Data/hora: 06/06/2024 13:24:34

Provedor de dados: | 5
País: | France
Título: | Glacial-interglacial modulation of the marine nitrogen cycle by high-latitude O-2 supply to the global thermocline
Autores: | Galbraith, Ed; Kienast, M; Pedersen, Tf; Calvert, Se.
Data: | 2004-10
Ano: | 2004
Palavras-chave: | Isotopes; Fixation; Denitrification.
Resumo: | An analysis of sedimentary nitrogen isotope records compiled from widely distributed marine environments emphasizes the global synchrony of denitrification changes and provides evidence for a strong temporal coupling of these variations to changes in nitrogen fixation as previously inferred. We explain the global coherence of these records by a simple physical control on the flux of dissolved oxygen to suboxic zones and the coupling to fixation via the supply of phosphorus to diazotrophs in suitable environments. According to our hypothesis, lower glacial-stage sea surface temperature increased oxygen solubility, while stronger winds in high-latitude regions enhanced the rate of thermocline ventilation. The resultant colder, rapidly flushed thermocline lessened the spatial extent of denitrification and, consequently, N fixation. During warm periods, sluggish circulation of warmer, less oxygen rich thermocline waters caused expansion of denitrification zones and a concomitant increase in N fixation. Local fluctuations in export productivity would have modulated this global signal.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00229/34026/32421.pdf

DOI:10.1029/2003PA001000

https://archimer.ifremer.fr/doc/00229/34026/

Editor: | Amer Geophysical Union
Formato: | application/pdf
Fonte: | Paleoceanography (0883-8305) (Amer Geophysical Union), 2004-10 , Vol. 19 , N. PA4007 , P. 1-12

Fonte:

Copyright 2004 by the American Geophysical Union.

info:eu-repo/semantics/openAccess

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