Intense photooxidative degradation of planktonic and bacterial lipids in sinking particles collected with sediment traps across the Canadian Beaufort Shelf (Arctic Ocean) - Aix-Marseille Université Access content directly
Journal Articles Biogeosciences Year : 2012

Intense photooxidative degradation of planktonic and bacterial lipids in sinking particles collected with sediment traps across the Canadian Beaufort Shelf (Arctic Ocean)

Abstract

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 (Arc-tic 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 her-bivorous 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 .
Fichier principal
Vignette du fichier
bg-9-4787-2012.pdf (5.97 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive
Loading...

Dates and versions

hal-02051678 , version 1 (16-10-2020)

Licence

Attribution

Identifiers

Cite

J.-F. Rontani, B. Charrière, A. Forest, S. Heussner, F. Vaultier, et al.. Intense photooxidative degradation of planktonic and bacterial lipids in sinking particles collected with sediment traps across the Canadian Beaufort Shelf (Arctic Ocean). Biogeosciences, 2012, 9 (11), pp.4787-4802. ⟨10.5194/bg-9-4787-2012⟩. ⟨hal-02051678⟩
103 View
40 Download

Altmetric

Share

Gmail Facebook X LinkedIn More