Microbiological, Physicochemical and Enzyme Activity Profile of Ayadehe Coastal Wetland Soils, Nigeria

Aims: The present study aimed to determine the microbiological, physicochemical and enzyme activities of Ayadehe Coastal wetland soils in Itu local government area of Akwa Ibom State, Nigeria to ascertain their potentials for effective management.

Study Design: Coastal wetland soils from three depths (0-15 cm, 15-30 cm and 30-45 cm) were assessed in the wet and dry seasons of 2016 and 2017.

Place and Duration of Study: The study was carried out at Ayadehe coastal wetland, Itu, Akwa Ibom state and the soil samples analysed at the Microbiology and Central Research Laboratories, University of Uyo, Uyo, Akwa Ibom state, Nigeria in 2016 and 2017.

Methodology: The isolation, enumeration, characterisation and identification of microbial isolates were carried out using cultural procedures. The physicochemical and enzyme activities of soils were assessed using standard procedures.

Results: Total heterotrophic bacterial and total Fungal counts from 0 – 45 cm soil depths ranged from 5.7 to 7.98 Log₁₀CFU g-1 in the wet and dry seasons. The nitrifying bacteria, phosphate solubilising bacteria and cellulolytic bacteria counts of the soils from 0 - 45 cm depth ranged from 0.0 to 5.6 Log10 CFU g-1which was 1.01 to 1.05 times higher in the wet season than the dry season, and the difference was significant at p = 0.05. The bacteria from the wetland soils included members of the genera Acinetobacter, Alcaligenes, Arthrobacter, Azotobacter, Bacillus, Beijirinckia, Cellulomonas, Flavobacterium, Micrococcus, Nitrobacter, Nitrosomonas, Proteus, Pseudomonas, Rhizobium, Sarcina, Serratia, and Staphylococcus. The fungi belonged to the genera Aspergillus, Cladosporium, Fusarium, Mucor, Penicillium, and Rhizopus. The particle size distribution indicated the soil was sandy clay loam and the pH ranged between 6.0 ± 0 and 6.2 ± 0.01. Enzyme activities of soils also showed variations (p = 0.05) in the wet and dry seasons with strong positive linear correlations between dehydrogenase and microbial densities.

Conclusion: The favourable pH, the presence of diverse enzymes and the rich assemblage of microorganisms to carry out critical ecosystem services indicates the potential to support crop production.