Spatio-Temporal Distribution of Phytoplankton and Water Quality of Some Rivers of Haute Sanaga Department (Central Africa)

Abstract

In Cameroon, rivers are subjected to physicochemical disturbances, which increase the degradation of water quality. The aim of this study was to determine the spatio-temporal diversity of the phytoplankton groups and to evaluate the environmental parameters of the sampling sites in order to assess the quality of water in two hydrographic networks. Physicochemicals analyzes were carried out according to the standard methods while phytoplankton organisms were harvested by direct sampling and analyzed by the Utermöhl method. The analysis of Ammonia Nitrogen, Dissolved Oxygen, Electric Conductivity, Nitrates, Orthophosphates, pH, Temperature, and Turbidity.of water revealed the poor state of health of the water. Data from the Long Dry Season differed significantly (p < 0.05) from those recorded in other seasons. The phytoplankton communities were made up of Chlorophyta, Chrysophyta, Cyanophyta, and Euglenophyta with 11 classes dominated by Bacilliarophyceae (12 210 Ind/mL) and Cyanophyceae (6 208 Ind/mL). Phytoplankton densities were higher the Long Rainy Season and much lower in the Small Dry Season than in the Long Dry Season. Station near NODISCAM indicated significant organic pollution under the effect of agro-industrial discharges operating upstream of this company. For this station, the different values showed significant differences (p < 0.05) from one station to another. Finally, spatio-seasonal variations of phytoplankton densities showed logical responses to changes of physicochemical conditions in the environment. This work highlights the need to treat wastewater from collection channels before its dump into the natural environment, to prevent progressive eutrophication of the receiving aquatic environment, and poisoning by water consumption.

Limnological Characteristics, Phytoplankton Assemblage and Environmental Assessment of Hadejia River, North-Western Nigeria: A Comprehensive Survey

“…Microcystis aeruginosa accounted for higher relative abundance in April, June, July, and August (Table 3), possibly due to their high tolerance for increased temperature and availability of adequate nutrients. In addition, due to their competitive nature, they produce cyanotoxins which exerts allelopathic effects on other phytoplankton and eradicate their predators like the zooplankton (Pascale et al, 2022), thus making them abundant, as observed in this study. Microcystis aeruginosa is a primary cause of the hazardous cyanobacterial bloom that is common around the world and affects freshwater systems (Yang & Wang, 2019).…”

Advances in the integration of microalgal communities for biomonitoring of metal pollution in aquatic ecosystems of sub-Saharan Africa

“…In West Africa’s Niger River system, Ezewudo et al ( 2021 ) noted weak to high potential ecological risks to aquatic communities, including microalgae, from As, Cd and Hg contamination. In the Cameroon Centre Region, the spatial-seasonal changes in algal densities in the streams of the Sanaga lotic system network draining urban and industrial settlements corresponded to changes in the aquatic physicochemical environment (Pascale 2023 ). According to Mangadze et al ( 2019a ), several ecological health studies on southern Africa’s rivers have applied benthic diatoms for biomonitoring.…”