Foraminiferal survival after long term experimentally induced anoxia

  • publication
  • 01-06-2013

D. Langlet 1, E. Geslin 1, C. Baal 2, E. Metzger 1, F. Lejzerowicz 3, B. Riedel 4, M. Zuschin 2, J. Pawlowski 3, M. Stachowitsch 4, and F. J. Jorissen 1. Biogeosciences Discuss., 10, 9243-9284, doi:10.5194/bgd-10-9243-2013, 2013.

Anoxia has been successfully induced in four benthic chambers installed on the Northern Adriatic seafloor from 1 week to 10 months. To accurately determine whether benthic foraminifera can survive experimentally induced prolonged anoxia, the CellTrackerGreen method has been applied. Numerous individuals have been found living at all sampling times and at all sampling depths, showing that benthic foraminifera can survive up to 10 months of anoxia with co-occurring hydrogen sulphides. However, foraminiferal standing stocks decrease with sampling time in an irregular way. A large difference in standing stock between two cores samples in initial conditions indicates the presence of a large spatial heterogeneity of the foraminiferal faunas. An unexpected increase in standing stocks after 1 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 a core sampled after 2 months of anoxia, to 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 sulphides, but rather due to a continuous diminution of labile organic matter.

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