Temperature acclimation alters cardiac performance in the lobster Homarus americanus |
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Authors: | Joseph Camacho Syed Aman Qadri Hongkun Wang Mary Kate Worden |
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Institution: | (1) Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA;(2) Division of Biostatistics and Epidemiology, University of Virginia, Charlottesville, VA 22908, USA |
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Abstract: | The American lobster is a poikilotherm that inhabits a marine environment where temperature varies over a 25°C range and depends
on the winds, the tides and the seasons. To determine how cardiac performance depends on the water temperature to which the
lobsters are acclimated we measured lobster heart rates in vivo. The upper limit for cardiac function in lobsters acclimated
to 20°C is approximately 29°C, 5°C warmer than that measured in lobsters acclimated to 4°C. Warm acclimation also slows the
lobster heart rate within the temperature range from 4 to 12°C. Both effects are apparent after relatively short periods of
warm acclimation (3–14 days). However, warm acclimation impairs cardiac function at cold temperatures: following several hours
exposure to frigid (<5°C) temperatures heart rates become slow and arrhythmic in warm acclimated, but not cold acclimated,
lobsters. Thus, acclimation temperature determines the thermal limits for cardiac function at both extremes of the 25°C temperature
range lobsters inhabit in the wild. These observations suggest that regulation of cardiac thermal tolerance by the prevailing
environmental temperature protects against the possibility of cardiac failure due to thermal stress. |
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Keywords: | Lobster Cardiac Temperature Acclimation Thermal tolerance |
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