Dinoflagellates are biflagellate, eukaryotic protists that comprise a large proportion of planktonic biomass and are therefore important components of marine and freshwater environments. Most dinoflagellates are either photosynthetic or heterotrophic, but some can be both.

Some dinoflagellate species (~15-20% of modern species [1]) produce a resting cyst, capable of being preserved in the sedimentary record, during the sexual phase of their life cycle and in preparation for a dormant period. These cysts are found throughout the world in surface sediments [2] and cysts recognized as produced by dinoflagellates have been reliably identified as far back as the Triassic (~250 Ma).
Dinoflagellate cysts may be organic-, calcareous- or, rarely, siliceous-walled. Organic-walled dinoflagellate cysts are composed of a resistant biomacromolecule termed dinosporin, which is unique to dinoflagellates. The primary method for identifying cyst species is through their morphology [3], particularly an opening in the cyst wall through which the dinoflagellate cell emerges called an archeopyle. Dinoflagellate cysts are exceedingly useful (i)] as sensitive environmental indicators in modern freshwater [4,5] and marine settings [6-14], often in conjunction with pollen [15], and (ii) in deeper time studies and biostratigraphy [16-21]. They therefore constitute an important link between organisms, the environment in which the cells lived, and the geological record.

Additional resources
Link to DINOFLAJ2 can be found here http://dinoflaj.smu.ca/dinoflaj3 and in our shop here: http://palynologyshop.org/product/dinoflaj3/
Quaternary dinoflagellate cysts: https://www.marum.de/en/Modern_Dinocyst_Key.html

1. Head, M. J. 1996. Modern dinoflagellate cysts and their biological affinities. In Jansonius, J. & McGregor, D. C. [Eds.] Palynology: Principles and Applications. AASP Foundation, Salt Lake City, UT, pp. 1197-1248.

2. Zonneveld, K., Marret, F., Versteegh, G., Bogus, K., Bonnet, S., Bouimetarhan, I., Crouch, E., de Vernal, A., Elshanawany, R., Edwards, L., Esper, O., Forke, S., Grøsfjeld, K., Henry, M., Holzwarth, U., Kielt, J.-F., Kim, S.-Y., Ladouceur, S., Ledu, D., Chen, L., Limoges, A., Londeix, L., Lu, S.-H., Mahmoud, M., Marino, G., Matsouka, K., Matthiessen, J., Mildenhal, D., Mudie, P., Neil, H.L., Pospelova, V., Qi, Y., Radi, T., Richerol, T., Rochon, A., Sangiorgi, F., Solignac, S., Turon, J.-L., Verleye, T., Wang, Y., Wang, Z. and Young, M. 2013. Atlas of modern dinoflagellate cyst distribution based on 2405 datapoints. Review of Palaeobotany and Palynology, 191, 1-197.

3. Fensome, R., Taylor, F.J.R., Norris, G., Sarjeant, W.A.S., Wharton, D.I. and Williams, G.L. 1993. A classification of fossil and living dinoflagellates. Micropaleontology Press Special Paper, 7, pp. 351.
4. McCarthy, F., Mertens, K.N., Ellegaard, M., Sherman, K., Pospelova, V., Ribeiro, S., Blasco, S. and Vercauteren, D. 2011. Resting cysts of freshwater dinoflagellates in southeastern Georgian Bay (Lake Huron) as proxies of cultural eutrophication. Review of Palaeobotany and Palynology, 166, 46-62.

5. Mertens, K.N., Rengefors, K., Moestrup, Ø. and Ellegaard, M. 2012. A review of recent freshwater dinoflagellate cysts: taxonomy, phylogeny, ecology and palaeocology. Phycologia, 51, 612-619.

6. Rochon, A., de Vernal, A., Turon, J.-L., Matthiessen, J. and Head, M.J. 1999. Distribution of recent dinoflagellate cysts in surface sediments from the North Atlantic Ocean and adjacent seas in relation to sea-surface parameters. American Association of Stratigraphic Palynologists, Contributions Series 35, 1–152.

7. de Vernal, A., Henry, M., Matthiessen, J., Mudie, P.J., Rochon, A., Boessenkool, K., Eynaud, F., Grøsfjeld, K., Guiot, J., Hamel, D., Harland, R., Head, M.J., Kunz-Pirrung, M., Levac, E., Loucheur, V., Peyron, O., Pospelova, V., Radi, T., Turon, J.-L. and Voronina, E. 2001. Dinoflagellate cyst assemblages as tracers of sea-surface conditions in the northern North Atlantic, Arctic and sub-Arctic seas: the new “n = 677” database and its application for quantitative paleoceanographic reconstruction. Journal of Quaternary Science, 16, 681-698.

8. Dale, B., Dale, A. L. and Jansen, J. H. F. 2002. Dinoflagellate cysts as environmental indicators in surface sediments from the Congo deep-see fan and adjacent regions. Palaeogeography, Palaeoclimatology, Palaeoecology, 2893, 1-30.

9. Marret, F. and Zonneveld, K., 2003. Atlas of modern organic-walled dinoflagellate cyst distribution. Marine Micropaleontology, 125, 1-200.

10. Matthiessen, J., de Vernal, A., Head, M., Okolodkov, Y., Zonneveld, K., and Harland, R., 2005. Modern organic-walled dinoflagellate cysts in Arctic marine environments and their (paleo-)environmental significance. Paläontologische Zeitschrift, 79, 3–51.

11. Pospelova, V., de Vernal, A. and Pedersen, T., 2008. Distribution of dinoflagellate cysts in surface sediments from the northeastern Pacific Ocean (43-25°N) in relation to sea-surface temperature, salinity, productivity and coastal upwelling. Marine Micropaleontology, 68, 21-48.

12. Bouimetarhan, I., Marret, F., Dupont, L. and Zonneveld, K. 2009. Dinoflagellate cyst distribution in marine surface sediments off West Africa (6-17°N) in relation to sea-surface conditions, freshwater input and seasonal coastal upwelling. Marine Micropaleontology, 71, 113-130.

13. Bonnet, S., de Vernal, A., Gersonde, R., and Lembke-Jene, L. 2012. Modern distribution of dinocysts from the North Pacific Ocean (37-64°N, 144°E-148°W) in relation to hydrographic conditions, sea-ice and productivity. Marine Micropaleontology, 84-85, 87-113.

14. Limoges, A., Londeix, L., and de Vernal, A. 2013. Organic-walled dinoflagellate cyst distribution in the Gulf of Mexico. Marine Micropaleontology, 102, 51-68.

15. Marret, F., Kim, S.Y. and Scourse, J. 2013. A 30,000 yr record of land-ocean interaction in the eastern Gulf of Guinea. Quaternary Research, 80, 1-8.

16. Evitt, W.R. [Ed.] 1975b. Proceedings of a forum on Dinoflagellates held at Anaheim, California, October 16, 1973 as part of the Sixth Annual Meeting A.A.S.P. American Association of Stratigraphic Palynologists Contributions Series, 4, 91 pp.

17. Helby, R., Morgan, R., Partridge, A.D., 1987. A palynological zonation of the Australian Mesozoic. Memoir of the Association of Australasian Palaeontologists 4, 1–94.

18. Powell, A.J., 1992. A stratigraphic index of dinoflagellate cysts. Chapman and Hall, London, 290 pp.

19. Stover, L.E., Brinkhuis, H., Damassa, S.P., de Verteuil, L., Helby, R.J., Monteil, E., Partridge, A.D., Powell, A.J., Riding, J.B., Smelror, M., Williams, G.L., 1996. Mesozoic-Tertiary dinoflagellates, acritarchs and prasinophytes. In: Jansonius, J., McGregor, D.C. (eds.). Palynology: principles and applications. American Association of Stratigraphic Palynologists Foundation, Dallas 2, 641–750.

20. Williams, G.L., Bujak, J.P., 1985. Mesozoic and Cenozoic dinoflagellates. In: Bolli, H.M., Saunders, J.B., Perch-Nielsen, K. (eds.). Plankton Stratigraphy. Cambridge University Press, 847-964.

21. Williams, G.L., Stover, L.E., Kidson, E.J., 1993. Morphology and stratigraphic ranges of selected Mesozoic-Cenozoic dinoflagellate taxa in the northern hemisphere. Geological Survey of Canada Paper 92-10, 137 pp, range charts 1–3.