Barite accumulation rates throughout Pliocene-Pleistocene in Eastern Equatorial Pacific at ODP Site 138-849, supplement to: Ma, Zhongwu; Ravelo, Ana Christina; Liu, Zhonghui; Zhou, Liping; Paytan, Adina (2015): Export production fluctuations in the eastern Equatorial Pacific during the Pliocene-Pleistocene: Reconstruction using barite accumulation rates. Paleoceanography


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 C/m2/yr) during the Pliocene than the Pleistocene (40 g C/m2/yr), decreasing between 3 and 1 Ma (from more than 60 to 20 g C/m**2/yr) 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 ~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.

Related Identifier
Metadata Access
Creator Ma, Zhongwu; Ravelo, Ana Christina; Liu, Zhonghui; Zhou, Liping; Paytan, Adina
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2015
Rights Creative Commons Attribution 3.0 Unported;
OpenAccess true
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 2899 data points
Discipline Earth System Research
Spatial Coverage (-110.518 LON, 0.183 LAT); North Pacific Ocean
Temporal Coverage Begin 1991-06-12T00:00:00Z
Temporal Coverage End 1991-09-07T00:00:00Z