158, 1954. Emiliani C.: Pleistocene temperatures, J. Geol., 63, 538–579, 1955. Ganssen, G. M., Brummer, G. J. A., Jung, S. J. A., Kroon, D., and Peeters, F. J. C.: The oxygen isotope composition in planktic foraminifera shells as recorder of maximum seasonal SST variation, Geophys. Res. Abstr., 7, 01775, 2005. Hemleben, Ch., Spindler, M., and Anderson, O. R.: Modern Planktonic Foraminifera, Springer Verlag, Berlin, 363~pp., 1989 Hut, G.: Consultants' group meeting on stable isotope reference samples for geochemical and hydrological investigations, Report to the Director General, International Atomic Energy Agency, Vienna, April, 1987. Ivanochko, T. S., Ganeshram, R. S., Brummer, G. J. A., Ganssen, G., Jung, S. J. A., Steven, G., Moreton, S. G., and Dick Kroon, D.:. Variations in tropical convection as an amplifier of global climate change at the millennial scale, Earth Planet. Sc. Lett., 235, 302–314, 2005. Ivanova, E.: Late Quaternary monsoon history and paleoproductivity of the western Arabian Sea, Phd Thesis, Free University, Amsterdam, 172~pp., 1999. Jung, S. J. A., Ivanova, E., Reichart, G. J., Davies, G. R., Ganssen, G., Kroon, D., and van Hinte, J. E.: Centennial-millenial-scale monsoon variations off Somalia over the last 35 ka, in: The tectonic and climatic evolution of the Arabian Sea region, edited by: Clift, P., Kroon, D., Gaedicke, C., and Craig, J., The Geological Society London, London, 341–352, 2002. Killingley, J. S., Johnson, R. F., and Berger, W. H.: Oxygen and carbon isotopes of individual shells of planktonic foraminifera from Ontong-Java Plateau, Equatorial Pacific. Palaeogeogr. Palaeoclim. Palaeoecol., 33, 193–204, 1981. Kim, S.-T. and O'Neil, J. R.: Equilibrium and nonequilibrium oxygen isotope effects in synthetic carbonates, Geochim. Cosmochim. Acta, 61, 3461–3475, 1997. Koutavas, A., deMenocal, P. B., Olive Col, G. C., and Lynch-Stieglitz, J.: Mid-Holocene El Nino–Southern Oscillation~(ENSO) attenuation revealed by individual foraminifera in eastern tropical Pacific sediments, Geology, 34, 993–996, doi:10.1130/G22810A, 2006. Kroon, D. and Ganssen, G.: Northern Indian Ocean upwelling cells and the stable isotope composition of living planktonic foraminifers, Deep Sea Res., 36, 1219–1236, 1989. Lea, D. W., Mashiotta, T. A., and Spero, H. J.: Controls on magnesium and strontium uptake in planktonic foraminifera determined by live culturing, Geochim. Cosmochim. Acta, 63, 2369–2379, doi:10.1016/S0016-7037(99)00197-0, 1999. Leduc, G., Vidal, L., Cartapanis, O., and Bard, E.: Modes of eastern equatorial Pacific thermocline variability: Implications for ENSO dynamics over the last glacial period, Paleoceanography, 24, PA3202, doi:10.1029/2008PA001701, 2009. Loncaric, N., Brummer, G.-J. A., and Kroon, D.: Lunar cycles and seasonal variations in deposition fluxes of planktic foraminiferal shell carbonate to the deep South Atlantic. Deep-Sea Res. Pt I, 52, 1175–1186, 2005. Nürnberg, D., Bijma, J., and Hemleben, C.: Assessing the reliability of magnesium in foraminiferal calcite as a proxy for water mass temperatures, Geochim. Cosmochim. Acta, 60, 803–814, doi:10.1016/0016-7037(95)00446-7, 1996. Oba, T.: Paleoceanographic information obtained by the isotopic measurement of individual foraminiferal specimens, Proceedings First Internationla Conference Asian Marine Geology, Shanghai, 1988, China Ocean Press, Beijing, 169–180, 1990. Oba, T.: Oxygen and carbon isotopic composition of of planktonic foraminifera tests collected with sediment traps from the Japan Trench, La mer – Societe franco-japonaise d'oceanographie, 29, 190–192, 1991. Peeters, F. J. C. and Brummer, G.-J. A: The seasonal distribution of living planktic foraminfera in the NW Arabian Sea, in: The tectonic and climatic evolution of the Arabian Sea region, Vol 195, edited by: Clift, P., Kroon, D., Gaedicke, C., and Craig, J., The Geological Society London, London, 463–497, 2002. Peeters, F. J. C., Brummer, G.-J. A., and Ganssen, G. M.: The effect of upwelling on the distribution and stable isotope composition of \textitGlobigerina bulloides and \textitGlobigerinoides ruber (planktic foraminifera) in modern surface waters of the NW~Arabian Sea, Global Planet. Change, 34, 269–291, 2002. Prahl, F. G. and Wakeham, S. G.: Calibration of unsaturation patterns in long-chain ketone compositions for paleotemperature assessment, Nature, 330, 367–369, doi:10.1038/330367a0, 1987. Schouten, S., Hopmans, E. C., and Sinninghe Damste, J. S.: Distributional variations in marine crenarchaeotal membrane lipids: A new organic proxy for reconstructing ancient sea water temperatures?, Earth Planet. Sc. Lett., 204, 265–274, doi:10.1016/S0012-821X(02)00979-2, 2002. Spero, H. J. and Williams, D. F.: Evidence for low salinity surface waters in the Gulf of Mexico over the last 16,000~years, Paleoceanography, 5, 963–975, 1990 Stott, L. D. and Tang, C. M.: Reassessment of Tropical sea surface $\delta^18$O paleotemperatures, Paleoceanography, 11, 37–56, 1996. Stuiver, M., Reimer, P. J., and Braziunas, T. F.: High-precision radiocarbon age calibration for terrestrial and marine samples, Radiocarbon, 40, 1127–1151, 1998. Swallow, J. C. and Bruce, J. G.: Current measurements off the Somali coast during the southwest monsoon of 1964, Deep-Sea Res., 13, 861–888, 1966. Tang, C. M. and Stott, L. D.: Seasonal salinity changes during Mediterranean sapropel deposition 9,000~years~B.P.: Evidence from isotopic analyses of individual planktonic foraminifera, Paleoceanography, 8, 473–494, 1993. Waelbroeck, C., Mulitza, S., Spero, H. J., Dokken, T., Kiefer, T., and Cortijo, E.: A global compilation of late Holocene planktonic $\delta^18$O: relationship between surface water and $\delta^18$O, Quaternary Sci. Rev., 24, 853–868, 2005. Wang, P., Clemens, S., Beaufort, L., Braconnot, P., Ganssen, G., Jian, Z., Kershaw, P., and Sarnthein, M.: Evolution and variability of the Asian monsoon system : State of the art and outstanding issues, Quaternary Sci. Rev., 24, 595–629, 2005. Wit, J. C., Reichart, G.-J., Jung, S. J. A., and Kroon, D.: Approaches to unravel seasonality in sea surface temperatures using paired single-specimen foraminiferal $\delta^18$O and Mg/Ca analyses, Paleoceanography, 25, PA4220, doi:10.1029/2009PA001857, 2010.