Title The potential of organic-walled dinoflagellate cysts for the reconstruction of past sea-surface conditions in the Southern Ocean
Author Esper, O.; Zonneveld, K.A.F.
Author Affil Esper, O., Alfred-Wegener- Institut for Polar and Marine Research, Bremerhaven, Federal Republic of Germany. Other: University of Bremen, Federal Republic of Germany
Source Marine Micropaleontology, 65(3-4), p.185-212, . Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398
Publication Date Dec. 5, 2007
Notes In English. Includes appendices; supplemental information/data is available in the online version of this article. 77 refs. Ant. Acc. No: 83642. CRREL Acc. No: 62003052
Index Terms climatic change; marine deposits; Pleistocene; Quaternary deposits; sediments; statistical analysis; Antarctica--Circum- Antarctic region; Indian Ocean; Atlantic Ocean--South Atlantic; Pacific Ocean-- Southeast Pacific; Southern Ocean; Agulhas Basin; Antarctic Circumpolar Current; Antarctica; assemblages; Atlantic Ocean; cannonical correspondence analysis; Cenozoic; Circum-Antarctic region; climate change; cores; Dinoflagellata; East Pacific; Gonyaulacaceae; Gonyaulacales; Gonyaulax; International Polar Year 2007-08; IPY 2007-08 Research Publications; marine sediments; Meteor Rise; microfossils; modern analogs; morphology; Pacific Ocean; paleotemperature; palynomorphs; Peridiniales; Protoperidiniaceae; Protoperidinium; quantitative analysis; Quaternary; sea- surface temperature; South Atlantic; South Pacific; Southeast Pacific; subantarctic regions; upper Pleistocene; upper Quaternary
Abstract In this study we investigate the potential of organic-walled dinoflagellate cysts (dinocysts) as tools for quantifying past sea-surface temperatures (SST) in the Southern Ocean. For this purpose, a dinocyst reference dataset has been formed, based on 138 surface sediment samples from different circum-Antarctic environments. The dinocyst assemblages of these samples are composed of phototrophic (gonyaulacoid) and heterotrophic (protoperidinioid) species that provide a broad spectrum of palaeoenvironmental information. The relationship between the environmental parameters in the upper water column and the dinocyst distribution patterns of individual species has been established using the statistical method of Canonical Correspondence Analysis (CCA). Among the variables tested, summer SST appeared to correspond to the maximum variance represented in the dataset. To establish quantitative summer SST reconstructions, a Modern Analogue Technique (MAT) has been performed on data from three Late Quaternary dinocyst records recovered from locations adjacent to prominent oceanic fronts in the Atlantic sector of the Southern Ocean. These dinocyst time series exhibit periodic changes in the dinocyst assemblage during the last two glacial/interglacial-cycles. During glacial conditions the relative abundance of protoperidinioid cysts was highest, whereas interglacial conditions are characterised by generally lower cyst concentrations and increased relative abundance of gonyaulacoid cysts. The MAT palaeotemperature estimates show trends in summer SST changes following the global oxygen isotope signal and a strong correlation with past temperatures of the last 140 000 years based on other proxies. However, by comparing the dinocyst results to quantitative estimates of summer SSTs based on diatoms, radiolarians and foraminifer- derived stable isotope records it can be shown that in several core intervals the dinocyst-based summer SSTs appeared to be extremely high. In these intervals the dinocyst record seems to be highly influenced by selective degradation, leading to unusual temperature ranges and to unrealistic palaeotemperatures. We used the selective degradation index (kt-index) to determine those intervals that have been biased by selective degradation in order to correct the palaeotemperature estimates. We show that after correction the dinocyst based SSTs correspond reasonably well with other palaeotemperature estimates for this region, supporting the great potential of dinoflagellate cysts as a basis for quantitative palaeoenvironmental studies.
URL http://hdl.handle.net/10.1016/j.marmicro.2007.07.002
Publication Type journal article
Record ID 282652