Efecto de la aclimatación sobre el tiempo de colapso de Aegla spp en ríos de la zona centro-sur de Chile
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2023
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
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El cambio climático está provocando respuestas biológicas a escala mundial impulsando organismos de agua dulce a cambiar sus rangos de distribución para mantenerse dentro de sus condiciones ambientales óptimas. La aclimatación es un mecanismo relevante para afrontar el cambio climático, el cual se define como cualquier modificación de un rasgo fisiológico de un genotipo en respuesta a cambios de una variable ambiental. Dentro de estos cambios, se encuentra la aclimatación térmica, que puede ocurrir cuando hay exposición prolongada a un aumento de temperatura que provoca cambios como el incremento del CTmax. El límite superior de tolerancia a mayores temperaturas puede ser descrito por CTmax y z (sensibilidad térmica), que pueden ser observados en curvas de temperatura (TDT), donde el tiempo de colapso es considerado de manera explícita. Se ha sugerido un posible compromiso entre una alta sensibilidad térmica y poseer un bajo límite térmico. En Chile habitan 18 especies del género Aegla, las cuales están amenazadas por alteración del hábitat por acción antrópica. En esta investigación se realizó un experimento de estrés térmico agudo a individuos de Aegla spp de tres ríos de la zona centro-sur de Chile, para determinar si el tiempo de colapso varía con el CTmax en distintas condiciones de aclimatación, a 13 y 23 °C. Se obtuvieron diferencias en el z, 4.93 y 2.18 °C para individuos aclimatados en frío y calor, respectivamente. Debido a esto, se registró un mayor tiempo de colapso para los individuos aclimatados en calor. Además, estos tienen una tolerancia al calor favorable en cuatro escenarios térmicos. De acuerdo con esto, se sugiere que la aclimatación en calor es un factor relevante para contrarrestar los aumentos de temperaturas del ambiente, pues permite mejorar la tolerancia térmica y así persistir ante el cambio climático.
Climate change is triggering biological responses on a global scale driving freshwater organisms to shift their ranges to stay within their optimal environmental conditions. Acclimation is a relevant mechanism for coping with climate change, which is defined as any modification of a physiological trait of a genotype in response to changes in an environmental factor. Among these changes is thermal acclimation, which can occur when there is prolonged exposure to an increase in temperature that causes changes such as an increase in CTmax. The upper limit of tolerance to higher temperatures can be described by CTmax and z (thermal sensitivity), which can be observed in temperature curves (TDT), where the collapse time is explicitly considered. A possible compromise between high thermal sensitivity and having a low thermal limit has been suggested. In Chile there are 18 species of the genus Aegla, which are threatened by habitat alteration by anthropogenic action. In this research, an acute thermal stress experiment was conducted on individuals of Aegla spp from three rivers in south-central Chile, to determine whether the collapse time varies with the CTmax under different acclimation conditions, at 13 and 23 °C. Differences in z were obtained, 4.93 and 2.18 °C for individuals acclimated in cold and heat, respectively. Because of this, a longer collapse time was recorded for individuals acclimated in heat. Furthermore, these have favorable warming tolerance in four thermal scenarios. Accordingly, it is suggested that heat acclimation is a relevant factor to counteract increases in environmental temperatures, since it allows improving thermal tolerance and thus persisting in the midst of climate change.
Climate change is triggering biological responses on a global scale driving freshwater organisms to shift their ranges to stay within their optimal environmental conditions. Acclimation is a relevant mechanism for coping with climate change, which is defined as any modification of a physiological trait of a genotype in response to changes in an environmental factor. Among these changes is thermal acclimation, which can occur when there is prolonged exposure to an increase in temperature that causes changes such as an increase in CTmax. The upper limit of tolerance to higher temperatures can be described by CTmax and z (thermal sensitivity), which can be observed in temperature curves (TDT), where the collapse time is explicitly considered. A possible compromise between high thermal sensitivity and having a low thermal limit has been suggested. In Chile there are 18 species of the genus Aegla, which are threatened by habitat alteration by anthropogenic action. In this research, an acute thermal stress experiment was conducted on individuals of Aegla spp from three rivers in south-central Chile, to determine whether the collapse time varies with the CTmax under different acclimation conditions, at 13 and 23 °C. Differences in z were obtained, 4.93 and 2.18 °C for individuals acclimated in cold and heat, respectively. Because of this, a longer collapse time was recorded for individuals acclimated in heat. Furthermore, these have favorable warming tolerance in four thermal scenarios. Accordingly, it is suggested that heat acclimation is a relevant factor to counteract increases in environmental temperatures, since it allows improving thermal tolerance and thus persisting in the midst of climate change.
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Tesis (Licenciado en Biología)
Palabras clave
Cambios Climáticos, Aclimatación, Aegla spp, Estrés Térmico.