A coccolithophore concept for constraining the Cenozoic carbon cycle
An urgent question for future climate, in light of increased burning of fossil fuels, is the temperature sensitivity of the climate system to atmospheric carbon dioxide (pCO>sub>2</sub>). To date, no direct proxy for past levels of pCO<sub>2</sub> exists beyond the reach of t...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2007-06-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/4/323/2007/bg-4-323-2007.pdf |
| Summary: | An urgent question for future climate, in light of increased burning of
fossil fuels, is the temperature sensitivity of the climate system to
atmospheric carbon dioxide (pCO>sub>2</sub>). To date, no direct proxy for past
levels of pCO<sub>2</sub> exists beyond the reach of the polar ice core records.
We propose a new methodology for placing a constraint on pCO<sub>2</sub> over the
Cenozoic based on the physiological plasticity of extant coccolithophores.
Specifically, our premise is that the contrasting calcification
tolerance of various extant
species of coccolithophore to raised pCO<sub>2</sub> reflects an "evolutionary
memory" of past atmospheric composition. The different times of evolution
of certain morphospecies allows an upper constraint of past pCO<sub>2</sub> to be
placed on Cenozoic timeslices. Further, our hypothesis has implications for
the response of marine calcifiers to ocean acidification. Geologically
"ancient" species, which have survived large changes in ocean chemistry,
are likely more resilient to predicted acidification. |
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| ISSN: | 1726-4170 1726-4189 |