The Mouanko mangrove is subjected to major anthropogenic activities such as agriculture, fishing and deforestation, hence information on Cladocerans and Rotifers amongst other aquatic organisms in order to monitor and...The Mouanko mangrove is subjected to major anthropogenic activities such as agriculture, fishing and deforestation, hence information on Cladocerans and Rotifers amongst other aquatic organisms in order to monitor and manage this ecosystem is vital. The aim of this work is to study the physicochemical parameters of the environment that influence the diversity and spatiotemporal distribution of Cladocerans and Rotifers in the mangrove waters of Mouanko. This study was carried out from November 2019 to October 2020 at 8 sampling stations. Both biological and physico-chemical sampling and analyses were done following standard recommendations. The results of the phyico-chemical analyses revealed that the waters of the Mouanko mangroves were slightly basic (7.64 ± 0.71 UC), moderately oxygenated (69.56% ± 14.29%) with low levels of nutrients [ NO <sup>-</sup>2</sub> (0. 06 ± 0.05 mg/L), NH<sup>+</sup>4</sub> (0.39 ± 0.3 mg/L) and PO<sup>3-</sup>4</sub> (up to 0.12 mg/L)] and high values of electrical conductivity (up to 6531.04 μS/cm), salinity (up to 3.71‰). 15 species of Cladocerans and 30 species of Rotifers were identified accounting for a total abundance of 612 ind/L. The species richness was higher in freshwater influenced zones (40 taxa) compared to marinewater influenced zones (17 taxa). Among these species, the Cladocera, Penilia avirostris was the most abundant in marinewater influenced zones (84 ind/L) while the Rotifer, Keratella tecta was the most abundant in freshwater influenced zones (64 ind/L). Shannon-Weaver’s diversity and Pielou’s equitability indices indicated that freshwater influenced zones host a diverse community with a tendency towards equi-partition of species while marinewater influenced zones revealed the opposite. The low levels of organic pollution indicator variables recorded and the high diversity of the freshwater influenced zones population studied attested to the low level of anthropization in this environment. High salinity and electrical conductivity values influence the distribution of these organisms.展开更多
A study to list Dinoflagellates species belonging to the genera Ceratium and Protoperidinium and some abiotic factors associated with them was carried out in the Kribi coast from February 2020 to February 2021 followi...A study to list Dinoflagellates species belonging to the genera Ceratium and Protoperidinium and some abiotic factors associated with them was carried out in the Kribi coast from February 2020 to February 2021 following a monthly sampling frequency. For the inventory, 60 L of water including 20 L on the surface, 20 L in the trophogen layer and 20 L in the tropholytic layer were filtered through a sieve of 20 μm and the retentate obtained was fixed whith lugol for identification and counting operations using an Olympus microscope. The morphotypes of the taxa were filmed using an Omax Toupvix eye camera. Physico-chemical results showed very good water oxygenation (89.35%), low Suspended Solid concentration (6.36 ± 4.71 mg/L), basic pH (8.53 ± 0.4 U.C), average salinity of 15.87 ± 3.1 g/L and conductivity around 26.73 ± 4.96 mS/cm. The average water temperature hovered around 29.51°C ± 1.28°C. The average values of nitrates and orthophosphates showed a progressive enrichment of the waters of the studied section with nitrate (1.52 ± 0.87 mg/L) and orthophosphate (1.84 ± 3.98 mg/L). This work allowed to identify 17 species of the genera Ceratium and 22 of Protoperidinium. The genera Protoperidinium was the most diverse while it was the taxa belonging to the genera Ceratium that had the highest densities. Ceratium furca was the only spatially and seasonally regular species with occurrence frequencies of 75.31% and 79.16% respectively. According to similar studies, 06 species reconized harmful were inventoried during this study. These are Ceratium furca, Ceratium fusus, Ceratium tripos, Protoperidinium divergens, Protoperidinium steinii, Protoperidinium crassipes. Temperature and oxygen are the abiotic factors that showed more affinities with the taxa inventoried in view of the significant correlations obtained. With a view to preventing blooms on the Cameroonian Atlantic coast, regular monitoring of the harmful species identified is desirable.展开更多
文摘The Mouanko mangrove is subjected to major anthropogenic activities such as agriculture, fishing and deforestation, hence information on Cladocerans and Rotifers amongst other aquatic organisms in order to monitor and manage this ecosystem is vital. The aim of this work is to study the physicochemical parameters of the environment that influence the diversity and spatiotemporal distribution of Cladocerans and Rotifers in the mangrove waters of Mouanko. This study was carried out from November 2019 to October 2020 at 8 sampling stations. Both biological and physico-chemical sampling and analyses were done following standard recommendations. The results of the phyico-chemical analyses revealed that the waters of the Mouanko mangroves were slightly basic (7.64 ± 0.71 UC), moderately oxygenated (69.56% ± 14.29%) with low levels of nutrients [ NO <sup>-</sup>2</sub> (0. 06 ± 0.05 mg/L), NH<sup>+</sup>4</sub> (0.39 ± 0.3 mg/L) and PO<sup>3-</sup>4</sub> (up to 0.12 mg/L)] and high values of electrical conductivity (up to 6531.04 μS/cm), salinity (up to 3.71‰). 15 species of Cladocerans and 30 species of Rotifers were identified accounting for a total abundance of 612 ind/L. The species richness was higher in freshwater influenced zones (40 taxa) compared to marinewater influenced zones (17 taxa). Among these species, the Cladocera, Penilia avirostris was the most abundant in marinewater influenced zones (84 ind/L) while the Rotifer, Keratella tecta was the most abundant in freshwater influenced zones (64 ind/L). Shannon-Weaver’s diversity and Pielou’s equitability indices indicated that freshwater influenced zones host a diverse community with a tendency towards equi-partition of species while marinewater influenced zones revealed the opposite. The low levels of organic pollution indicator variables recorded and the high diversity of the freshwater influenced zones population studied attested to the low level of anthropization in this environment. High salinity and electrical conductivity values influence the distribution of these organisms.
文摘A study to list Dinoflagellates species belonging to the genera Ceratium and Protoperidinium and some abiotic factors associated with them was carried out in the Kribi coast from February 2020 to February 2021 following a monthly sampling frequency. For the inventory, 60 L of water including 20 L on the surface, 20 L in the trophogen layer and 20 L in the tropholytic layer were filtered through a sieve of 20 μm and the retentate obtained was fixed whith lugol for identification and counting operations using an Olympus microscope. The morphotypes of the taxa were filmed using an Omax Toupvix eye camera. Physico-chemical results showed very good water oxygenation (89.35%), low Suspended Solid concentration (6.36 ± 4.71 mg/L), basic pH (8.53 ± 0.4 U.C), average salinity of 15.87 ± 3.1 g/L and conductivity around 26.73 ± 4.96 mS/cm. The average water temperature hovered around 29.51°C ± 1.28°C. The average values of nitrates and orthophosphates showed a progressive enrichment of the waters of the studied section with nitrate (1.52 ± 0.87 mg/L) and orthophosphate (1.84 ± 3.98 mg/L). This work allowed to identify 17 species of the genera Ceratium and 22 of Protoperidinium. The genera Protoperidinium was the most diverse while it was the taxa belonging to the genera Ceratium that had the highest densities. Ceratium furca was the only spatially and seasonally regular species with occurrence frequencies of 75.31% and 79.16% respectively. According to similar studies, 06 species reconized harmful were inventoried during this study. These are Ceratium furca, Ceratium fusus, Ceratium tripos, Protoperidinium divergens, Protoperidinium steinii, Protoperidinium crassipes. Temperature and oxygen are the abiotic factors that showed more affinities with the taxa inventoried in view of the significant correlations obtained. With a view to preventing blooms on the Cameroonian Atlantic coast, regular monitoring of the harmful species identified is desirable.
