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| Gray, William R.; Rae, James W. B.; Wills, Robert C. J.; Shevenell, Amelia E.; Taylor, Ben; Burke, Andrea; Foster, Gavin L.; Lear, Caroline H.. |
| The interplay between ocean circulation and biological productivity affects atmospheric CO2 levels and marine oxygen concentrations. During the warming of the last deglaciation, the North Pacific experienced a peak in productivity and widespread hypoxia, with changes in circulation, iron supply and light limitation all proposed as potential drivers. Here we use the boronisotope composition of planktic foraminifera from a sediment core in the western North Pacific to reconstruct pH and dissolved CO2 concentrations from 24,000 to 8,000 years ago. We find that the productivity peak during the Bolling-Allerod warm interval, 14,700 to 12,900 years ago, was associated with a decrease in near-surface pH and an increase in pCO(2), and must therefore have been... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00496/60787/64968.pdf |
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| Burke, Andrea. |
| Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean's role in climate change over the last deglaciation. I present a new method for rapid radiocarbon analyses as a means of age-screening deep-sea corals for further study. Based on age survey results, I selected forty corals from the Drake Passage and thirteen from the Reykjanes Ridge off Iceland and dated them with uranium series isotopes. The uranium series dates give independent ages that allow radiocarbon to be used as a tracer of circulation and carbon cycle changes. The radiocarbon records generated from the Drake Passage corals show increased stratification in the... |
| Tipo: Text |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00493/60455/63900.pdf |
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