Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 10, issue 11
Biogeosciences, 10, 7463–7480, 2013
https://doi.org/10.5194/bg-10-7463-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Coastal hypoxia and anoxia: a multi-tiered, holistic...

Biogeosciences, 10, 7463–7480, 2013
https://doi.org/10.5194/bg-10-7463-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 21 Nov 2013

Research article | 21 Nov 2013

Foraminiferal survival after long-term in situ experimentally induced anoxia

D. Langlet1, E. Geslin1, C. Baal2, E. Metzger1, F. Lejzerowicz3, B. Riedel4, M. Zuschin2, J. Pawlowski3, M. Stachowitsch4, and F. J. Jorissen1 D. Langlet et al.
  • 1Université d'Angers, UMR6112 CNRS LPG-BIAF – Bio-Indicateurs Actuels et Fossiles, 2 Boulevard Lavoisier, 49045 Angers Cedex, France
  • 2University of Vienna, Department of Palaeontology, Althanstrasse 14, 1090 Vienna, Austria
  • 3University of Geneva, Department of Genetics and Evolution, CH 1211 Genève 4, Switzerland
  • 4University of Vienna, Department of Limnology and Oceanography, Althanstrasse 14, 1090 Vienna, Austria

Abstract. Anoxia was successfully induced in four benthic chambers installed at 24 m depth on the northern Adriatic seafloor from 9 days to 10 months. To accurately determine whether benthic foraminifera can survive experimentally induced prolonged anoxia, the CellTrackerTM Green method was applied and calcareous and agglutinated foraminifera were analyzed. Numerous individuals were found living at all sampling times and at all sampling depths (to 5 cm), supported by a ribosomal RNA analysis that revealed that certain benthic foraminifera were active after 10 months of anoxia. The results show that benthic foraminifera can survive up to 10 months of anoxia with co-occurring hydrogen sulfides. However, foraminiferal standing stocks decrease with sampling time in an irregular manner. A large difference in standing stock between two cores sampled under initial conditions indicates the presence of a large spatial heterogeneity of the foraminiferal faunas. An unexpected increase in standing stocks after one month is tentatively interpreted as a reaction to increased food availability due to the massive mortality of infaunal macrofaunal organisms. After this, standing stocks decrease again in cores sampled after 2 months of anoxia to then attain a minimum in the cores sampled after 10 months. We speculate that the trend of overall decrease of standing stocks is not due to the adverse effects of anoxia and hydrogen sulfides but rather due to a continuous diminution of labile organic matter.

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