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 <i>Lacinutrix</i>,<i>Halarcobacter</i> and Candidatus <i>Pseudothioglobus</i>. 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.