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Yundan Pi

Laboratory for Molecular Biogeochemistry and Organic Geochemistry
Department of Earth and Planetary Sciences
Harvard University
20 Oxford St, Cambridge, MA 02138
E-mail: yundanpiat fas dot harvard dot edu

Yundan Pi received a bachelor's degree in Chemistry from the University of Science and Technology of China, and a master's degree in Geochemistry from the School of Earth and Space Sciences, also of the University of Science and Technology of China. She is currently a second-year graduate student in the Department of Earth and Planetary Sciences, Harvard University. Her research aims to investigate the microbial diversity of lipid biosynthesis in extreme environments, including extremes of temperature, pH, and salinity. Interactions between microbes and the environments they reside in might induce changes in both the microbial community and in the lipid profiles they expres. Understanding the results of those interactions can yield a better understanding of the development of both current and past environments. Her previous work focussed on the distribution of tetraether lipids of Archaea in terrestrial hot springs and in methaogenic marine sediments. Presently, she is devoted to the study of sqhC gene (squalene-hopene cyclase) and hopanoid distributions in samples from different environments. Little is known about the phenotypes conferred by hopanoids, and she hopes to investigate differing patterns of hopanoid biosynthesis to search forinformative patterns.

Yundan is working with a variety of samples. These include a cryptogamic desert crust from Moab, UT. DNA has been extracted from this sample and the primary results revealed the appearance of the sqhC gene. Phylogenetic analysis suggests that many (or most) of the organismal sources of these sqhC genes are Cyanobacteria. Further work on this sample is on-going.In addition, she will examine samples from a hypersaline lake in the Bahamas (Storr's Lake). For a more extreme environment, she will include Mono Lake waters and sediments in subsequent research. The water in Mono lake contains chlorides, carbonates, and sulfates, with a pH of 10, and is almost three times as salty as the ocean. Mono Lake represents an extreme environment that is likely to harbor unique microbes. However, the relationshipts between their phylogenetic diversity, taxonomy and ecology and their distribution of lipid biosynthetic pathways remain a mystery. The full range of these results may help gain deeper insight into the interaction between contemporary ecological environments and hopanoid-producing microorganisms.