Diatom abundance in surface sediments of the Southern Ocean

• Main Authors: Esper, Oliver, Gersonde, Rainer
• Format: Dataset
• Language: English
• Published: PANGAEA 2014
• Subjects: Actinocyclus actinochilus; Actinocyclus curvatulus; Alveus marinus; Amundsen Sea; ANT-XX/2; ANT-XXII/4; ANT-XXIII/4; ANT-XXVI/2; Asteromphalus hookeri; Asteromphalus hyalinus; Asteromphalus parvulus; AWI_Paleo; Azpeitia tabularis var. tabularis; Azpeitia tabularis var egregius; Central South Atlantic; Chaetoceros spp.; Corethron pennatum; Counting; diatoms; CTD/Rosette; CTD-RO; DEPTH; sediment/rock; Diatoms indeterminata; Elevation of event; Eucampia antarctica; Event label; Fragilariopsis curta; Fragilariopsis cylindrus; Fragilariopsis doliolus; Fragilariopsis kerguelensis; Fragilariopsis obliquecostata; Fragilariopsis rhombica; Fragilariopsis ritscheri; Fragilariopsis separanda; Fragilariopsis sublinearis; Fragilariopsis vanheurckii; GC; GeoB6403-4; GeoB6404-3; GeoB6405-8; GeoB6406-1; GeoB6407-2; GeoB6409-2; GeoB6410-1; GeoB6411-4; GeoB6416-2; GeoB6419-1; GeoB6420-2; Antarctic; Southern Ocean; Pacific; Indian; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.828674; https://doi.org/10.1594/PANGAEA.828674

Based on the quantitative analysis of diatom assemblages preserved in 274 surface sediment samples recovered in the Pacific, Atlantic and western Indian sectors of the Southern Ocean we have defined a new reference database for quantitative estimation of late-middle Pleistocene Antarctic sea ice fields using the transfer function technique. The Detrended Canonical Analysis (DCA) of the diatom data set points to a unimodal distribution of the diatom assemblages. Canonical Correspondence Analysis (CCA) indicates that winter sea ice (WSI) but also summer sea surface temperature (SSST) represent the most prominent environmental variables that control the spatial species distribution. To test the applicability of transfer functions for sea ice reconstruction in terms of concentration and occurrence probability we applied four different methods, the Imbrie and Kipp Method (IKM), the Modern Analog Technique (MAT), Weighted Averaging (WA), and Weighted Averaging Partial Least Squares (WAPLS), using logarithm-transformed diatom data and satellite-derived (1981–2010) sea ice data as a reference. The best performance for IKM results was obtained using a subset of 172 samples with 28 diatom taxa/taxa groups, quadratic regression and a three-factor model (IKM-D172/28/3q) resulting in root mean square errors of prediction (RMSEP) of 7.27% and 11.4% for WSI and summer sea ice (SSI) concentration, respectively. MAT estimates were calculated with different numbers of analogs (4, 6) using a 274-sample/28-taxa reference data set (MAT-D274/28/4an, -6an) resulting in RMSEP's ranging from 5.52% (4an) to 5.91% (6an) for WSI as well as 8.93% (4an) to 9.05% (6an) for SSI. WA and WAPLS performed less well with the D274 data set, compared to MAT, achieving WSI concentration RMSEP's of 9.91% with WA and 11.29% with WAPLS, recommending the use of IKM and MAT. The application of IKM and MAT to surface sediment data revealed strong relations to the satellite-derived winter and summer sea ice field. Sea ice reconstructions performed on an ...