Benthic foraminifera in South Atlantic Ocean surface sediments

• Main Author: Schumacher, Stefanie
• Format: Dataset
• Language: English
• Published: PANGAEA 2001
• Subjects: AWI_Paleo; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; SFB261; South Atlantic in Late Quaternary: Reconstruction of Budget and Currents; Berichte zur Polar- und Meeresforschung; Reports on Polar and Marine Research; South Atlantic Ocean
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.787450; https://doi.org/10.1594/PANGAEA.787450

Benthic foraminiferal assemblages were analyzed on forty-eight surfacesediment samples which were taken with a multiple corer from the southern South Atlantic Ocean and the northern Angola-Basin. The short cores were split into 1-cm-thick slices down to 15 cm sediment depth. Live (with Rose Bengal stained) and dead faunas were counted separately. The data were used to calculate numerical faunal characteristics like standing stocks, benthic foraminifera accumulation rates, diversity, average living depth, and habitat depth. Additionally the live and dead faunas were grouped into a number of principal faunal endmembers by Q-mode principal component analysis. Faunal composition, numerical faunal characteristics, and isotopic composition of calcareous tests were correlated with available environmental variables. Oxygen content in Pore water and rates of primary production were calculated by faunal composition and benthic foraminifera accumulation rate. Some principal faunal endmembers of the analysis for the living fauna of the sediment surface, for the living fauna down to 11 cm sediment depth, and for the dead fauna of the sediment surface show almost identical assemblages. The total number of live specimens decreases with decreasing organic carbon flux rates. Living benthic foraminifera are found down to a maximum sediment depth of 11 cm in the southern South Atlantic Ocean and down to 5 cm in the northern Angola-Basin with a maximum number of specimens in the uppermost centimeter. Standing stock, species number, and diversity decrease with increasing sediment depth. Between 30 and 70 % of the total living population settles on the surface and within the uppermost centimeter of the sediment. Epifaunal species are living on the surface and within the first centimeter of the sediment. Most of infaunal species depict a maximum abundance near the surface. In sediments with low oxygen penetration depth specific calcareous species clearly depict a subsurface maximum. Comparisons of pore water dissolved oxygen contents ...