Davila Aleman et al 2024 SuppTables EMI

The Arctic Ocean is an oligotrophic ecosystem facing escalating threats of oil spills as ship traffic increases owing to climate change-induced sea ice retreat. Biostimulation is an oil spill mitigation strategy that involves introducing bioavailable nutrients to enhance crude oil biodegradation by endemic oil-degrading microbes. For bioremediation to offer a viable response for future oil spill mitigation in extreme Arctic conditions, a better understanding of the effects of nutrient addition on Arctic marine microorganisms is needed. Controlled experiments tracking microbial populations in revealed a significant decline in community diversity together with changes in microbial community composition. Notably, differential abundance analysis highlighted significant enrichment of unexpected genera Lacinutrix,Halarcobacter and Candidatus Pseudothioglobus. These groups have not been associated with hydrocarbon biodegradation until now, despite closer inspection of genomes from closely related isolates confirming the potential for hydrocarbon metabolism. Co-occurrence analysis further revealed significant associations between these genera and known hydrocarbon-degrading bacteria, suggesting potential synergistic interactions in oil biodegradation. While these findings broaden our understanding of how biostimulation promotes enrichment of endemic hydrocarbon-degrading genera, further research is needed to fully assess the suitability of nutrient addition as a stand-alone oil spill mitigation strategy in this sensitive ecosystem.