The potential of organic-walled dinoflagellate cysts for the reconstruction of past sea-surface conditions in the Southern Ocean

摘要: Abstract In this study we investigate the potential of organic-walled dinoflagellate cysts (dinocysts) as tools for quantifying past sea-surface temperatures (SST) in Southern Ocean. For purpose, a dinocyst reference dataset has been formed, based on 138 surface sediment samples from different circum-Antarctic environments. The assemblages these are composed phototrophic (gonyaulacoid) and heterotrophic (protoperidinioid) species that provide broad spectrum palaeoenvironmental information. relationship between environmental parameters upper water column distribution patterns individual established using statistical method Canonical Correspondence Analysis (CCA). Among variables tested, summer SST appeared to correspond maximum variance represented dataset. To establish quantitative reconstructions, Modern Analogue Technique (MAT) performed data three Late Quaternary records recovered locations adjacent prominent oceanic fronts Atlantic sector These time series exhibit periodic changes assemblage during last two glacial/interglacial-cycles. During glacial conditions relative abundance protoperidinioid was highest, whereas interglacial characterised by generally lower cyst concentrations increased gonyaulacoid cysts. MAT palaeotemperature estimates show trends following global oxygen isotope signal strong correlation with 140 000 years other proxies. However, comparing results SSTs diatoms, radiolarians foraminifer-derived stable it can be shown several core intervals dinocyst-based extremely high. record seems highly influenced selective degradation, leading unusual temperature ranges unrealistic palaeotemperatures. We used degradation index (kt-index) determine those have biased order correct estimates. after correction reasonably well region, supporting great basis studies.