Biodegradation, Photo-oxidation, and Dissolution of Petroleum Compounds in an Arctic Fjord during Summer

Abstract

Increased economic activity in the Arctic may increase the risk of oil spills. Yet, little is known about the degradation of oil spills by solar radiation and the impact of nutrient limitation on oil biodegradation under Arctic conditions. We deployed adsorbents coated with thin oil films for up to 4 months in a fjord in SW Greenland to simulate and investigate in situ biodegradation and photo-oxidation of dispersed oil droplets. Oil compound depletion by dissolution, biodegradation, and photo-oxidation was untangled by gas chromatography–mass spectrometry-based oil fingerprinting. Biodegradation was limited by low nutrient concentrations, reaching 97% removal of nC13–26-alkanes only after 112 days. Sequencing of bacterial DNA showed the slow development of a bacterial biofilm on the oil films predominated by the known oil degrading bacteria Oleispira, Alkanindiges and Cycloclasticus. These taxa could be related to biodegradation of shorter-chain (≤C26) alkanes, longer-chain (≥C16) and branched alkanes, and polycyclic aromatic compounds (PACs), respectively. The combination of biodegradation, dissolution, and photo-oxidation depleted most PACs at substantially faster rates than the biodegradation of alkanes. In Arctic fjords during summer, nutrient limitation may severely delay oil biodegradation, but in the photic zone, photolytic transformation of PACs may play an important role.

Assessment of Hydrocarbon Degradation Potential in Microbial Communities in Arctic Sea Ice

“…However, an implementation of the whole-genome shotgun sequencing of the total DNA progressively contributes to the understanding of microbial diversity and biochemical pathways [16,17]. Several metagenomic studies have shown microorganisms with the potential to degrade crude oil components, such as alkanes and mono-and polyaromatic hydrocarbons, in Arctic seawater [18,19] and revealed oildegradation pathways for specific areas by the genes that encoded the enzymes involved in these pathways [20][21][22].…”

Pre-evaluation of contaminated soil for oil field reactivation in Moloacan, Veracruz, Mexico

“…For example, hydrocarbons can interact with biotic and abiotic factors in the system so their chemical composition can change, especially when exposed to the environment for a long time (Gómez-Mellado et al, 2020). Adams et al (2016) and Vergeynst et al (2019) found that the soil type could influence the response to the pollutant since when evaluating areas with old spills. They observed that forage grasses developed in fine-textured soils; in contrast to soils with coarse texture where grass could not develop.…”

Changes in chemical composition and copepod toxicity during petroleum photooxidation

“…We previously established that the majority (>80%) of oil photo-oxidation by sunlight is caused by visible light (>400nm), 2 in line with other studies that found oil photooxidation using light in the visible range, 60,61 or at reduced UV irradiation (at 5 m depth in seawater or under 50 cm of sea ice). 62,63 Fourth, we conducted the photooxidation experiments in the absence of water, in line with previous laboratory experiments. 64 Since the source of oxygen incorporated into the oil is mainly molecular O2 rather than H2O, 35 the photooxidation mechanism is not expected to be influenced by the absence of water.…”