Temporal variations in water chemistry and chlorophyll-a at the Tomaro creek Lagos, Nigeria

Abstract

Temporal variations of the water chemistry and chlorophyll-a dynamics at the Tomaro creek Lagos were investigated for six months (October, 2007 to March, 2008). Temperature remained high (>27°C) all through the sampled period while total suspended solids and transparency increased in the dry months. Total dissolved solids were high (≥8160 mg/L) between December and March while lower values (≤2529 mg/L) were recorded between October and November. Salinity, conductivity and pH values increased steadily during the sampled months. Chemical oxygen demand and biological oxygen demand values at the site remained low (<12.80 mg/L; ≤2.0 mg/L) between the period free of organic pollution and moderately (≤52.2 mg/L; 7.0 mg/L) organically polluted period. Heavy metals (Pb, Fe, Cu) especially Fe followed almost same pattern as chlorophyll-a recorded. Phytoplankton abundance dropped (80cells/ml) between November and December. Phytoplankton diversity was high while the species were evenly distributed.

Dynamics of nutrient and phytoplankton in Epe Lagoon, Nigeria: possible causes and consequences of reoccurring cyanobacterial blooms

“…The observed lowest temperature (≤ 27 °C) in the wet season (late wet I) might be attributed to the influx of cooler flood waters from wetlands, adjoining creeks and rivers. These assertions confirm temperature regimes in coastal lagoons of south-west, Nigeria (Onuoha and Vyverman 2010;Nwankwo et al 2013). The low total suspended solids and total dissolved solids in the wet months agree with observations of Nwankwo (1996Nwankwo ( , 1997, Onyema and Nwankwo (2006), Adesalu and Nwankwo (2010) and Onuoha and Vyverman (2010) in coastal waters of south-west Nigeria.…”

“…Flood water intrusion causes dilution, high flushing rate and low retention time during the rainy season, which is different from the situations in the dry season and the onset of the rainfall. pH indicated an acidic condition in certain occasion (July 2013) which could be attributed to the seepage of humic and fulvic acid exudates from surrounding wetlands (Nwankwo et al 2013;Canini et al 2013). The slightly acidic to neutral nature of Epe lagoon probably accounted for the dominance of Aulacoseira granulata at Epe during the off-bloom season.…”

Dynamics of Crustacean Larvae Composition and Abundance in Mesohaline Creeks of Lagos Lagoon, Nigeria

“…The observed low air and water temperatures in July in both creeks may be due to the harmattan haze prevalent at the period and the possible increase in cloud cover that reduced isolation. Similar reports have been made on tidal creeks of south-west Nigeria (Chukwu and Nwankwo, 2004;Nwankwo, 2013). Nwankwo (1990) highlighted that seasonal variation in transparency in the coastal waters of South-Western Nigeria is linked to the rainfall pattern and associated floods.…”

“…The low dissolved oxygen values between April and May, low chemical oxygen demand values in July as well as low biological oxygen demand values in May and July could be an indication of the level of pollution in both Abule-Eledu and Abule-Agege creeks. According to Nwankwo et al (2013), Biological oxygen demand values less than 2.0 mg/L indicate clean water, 2.0 to 4.0 mg/L indicate moderate pollution while above 8.0 mg/L indicate severe stress. In this regard, Abule-Agege Creek may be said to be more polluted than polluted although both exhibited moderate pollution.…”

Environmental Health Status of Some Aquatic Ecosystems in Badagry Division, Lagos, Nigeria

“…The parameters (except alkalinity, hardness, BOD, conductivity and COD) in this study were higher than that reported in Badagry creek [19]. It was also higher than that reported in Cross River Estuary, in Ogbe creek, in Tomaro creek, Tidal creek and from Asejire Lake respectively [10,[20][21][22][23]. On the other hand, the values of phosphate, hardness, salinity and TDS in this study were lower than that recorded in Majidun River in Lagos, Nigeria [24].…”