The oceanic fixed nitrogen and nitrous oxide budgets: Moving targets as we enter the anthropocene?
DRS at CSIR-National Institute of Oceanography
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Title |
The oceanic fixed nitrogen and nitrous oxide budgets: Moving targets as we enter the anthropocene?
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Creator |
Codispoti, L.A.
Brandes, J.A. Christensen, J.P. Devol, A.H. Naqvi, S.W.A. Paerl, H.W. Yoshinari, T. |
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Subject |
dissolved gases
nitrogen fixation nitrogen budget nitrous oxide denitrification continental shelves dissolved oxygen |
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Description |
New data forced to raise previous estimates of oceanic denitrification. The revised estimate of approx. 450 Tg N yr sup(-1) (Tg = 10 sup(12) g) produces an oceanic fixed N budget with a large deficit (approx. 200 Tg N yr sup(1)) that can be explained only by positing an ocean that has deviated far from a steady-state, the need for a major upwards revision of fixed N inputs, particularly nitrogen fixation, or both. Oceanic denitrification can be significantly altered by small re-distributions of carbon and dissolved oxygen. Since fixed N is a limiting nutrient, uncompensated changes in denitrification affect the ocean's ability to sequester atmospheric CO sub(2) via the "biological pump". Our concepts of the oceanic N sub(2) O regime to take better account of the extremely high N sub(2)O saturations that can arise in productive, low oxygen waters had to be modified. Recent results from the western Indian Shelf during a period when hypoxic, suboxic and anoxic waters were present produced a maximum surface N sub(2)O saturation of greater than 8000%, a likely consequence of "stop and go" denitrification. The sensitivity of N sub(2) O production and consumption to small changes in the oceanic dissolved oxygen distribution and to the "spin-up" phase of denitrification suggests that the oceanic source term for N sub(2)O could change rapidly
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Date |
2009-01-07T10:50:26Z
2009-01-07T10:50:26Z 2001 |
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Type |
Journal Article
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Identifier |
Scientia Marina, Vol.65 (suppl. 2); 85-105p.
http://drs.nio.org/drs/handle/2264/1573 |
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Language |
en
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Rights |
Copyright [2001]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository.
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Publisher |
Institut de Ciencies del Mar de Barcelona
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