Publication Date:
2024-02-16
Description:
The Mg/Ca of planktic foraminifera Globigerinoides 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 (2 Sigma), 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 ([CO3**2-]) 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 [CO3**2-] 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 [CO3**2-] is the controlling parameter.
Keywords:
110, M31/3-110.4_MSN1; 414; 601; Arabian Sea; Bay of Bengal; Bermuda; BIGSET; Cape Blanc; Carbonate ion; CB_trap; CBi3; Cenderawasih Bay; Day of study; Event label; Formosa Strait; Globigerinoides ruber white, Magnesium/Calcium ratio; GOC_trap; Guaymas Basin, Gulf of California; HAI; IMAGES VII - WEPAMA; Indian Ocean; JAM-1; JAM-2; JGOFS-IN-2; Latitude of event; Location; Longitude of event; M31/3; M31/3_MSN913; M32/5; M32/5_MSN974; M33/1; M33/1_MSN1007; Marion Dufresne (1995); MD122; MD122-PT10; MD122-PT12; MD122-PT17; MD122-PT18; MD122-PT26; Meteor (1986); MOOR; Mooring; Morphotype; MOZ1_trap; MOZ2; Mozambique Channel; MS-5; MSN; Multiple opening/closing net; NBBT-09; Oceanic Flux Program; off Cap Blanc; off south Java; OFP_trap; pH; POS344/1; Poseidon; Reference/source; Salinity; Sample ID; Sargasso Sea; SCIFF_site; SCS_M1s_trap; SCS_M2_trap; SCS_M3_trap; Sigma; Size fraction; SO119; SO119_MSN1284; Sonne; South China Sea; Sulu Sea; Temperature, water; Towed zooplankton net; Trap; TRAP; Trap, sediment; TRAPS
Type:
Dataset
Format:
text/tab-separated-values, 7480 data points
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