Biometric and biomass analysis of Quaternary Uvigerinidae (Foraminifera) from the Southern Brazilian continental slope

The relative abundance, test size, elongation index, volume, and biomass variations of the Uvigerinidae species were analyzed in 1921 tests from 42 samples of two cores obtained from the continental slope of the Western South Atlantic. Variations in uvigerinid distribution and their test metrics are discussed based on the main climatic and oceanographic changes through the last glacial cycle. The higher dominance of Trifarina angulosa during the interglacial stages suggests that this species is favored by a stronger influence of the warm, nutrient-poor and oxygen-rich North Atlantic Deep Water (NADW), and near-bottom currents. Uvigerinid richness, the number of larger and less elongated tests and the accumulated biomass increased during the glacial stages, when the lower continental slope was more influenced by the Circumpolar Deep Water (CDW) close to the bottom and nutrient-enriched surface waters. In this sense, these biotic descriptors have the potential to be applied as proxies in studies on the paleocirculation and carbon flows to the seafloor through the late Quaternary in the South Atlantic. A regression model was also formulated to convert the test length to the total test volume for Uvigerinidae, which can facilitate data acquisition in future studies, expanding their use as paleoceanographical proxies. •High abundance and small test size of uvigerinids suggest high organic flux to continental slope throughout late Quaternary.•Variations in abundance of uvigerinids can be related to the the intermittent vertical vs. continuous lateral supply of carbon.•Trifarina angulosa's higher dominance is related to sea-level falling stages and strengthening of the bottom currents.•Richness of Uvigerinidae family increased as Circumpolar Deep-Water advances northward during MIS 2.•Accumulated biomass peaked during last glacial stage with major contribution of U. hispidocostata and U. peregrina.