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| Stott, Lowell D; Shao, Jun; Yu, Jimin; Harazin, Kathleen M. |
| The prevailing hypothesis to explain pCO2 rise at the last glacial termination calls upon enhanced ventilation of excess respired carbon that accumulated in the deep sea during the glacial. Recent studies argue lower [O2] in the glacial ocean is indicative of increased carbon respiration. The magnitude of [O2] depletion was 100–140 µ mol/kg at the glacial maximum. Because respiration is coupled to δ13C of dissolved inorganic carbon (DIC), [O2] depletion of 100–140 µ mol/kg from carbon respiration would lower deep water δ13CDIC by ∼1‰ relative to surface water. Prolonged sequestration of respired carbon would also lower the amount of 14C in the deep sea. We show that Pacific Deep Water δ13CDIC did not decrease relative to the surface ocean and Δ14C was only... |
| Tipo: Text |
Palavras-chave: Carbon isotope proxies; Carbon respiration hypothesis; Deep water ventilation; Glacial pCO2. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79437/82043.pdf |
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| Chen, Pujiao; Yu, Jimin; Jin, Zhangdong. |
| The deep ocean is thought to have played a crucial role in modulating atmospheric CO2 changes, and thus reconstructions of deep ocean conditions can place important constraints on the past global carbon cycle. Some previous studies suggested that foraminiferal U/Ca could be used to infer seawater carbonate chemistry changes, but others showed complications from diagenesis and temperature. A recent downcore study suggested that foraminiferal U/Mn may be used for sedimentary redoxconditions, but no core-top work has been done to investigate factors affecting U/Mn. We investigate controlling factors on U/Ca and U/Mn in two benthic foraminiferal species from 120 global core-tops and three Atlantic sediment cores. Our core-top data reveal no significant... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53185/55029.pdf |
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