Statistical analysis of planktic foraminifera of the surface Continental shelf sediments off Southwestern Nigeria
Planktic foraminiferal assemblage recorded from selected samples obtained from shallow continental shelf sediments off southwestern Nigeria were subjected to statistical analysis. The Principal Component Analysis (PCA) was used to determine variants of planktic parameters. Values obtained for these parameters were later subjected to PCA for comparison. The PCA was employed to differentiate the planktic species into different reaction groups in order to determine their preferred environmental condition. Species ratio, most especially non-tropical/tropical ratio, proved to be the most reliable ecological/climatic indicator in the study area. The planktic/benthic ratio, species diversity, planktic number and species ratio trends increased oceanwards. Conversely, the planktic species dominance, relative abundances of Globigerinoides ruber, G. trilobus immaturus and Globigerina bulloides patterns decreased oceanwards. The relative abundances of Globigerinoides ruber, G. Trilobus immaturus and Globigerina bulloides as well as planktic species dominance correlated with climatic indicator. However, the climatic indicator did not correlate with P/B ratio, planktic number and planktonic diversity. PCA indicated the clustering of Globigerina bulloides abundance and non-tropical/tropical species ratio, ratios of pair of species and planktic diversity, and planktic dominance, G.ruber and G. trilobus immaturus abundances respectively. On the contrary, the P/B ratio and Planktic number stood as outliers. The PCA distinguished eight planktic foraminiferal reaction groups which were dependent upon a complex interaction of abiotic (temperature and salinity) and biotic factors.
Keywords: Statistical Analysis, Planktic, Foraminifera, Continental Shelf, Southwestern Nigeria.