All animals are subject to environmental stress during their lives and oxygen availability may be a particular problem for animals in aquatic habitats, where solubility is low and competition for it is high. One animal, the Western painted turtle has evolved the capacity to survive complete oxygen deprivation, also called anoxia, for over 30 hours at 20°C and for more than three months at 3°C, which is longer than any other tetrapod. This ability allows the painted turtle to overwinter in oxygen-depleted, ice-covered ponds in the wild. To understand the underlying mechanisms, this research uses the recently sequenced painted turtle genome to determine the gene expression changes that occur during anoxia and to relate them to the physiological changes that are already known to occur. It focuses on the turtle's heart, which, in other vertebrates, is extremely sensitive to oxygen deprivation, including humans. It also focuses on development, because hatchling turtles are less tolerant of anoxia than adults. This research also explores processes related to the handling of the massive lactic acid loads, which accumulate to levels higher than seen in any other animal. This includes studies of how lactic acid affects the turtle shell and heart and how that lactic acid metabolized by the body. There is also educational component involving the St. Louis Zoo, which will enhance one of its existing educational apprenticeship program representing mostly underserved and underrepresented minorities. It also supports an annual workshop to promote civic science, which will provide resources and opportunities for St. Louis area scientists to connect with high school and college students looking to gain scientific research experience. The broader impacts of this project will be to provide important insights into an economically, ecologically, and clinically relevant problem, namely why some animals are more tolerant of oxygen deprivation than others. It will also increase student participation in the sciences, generally, and comparative animal physiology, specifically.
