Autecology of microalgae in Nsit Ubium river

Analysis of water such as river and lakes can provide an insight into their composition and potential impact on the environment. Nsit Ubium River is a fresh water body that flows through urban areas in Akwa Ibom state. The locals attached a lot of socio-economic importance to the river, as a result of this a lot of humans generated pollutants find their way into it. Researching on the autecology of microalgae in the river, water and algae sample were collected from the river for the period of four months (October 2021 to January 2022) and analyzed for physiochemical parameters and species diversity using standard procedures. Water samples were collected using 1 litre transparent bottle while microalgae samples were collected by scrapping the attached plants on the river bank into a transparent bottle and preserved with a drop of a mixture of formaldehyde and lugol iodine. pH ranged between (4.1 and 5.8), conductivity between (15 and 153), alkalinity between (5.0 and 5.8), Nitrate between (0.5 and 0.80Mg/L), phosphate between (5.01 and 7.8Mg/L) and dissolve oxygen between (6.27 and 9.22mg/l) were determined. Five divisions of algae comprising of 92 taxa were identified during this study. The division, Bacillariophyta was the most represented division accounting for 80% occurrence and a total of 72 species, this was followed by Chlorophyta with 10%, Euglenophyta (7%), Cyanophyta (2%) which were accounted for 9, 6 and 2 taxa respectively. Dinophyta was the least represented with (1%) and contributed only one taxon. The month of November has the highest number of species with total of 54 taxa while December has the least occurrence (31 taxa). The composition of microalgae in Nsit Ubium River were dominated by diatoms (Bacillariophyta) which are good pollution bio-indicators. The Cyanophyta indicates higher nutrient enrichment which could have been due to runoff from agricultural land or waste water discharge. Therefore, the documented algae in the river could be usedful as a pollutant indicator in assessing pollution status of rivers.