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| Titel |
Intense photooxidative degradation of planktonic and bacterial lipids in sinking particles collected with sediment traps across the Canadian Beaufort Shelf (Arctic Ocean) |
| VerfasserIn |
J.-F. Rontani, B. Charrière, A. Forest, S. Heussner, F. Vaultier, M. Petit, N. Delsaut, L. Fortier, R. Sempéré |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 11 ; Nr. 9, no. 11 (2012-11-23), S.4787-4802 |
| Datensatznummer |
250007412
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| Publikation (Nr.) |
 copernicus.org/bg-9-4787-2012.pdf |
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| Zusammenfassung |
| The lipid content of seven samples of sinking particles
collected with sediment traps moored at ~ 100 m depth in
summer and fall across the Canadian Beaufort Shelf (Arctic Ocean) was
investigated. Our main goal was to quantify and characterize the biotic and
abiotic degradation processes that acted on sinking material during these
periods. Diatoms, which dominated the phytoplanktonic assemblage in every
trap sample, appeared to be remarkably sensitive to Type II (i.e. involving
singlet oxygen) photodegradation processes in summer, but seemed to be
relatively unaffected by biotic degradation at the same time. Hence, the
relative recalcitrance of phytodetritus towards biodegradation processes
during the Arctic midnight sun period was attributed to the strong
photodegradation state of heterotrophic bacteria, which likely resulted from
the efficient transfer of singlet oxygen from photodegraded phytoplanktonic
cells to attached bacteria. In addition, the detection in trap samples of
photoproducts specific to wax ester components found in herbivorous copepods
demonstrated that zooplanktonic faecal material exported out of the euphotic
zone in summer were affected by Type II photodegradation processes as well.
By contrast, sinking particles collected during the autumn were not
influenced by any light-driven stress. Further chemical analyses showed that
photodegraded sinking particles contained an important amount of intact
hydroperoxides, which could then induce a strong oxidative stress in
underlying sediments. |
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