| PALEOCEANOGRAPHY |
Arabian Sea Denitrification Data
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Altabet, M.A., M.J. Higginson, and D.W. Murray. 2002. The effect of millennial-scale changes in Arabian Sea denitrification
on atmospheric CO2. Nature 415:159-162.
| Data Coverage |
North: 18.25 * South: 18 |
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West: 57.58 * East: 57.65 |
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Altitude: -820 m |
Start Year: 63578 14C yr BP
* End Year: 130 14C yr BP
Data: Please Cite Data Contributors!
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Summary: Most global biogeochemical processes are known to respond to climate change, some of which have the capacity to produce feedbacks
through the regulation of atmospheric greenhouse gases. Marine denitrification-the reduction of nitrate to gaseous nitrogen-is
an important process in this regard, affecting greenhouse gas concentrations directly through the incidental production of
nitrous oxide, and indirectly through modification of the marine nitrogen inventory and hence the biological pump for CO2.
Although denitrification has been shown to vary with glacial-interglacial cycles, its response to more rapid climate change
has not yet been well characterized. Here we present nitrogen isotope ratio, nitrogen content and chlorin abundance data from
sediment cores with high accumulation rates on the Oman continental margin that reveal substantial millennial-scale variability
in Arabian Sea denitrification and productivity during the last glacial period. The detailed correspondence of these changes
with Dansgaard-Oeschger events recorded in Greenland ice cores indicates rapid, century-scale reorganization of the Arabian
Sea ecosystem in response to climate excursions, mediated through the intensity of summer monsoonal upwelling. Considering
the several-thousand-year residence time of fixed nitrogen in the ocean, the response of global marine productivity to changes
in denitrification would have occurred at lower frequency and appears to be related to climatic and atmospheric CO2 oscillations
observed in Antarctic ice cores between 20 and 60 kyr ago.
More Info on Paleoceanography Data |
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Parameters: Chlorins (µg/g); radiocarbon years before 1950AD; Nitrogen percent; delta N15
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Complete XML Record: noaa-ocean-2617
(Last Revised: 2008-04-10 )
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| http://www.ncdc.noaa.gov/paleo/ |
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