Hydro-environmental factors and phytoplankton of the Atlantic Ocean, off the Light House Beach, Lagos, Nigeria

Abstract

The Atlantic Ocean, off the Lighthouse Beach was investigated (August–December 2014) to determine the hydro-environmental and phytoplankton characteristics. Mean and standard deviation values for air temperature were 27.67±2.98 ^oC, water temperature (28.37±1.88), pH (7.85±0.17), conductivity (44738.75±6262.76 μS/cm), total dissolved solids (29236.71±4273.30 mg/L), salinity (27.11±3.91 ‰), alkalinity (126.99±42.81 mg/L) and chloride (15056. 67±2165.78 mg/L). These parameters recorded higher values in August, November and December, than in September and October. Conversely, reducing values were recorded for acidity (2.34±0.63 mg/L), total hardness (4711.98±691.50 mg/L), phosphate (1.1±0.78 mg/L), sulphate (2601.99±447.04 mg/L) and nitrate (0.12±0.06 mg/L). Twenty-one species from four divisions were recorded. Diatoms constituted 80.92%. Hemidiscus cuneiformis, Coscinodiscus centralis, Coscinodiscus lineatus, Coscinodiscus radiatus and Oscillatoria limosa were the more frequently occurring species. Biddulphia sinensis and four species of Ceratium, better represented the dry season. Species abundance (N) was highest in December at Station 1 (13.15%) (dry season) and lowest in August (wet season) at Station 3 (2.96%). The hydro-environmental factors and phytoplankton components reflected a tropical unpolluted neritic and oceanic environment.

Keywords: Physico-chemistry, micro-algae, sea, Lighthouse Beach, Atlantic Ocean