Abstract :  Phytoplanktons form the basis of the marine food web. Therefore, to understand the impact of climate change on our ecosystem, it is crucial to understand how phytoplanktons may respond to climate change. In particular, we need to characterize the adaptive capacities of species over long timescales. Examining populations of phytoplanktons revived from recent and millennia old resting spores deposited in sub-seafloor sediments is an ideal system for long-term evolutionary studies. To establish phytoplanktons as a model to study long-term impact of climate change, we revived resting spores of the diatom Chaetoceros from three time periods (recent: 0 to 80 years; ancient: ~1250 (Medieval Climate Anomaly) and ~6600 (Holocene Thermal Maximum). We measured the response of the revived populations from the three ages to varying temperature, light and salinity conditions was determined by measuring growth rate, cell density, and chlorophyll a content. We observed a significant effect of temperature and light but not salinity. The growth rate of the populations from a deeper layer were significantly lower than the surface layer revealing that these revived phytoplankton populations can be good model system to study the effect of climate change and human actions on phytoplanktons and temperature seems to be an important variable to study the effect of climate change on phytoplanktons. 

Short Bio: Anushree Sanyal is a Group Leader in Environmental and Natural Sciences at Södertörn University, Stockholm Sweden. She is interested in understanding the response of phytoplanktons to climate change due to natural events and human actions over long timescales. Her work has established a new model system for studying the effect of climate change on diatoms. Currently, her group is investigating the effect of several environmental variables on the response and adaptation of diatoms. In addition, her group is also examining the changes in the genetic signatures in revived diatom populations over long timescales. Anushree Sanyal studied Botany (Honours) from the University of Calcutta, India and obtained a master’s in science degree in 2002 from University of Oklahoma, USA. In 2002 she moved to Texas to pursue her doctoral research in quantitative genetics and evolutionary and ecological genomics and obtained a Ph.D. in evolutionary biology from the University in Texas at Austin, USA in 2010. After a postdoctoral stint at University of Wisconsin-Madison, USA in 2013 she joined the French National Centre for Scientific Research. In 2016 she moved to Uppsala University, Stockholm Sweden as a researcher. In 2020, she started her own research group at Södertörn University, Stockholm, Sweden. She is also a researcher at the Swedish University of Agricultural Sciences.