Efecto de la salinidad sobre la masa de estuches y el consumo de oxígeno de poblaciones de smicridea annulicornis (Blanchard, 1851) del Río Mapocho
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Fecha
2023
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Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
La salinización secundaria (definida como el aumento de la salinidad
producto de las actividades humanas) en ríos constituye una situación
preocupante. La exposición ante medios elevadamente salinos afecta
negativamente distintos caracteres de los organismos más sensibles, lo cual,
sumado al esfuerzo de realizar la osmorregulación, se traduce en mayores costos
energéticos. Uno de los principales grupos de macroinvertebrados de las
comunidades bentónicas del río Mapocho son las larvas del orden Trichoptera,
quienes construyen “estuches”, fijando piedras y otros materiales con seda,
proceso que también requiere recursos que podrían ser requeridos para
completar el desarrollo de las larvas. Se postuló como hipótesis que la salinidad
tiene un efecto negativo sobre la actividad de construcción y el consumo de
oxígeno. Con el objetivo de evaluar dichas respuestas en poblaciones de larvas
del tricóptero Smicridea annulicornis ante distintas condiciones de salinidad, se
pesaron construcciones provenientes de cuatro sitios de muestreo
correspondientes a las localidades de Aguas de Ramón, El Arrayán, Lo Curro y
El Trapiche. También se recolectaron 105 individuos provenientes de tres de las
localidades, los cuales fueron expuestos a tres condiciones de salinidad
(trabajada como conductividad eléctrica): 175, 1100 y 2200 µs/cm. Finalmente,
se midieron sus consumos de oxígeno a cuatro temperaturas y se calculó el Q10
de cada larva para comparar variaciones en la tasa metabólica. Se encontraron
diferencias significativas en la masa de “estuches” al comparar entre sitios, sin
embargo, no se pudo comprobar que dicho efecto sea producto de la salinidad.
No se encontraron diferencias entre los Q10 al comparar entre tratamientos
experimentales, pero sí al comparar entre sitios. Los resultados sugieren una
capacidad de adaptación local de la osmorregulación de las larvas de S.
annulicornis distinta para cada sitio, la cual les permite ser tolerantes ante las
condiciones de salinidad trabajadas. Se sugiere complementar este estudio con
un análisis de individuos adultos con el fin de conocer como dichas adaptaciones
afectan la capacidad reproductiva de la especie.
Secondary salinization (defined as the increase in salinity due human activities) in rivers is a worrying situation. Exposure to highly saline environments negatively affects different characters of the most sensitive organisms, which added to the effort of carrying out osmoregulation translates into higher energetic costs. One of the main groups of macroinvertebrates of the benthic communities from the Mapocho River are the larvae of the order Trichoptera, who build cases, fixing stones and other materials with silk, process which also requires resources which would be destined to complete the development of the larvae. It was hypothesized that salinity negatively affects construction activity and oxygen consumption. In order to evaluate both answers in populations of the caddis larvae Smicridea annulicornis at different salinity conditions, cases were collected and weighed from four sampling sites: Aguas de Ramón, El Arrayán, Lo Curro and El Trapiche. Subsequently, 105 individuals from three of the locations were collected and exposed to different salinity conditions (worked as electric conductivity): 175, 1100 and 2200 µs/cm. Finally, oxygen consumption of the larvae was measured at four temperatures and the Q10 coefficient for each specimen was calculated to evaluate differences between metabolic rates. Significant differences were found for case weight between sites, however, it could not be verified that this effect was a result of salinity. No differences for Q10 were found when experimental treatments were compared, however, differences were found when sites were compared. The results suggest a capacity for local adaptation of osmoregulation in S. annulicornis larvae that was different for each site, which allows them to be tolerant to the salinity conditions worked in this thesis. It is suggested to complement this study with an analysis of adult caddisflies in order to known how these adaptations affect the reproductive capacity of the species due resource allocation.
Secondary salinization (defined as the increase in salinity due human activities) in rivers is a worrying situation. Exposure to highly saline environments negatively affects different characters of the most sensitive organisms, which added to the effort of carrying out osmoregulation translates into higher energetic costs. One of the main groups of macroinvertebrates of the benthic communities from the Mapocho River are the larvae of the order Trichoptera, who build cases, fixing stones and other materials with silk, process which also requires resources which would be destined to complete the development of the larvae. It was hypothesized that salinity negatively affects construction activity and oxygen consumption. In order to evaluate both answers in populations of the caddis larvae Smicridea annulicornis at different salinity conditions, cases were collected and weighed from four sampling sites: Aguas de Ramón, El Arrayán, Lo Curro and El Trapiche. Subsequently, 105 individuals from three of the locations were collected and exposed to different salinity conditions (worked as electric conductivity): 175, 1100 and 2200 µs/cm. Finally, oxygen consumption of the larvae was measured at four temperatures and the Q10 coefficient for each specimen was calculated to evaluate differences between metabolic rates. Significant differences were found for case weight between sites, however, it could not be verified that this effect was a result of salinity. No differences for Q10 were found when experimental treatments were compared, however, differences were found when sites were compared. The results suggest a capacity for local adaptation of osmoregulation in S. annulicornis larvae that was different for each site, which allows them to be tolerant to the salinity conditions worked in this thesis. It is suggested to complement this study with an analysis of adult caddisflies in order to known how these adaptations affect the reproductive capacity of the species due resource allocation.
Notas
Tesis (Licenciado en Biología)
Palabras clave
Salinidad de Corrientes de Agua, Smicridea Annulicornis, Consumo de Oxígeno, Chile, Río Mapocho