Complex response of dinoﬂagellate cyst distribution patterns to cooler early Oligocene oceans Mark A. Woods a, ⁎, Thijs R.A. Vandenbroucke b , Mark Williams c , James B. Riding a , Stijn De Schepper d , Koen Sabbe e a British Geological Survey Environmental Science Centre, Keyworth, Nottingham, NG12 5GG, UK b UMR 8217 du CNRS: Géosystèmes, Université Lille 1, Avenue Paul Langevin, bâtiment SN5, 59655 Villeneuve d'Ascq Cedex, France c Department of Geology, University of Leicester, University Road, Leicester, LE1 7RH, UK d Department of Earth Science, University of Bergen, Allégaten 41, 5007 Bergen, Norway e Protistology and Aquatic Ecology, Department of Biology, Ghent University, Krijgslaan 281-S8, 9000 Ghent, Belgium abstract article info Article history: Received 28 February 2013 Accepted 7 February 2014 Available online xxxx Keywords: Dinoﬂagellate cysts Eocene Oligocene Palaeoclimatology Previous studies have made extensive use of dinoﬂagellate cysts to reconstruct past sea surface temperature (SST). Analysis of associations of dinoﬂagellate cysts using two new ocean datasets for the mid Eocene (Bartonian) and early Oligocene (Rupelian) reveals clear latitudinally constrained distributions for the Bartonian, but unexpected changes in their Rupelian distribution; a signiﬁcant number of species with low and mid latitude northern hemi- sphere occurrences in the Bartonian extend their northward ranges in the Rupelian, including some forms characterised as ‘warm water’ by previous studies. This suggests either that dinoﬂagellates are faithfully tracking a complex oceanographic response to Rupelian cooling, or that dinoﬂagellate sensitivity/adaptability to a range of ecological variables means that at a global scale their distributions are not primarily controlled by sea surface temperature-variability. Previous use of dinoﬂagellate cysts for palaeoclimate work has relied on rather subjective and inconsistent identiﬁcation of ‘warm’ and ‘cold’ water forms, rather than comprehensive analysis of community associations at the global-scale. It is clear from this study that a better understanding of the (palaeo-)ecology of dinoﬂagellates and their cysts is required. Rupelian dinoﬂagellate cyst distribution may reﬂect changes in a range of environmental variables linked to early Oligocene climate-cooling, for example changes in nutrient ﬂuxes triggered by glacially-induced base-level fall; complex reorganisation of ocean current systems between the Bartonian and Rupelian, or muted changes to Rupelian summer SSTs in the northern hemisphere that have previously been reported. Many extant dinoﬂagellate species also exhibit relatively broad temperature tolerance. Moreover, they have potentially extensive cryptic diver- sity, and are able to produce dormant cysts during short-lived environmental deterioration, all of which may act to limit the value of undifferentiated dinoﬂagellate cyst assemblages for identifying climate signals. © 2014 Natural Environment Research Council. Published by Elsevier B.V. All rights reserved. Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3.1. Dating: chronostratigraphy, biostratigraphy, magnetostratigraphy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.2. Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.3. Lithostratigraphy and palaeoenvironment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.4. Dinoﬂagellate cyst data, taxonomy and nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Earth-Science Reviews (2014) xxx–xxx ⁎ Corresponding author. Tel.: +44 115 9363155. E-mail addresses: maw@bgs.ac.uk (M.A. Woods), Thijs.Vandenbroucke@univ-lille1.fr (T.R.A. Vandenbroucke), mri@leicester.ac.uk (M. Williams), jbri@bgs.ac.uk (J.B. Riding), stijn.deschepper@geo.uib.no (S. De Schepper), Koen.Sabbe@UGent.be (K. Sabbe). EARTH-01954; No of Pages 16 http://dx.doi.org/10.1016/j.earscirev.2014.02.004 0012-8252/© 2014 Natural Environment Research Council. Published by Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Please cite this article as: Woods, M.A., et al., Complex response of dinoﬂagellate cyst distribution patterns to cooler early Oligocene oceans, Earth- Sci. Rev. (2014), http://dx.doi.org/10.1016/j.earscirev.2014.02.004