High-resolution palynological studies across the Cretaceous-Paleogene Boundary (K/Pg) Southern Hemisphere, New Zealand, preformed the last 15 years, have shown the importance of this fossil group when past catastrophic events are investigated (Ferrow et al. 2011 and references herein). The onset of the fern-spore spike, reported from both hemispheres, at this event indicates widespread instantaneous (days to months) destruction of diverse forest communities on land. A thin layer of fungi preceding the fern recovery succession in the terrestrial K/Pg site, Moody Creek Mine, has been interpreted as photosynthesis shut off due to low light indicating that plants and animals in detritus-based food-chains were apparently less affected and perhaps also had an important role to play in recovery after the devastation caused by the impact.

Dinoflagellate cyst studies of K/Pg boundaries globally revealed that this phytoplankton group did not experience a mass extinction similar to other primary producers in the oceans, but significant compositional shifts in the dinoflagellate cysts assemblages are observed in connection with the K/Pg event (Ferrow et al. 2011; Willumsen 2011). The uniqueness of dinoflagellates, compared with other marine phytoplankton groups, is their ability to form cysts that can become motile even after a dormancy period of >100 years (Ribeiro et al. 2011). This group also has a wide range of different lifestyles ranging from autrophic, mesotrophic, or heterophic providing them with a number of adaptation abilities.

In the southwest Pacific, Southern Hemisphere, New Zealand, the first occurrence of Trithyrodinium evittii is immediately above the K/Pg and during the first approx. 1-2 Ma of the Paleocene period this species dominates the cyst assemblages. The abrupt dinoflagellate cyst assemblage’s shifts reflect a much extended recovery period in the marine realm compared with the terrestrial record. Thus, earliest Paleocene acme intervals of T. evittii have also been observed in middle to higher latitudes on the Northern Hemisphere, Nuussuaq, West Greenland and Stevns Klint, Denmark. A sudden abundance of this “warm-water” sea surface species has been interpreted to reflect earliest Paleocene global warming which caused migration of various phytoplankton groups e.g. dinoflagellates and foraminifera. However, globally dinoflagellate migrations patterns still have to be mapped in detail and compared against other paleoenvironmental proxies before the recovery following the K/Pg boundary event is fully elucidated.

Ferrow, M., Vajda, V., Bender Koch, C., Peucker-Ehrenbrink, B. and Willumsen, P.S. (2011). Multiproxy analysis of a new terrestrial and a marine Cretaceous–Paleogene (K–Pg) boundary site from New Zealand. Geochimica et Cosmochimica Acta 75, 657–672.

Ribeiro,S., Berge, T., Lundholm, N., Andersen, T.J., Abrantes, F. and Ellegaard, M. (2011). Phytoplankton growth after a century of dormancy illuminates past resilience to catastrophic darkness. Nature Communcations 311, 1–7.

Willumsen, P.S. (2011). Maastrichtian to Paleocene dinoflagellate cysts assemblages from Clarence Valley, southeastern Marlborough, New Zealand. Alcheringa: An Australasian Journal of Palaeontology 35, 199–240.