Palynological Study of Recent Sediments from an Urban Creek in Lagos State, Southwestern Nigeria

A palynological study of recent sediments from Ijora Creek, an Urban Creek in Lagos, Southwestern Nigeria was carried out to provide inferences on paleovegetation and climate change over time in the study area. Two stations 90m apart were sampled at low tide in a boat using a Russian peat corer. Samples were taken at 10cm intervals and eighteen sediments samples were collected and processed using standard palynological methods. Two hundred and sixty six (266) and two hundred and thirty three (231) palynomorphs were recovered from stations 1 and 2 respectively. Palynomorphs recovered and identified to species level include Alchornea cordifolia, Hymenocardia acida, Elaeis guineensis, Spathodea companulata, Triumfetta pentandra, Uapaca acuminata, Tridax procumbens, Berlinia sp., Eugenia sp., Celtis sp., Albizia sp., Cyperus sp. together with species of Poaceae, Asteraceae, Arecaceae, Eurphorbiaceae, Acanthaceae, with common microforaminiferal test linings and fungal spores. Poaceae and fungal spores dominated the assemblage while station 1 recorded the highest pollen and spore abundance. The presence of microforaminiferal wall linings, fungal spores and the freshwater swamp species Alchornea cordifolia and the oil palm pollen Elaeis guineensis suggests a dominantly wet period in which, there was a marked marine transgression into the creek, interrupted occasionally by dry climate as inferred from the abundant records of Poaceae and Asteraceae. The presence of secondary forest species especially Elaeis guineensis suggests the impact of human activities on the paleovegetation.