Foraminiferal survival after long-term in situ experimentally induced anoxia
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 CellTracker<sup>TM</sup> Green method...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2013-11-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/10/7463/2013/bg-10-7463-2013.pdf |
| Summary: | 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 CellTracker<sup>TM</sup> 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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| ISSN: | 1726-4170 1726-4189 |