Marine Biodiversity of São Tomé and Príncipe: Geographic, Climatic, Oceanographic, and Biogeochemical settings

Aim: To understand and describe the oceanic conditions that influence marine biodiversity in the São Tomé and Principe archipelago.

Methods: Review of published and unpublished research publications on marine biodiversity, ocean productivity and oceanography in São Tomé and Principe and the nearby regions.

Results: The geographic location of the oceanic islands of São Tomé and Principe, in the Gulf of Guinea, strongly determine its climate, oceanic circulation and ultimately marine biodiversity. The climate is controlled by the seasonal displacement of the Intertropical Convergence Zone (ITCZ) that also controls the year-round oceanic biological production with two seasons: a cold upwelling season from July to September marked by cooling and nitrate enrichment of the surface waters and a predominant warm rainy season (from October to June) characterized by nutrients input by runoff. Despite being geographically isolated, these islands have a relatively low level of marine endemism although high species richness. Many shallow-water marine fish and invertebrate species and genera found here are also present in Cape Verde Islands and Tropical Western Atlantic. This similarity is largely attributed by the authors to the strong oceanographic connections with the coast of African and the Tropical Western Atlantic, facilitated by zonal equatorial currents like the Guinea Current and the subsurface Equatorial Undercurrent.

Main conclusion: Marine biodiversity in São Tomé is strongly influenced by the ITCZ and the oceanographic connectivity within the Tropical Eastern and Western Atlantic.