Meeting Abstract

20.5  Wednesday, Jan. 4  Real-time measurements of metabolism during freezing and thawing in wood frogs, Rana sylvatica SINCLAIR, BJ*; STINZIANO, JR; WILLIAMS, CM; MARSHALL, KE; MACMILLAN, HA; STOREY, KB; University of Western Ontario; University of Western Ontario; University of Western Ontario; University of Western Ontario; University of Western Ontario; Carleton University bsincla7@uwo.ca

The wood frog, Rana sylvatica, survives freezing because of a dynamic process of mobilization of glucose from glycogen in response to ice formation. This glucose is restored to glycogen after freezing, but repeated freezing leads to depletion of glycogen, which suggests that freezing and thawing have a metabolic cost. Here, we measure oxygen consumption and carbon dioxide production in R. sylvatica during complete freeze-thaw cycles in real time using flow-through respirometry. Initiation of freezing results in a very large increase in metabolic rate. While frozen, metabolic rate is significantly depressed, and there is a spike in metabolic rate upon thawing, although it is unclear whether this reflects a cost of thawing, or the cost of metabolizing anaerobic byproducts accumulated while frozen. The ecological implications of these costs will be discussed in the context of ongoing climate change which modifies the frequency and duration of freeze-thaw cycles.