Physiology and metabolism of lipids: implications for vertebrate ecology ,life histories, and conservation

My research program combines comparative physiology and ecology with lipid biochemistry and metabolism in vertebrates. I integrate field and laboratory studies on issues of interest to medical and biological communities, which have applications to conservation and management of mammal, seabird, and fish populations, and which further our understanding of both physiological and ecosystem processes. The long-term goals of my research program are 3-fold: 1) to advance our understanding of lipid metabolism and its regulation in vertebrates, 2) to apply this and related knowledge to gain a better understanding of the foraging ecology of free-ranging animals and the ecosystems within which they function, and 3) to better understand the physiology of lactation in relation to lipid metabolism and mammalian life history strategies. During the next 5 years, I will expand research in these inter-related areas. A major focus of my research has been to better understand processes of fatty acid (FA) metabolism, deposition and mobilization in adipose tissue and milk, the implications this has to using FAs to quantitatively estimate predator diets from their metabolically active fat stores, and by doing so to better understand trophic dependencies and adaptations of individual species, marine food web structure, and ecosystem dynamics. Although I developed quantitative FA signature analysis in 2004, it remains a first generation tool and there is a rapidly growing need to improve its accuracy, precision, and confidence in diet estimation of wild animal populations and, thus, our understanding of food web structure and function in key ecosystems. The other focus of my program is on the interplay between lipid metabolism, prolonged fasting and lactation, and their regulation in marine mammals. We will examine the influence of parity (including physiological senescence) and genotype on lactation performance of individuals, factors that have not previously been investigated in a large wild mammal. These studies aim to advance our understanding of the onset, regulation, maintenance and decline in milk production and lipid metabolism in capital-breeding females and the genetics that underlie individual variation in lactation performance.