Sunday B. Akinde and Omokaro Obire
The in-situ parameters of water have in the time past been determined by collection of water samples, followed by use of common probes and indirect calculations. This work however, presents the in-situ physic-chemical properties of the deep Atlantic Ocean water column using Conductivity, Temperature, Depth (CTD) profilers and their implications on the Atlantic Ocean’s heterotrophic bacterial distribution. Measurement was done at 1 m depth intervals from surface to bottom (about 2,774 m) in four (4) locations. ASTM, APHA and other international methods were adapted for NO3, PO3, SO4 and CO3. Quantitative analysis of the total heterotrophic bacteria (THB) was conducted using culture-dependent technique. The in-situ physico-chemical parameters are in the range of 7.96 – 8.14 for pH, 3.09 – 29.0 oC for temperature, 32,700 – 54,000 μS/cm for conductivity, 32.3 – 34.9 g/l for salinity and 2.62 – 7.44 mg/l for dissolved oxygen (DO). The nutrient characteristics of seawater provide an insight into the existing health status of the deep sea environment of the Atlantic Ocean with average range of 0.31 – 0.49 mg/I for NO3, 0.97 – 1.91 mg/l for PO3, 2,525 – 2,735 mg/l for SO4 and <1.00 – 32.0 mg/l for CO3. THB count is in the range of 1.91 x 103 – 2.45 x 103 cfu/ml in surface seawater, 1.28 x 103 – 2.19 x 103 cfu/ml in middle seawater and 0.93 x 103 – 1.74 x 103 cfu/ml in bottom seawater. The THB population of the seawater column is in the order surface>middle>bottom. Difference in THB values observed at various depths was significant (p<0.05) but values were consistent across sample stations (p>0.05). Phenotypic characterization based on key morphological and biochemical traits showed that all of the deep seawater isolates showed taxonomic affinities to the genus Pseudomonas.
