Effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost (Girella nigricans)
Although most animals live in complex, thermally variable environments, the impact of this variability on specific physiological systems is still unresolved. The ectotherm heart is known to change in both structure and function to ensure appropriate oxygen delivery under different thermal regimes, b...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-01-01
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| Series: | Current Research in Physiology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2665944122000098 |
| _version_ | 1811295244670468096 |
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| author | Gail D. Schwieterman Emily A. Hardison Erika J. Eliason |
| author_facet | Gail D. Schwieterman Emily A. Hardison Erika J. Eliason |
| author_sort | Gail D. Schwieterman |
| collection | DOAJ |
| description | Although most animals live in complex, thermally variable environments, the impact of this variability on specific physiological systems is still unresolved. The ectotherm heart is known to change in both structure and function to ensure appropriate oxygen delivery under different thermal regimes, but the plasticity of the upper thermal limits of the heart under stable or variable thermal acclimation conditions remains unknown. To investigate the role of thermal variability on cardiac acclimation potential, we acclimated a eurythermal fish, opaleye (Girella nigricans), to three static temperature treatments (13, 16, and 19 °C) as well as two oscillating treatments which cycled between maximum and minimum temperatures every 12 h (13–19 °C and 16–22 °C). These temperatures and daily thermal ranges were chosen to mimic the conditions observed in the rocky intertidal environments in Santa Barbara, CA, USA where the fish were collected. We hypothesized that increasing temperature would increase upper thermal limits of the heart, and that variable acclimations would result in broader acute thermal performance curves (TPCs) compared to static acclimations. We measured maximum heart rate during acute warming to determine cardiac thermal performance (i.e., the temperature corresponding to the onset of cardiac arrythmia, the temperature at maximum heart rate, absolute maximum heart rate, and the Arrhenius breakpoint temperature) and construct acute TPCs. Rising static acclimation temperatures increased upper thermal limits but had no impact on peak maximum heart rate. The warmest static temperature did, however, cause a narrowing of the acute TPC. Fish acclimated to variable conditions had the same upper thermal limits compared to fish acclimated to static conditions with the same mean temperature in all metrics of thermal performance. Further, there was no significant broadening of the acute TPC. This study suggests that cardiac plasticity is robust to thermal variation in this eurythermal fish. |
| first_indexed | 2024-04-13T05:30:31Z |
| format | Article |
| id | doaj.art-b80ac8cad793453fb4010910d243491a |
| institution | Directory Open Access Journal |
| issn | 2665-9441 |
| language | English |
| last_indexed | 2024-04-13T05:30:31Z |
| publishDate | 2022-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Current Research in Physiology |
| spelling | doaj.art-b80ac8cad793453fb4010910d243491a2022-12-22T03:00:28ZengElsevierCurrent Research in Physiology2665-94412022-01-015109117Effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost (Girella nigricans)Gail D. Schwieterman0Emily A. Hardison1Erika J. Eliason2Corresponding author.; University of California, Santa Barbara, Santa Barbara, CA, 93106, USAUniversity of California, Santa Barbara, Santa Barbara, CA, 93106, USAUniversity of California, Santa Barbara, Santa Barbara, CA, 93106, USAAlthough most animals live in complex, thermally variable environments, the impact of this variability on specific physiological systems is still unresolved. The ectotherm heart is known to change in both structure and function to ensure appropriate oxygen delivery under different thermal regimes, but the plasticity of the upper thermal limits of the heart under stable or variable thermal acclimation conditions remains unknown. To investigate the role of thermal variability on cardiac acclimation potential, we acclimated a eurythermal fish, opaleye (Girella nigricans), to three static temperature treatments (13, 16, and 19 °C) as well as two oscillating treatments which cycled between maximum and minimum temperatures every 12 h (13–19 °C and 16–22 °C). These temperatures and daily thermal ranges were chosen to mimic the conditions observed in the rocky intertidal environments in Santa Barbara, CA, USA where the fish were collected. We hypothesized that increasing temperature would increase upper thermal limits of the heart, and that variable acclimations would result in broader acute thermal performance curves (TPCs) compared to static acclimations. We measured maximum heart rate during acute warming to determine cardiac thermal performance (i.e., the temperature corresponding to the onset of cardiac arrythmia, the temperature at maximum heart rate, absolute maximum heart rate, and the Arrhenius breakpoint temperature) and construct acute TPCs. Rising static acclimation temperatures increased upper thermal limits but had no impact on peak maximum heart rate. The warmest static temperature did, however, cause a narrowing of the acute TPC. Fish acclimated to variable conditions had the same upper thermal limits compared to fish acclimated to static conditions with the same mean temperature in all metrics of thermal performance. Further, there was no significant broadening of the acute TPC. This study suggests that cardiac plasticity is robust to thermal variation in this eurythermal fish.http://www.sciencedirect.com/science/article/pii/S2665944122000098Arrhenius breakpointCardiac functionThermal performance curveThermal acclimation |
| spellingShingle | Gail D. Schwieterman Emily A. Hardison Erika J. Eliason Effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost (Girella nigricans) Current Research in Physiology Arrhenius breakpoint Cardiac function Thermal performance curve Thermal acclimation |
| title | Effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost (Girella nigricans) |
| title_full | Effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost (Girella nigricans) |
| title_fullStr | Effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost (Girella nigricans) |
| title_full_unstemmed | Effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost (Girella nigricans) |
| title_short | Effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost (Girella nigricans) |
| title_sort | effect of thermal variation on the cardiac thermal limits of a eurythermal marine teleost girella nigricans |
| topic | Arrhenius breakpoint Cardiac function Thermal performance curve Thermal acclimation |
| url | http://www.sciencedirect.com/science/article/pii/S2665944122000098 |
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