A rapid expansion of human economic activity and population growth over the last decades is having a profound impact on the environment. An accurate understanding of this complex process, superimposed on natural change, is the major goal of modern science, with the outcome potentially affecting every living species on Earth. In order to have accurate estimates of present rates of change and reliable predictions for the future, we need to finesse their understanding of Earth’s past and be able to assess the environmental change at all spatial and temporal scales.
Understanding of causes and mechanisms of environmental change, whether it is related to climate change, or ecosystem degradation due to natural variability, or anthropogenic activity, requires the compilation of environmental data that span beyond the period of instrumental measurements. If long-term monitoring measurements are scarce or unavailable, such information could be obtained only by studying (paleo)proxies from sedimentary records. My group is using organic-walled microfossils (dinoflagellate cysts, foraminiferal organic linings, pollen and spores, etc.) and geochemical proxies as indicators of past and present environmental conditions.
Dinoflagellates are one of the principal components of phytoplankton, responsible for the primary production in marine environments. They are particularly diverse and ubiquitous in coastal waters and their cysts are abundant and well-preserved since they are not affected by dissolution processes as most of calcareous or siliceous microfossils are. Analysis of dinoflagellate cyst assemblages found in marine sediments is widely used to interpret environmental history.
Some of my group's projects are focused on centennial-to-annual reconstructions of marine primary productivity, sea-surface temperature, and salinity recorded on a number of “laminated” sediment cores taken from high sedimentation rate areas. The aim of this research is to:
- map at high-resolution the chronology of major climatic events in the eastern North Pacific over the last 50 kyr recorded in marine sediments
- investigate how the climatic changes of different magnitude affect phytoplankton composition and primary production
- make a quantitative reconstruction of past oceanographic conditions with the use of the transfer function technique
- identify natural and human-induced environmental changes in estuarine and coastal waters of North America
- provide insights on the magnitude and frequency of harmful algal blooms that can be traced by dinoflagellates cyst records in sediments
Karin Zonneveld & Vera Pospelova, 2014. Modern dinoflagellate cyst determination key. See the website