Composición y abundancia de foraminíferos planctónicos en la estación cosmos, frente a la costa de Coquimbo (30°s) durante verano e invierno 2023 y verano 2024.
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Date
2025
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Universidad de Concepción
Abstract
El presente estudio analiza la composición y abundancia de foraminíferos planctónicos recolectados en el Pacifico Suroriental frente a la costa de Coquimbo (30°S) durante el verano e invierno de 2023 y el verano de 2024. Este trabajo se enmarca en el proyecto de colaboración internacional entre Chile y Reino Unido "Desenredando el desafío del proxy genotípico en foraminíferos planctónicos en el Sistema de la Corriente de Humboldt – DETECTORS", buscando mejorar el entendimiento de estos organismos como indicadores de condiciones oceanográficas en el Pacífico Suroriental. Los tres muestreos, realizados a bordo de la nave VENUS en la estación COSMOS (29° 41´S; 72° 02´W) ubicada a 12 km de la costa, abarcaron tres profundidades de la columna de agua: superficial, oxiclina y Zona Mínima de Oxígeno. Se recolectaron muestras fisicoquímicas y biológicas mediante botellas Niskin y redes de plancton, respectivamente. La identificación y cuantificación de los foraminíferos se llevó a cabo mediante lupa binocular y microscopía electrónica, complementando los análisis con índices ecológicos y pruebas estadísticas. Se identificaron un total de 22 especies, de las cuales tres dominaron la asociación total de foraminíferos en los tres muestreos: Neogloboquadrina incompta, Globigerina bulloides y Globorotaloides hexagonus, representando aproximadamente el 80 % de la comunidad total, reflejando su relación con factores ambientales como temperatura y oxígeno a través de la presencia o ausencia de estas especies y su abundancia en cada asociación. Otras especies con baja dominancia también mostraron variaciones estacionales significativas en su abundancia, así como también se identificó una especie que podría reflejar ciertos eventos como El Niño el cual estuvo presente en los años 2023 y 2024. Se identificaron un total de 3.636 individuos de foraminíferos planctónicos correspondientes a 22 especies y 13 géneros, de las cuales 19 fueron reportadas previamente para el área. Una notable diferencia entre los estudios previos y el presente fue la baja abundancia de Globigerinella calida en COSMOS. Los resultados arrojaron diferencias significativas entre las asociaciones de foraminíferos planctónicos de las diferentes temporadas entre estratos, por lo que se acepta la primera hipótesis sobre si hay diferencias entre las asociaciones en las tres temporadas estudiadas. Por otro lado, no hubo resultados consistentes al momento de evaluar El Niño, por lo que la hipótesis sobre si este evento afectó o no estas asociaciones no pudo ser evaluada.
The present study analyzes the composition and abundance of planktonic foraminifera collected in the Southeastern Pacific off the coast of Coquimbo (30°S) during the summer and winter of 2023 and the summer of 2024. This work is part of an international collaborative project between Chile and the United Kingdom “The Genotypic Proxy Challenge in Planktonic Foraminifera in the Humboldt Current System – DETECTORS," aims to improve the understanding of these organisms as indicators of oceanographic conditions in the Southeastern Pacific. The three sampling campaigns, conducted aboard the VENUS vessel at the COSMOS station (29°41'S; 72°02'W), located 12 km offshore, covered three depths of the water column: surface, oxycline, and the Oxygen Minimum Zone. Physicochemical data and biological samples were collected using Niskin bottles and plankton nets. The identification and quantification of foraminifera were carried out through binocular scope and electron microscopy, complemented by ecological indices and statistical analyses. A total of 22 species were identified, with three dominating the total foraminiferal association across all three campaigns: Neogloboquadrina incompta, Globigerina bulloides and Globorotaloides hexagonus, collectively representing approximately 80% of the total community. These species reflect their relationship with environmental factors such as temperature and oxygen, as evidenced by their presence, absence, and abundance within each association. Other, less dominant species, also displayed significant seasonal variations in abundance, including one species that may reflect the El Niño event, which occurred in 2023 and 2024. A total of 3636 individuals of planktonic foraminifera, corresponding to 22 species and 13 genera, were identified. Of these, 19 species had previously been reported by Marchant et al. (2004) and Coloma et al. (2005). A notable difference between those studies and the present one was the low abundance of Globigerinella calida at COSMOS. The results revealed significant differences between planktonic foraminiferal assemblages across seasons and water column strata, supporting the hypothesis that differences exist between associations during the three seasons studied. However, consistent results regarding the impact of the El Niño event were not obtained, leaving the hypothesis about its effects on these associations unevaluated.
The present study analyzes the composition and abundance of planktonic foraminifera collected in the Southeastern Pacific off the coast of Coquimbo (30°S) during the summer and winter of 2023 and the summer of 2024. This work is part of an international collaborative project between Chile and the United Kingdom “The Genotypic Proxy Challenge in Planktonic Foraminifera in the Humboldt Current System – DETECTORS," aims to improve the understanding of these organisms as indicators of oceanographic conditions in the Southeastern Pacific. The three sampling campaigns, conducted aboard the VENUS vessel at the COSMOS station (29°41'S; 72°02'W), located 12 km offshore, covered three depths of the water column: surface, oxycline, and the Oxygen Minimum Zone. Physicochemical data and biological samples were collected using Niskin bottles and plankton nets. The identification and quantification of foraminifera were carried out through binocular scope and electron microscopy, complemented by ecological indices and statistical analyses. A total of 22 species were identified, with three dominating the total foraminiferal association across all three campaigns: Neogloboquadrina incompta, Globigerina bulloides and Globorotaloides hexagonus, collectively representing approximately 80% of the total community. These species reflect their relationship with environmental factors such as temperature and oxygen, as evidenced by their presence, absence, and abundance within each association. Other, less dominant species, also displayed significant seasonal variations in abundance, including one species that may reflect the El Niño event, which occurred in 2023 and 2024. A total of 3636 individuals of planktonic foraminifera, corresponding to 22 species and 13 genera, were identified. Of these, 19 species had previously been reported by Marchant et al. (2004) and Coloma et al. (2005). A notable difference between those studies and the present one was the low abundance of Globigerinella calida at COSMOS. The results revealed significant differences between planktonic foraminiferal assemblages across seasons and water column strata, supporting the hypothesis that differences exist between associations during the three seasons studied. However, consistent results regarding the impact of the El Niño event were not obtained, leaving the hypothesis about its effects on these associations unevaluated.
Description
Tesis presentada para optar al título de Biólogo Marino
Keywords
Ecología marina, Foraminíferos, Laboratorios marinos