A low-cost laboratory demonstration of the effects of temperature on the metabolism of an aquatic poikilotherm

Abstract

ABSTRACT While metabolism is a fundamental process in physiology, the measurement of metabolism by living animals often requires specialized and expensive equipment. In 2016, I developed a novel laboratory exercise for animal physiology students where students were able to observe the effects of temperature and long-term temperature acclimation on the physiology of the Eastern grass shrimp, Palaemonetes paludosus. In this lab, grass shrimp were housed for 1 week at one of three temperatures, 20°C, 24°C, and 28°C. While grass shrimp encounter temperatures considerably colder than this in the wild, we were limited by the temperatures we could achieve without access to aquarium chillers. The students then moved shrimp into water of different temperatures and measured metabolic rates indirectly using heart rate and oxygen consumption. The initial results showed noticeable shifts in baseline metabolic rate over a relatively short, 2 week long acclimation period. In both heart rate and oxygen consumption, metabolic rates climbed predictably with temperature, consistent with the literature on responses in ectotherms. Also, consistent with the literature, the shrimp that were acclimated to warmer temperatures downregulated their metabolism to compensate, showing the lower metabolic rate at all three temperatures.