Control of the preservation of sympagic algal material in surficial sediments of central and eastern Baffin Bay by bactericidal hydroperoxides and free fatty acids

Cellular Damage of Bacteria Attached to Senescent Phytoplankton Cells as a Result of the Transfer of Photochemically Produced Singlet Oxygen: A Review

“…Examination of several particulate matter and sediment samples revealed the presence of varying proportions of 13-hydroperoxyoctadec-11(cis)-enoic acid and 10-hydroperoxyoctadec-11(cis)-enoic acid among the oxidation products of cis-vaccenic acid [ 7 , 14 , 15 , 112 ], which confirms the involvement of autoxidation processes in bacteria attached to particles. A study comparing the oxidation state of cis-vaccenic acid in particulate matter samples and in the underlying surficial sediments collected in Baffin Bay in the Arctic [ 112 ] shows that bacteria attached to sinking particles are mainly photo-oxidized whereas bacteria present in the underlying sediments are strongly autoxidized. These interesting results clearly establish that bacteria associated with sinking algal material are strongly affected by the 1 O 2 photochemically produced in senescent algae during their transfer through the euphotic layer of the water column of the oceans.…”

Singlet oxygen‐induced alteration of bacteria associated with phytodetritus: Effect of irradiance

“…To confirm the enhancement of the efficiency of photooxidation processes on bacteria attached to phytoplankton cells, we analyzed a variety ( n = 58) of sinking particulate matter and sea‐ice samples collected in the Arctic (Figure 1), where irradiance at the sea ice–water interface and in the water column varies strongly according to the albedo of snow and ice and to snow and ice thickness (Lund‐Hansen et al, 2021). Sinking particulate matter samples were collected: (i) in summer at 100 m in open water in the Beaufort Sea (Rontani et al, 2016), (ii) in summer at 25 m in the marginal ice zone of central Baffin Bay (Rontani et al, 2022), and (iii) in spring at 5 and 30 m in ice‐covered Resolute Passage (Rontani et al, 2016). Sea‐ice samples (0–10 cm) were collected in spring during the GreenEdge campaign at Qikiqtarjuaq (Baffin Bay, Arctic Ocean; Amiraux et al, 2020).…”

Gas chromatography–mass spectrometry selected ion monitoring and gas chromatography–tandem mass spectrometry selected reaction monitoring analyses of mono‐, di‐ and tri‐unsaturated C25 highly branched isoprenoid alkene biomarkers in sea ice and sediment samples: A comparative study

“…Accurate mass measurements were made in full‐scan mode using an Agilent 7890B/7200 GC/QTOF system (Agilent Technologies, Courtaboeuf, Les Ulis, France) with a cross‐linked 5% phenylmethylpolysiloxane (Agilent Technologies; HP‐5MS Ultra inert, 30 m × 0.25 mm, 0.25 μm film thickness) capillary column. The operating conditions used have been described previously by Rontani et al 16 …”

“…Gas chromatography-tandem mass spectrometry GC/MS and GC/MS/MS analyses were performed using an Agilent 7890A/7010 tandem quadrupole gas chromatograph system equipped with a high-efficiency source (Agilent Technologies, Courtaboeuf, Les Ulis, France) with a cross-linked 5% phenylmethylpolysiloxane capillary column (Agilent; HP-5MS Ultra Inert, 30 m  0.25 mm, film thickness 0.25 μm). The operating conditions used have been described previously by Rontani et al16 Quantification of HBI alkenes was carried out in SIM and SRM modes. Precursor ions were selected from the more specific ions observed in the individual electron ionization (EI) spectra.…”