Per citar aquest document: http://ddd.uab.cat/record/119108
Seasonal patterns of shell flux, δ18O and δ13C of small and large N. pachyderma (s) and G. bulloides in the subpolar North Atlantic
Jonkers, Lukas (Universitat Autònoma de Bacelona. Institut de Ciència i Tecnologia Ambientals)
Heuven, Steven van (Cardiff University. School of Earth and Ocean Sciences)
Zahn, Rainer (Universitat Autònoma de Bacelona. Institut de Ciència i Tecnologia Ambientals)
Peeters, Frank J.C. (Vrije Universiteit Amsterdam. Faculteit der Aard- en Levenswetenschappen)

Data: 2013
Resum: Past water column stratification can be assessed through comparison of the δ18O of different planktonic foraminiferal species. The underlying assumption is that different species form their shells simultaneously, but at different depths in the water column. We evaluate this assumption using a sediment trap time-series of Neogloboquadrina pachyderma (s) and Globigerina bulloides from the NW North Atlantic. We determined fluxes, δ18O and δ13C of shells from two size fractions to assess size-related effects on shell chemistry and to better constrain the underlying causes of isotopic differences between foraminifera in deep-sea sediments. Our data indicate that in the subpolar North Atlantic differences in the seasonality of the shell flux, and not in depth habitat or test size, determine the interspecies Δδ18O. N. pachyderma (s) preferentially forms from early spring to late summer, whereas the flux of G. bulloides peaks later in the season and is sustained until autumn. Likewise, seasonality influences large and small specimens differently, with large shells settling earlier in the season. The similarity of the seasonal δ18O patterns between the two species indicates that they calcify in an overlapping depth zone close to the surface. However, their δ13C patterns are markedly different (>1‰). Both species have a seasonally variable offset from δ13CDIC that appears to be governed primarily by temperature, with larger offsets associated with higher temperatures. The variable offset from δ13CDIC implies that seasonality of the flux affects the fossil δ13C signal, which has implications for reconstruction of the past oceanic carbon cycle.
Nota: Número d'acord de subvenció EC/FP7/238512
Drets: Tots els drets reservats
Llengua: Anglès
Document: article ; recerca ; publishedVersion
Matèria: Plàncton ; Atlàntic Nord (Regió) ; Planktonic foraminifera ; Foraminífers planctònics ; N. pachyderma ; Neogloboquadrina pachyderma ; G. bulloides ; Globigerina bulloides ; Oxygen isotopes ; Isòtops de l'oxígen ; Carbon isotopes ; Isòtops de carboni ; Seasonality ; Estacionalitat
Publicat a: Paleoceanography, Vol. 28, No. 1 (March 2013) , p. 164-174, ISSN 1944-9186

DOI: 10.1002/palo.20018


11 p, 804.1 KB

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 Registre creat el 2014-07-15, darrera modificació el 2016-07-12



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