Modelling Environmental Factors on Bloom Forming Cyclotella species (Stephanodiscaceae Glezer & Makarova (1986) in the Central Bonny Estuary, Rivers State, Nigeria

DIENYE, EYINA HENRY; Sikoki, F. D.; Woke, G. N.; Olopade, O. A.; Ikwuemesi, J. C.

doi:10.21608/jsrs.2023.331821

Modelling Environmental Factors on Bloom Forming Cyclotella species (Stephanodiscaceae Glezer & Makarova (1986) in the Central Bonny Estuary, Rivers State, Nigeria

Document Type : Original Article

Authors

¹ Department of Fisheries, Faculty of Agriculture, University of Port Harcourt Choba, Nigeria.

² Department of Animal and Environmental Biology, University of Port Harcourt Choba, Nigeria.

³ Department of Fisheries and Aquatic Resources Management, Michael Okpara University of Agriculture, Umudike. Nigeria.

10.21608/jsrs.2023.331821

Abstract

This study was carried out to examine modelling the effects of environmental gradients on bloom-forming Cyclotella species. Plankton samples were collected with a 20 µm mesh plankton net. The physicochemical characteristics were determined in situ, and the nutrients were analyzed in the laboratory using the APHA 2012. The highest mean cell density of 355.43±49.55 Cells L^-1 was recorded in station 4, and the lowest of 63.33±17.02 Cells L^-1 in station 2 for C. antiqua. In contrast, 360.81±70.05 Cells L^-1 was recorded in station 3, with the lowest of 204.67±61.67 Cells L^-1 in station 2 for C. meneghiniana spp. respectively. Principal component analysis revealed that TDS, DO, PO₄, NO₃ and NO_2.
In contrast, a positive relationship, while pH and salinity had a negative relationship with C. antiqua. Nitrite, TDS, and DO show a positive relationship, while salinity, phosphate, temperature, and pH negatively correlated with C. meneghiniana across stations. TDS, DO, and NO₂ were the most used forecast predictors for Cyclotella spp., which were positively correlated. The observed data were compared with the simulated result. Cyclotella antiqua and meneghiniana increased with a rise in TDS and NO₂ as the forecast predictors to ascertain its effect on the predicted species. The increasing human-induced anthropogenic pressure is primarily influencing the eutrophication of water. With an increase in nutrients (TDS and NO₂), that species may form a bloom. There is a need for best management practices to address nutrient discharge in the central Bonny estuary.

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