An eddy, a wake and a plume: controls on bathyal foraminifera around Tobago, western tropical Atlantic Ocean

Preliminary foraminiferal survey in Chichiriviche de La Costa, Vargas, Venezuela

“…Along the Venezuelan shelf, a separation between clastic and carbonate prone areas, comparable to that in the Gulf of Mexico, might be anticipated. This southern Caribbean Sea continental shelf is to the east impacted by the hypopycnal, nutrient-rich Orinoco plume (van der Zwaan & Jorissen, 1991;Wilson & Hayek, 2015Wilson et al, 2018), but not so to the west (Sellier de Civrieux, 1977a, b). The benthic foraminifera on the shelf of the clasticprone area of the SE Caribbean Sea are well documented (Drooger & Kaasschieter, 1958;Wilson & Hayek, 2017).…”

“…The pattern of sediment redistribution and upwelling in the southern Caribbean Sea changes seasonally with the arrival of the Trade Winds in the dry season and heavy rains in the hurricane season (Wilson, 2010), at which time the Inter-Tropical Convergence Zone (ITCZ) moves north into the area (Hoffmann et al, 2014). The heavy rains influence the freshwater discharge from the Orinoco (Hu et al, 2004;Wilson & Hayek, 2015;Wilson et al, 2018), which is the fourth largest river worldwide in terms of outflow (Hu et al, 2004) and has the greatest range between dry and rainy season outflows of any river worldwide (van Andel, 1967). The Orinoco Plume reaches as far as north Puerto Rico (Froelich et al, 1978;López et al, 2013), and the Orinoco discharge controls the annual cycle of chlorophyll and primary productivity over that area (Müller-Karger et al, 1989).…”

“…West of the plume, the western edge of which extends NW from western Trinidad, planktonic foraminifera respond to changes in upwelling associated with the migration of the ITCZ and Trade Winds fluctuations, as Tedesco & Thunell (2003a, b) showed in their study of the monthly flux of Globigerina bulloides in the Cariaco Basin. Benthic foraminiferal populations can also be useful tools for the identification of seasonal effects (Wilson & Dave, 2006;Wilson & Hayek, 2015;Wilson et al, 2018) if their populations have been monitored to identify their changes after any event.…”