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 Dept of fisheries faculty of Agric University of Portharcourt

2 UNIVERSITY OF PORTHARCOURT CHOBA

3 UNIVERSITY OF PORTHARCOURT CHOBA FACULTY OF AGRICULTURE

4 Michael Okpara university of agriculture umudike

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 NO2.
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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