The Quarmby Lab is evolving January 13, 2016 We are developing a new project at the intersection of cell biology and ecology, studying a sister species of our beloved single-celled green alga, Chlamydomonas reinhardtii. Chlamydomonas nivalis grows in thin layers of melt-water on snow and ice. It has been found in alpine regions worldwide and is especially abundant in the high arctic. The alga protects itself from UV irradiation by synthesizing red pigment granules, giving snow a red hue and reducing albedo (reflection of sunlight) to 40%. The lower albedo increases local temperature, promoting snow and ice melting and increasing the abundance of C. nivalis. Through this positive feedback loop, C. nivalis amplifies snow and ice melting. Historical documents and satellite images suggest that the fraction of snow and ice covered with ‘watermelon snow’ might be rapidly expanding as the earth warms. C. nivalis lives intimately with a community of bacteria and phage (viruses that attack bacteria). The algae produce mucus that traps and holds these microbes. It is of interest that similar communities of phage and bacteria live in the mucus layers of our gut, influencing our health in ways that we do not yet understand. For over two decades, the Quarmby lab has done cell biology lab experiments using the sister species, C. reinhardtii. Through this work we and others made discoveries that help us understand the fundamental machines of cellular life and consequently, the etiology of several human diseases (see video above). We now propose to study the ecology of this globally important microbial community, including the symbiotic relationships that provide this community the ability to thrive in the harsh conditions of nutrient impoverishment and low temperature. Importantly, C. nivalis and its microbial community may serve as a model system for understanding the complex cellular interactions of the human microbiome.