Export production fluctuations in the eastern equatorial Pacific during the Pliocene-Pleistocene: Reconstruction using barite accumulation rates

Export production is an important component of the carbon cycle, modulating the climate system by transferring CO2 from the atmosphere to the deep ocean via the biological pump. Here we use barite accumulation rates to reconstruct export production in the eastern equatorial Pacific over the past 4.3...

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Bibliographic Details
Published in:Paleoceanography
Main Authors: Ma, Zhongwu, Ravelo, Ana Christina, Liu, Zhonghui, Zhou, Liping, Paytan, Adina
Other Authors: Paytan, A (reprint author), Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA., Peking Univ, Dept Geog, Lab Earth Surface Proc, Beijing 100871, Peoples R China., Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA., Univ Hong Kong, Dept Earth Sci, Hong Kong, Hong Kong, Peoples R China., Peking Univ, Ocean Res Inst, Beijing 100871, Peoples R China.
Format: Journal/Newspaper
Language:English
Published: PALEOCEANOGRAPHY 2015
Subjects:
Online Access:https://hdl.handle.net/20.500.11897/439271
https://doi.org/10.1002/2015PA002860
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Summary:Export production is an important component of the carbon cycle, modulating the climate system by transferring CO2 from the atmosphere to the deep ocean via the biological pump. Here we use barite accumulation rates to reconstruct export production in the eastern equatorial Pacific over the past 4.3 Ma. We find that export production fluctuated considerably on multiple time scales. Export production was on average higher (51 g Cm-2 yr(-1)) during the Pliocene than the Pleistocene (40 g Cm-2 yr(-1)), decreasing between 3 and 1 Ma (from more than 60 to 20 g Cm-2 yr(-1)) followed by an increase over the last million years. These trends likely reflect basin-scale changes in nutrient inventory and ocean circulation. Our record reveals decoupling between export production and temperatures on these long (million years) time scale. On orbital time scales, export production was generally higher during cold periods (glacial maxima) between 4.3 and 1.1 Ma. This could be due to stronger wind stress and higher upwelling rates during glacial periods. A shift in the timing of maximum export production to deglaciations is seen in the last similar to 1.1 million years. Results from this study suggest that, in the eastern equatorial Pacific, mechanisms that affect nutrient supply and/or ecosystem structure and in turn carbon export on orbital time scales differ from those operating on longer time scales and that processes linking export production and climate-modulated oceanic conditions changed about 1.1 million years ago. These observations should be accounted for in climate models to ensure better predictions of future climate change. NSFC [41406053]; Ministry of Education, China [B14001]; NSF CAREER [OCE-0449732] SCI(E) ARTICLE apaytan@ucsc.edu 11 1455-1469 30