Environmental controls on the distribution of living (stained) benthic foraminifera on the continental slope in the Campos Basin area (SW Atlantic)

Controlling Parameters of Benthic Deep-Sea Foraminiferal Biogeography at the Brazilian Continental Margin (11-22°S)

“…This interpretation is further validated by C:N ratios between 4 and 10, indicating that nitrogen is remineralized and nutrients are released (Table 2; Anderson, 1992;Rumolo et al, 2011). The main food source on the continental slope in the Campos Basin was previously reported to be autochthonous organic material derived from primary production (Carreira et al, 2010;Yamashita et al, 2018). Despite the exceedingly narrow shelf at the Rio de Contas and the Rio Sao Francisco (11-14°S), the southward drift of sediments delivered by these rivers prevents their transport to the continental slope (Rebouças et al, 2011;Cavalcante et al, 2020).…”

“…Their distribution is largely determined by the interplay of organic carbon influx, physical and chemical properties of major water masses, and the hydrodynamic regime at the sediment-water interface (Mackensen et al, 1995;Schmiedl et al, 1997;Gooday and Jorissen, 2012). At the extensive Brazilian continental margin, the impact of such environmental factors on the benthic foraminiferal fauna is poorly understood as previous studies have mainly focused on shelf areas south of 20°S (Oliveira-Silva et al, 2005; de Mello e Sousa et al, 2006;Eichler et al, 2008;Burone et al, 2011;Eichler et al, 2012;Vieira et al, 2015;Yamashita et al, 2018;Yamashita et al, 2020). Studies on benthic foraminiferal assemblages on the continental slope are particularly rare and limited to the Campos Basin (~ 22°S; de Mello e Sousa et al, 2006;Yamashita et al, 2018;de Almeida et al, 2022).…”

“…At the extensive Brazilian continental margin, the impact of such environmental factors on the benthic foraminiferal fauna is poorly understood as previous studies have mainly focused on shelf areas south of 20°S (Oliveira-Silva et al, 2005; de Mello e Sousa et al, 2006;Eichler et al, 2008;Burone et al, 2011;Eichler et al, 2012;Vieira et al, 2015;Yamashita et al, 2018;Yamashita et al, 2020). Studies on benthic foraminiferal assemblages on the continental slope are particularly rare and limited to the Campos Basin (~ 22°S; de Mello e Sousa et al, 2006;Yamashita et al, 2018;de Almeida et al, 2022). Analyses of modern deep-sea foraminifera from the continental shelf and slope north of 20°S off Eastern Brazil are lacking (Murray, 2006).…”

Deep-sea living (stained) benthic foraminifera from the continental slope and São Paulo Plateau, Santos Basin (SW Atlantic): ecological insights

“…In environments characterized by the occurrence of gravity flows, the community shows low densities and high dominance (e.g., Koho et al, 2007;Nardelli et al, 2010;Duros et al, 2011). Furthermore, differences in hydrodynamic conditions promoted by water masses, their surface fronts, eddies, and bottom current intensity can determine energy conditions that interfere with the input of organic matter, sediments texture and oxygen availability in the environment, changing the ecological parameters of BF assemblages (Mello et al, 2014;Yamashita et al, 2016Yamashita et al, , 2018Yamashita et al, , 2020Vicente et al, 2021). Moreover, the competition for microhabitat and resources are also important controlling factors of the foraminiferal dynamics (Boltovskoy and Wright, 1976;Murray, 1991Murray, , 2006.…”

“…However, it is often difficult to understand how much of what is produced in the surface ocean reaches the ocean bottom and becomes available to the benthic fauna, and also to comprehend the oceanographic processes that enable the fertilization in deep sea environments. One of the most sensitive groups to these changes are the benthic foraminifera (Jorissen et al, 1995;Gooday, 2003;Burone et al, 2011;Yamashita et al, 2016Yamashita et al, , 2018Yamashita et al, , 2020Vicente et al, 2021). Thus, this study aimed to characterize the spatial distribution and composition of living BF in the northern and southern sectors of SB, on the continental slope and São Paulo Plateau, and to understand how the abiotic factors (e.g., organic supply) and the hydro-sedimentary can influence the BF community in remote regions.…”