Protists are single-celled eukaryotes that exhibit an extraordinary range of physiological traits, ecological behaviors and nutritional modes. In particular, many species are mixotrophs, and can use multiple nutritional pathways. As these organisms can both fix carbon through photoautotrophy and consume organic carbon sources through heterotrophy, a better understanding of their physiology, genetics and ecology is central to our knowledge of nutrient cycling in aquatic habitats. In particular, mixotrophs are known to be important in polar regions, and it has been hypothesized that the ability to switch between nutritional modes may be a critical trait in ecosystems that undergo dramatic seasonal changes in light availability. This project will involve the organization of a special symposium on mixotrophs at the International Congress on Protistology Meeting, (ICOP XIV). Seven speakers will be recruited to speak on topics ranging from mixotrophic genetics, ecology, physiology and nutrient cycling. This activity will bring scientists together from multiple subdisciplines, allowing new collaborations to be forged and new research directions to be planned. Special efforts will be made to recruit individuals from groups traditionally underrepresented in science. Speakers will be invited to submit manuscripts on their presented work to the Journal of Eukaryotic Microbiology to increase the impact of this session beyond meeting participants.
The goal of this grant was to host a symposium that examined our current state of knowledge of physiological flexibilities of protist taxa. Many protistan species employ more than one mode of nutrition in an single cell (e.g. the consumption of particles by algae, chloroplast acquisition by ciliates and dinoflagellates), and many also enter into various symbiotic relationships with other protists or invertebrates that ultimately expand their ecological success and importance. The symposium "Physiological Flexibility among Protists: Insights from studies of genes to ecosystems" took place on August 2, 2013 at the 14th International Congress of Protistology, held in Vancouver, British Columbia. The Congress is a unique opportunity for young investigators, postdocs and students to meet and talk with established scientists from around the world. Our invited speakers included both established and young investigators, with international and U.S. affiliations. The speakers and the titles of their talks are listed below. Diane K. Stoecker University of Maryland "Mixotrophy in Planktonic Protists: Diversity of Taxa, Physiologies, Habitats and Ecosystem Effects" Johan D Decelle CNRS/UPMC Roscoff France "New Perspectives on the Functioning of Photosymbiosis in Radiolaria and Foraminifera" Karla B Heidelberg University of Southern California "Comparative Functional Analysis of the Harful Algae Haptophyte, Prymnesium parvum." Ben A Ward Ecole Normale Superieure Paris France " Evaluating the Basin-scale Impact and Uncertainties of Mixotrophy in the North Atlantic"
