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Helena Filipsson, foto Erik Thor

Helena Filipsson

Professor

Helena Filipsson, foto Erik Thor

Experimental evidence for foraminiferal calcification under anoxia

Författare

  • M. P. Nardelli
  • C. Barras
  • E. Metzger
  • A. Mouret
  • Helena Filipsson
  • F. Jorissen
  • E. Geslin

Summary, in English

Benthic foraminiferal tests are widely used for paleoceanographic reconstructions from a range of different environments with varying dissolved oxygen concentrations in the bottom water. There is ample evidence that foraminifera can live in anoxic sediments. For some species, this is explained by a switch to facultative anaerobic metabolism (i.e. denitrification). Here we show for the first time that adult specimens of three benthic foraminiferal species are not only able to survive, but are also able to calcify under anoxic conditions, at various depths in the sediment, and with or without nitrates. In fact, several specimens of Ammonia tepida (1-4 %), Bulimina marginata (8-24 %) and Cassidulina laevigata (16-23 %) were able to calcify at different redox fronts of sediment cores, under laboratory conditions. This demonstrates ongoing metabolic processes, even in microenvironments where denitrification is not possible. Earlier observations suggest that the disappearance of foraminiferal communities after prolonged anoxia is not due to instantaneous or strongly increased adult mortality. Here we show that it cannot be explained by an inhibition of growth through chamber addition either. Our observations of ongoing calcification under anoxic conditions mean that geochemical proxy data obtained from benthic foraminifera in settings experiencing intermittent anoxia have to be reconsidered. The analysis of whole single specimens or of their successive chambers may provide essential information about short-term environmental variability and/or the causes of anoxia.

Avdelning/ar

  • Kvartärgeologi

Publiceringsår

2014

Språk

Engelska

Sidor

4029-4038

Publikation/Tidskrift/Serie

Biogeosciences

Volym

11

Issue

14

Dokumenttyp

Artikel i tidskrift

Förlag

Copernicus Publications

Ämne

  • Geology

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 1726-4189