Seasonal Variation and Nutrient Dynamics in Sediment Physicochemical Characteristics of Douglas Creek, Niger Delta

Abstract

Aims: This study investigated seasonal variations in the physicochemical characteristics of sediments from Douglas Creek, Niger Delta, with emphasis on nutrient dynamics and ecological implications. Study Design: A cross-sectional seasonal study design was employed. Place and Duration of Study: Sediment samples were collected from Douglas Creek in Ibeno Local Government Area, Akwa Ibom State, Nigeria, with sampling points desingtaed as SS1, SS2, and SS3 during both the wet (April–October) and dry (November–March) seasons of 2024. Methodology: Surface sediments (0–10 cm) were collected at georeferenced stations using a Van Veen grab sampler. Samples were air-dried, homogenized, and analyzed for pH, electrical conductivity (EC), redox potential, total organic carbon (TOC), nitrate (NO₃⁻), calcium (Ca), magnesium (Mg), and other ions following standardized methods (APHA, ASTM, EPA). Quality control was maintained with blanks, duplicates, and certified reference materials. Data were subjected to descriptive statistics, t-test, one-way ANOVA, and Pearson’s correlation analysis at a 95% confidence level (P < .05). Results: Stable parameters with no significant seasonal difference (P > .05) included pH, temperature, chloride, phosphate, sulphate, and total petroleum hydrocarbons (TPH). In contrast, TOC, Ca, and Mg were significantly higher during the wet season (0.79 mg/kg, 79.77 mg/kg, and 286.00 mg/kg, respectively), reflecting enhanced organic and mineral inputs from catchment runoff. Nitrate concentrations peaked in the dry season (22.13 mg/kg), indicating nutrient accumulation under low-flow conditions. Correlation analysis showed that sodium strongly influenced EC and pH buffering during the dry season, while mineral influx dominated ionic interactions in the wet season. Conclusion: Seasonal hydrology exerts strong control on sediment nutrient dynamics in Douglas Creek. Wet-season enrichment of organic matter and divalent cations increases microbial oxygen demand and buffering capacity, while dry-season nitrate accumulation poses risks of eutrophication. Sediment-based monitoring provides critical evidence for ecological management in oil-impacted creeks of the Niger Delta.