ABUNDANCE, DIVERTY AND DEPTH DISTRIBUTION OF BACTERIAL AND FUNGAL POPULATION IN UNIVERSITY OF UYO ARBORETUM

Godwin Umoren Akpan

ABSTRACT

The extent of the diversity of microorganisms in soil are seen to be critical to the maintenance of soil health and quality, as a wide range of microorganisms are involved in important soil functions. The objectives of this study were to investigate the abundance, diversity and depth distribution of bacterial population at University of Uyo Arboretum, and was conducted from 2022 to 2023. The soils were collected at a depth of 0-10cm, 10-20cm and 20-30cm; total of nine (9) samples were collected, samples were divided into two (2) parts, one for soil routine analysis while the other for soil microbial analysis. Aseptic techniques were deployed to handle samples meant for microbial studies. Soil analysis results showed that the percentage sand decreases with depth, while silt and clay increases. The pH was slightly acidic at all sample depths. The electrical conductivity (EC), soil organic carbon (SOC), soil organic matter (SOM), total nitrogen (TN), available phosphorus (AVP), potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) also vary with depth. seventeen (17) microbial species, ten (10) bacteria species (Baccillus ceresus, Baccillus substlilis, Serratia sp, Pseudomonas aeruginosa, Micrococcus sp, Clostridium sp, Dissulfurvibriospp, Staphylococcus albus, Staphylococcus aureus, and Proteus mirabilis) and seven (7) fungi, Aspergillus fumigatus, Aspergillus niger, Candida albicans, Rhizopus stolonife, Clasdosparum spp, Penicillum expansum and Vertiocillium spp) were found in the 9 soil samples investigated. Bacillus cereus was found to be more prevalent in the upper layers of soil (0-10 cm and 10-20 cm) while Bacillus subtilis was found in higher abundance in the deeper layers (10-20 cm and 20-30 cm), Serratia sp. and Pseudomonas aeruginosa were identified but were swarming, meaning they were moving rapidly on the surface of the agar plate, Micrococcus sp. was found in all three soil layers, with the highest abundance in the topmost layer (0-10 cm), Clostridium sp. was found to be more prevalent in the upper two layers of soil (0-10 cm and 10-20 cm) and less so in the deepest layer (20-30 cm), Staphylococcus albus was found only in the topmost layer (0-10 cm) while Staphylococcus aureus was found in the upper and lower layers (0-10 cm and 20-30 cm), Proteus mirabilis was detected but swarming too. Shannon Weiner’s index exhibited that the bacterial and fungal community in the soil diversed and even, with a higher number of species at the surface soil layer. However, there was a decrease in both diversity and evenness with increasing soil depth, indicating a shift in the fungal community composition at deeper soil depths. The microbial population decreases with increase in depth in terms of aerobic organisms but the anaerobes increased with increase in depth.

Keywords: Abundance, Diversity. Bacterial, fungal, Arboretum