Oil biodegradation and marine oil snow formation in Arctic seawater microcosms at 4 °C
- 1University of Manitoba
Abstract
Hudson Bay is a sub-Arctic inland sea characterized by seasonal sea-ice cover, which governs marine circulation, biological productivity, and ecosystem structure. In recent decades, the duration of sea-ice cover has declined, resulting in longer ice-free seasons that are expected to elevate marine activity and environmental exposure to anthropogenic disturbances. As such, the potential for oil spill incidents associated with increased marine operations is expected to rise. To understand microbial biodegradation dynamics associated with marine oil snow (MOS), seawater microcosms amended with diesel fuel were incubated at 4 {degrees}C for 6 weeks. We amended all our microcosms with UV-weathered Churchill diesel fuel at 1% (v/v). 16S rRNA sequencing of the incubations revealed a decline in overall microbial diversity and a dramatic increase in specialized oil-degrading taxa, with Pseudomonas and Pseudoalteromonas being the main taxa involved, as both effectively degrade hydrocarbons under ambient and stimulated conditions. Biostimulation with nutrients (NaNO3, KH2PO4) and an alternative dispersant at 0.1% (v/v) resulted in a greater abundance of MOS aggregates and rapid enrichment of oil-degraders. Simple n-alkanes exhibited the highest biodegradation loss relative to complex polycyclic aromatic hydrocarbons (PAHs); however, biostimulation did not substantially enhance their degradation. Additionally, UV weathering resulted in a 22% loss of PAHs, which is three times higher than the UV loss observed for n-alkanes. Biostimulated samples exhibited an elevated transfer of high molecular weight alkanes and PAHs from the oil into the aqueous phase, accompanied by a rapid enrichment of oil-degrading taxa.
Related
- Marine oil snow formation in microcosm incubations of artificial seawater at 4 °C
- Marine Group II Archaea: A Review with a Focus on the Arctic Ocean
- Walrus population-specific marine reservoir offsets (ΔR) for calibration of radiocarbon dates: Implications for Arctic chronologies and medieval trade.
- Metagenome-assembled genomes reveal water-mass-associated distribution ecotypes of marine Archaea in the Western Arctic Ocean
- A remarkable sample of bird teeth from the palaeo-Arctic Prince Creek Formation of northern Alaska elucidates Late Cretaceous avialan richness
BibTeX
@misc{vidanage2026biodegradation,
title = {{Oil biodegradation and marine oil snow formation in Arctic seawater microcosms at 4 °C}},
author = {T. Vidanage and D. Desmond and D. Isleifson and G. Stern and R. E. Collins},
howpublished = {bioRxiv},
year = {2026},
month = nov,
doi = {10.64898/2026.11.02.763557},
url = {https://www.biorxiv.org/content/10.64898/2026.11.02.763557v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Oil biodegradation and marine oil snow formation in Arctic seawater microcosms at 4 °C
AU - T. Vidanage
AU - D. Desmond
AU - D. Isleifson
AU - G. Stern
AU - R. E. Collins
PY - 2026
DA - 2026/11/02
PB - bioRxiv
DO - 10.64898/2026.11.02.763557
UR - https://www.biorxiv.org/content/10.64898/2026.11.02.763557v1
AB - Hudson Bay is a sub-Arctic inland sea characterized by seasonal sea-ice cover, which governs marine circulation, biological productivity, and ecosystem structure. In recent decades, the duration of sea-ice cover has declined, resulting in longer ice-free seasons that are expected to elevate marine activity and environmental exposure to anthropogenic disturbances. As such, the potential for oil spill incidents associated with increased marine operations is expected to rise. To understand microbial biodegradation dynamics associated with marine oil snow (MOS), seawater microcosms amended with diesel fuel were incubated at 4 {degrees}C for 6 weeks. We amended all our microcosms with UV-weathered Churchill diesel fuel at 1% (v/v). 16S rRNA sequencing of the incubations revealed a decline in overall microbial diversity and a dramatic increase in specialized oil-degrading taxa, with Pseudomonas and Pseudoalteromonas being the main taxa involved, as both effectively degrade hydrocarbons under ambient and stimulated conditions. Biostimulation with nutrients (NaNO3, KH2PO4) and an alternative dispersant at 0.1% (v/v) resulted in a greater abundance of MOS aggregates and rapid enrichment of oil-degraders. Simple n-alkanes exhibited the highest biodegradation loss relative to complex polycyclic aromatic hydrocarbons (PAHs); however, biostimulation did not substantially enhance their degradation. Additionally, UV weathering resulted in a 22% loss of PAHs, which is three times higher than the UV loss observed for n-alkanes. Biostimulated samples exhibited an elevated transfer of high molecular weight alkanes and PAHs from the oil into the aqueous phase, accompanied by a rapid enrichment of oil-degrading taxa.
ER -