Reconciling down core anticorrelation of diatom carbon and nitrogen isotopic ratios from the Southern Ocean - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Paleoceanography Année : 2002

Reconciling down core anticorrelation of diatom carbon and nitrogen isotopic ratios from the Southern Ocean

Résumé

Oceanic nutrient cycling in the Southern Ocean is supposed to have an important impact on glacial-interglacial atmospheric CO 2 changes and global climate. In order to characterize such nutrient cycling over the last two climatic cycles we investigated carbon and nitrogen isotopic ratios of diatom-bound organic matter (d 13 C diat and d 15 N diat , respectively) in two cores retrieved form the Atlantic and Indian sectors of the Antarctic Ocean. The two cores show the same isotopic patterns. The d 13 C diat values are depleted during glacial periods and enriched during interglacial periods, indicating lower productivity during cold times. The d 15 N diat values are enriched during glacial periods and depleted during interglacial periods, arguing for greater nitrate utilization during cold times. Taken at face value, this apparent contradiction leads to opposite conclusions on the role of the Southern Ocean biological pump on the atmospheric CO 2 changes. However, the two sets of data can be reconciled by a ''sea ice plus mixing rate scenario'' that calls upon a balance between the effect of cutting off gas transfer at the ocean-atmosphere boundary and the effect of reducing vertical transport of nutrients through the pycnocline.
Fichier principal
Vignette du fichier
Crosta_Paleocean2002.pdf (180.65 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-02105706 , version 1 (21-04-2019)

Identifiants

Citer

Xavier Crosta, A. Shemesh. Reconciling down core anticorrelation of diatom carbon and nitrogen isotopic ratios from the Southern Ocean. Paleoceanography, 2002, 17 (1), pp.10-1-10-8. ⟨10.1029/2000PA000565⟩. ⟨hal-02105706⟩

Collections

INSU EPHE CNRS PSL
13 Consultations
104 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More