![Evidence for changes in large-scale upwelling in the California Current over the past 700 years [abstract]](/search/themes/bootstrap3/images/libros.png)
Evidence for changes in large-scale upwelling in the California Current over the past 700 years [abstract]
EXTRACT (SEE PDF FOR FULL ABSTRACT):Bidecadal radiocarbon measurements on tree rings provide a detailed series of carbon-14 activities at isotopic equilibrium with atmospheric carbon dioxide. ... Most marine environments do not permit development of a comparable series of carbon-14 ages with which to compare the terrestrial tree ring series. However, we have recently begun work on such a series using material from the varved sediments of the Santa Barbara Basin off southern California. ... We now have a nearly continuous record of carbon-14 dates representing the age of the water over the upper 100 meters. ... The ocean reservoir ages show an increase prior to 1450 and a progressive decrease with time after 1450. Although there may be other explanations, we believe this trend is principally the result of changes in large-scale upwelling of water from below 500 meters. These changes were probably also associated with changes in the intensity of the California Current.
| Main Authors: | , |
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| Format: | conference_item biblioteca |
| Language: | English |
| Published: |
1996
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| Subjects: | Earth Sciences, Oceanography, PACLIM, |
| Online Access: | http://hdl.handle.net/1834/31620 |
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| Summary: | EXTRACT (SEE PDF FOR FULL ABSTRACT):Bidecadal radiocarbon measurements on tree rings provide a detailed series of carbon-14 activities at isotopic equilibrium with atmospheric carbon dioxide. ... Most marine environments do not permit development of a comparable series of carbon-14 ages with which to compare the terrestrial tree ring series. However, we have recently begun work on such a series using material from the varved sediments of the Santa Barbara Basin off southern California. ... We now have a nearly continuous record of carbon-14 dates representing the age of the water over the upper 100 meters. ... The ocean reservoir ages show an increase prior to 1450 and a progressive decrease with time after 1450. Although there may be other explanations, we believe this trend is principally the result of changes in large-scale upwelling of water from below 500 meters. These changes were probably also associated with changes in the intensity of the California Current. |
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