Global sediment trap calibration of Mg/Ca in G. ruber white, with associated temperature, salinity and carbonate system data Gray, W.R.; Weldeab, S.; Lea, D.W.; Rosenthal, Y.; Gruber, N.; Donner, B.; Fischer, G. Gray, W.R. Weldeab, S. Lea, D.W. Rosenthal, Y. Gruber, N. Donner, B. Fischer, G. earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,morphotype of G. ruber analysed; m = mixed; ss = sensustricto; sl = sensu lato) earth science/paleoclimate/instrumental (sea surface temperature,null,one standard deviation,degree Celsius,null,instrumental,null,null,N,Climatological temperature (0-50m depth) associated with each trap/tow sample; WOA13 extrapolation - see Gray et al. 2018 for details) earth science/paleoclimate/instrumental (pH,sea water,one standard deviation,dimensionless,null,instrumental,null,null,N,pH (0-50m depth) associated with each trap/tow sample; seawater scale; see Gray et al. 2018) earth science/paleoclimate/instrumental|paleoceanography (collection date,null,null,day of year,null,instrumental|paleoceanography,null,null,N,end date represented by trap sample cup or plankton tow) earth science/paleoclimate/paleoceanography (diameter,Globigerinoides ruber white,null,micrometer,null,paleoceanography,null,null,N,minimum test size) earth science/paleoclimate/instrumental|paleoceanography (sample identification,null,null,null,null,instrumental|paleoceanography,null,null,C,ID used in original publication) earth science/paleoclimate/paleoceanography (magnesium/calcium,Globigerinoides ruber white,null,millimole per mole,null,paleoceanography,null,inductively-coupled plasma atomic emission spectroscopy,N,all data are oxidatively cleaned and measured by solution ICP-MS/OES (see original publication - indicated by the 'trap_ref' variable - for details); the data of Huang et al.) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,descriptive location of sediment trap/plankton tow) earth science/paleoclimate/instrumental (salinity,sea water,null,practical salinity unit,null,instrumental,null,null,N,Climatological salinity (0-50m depth) associated with each trap/tow sample; WOA13 extrapolation - see Gray et al. 2018 for details) earth science/paleoclimate/instrumental (carbonate ion,sea water,one standard deviation,micromole per kilogram,null,instrumental,null,null,N,carbonate ion concentration (0-50m depth) associated with each trap/tow sample; see Gray et al. 2018) earth science/paleoclimate/instrumental|paleoceanography (longitude,null,null,degree east,null,instrumental|paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (diameter,Globigerinoides ruber white,null,micrometer,null,paleoceanography,null,null,N,maximum test size) earth science/paleoclimate/instrumental (carbonate ion,sea water,null,micromole per kilogram,null,instrumental,null,null,N,carbonate ion concentration (0-50m depth) associated with each trap/tow sample; see Gray et al. 2018) earth science/paleoclimate/instrumental (sea surface temperature,null,null,degree Celsius,null,instrumental,null,null,N,Climatological temperature (0-50m depth) associated with each trap/tow sample; WOA13 extrapolation - see Gray et al. 2018 for details) earth science/paleoclimate/instrumental|paleoceanography (latitude,null,null,degree north,null,instrumental|paleoceanography,null,null,N,null) earth science/paleoclimate/instrumental|paleoceanography (collection date,null,null,day of year,null,instrumental|paleoceanography,null,null,N,start date represented by trap sample cup or plankton tow) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,reference for Mg/Ca data) earth science/paleoclimate/instrumental (salinity,sea water,one standard deviation,practical salinity unit,null,instrumental,null,null,N,Climatological salinity (0-50m depth) associated with each trap/tow sample; WOA13 extrapolation - see Gray et al. 2018 for details) earth science/paleoclimate/instrumental (pH,sea water,null,dimensionless,null,instrumental,null,null,N,pH (0-50m depth) associated with each trap/tow sample; seawater scale; see Gray et al. 2018) earth science/paleoclimate/paleocean (Atlantic, Pacific and Indian Tropical and Subtropical Ocean>LATITUDE >LONGITUDE ) The Mg/Ca of planktic foraminifera Globeriginoides ruber (white) is a widely applied proxy for tropical and sub-tropical sea-surface temperature. The accuracy with which temperature can be reconstructed depends on how accurately relationships between Mg/Ca and temperature and the multiple secondary controls on Mg/Ca are known; however, these relationships remain poorly quantified under oceanic conditions. Here, we present new calibrations based on 440 sediment trap/plankton tow samples from the Atlantic, Pacific and Indian Oceans, including 130 new samples from the Bay of Bengal/Arabian Sea and the tropical Atlantic Ocean. Our results indicate temperature, salinity and the carbonate system all significantly influence Mg/Ca in G. ruber (white). We propose two calibration models: The first model assumes pH is the controlling carbonate system parameter. In this model, Mg/Ca has a temperature sensitivity of 6.0±0.8 %/°C (2s), a salinity sensitivity of 3.3±2.2 %/PSU and a pH sensitivity of -8.3±7.7 %/0.1 pH units; The second model assumes carbonate ion concentration ([CO32-]) is the controlling carbonate system parameter. In this model, Mg/Ca has a temperature sensitivity of 6.7±0.8 %/°C, a salinity sensitivity of 5.0±3.0 %/PSU and a [CO32-] sensitivity of -0.24±0.11 %/µmol kg-1. In both models, the temperature sensitivity is significantly lower than the widely-applied sensitivity of 9.0±0.6 %/°C. Application of our new calibrations to down-core data from the Last Glacial Maximum, considering whole ocean changes in salinity and carbonate chemistry, indicate a cooling of 2.4±1.6 °C in the tropical oceans if pH is the controlling parameter and 1.5±1.4 °C if [CO32-] is the controlling parameter. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Gray, W.R. Investigator : Weldeab, S. Investigator : Lea, D.W. Investigator : Rosenthal, Y. Investigator : Gruber, N. Investigator : Donner, B. Investigator : Fischer, G. 2017-11-16 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/23110 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gray2018/gray2018-mgca.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gray2018/gray2018-mgca.txt English https://www.ncdc.noaa.gov/paleo/study/23110 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/gray2018/gray2018-mgca.txt Gray, W.R., S. Weldeab, D.W. Lea, Y. Rosenthal, N. Gruber, B. Donner, and G. Fischer2018The effects of temperature, salinity, and the carbonate system on Mg/Ca in Globigerinoides ruber (white): a global sediment trap calibrationEarth and Planetary Science Letters482607-62010.1016/j.epsl.2017.11.026 START YEAR: 1978 AD * END YEAR: 2006 AD -111.7 -16.2 134.3 32.1