Research Article
Water Quality, Biodiversity and Abundance of Blue-Green Algae in Nyong and Kienké River Mouths (South-Cameroon)
Christelle Chimène Mokam,
Andrea Sarah Kenne Toukem,
Christian Dongmo Teufack,
Fabien Trésor Amougou Dzou,
Sedrick Junior Tsekane,
Mohammadou Moukhtar,
Auguste Pharaon Mbianda,
Martin Kenne*
Issue:
Volume 9, Issue 1, April 2024
Pages:
1-27
Received:
3 January 2024
Accepted:
15 January 2024
Published:
23 January 2024
Abstract: A survey was undertaken from March to June 2014 on the water quality and the occurrence of Cyanobacteria bio-indicator species in Nyong and Kienké warm river mouths. Physico-chemical parameters were measured in-situ. Species were identified and counted in laboratory. The pH varied from slightly acidic to slightly basic. Temperature, pH and transparency were within the tolerable limits for drinking water or fish farming. NO3-, Chlorophyll a and biomass were lower than standards. DO and FC were higher than upper limits, except DO in Kienké. NO2- was higher in Nyong than the upper limit. It was within the recommended range in Kienké. TSS was within acceptable standards for fish farming but above the upper limit for drinking water. NO2-, NH4+ and PO43- proved good conditions for bio-fertilizers or toxin-producers. Chlorophyll a and biomass contains were low but FC and TSS exceeded standards for drinking water, and were within standards for fish farming. Thirty-seven species belonging to 28 genera, 15 families and four orders, were divided into 25 freshwater species and 12 tolerant species. Sixteen toxigenic species, 15 useful species and six species of unknown status were identified. The species diversity was low and Microcystaceae (Chroococales) was the most species-rich family (eight species i.e. 21.6%) and was the most abundant (34.7%), followed by Rivulariaceae (Nostocales) (five species i.e. 13.5% and 12.4% of abundance), Aphanizomenonaceae (Nostocales) (four species i.e 10.8% and 20.8% of abundance), Hapalosiphonaceae (Nostocales) (two species i.e.5.4% and 0.8% of abundance), Microcoleaceae (Oscillatoriales) (two species i.e. 5.4% and 2.1% of abundance), Nodulariaceae (Nostocales) (three species i.e. 8.1% and 7.9% of abundance), Nostocaceae (Nostocales) (two species i.e. 5.4% and 1.9% of abundance), and Oscillatoriaceae (Oscillatoriales) (three species i.e. 8.1% and 0.8% of abundance). Eight families [Chroococcaceae (Chroococales), Coelosphaeriaceae (Synechococcales), Cyanothecaceae (Gomontiellales), Cymatolegaceae (Nodosilineales), Cyanothrichaceae (Chroococales), Gomphosphaeriaceae (Chroococales), Pseudanabaenaceae (Pseudanabaenales), and Tolypothrichaceae (Nostocales)] presented each one rare species (2.7%). According to abundances, species classification in descending order is Raphidiopsis mediterranea (14.3%), Synechocystis aquatilis (11.9%), Aphanothece elabens (7.3%), Microcystis aeruginosa (5.1%). Other species were rare. Twenty-three co-dominants (62.2%) were identified. Globally, a positive association was noted between species in each river. The pooled assemblage at low tide fitted the log-linear niche partitioning model with a high environmental constant while other assemblages fitted the lognormal model with in each case a low environmental constant. Although these two river mouths were suitable for fish farming, direct consumption of raw water is detrimental to human health.
Abstract: A survey was undertaken from March to June 2014 on the water quality and the occurrence of Cyanobacteria bio-indicator species in Nyong and Kienké warm river mouths. Physico-chemical parameters were measured in-situ. Species were identified and counted in laboratory. The pH varied from slightly acidic to slightly basic. Temperature, pH and transpar...
Show More
Research Article
Biodiversity and the Community Structure of Chromista Cavalier-Smith, 1981 in Nyong and Kienke River Mouths (South-Cameroon)
Issue:
Volume 9, Issue 1, March 2024
Pages:
28-55
Received:
1 March 2024
Accepted:
18 March 2024
Published:
2 April 2024
Abstract: A survey was undertaken from March to June 2014 on the biodiversity and the community structure of Chromista Cavalier-Smith, 1981 in Nyong and Kienke River mouths (South-Cameroon). In each river, raw waters were collected from upstream to downstream at four sites. Cells were counted using the Malassez cells procedure and species were identified. A total of 10427.1x105 cells corresponded to three phyla, eight classes, 23 orders, 32 genera and 40 species (24 freshwater species (60.0% of total species richness and total collection respectively), three marine species (7.5% and 2.4% of the total species richness; and total collection respectively), and one brackish water specialist in Kienke (2.5% and 5.1%), 13 tolerant species (32.5% and 32.6%)). The trophic diatom index revealed undisturbed conditions with no or little alteration of human origin and a low organic pollution (oligotrophic or mesotrophic state) (Nyong: TDI=52.7; Kienke: TDI=69.7; pooled assemblage: TDI=65.0). A low species richness was detected (richness ratio in Nyong: d=0.008; Kienke: d=0.003; pooled rivers: d=0.004), a high species diversity (Shannon index close to maximum) (Nyong: H’=2.742 and H’max=2.996; Kienke: H’=2.685 and H’max=2.996; pooled rivers: H’=3.245 and H’max=3.689), a very low dominance by a few species (Berger-Parker index close to 0) (Nyong: IBP=0.156; Kienke: IBP=0.175; pooled rivers: IBP=0.134), and Hill’s ratio were close to 1 (Nyong: Hill=0.819; Kienke: Hill=0.803; pooled rivers: Hill=0.722). The community was highly even with a high value of the Pielou’s evenness close to 1 (Nyong: J=0.915; Kienke: J=0.896; pooled rivers: J=0.880). Two useful species and one harmful species to fish were rare in Kienke. Species exhibited in Kienke and pooled data in rainy season, a positive global net association while it was negative in Nyong. Assemblage fitted Preston’s model in Nyong with a high environmental constant in the dry season (m’=1.469), low constant in the rainy season (m’=0.947) and the pooled seasons (m’=0.853). In Kienke constants were low (dry season: m’=0.574; rainy season: m’=0.566; pooled seasons: m’=0.581) suggesting a evolved community in less disturbed environments where the majority of species showed moderate abundances. In the dry season, the pooled assemblage functionned on the basis of maintaining a complex information network (close to ecological balance) developed at spatio-temporal scales (ZM model) and it presented a low force of regeneration (fractal dimension of the distribution of individuals among species (1/γ)=0.925<1). The evolved oligotrophic state (close to natural balance) of the chromists’ community should be preserved and protected and the studied rivers classified as reference.
Abstract: A survey was undertaken from March to June 2014 on the biodiversity and the community structure of Chromista Cavalier-Smith, 1981 in Nyong and Kienke River mouths (South-Cameroon). In each river, raw waters were collected from upstream to downstream at four sites. Cells were counted using the Malassez cells procedure and species were identified. A ...
Show More
,
Andrea Sarah Kenne Toukem
