Marine Sciences-Scholarly Publications

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Browsing Marine Sciences-Scholarly Publications by Subject "Algae"

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  • Item
    Open Access
    Plankton and Macrobiota Composition and Diversity of Three Tropical Freshwaters Rivers in Ogun and Ondo States, Southwest Nigeria
    (Notulae Scientia Biologicae, 2016) Lawal, M. O.; Adesalu, T.A.; Kunrunmi, O.A.
    Three different rivers in Ogun and Ondo states were investigated for both micro and macro-biota of the water bodies. Several physical and chemical properties of these rivers were determined. The pH value of the studied water bodies was essentially neutral with salinity values between 0.02 - 4.0‰. Microalgae communities were represented by three divisions: Cyanophyta, Bacillariophyta and Chlorophyta at Oluwa and Ifara Rivers (Ondo state), while at Ibefun River (Ogun state), five divisions: Cyanophyta, Bacillariophyta, Chlorophyta, Euglenophyta and Pyrrhophyta were identified. Diatoms dominated these water bodies, with Navicula radiosa Kutz. at Ifara River, Fragilaria sp. in Oluwa River, while out of 90 algal taxa identified in Ibefun river, 64 were diatoms species belonging to 26 genera, with Melosira sp. and Synedra sp. recording the highest numbers of cell count. Dinoflagellates recorded only Peridinium sp. while Phacus orbicularis Hubner and Trachelomonas sp. dominated the euglenoids. For the zooplankton composition at Ibefun, rotifers (75.95%) were represented by Brachionus sp., which recorded 62.03%, and Gastropus sp. with 13.92% of the total zooplankton, thus dominated the spectrum, while the copepod recorded 22.78% of the total organisms, with Copilia sp. and Euchirella sp. having 8.86% each. The macrobenthic invertebrates were represented by 3 taxa, belonging to 3 groups, with the dominant group Insecta accounted for 57% of the total individuals (7 individuals/m2), while Oligochaeta and Hirudinea accounted for 29% and 14% respectively of the total individuals at Oluwa and Ifara Rivers. At Ibefun River, the macrobenthic invertebrates were represented by 5 taxa, belonging to 3 groups, Bivalves, Oligochaeta and Insecta, with bivalves being the dominant group (51.7% of the total individuals, as 64 individuals/m2), while Oligochaeta and Insecta accounted for 26.6% and 21.9% respectively of the total individuals. The dominant taxon, Macoma cumana, accounted for 42.2%. A total of seventeen (17) finfish and shellfish species comprised of thirteen (13) finfish and four (4) shellfish species were recorded, being representative of freshwater and brackish water species; Clarias anguillaris (Clariidae), Tilapia zilli (Cichlidae), Chrysichthys nigrodigitatus (Bagridae), Alestes spp. and Macrobrachium vollenhovenii (Palaemonidae) were the most common species observed.
  • Item
    Open Access
    Toxicity of Water Accommodated Fractions of Waste Engine Oil on Growth of Selected Marine Algae
    (West African Journal of Fisheries and Aquatic Sciences, 2021-05-22) Olaleye, Y.O; Kadiri, M.O
    Water Accommodated Fraction (WAF) is formed when water mix with oil under the influence of low or high energy. It is a solution of highly toxic mixtures of compounds which have high bioavailability to marine organisms and the potential of causing harmful effects. In this study, the growth inhibitory effects of WAF of waste engine oil on three (3) marine phytoplankton algae; Isochrysis galbana, Thalassiosira pseudonanaand Skeletonema tropicumwere investigated. The research was conducted in the laboratory for 14 days using different concentrations of WAF (5 %, 10 %, 15 %, 25 %, 50 %, 75 % and 100 %). Growth responses were measured spectrophotometrically at 750 nm absorbance. All the test algae were inhibited at concentrations ranging from 10 % to 100 % of WAF of waste engine oilwhereas, at 5% concentration algalgrowth stimulation was observed. Similarly, there was a consistent decrease in dry weight of all the algae with increasing concentration of WAF of waste engine oil except at 5 %. Isochrysis galbanawas generally more inhibited thanThalassiosira pseudonanaand Skeletonema tropicum. There were significant differences (p<0.05) in growth of microalgae at various concentrations of the WAF of waste engine oil.