Efectos de la exposición a ácido okadaico y variaciones ambientales sobre mecanoreceptores de larvas tempranas de anchoveta (Engraulis ringens).
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Date
2024
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Universidad de Concepción
Abstract
El impacto de las toxinas marinas producidas por floraciones algales, como el ácido okadaico (AO), en combinación con variaciones ambientales como la temperatura y la salinidad sobre organismos de la columna de agua, es un campo poco explorado pero de gran relevancia ecológica. Especies pelágicas de importancia comercial como la anchoveta (Engraulis ringens) pueden estar expuestas a estos factores en un escenario de cambio climático, que no solo afecta las condiciones normales de temperatura y salinidad en la columna de agua, sino que también aumenta la probabilidad de floraciones algales de especies productoras de estas toxinas y, por ende, aumenta la probabilidad de que esta especie de pez pueda entrar en contacto con las biotoxinas producidas durante estos eventos. En este estudio, se evaluó la integridad de las células ciliadas de órganos mecanosensoriales presentes en larvas de peces (llamados neuromastos), ante la exposición por inmersión a distintas combinaciones de AO (1 ng/mL), temperatura (12 y 14°C) y salinidad (32 y 34 PSU). Para estas evaluaciones se realizó el conteo de células ciliadas viables en neuromastos específicos usando tinciones vitales en larvas con saco vitelino de anchoveta provenientes de huevos recolectados en la zona de desove en la región del Biobío frente a Bahía Coliumo. El análisis de los resultados mostró un efecto significativo en el número promedio de células ciliadas viables por neuromasto asociado a ciertos tratamientos. En primer lugar, se observó una disminución significativa (Test de Dunn p=0.0161; p=0.0019) en la integridad de estos órganos en respuesta a cambios en la salinidad del entorno con un menor número de células en el tratamiento de 32 PSU respecto a las condiciones normales (34 PSU, 12°C); además de una variación estacional asociada al avance del periodo reproductivo de la especie (promedio inicial (septiembre): 7,4 células viables; final (diciembre): 4,4 células viables). Se evidenció también, un efecto combinado de la exposición a AO y los parámetros ambientales, con una disminución significativa en la cantidad de células ciliadas viables en la mayoría de las combinaciones probadas, evidenciándose el daño influenciado por la toxina, junto con un papel sinérgico y/o aditivo de la temperatura. Estos hallazgos, que demuestran cómo la acción de AO sobre los neuromastos aumenta por factores ambientales, resaltan la importancia de considerar múltiples factores al estudiar los efectos de las toxinas marinas en larvas de peces y su supervivencia en el ambiente, proporcionando una nueva perspectiva sobre cómo estas toxinas pueden interactuar con elementos abióticos y afectar a los organismos que coexisten en la columna de agua.
The impact of marine toxins produced by algal blooms, such as okadaic acid (OA), in combination with environmental variations such as temperature and salinity, on organisms in the water column, is a field that is poorly explored but of great ecological relevance. Pelagic species of commercial importance such as the anchoveta (Engraulis ringens) may be exposed to these factors in a scenario of climate change, which not only affects the normal conditions of temperature and salinity in the water column but also increases the probability of algal blooms of species producing these toxins and therefore increases the likelihood of these fish species coming into contact with the biotoxins produced during these events. In this study, the integrity of ciliated cells of neuromasts, mechanosensory organs present in fish larvae, was evaluated under immersion exposure to different combinations of OA (1 ng/mL), temperature (12 and 14°C), and salinity (32 and 34 PSU). For these evaluations, the count of viable ciliated cells in specific neuromasts was performed using vital stains in yolk-sac anchoveta larvae collected from eggs spawned in this species spawning area in the Biobío region off Bahía Coliumo. The analysis of the results showed a significant effect on the average number of viable ciliated cells per neuromast associated with certain treatments. Firstly, a significant decrease (Dunn's test p=0.0161; p=0.0019) in the integrity of these organs was observed in response to changes in environmental salinity, with a lower number of cells in the 32 PSU treatment compared to normal conditions (34 PSU; 12°C). Additionally, a seasonal variation associated with the advancement of the species' reproductive period was evidenced (Initial average (September): 7.4 viable cells; final (December): 4.4 viable cells). A combined effect of OA exposure and environmental parameters was also evident, with a significant decrease in the quantity of viable ciliated cells in most of the tested combinations, indicating damage influenced by the toxin, along with a synergistic and/or additive role of temperature. These findings, demonstrating how the action of OA on neuromasts is enhanced by environmental factors, highlight the importance of considering multiple factors when studying the effects of marine toxins on fish larvae and their survival in the environment, providing a new perspective on how these toxins may interact with abiotic elements and affect organisms coexisting in the water column.
The impact of marine toxins produced by algal blooms, such as okadaic acid (OA), in combination with environmental variations such as temperature and salinity, on organisms in the water column, is a field that is poorly explored but of great ecological relevance. Pelagic species of commercial importance such as the anchoveta (Engraulis ringens) may be exposed to these factors in a scenario of climate change, which not only affects the normal conditions of temperature and salinity in the water column but also increases the probability of algal blooms of species producing these toxins and therefore increases the likelihood of these fish species coming into contact with the biotoxins produced during these events. In this study, the integrity of ciliated cells of neuromasts, mechanosensory organs present in fish larvae, was evaluated under immersion exposure to different combinations of OA (1 ng/mL), temperature (12 and 14°C), and salinity (32 and 34 PSU). For these evaluations, the count of viable ciliated cells in specific neuromasts was performed using vital stains in yolk-sac anchoveta larvae collected from eggs spawned in this species spawning area in the Biobío region off Bahía Coliumo. The analysis of the results showed a significant effect on the average number of viable ciliated cells per neuromast associated with certain treatments. Firstly, a significant decrease (Dunn's test p=0.0161; p=0.0019) in the integrity of these organs was observed in response to changes in environmental salinity, with a lower number of cells in the 32 PSU treatment compared to normal conditions (34 PSU; 12°C). Additionally, a seasonal variation associated with the advancement of the species' reproductive period was evidenced (Initial average (September): 7.4 viable cells; final (December): 4.4 viable cells). A combined effect of OA exposure and environmental parameters was also evident, with a significant decrease in the quantity of viable ciliated cells in most of the tested combinations, indicating damage influenced by the toxin, along with a synergistic and/or additive role of temperature. These findings, demonstrating how the action of OA on neuromasts is enhanced by environmental factors, highlight the importance of considering multiple factors when studying the effects of marine toxins on fish larvae and their survival in the environment, providing a new perspective on how these toxins may interact with abiotic elements and affect organisms coexisting in the water column.
Description
Tesis presentada para optar al grado académico de Magister en Ciencias mención Oceanografía
Keywords
Anchoveta peruana, Ecología acuática, Toxicología