The biodegradation was considered as the prime mechanism of crude oil degradation.To validate the efficacy and survival of the crude oil-degrading strain in a bioremediation pro-cess,the enhanced green fluorescent protein gene(egfp)was introduced into Acinetobacter sp.HC8-3S.In this study,an oil-contaminated sediment microcosm was conducted to inves-tigate the temporal dynamics of the physicochemical characterization and microbial com-munity in response to bacterium amendment.The introduced strains were able to survive,flourish and degrade crude oil quickly in the early stage of the bioremediation.However,the high abundance cannot be maintained due to the ammonium(NH4+-N)and phospho-rus(PO43--P)contents decreased rapidly after 15 days of remediation.The sediment micro-bial community changed considerably and reached relatively stable after nutrient depletion.Therefore,the addition of crude oil and degrading cells did not show a long-time impact on the original microbial communities,and sufficient nitrogen and phosphorus nutrients en-sures the survive and activity of degrader.Our studies expand the understanding of the crude oil degradative processes,which will help to develop more rational bioremediation strategies.