Environmental Impact Assessment of Oil Exploration and Ecosystem Disruption in the Iko River Estuary

The Niger Delta's Iko River estuary, chronically impacted by petroleum extraction, represents a critical site for assessing microbial adaptation to hydrocarbon pollution. This study integrated physicochemical, heavy metal, hydrocarbon, and molecular analyses to characterize indigenous microbial consortia and their functional potential. Sediment samples exhibited the highest microbial densities, particularly hydrocarbon-degrading taxa. Environmental conditions were mildly acidic (pH 5.5-6.9), saline (910-4300 ppt), and nutrient-enriched, with elevated levels of Cu, Ni, Pb, Zn, Cr, and V, alongside significant hydrocarbon accumulation (TPH, PAH, BTEX). Functional gene screening detected alkB, ndoB, and nidA in isolates of Rhodococcus, Pseudomonas putida, and Mycobacterium, respectively, indicating active hydrocarbon metabolism. These findings provide novel molecular evidence of adaptive microbial responses in an oil-impacted tropical estuary, highlighting the ecological role of native microbial communities in natural attenuation and their potential application in the bioremediation of petroleum-contaminated environments.