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Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica ArchiMer
Rosenthal, Yair; Morley, Audrey; Barras, Christine; Katz, Miriam E.; Jorissen, Frans; Reichart, Gert-jan; Oppo, Delia W.; Linsley, Braddock K..
Core top samples from Indonesian and northeast Atlantic depth transects were used to calibrate Mg/Ca and delta O-18 in tests of the calcitic benthic foraminifer Hyalinea balthica to bottom water temperature between 4 degrees C and 13 degrees C. This shallow infaunal species is primarily abundant in neritic to upper bathyal sediments (< 600 m). Both linear and exponential calibrations suggest a temperature sensitivity of similar to 12% per degrees C that is similar to 4 times higher than observed in other species of deep-sea benthic foraminifera. Culture experiments support the core top calibration. We find no discernible effect of salinity and saturation on Mg/Ca. Comparison between the measured benthic foraminiferal delta O-18 and predicted equilibrium...
Tipo: Text Palavras-chave: Mg/Ca; Benthic foraminifera; Temperature calibration; Isotope.
Ano: 2011 URL: https://archimer.ifremer.fr/doc/00215/32579/33686.pdf
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Deglacial delta δ18 and hydrologic variability in the tropical Pacific and Indian Oceans ArchiMer
Gibbons, Fern T.; Oppo, Delia W.; Mohtadi, Mahyar; Rosenthal, Yair; Cheng, Jun; Liu, Zhengyu; Linsley, Braddock K..
Evidence from geologic archives suggests that there were large changes in the tropical hydrologic cycle associated with the two prominent northern hemisphere deglacial cooling events, Heinrich Stadial 1 (HS1; similar to 19 to 15 kyr BP; kyr BP = 1000 yr before present) and the Younger Dryas (similar to 12.9 to 11.7 kyr BP). These hydrologic shifts have been alternatively attributed to high and low latitude origin. Here, we present a new record of hydrologic variability based on planktic foraminifera-derived delta O-18 of seawater (delta O-18(sw)) estimates from a sediment core from the tropical Eastern Indian Ocean, and using 12 additional delta O-18(sw) records, construct a single record of the dominant mode of tropical Eastern Equatorial Pacific and...
Tipo: Text Palavras-chave: Indo-Pacific; Eastern Equatorial Pacific; Delta O-18 of seawater; Deglaciation; Heat transport.
Ano: 2014 URL: https://archimer.ifremer.fr/doc/00496/60737/65207.pdf
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The Suess effect in Fiji coral delta C-13 and its potential as a tracer of anthropogenlc CO2 uptake ArchiMer
Dassie, Emilie P.; Lemley, Gavin M.; Linsley, Braddock K..
In the context of increasing anthropogenic CO2 emissions, determining the rate of oceanic CO2 uptake is of high interest. Centennial-scale changes in delta C-13 of the surface water dissolved inorganic carbon (DIC) reservoir have been shown to be influenced by the carbon isotopic composition of atmospheric CO2. However, the availability of direct oceanic delta C-13 measurements is limited and methods for reconstructing past delta C-13 variability of the oceanic DIC are needed. Geochemical reconstructions of DIC variability can help in understanding how the ocean has reacted to historical changes in the carbon cycle. This study explores the potential of using temporal variations in delta C-13 measured in five Fijian Porites corals for reconstructing oceanic...
Tipo: Text Palavras-chave: Coral; Carbon isotope; CO2; Suess effect; Dissolved inorganic carbon; Fiji; Water depth; Skeletal extension rate.
Ano: 2013 URL: https://archimer.ifremer.fr/doc/00138/24954/23046.pdf
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Intensification of the meridional temperature gradient in the Great Barrier Reef following the Last Glacial Maximum ArchiMer
Felis, Thomas; Mcgregor, Helen V.; Linsley, Braddock K.; Tudhope, Alexander W.; Gagan, Michael K.; Suzuki, Atsushi; Inoue, Mayuri; Thomas, Alexander L.; Esat, Tezer M.; Thompson, William G.; Tiwari, Manish; Potts, Donald C.; Mudelsee, Manfred; Yokoyama, Yusuke; Webster, Jody M..
Tropical south-western Pacific temperatures are of vital importance to the Great Barrier Reef (GBR), but the role of sea surface temperatures (SSTs) in the growth of the GBR since the Last Glacial Maximum remains largely unknown. Here we present records of Sr/Ca and delta O-18 for Last Glacial Maximum and deglacial corals that show a considerably steeper meridional SST gradient than the present day in the central GBR. We find a 1-2 degrees C larger temperature decrease between 17 degrees and 20 degrees S about 20,000 to 13,000 years ago. The result is best explained by the northward expansion of cooler subtropical waters due to a weakening of the South Pacific gyre and East Australian Current. Our findings indicate that the GBR experienced substantial...
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Ano: 2014 URL: https://archimer.ifremer.fr/doc/00290/40136/39239.pdf
Registros recuperados: 4
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