Aspectos morfológicos y reproductivos del género Sargassum (Phaeophyceae, Fucales) en Rapa Nui.
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Date
2024
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
El género Sargassum (Phaeophyceae, Fucales) se encuentra distribuido en distintas partes del mundo, predominando en zonas tropicales y subtropicales. Habita desde la zona litoral media hasta la zona sublitoral en sustratos rocosos y arrecifes. Algunas especies del género son capaces de desarrollar adaptaciones para evitar la colonización y herbivoría, además de emitir señales químicas para inducir el asentamiento de otros organismos, por lo que se considera que juegan un rol importante como reguladores de la biodiversidad de algunos ecosistemas. Son numerosos los estudios que han aportado información sobre el género Sargassum, sin embargo, a pesar de su abundancia, en Rapa Nui ha sido escasamente estudiado. Se han identificado dos especies para la zona: S. aquifolium y S. obtusifolium, no obstante, existe un gran vacío en cuanto a caracteres descriptivos, ciclo de vida y aspectos reproductivos del género en la isla. Este estudio tuvo como objetivo evaluar caracteres morfológicos y aspectos reproductivos de Sargassum, incluyendo caracteres taxonómicos como el tamaño del disco, talo, láminas y receptáculos. Para esto, se analizaron muestras de Sargassum recolectadas en marzo del 2023, en 5 sitios de muestreo alrededor de la isla. A través de un análisis de componentes principales (PCA) se determinó que los caracteres morfológicos más importantes y que presentaron mayor variación entre las muestras, fueron la longitud y diámetro de aerocistos apicales, número de ejes principales y secundarios, diámetro del disco de adhesión y características de conceptáculos y oogonios. Todas las muestras recolectadas presentaron estructuras reproductivas, los receptáculos fueron mayormente dioicos (80%) mientras que el 19% restante correspondió a receptáculos monoicos y 1% de los receptáculos se encontró senescente. La importancia del presente trabajo se fundamenta en su contribución a los aspectos morfológicos y caracteres reproductivos del género Sargassum, como línea base para futuros estudios (e.g., eventuales trabajos de repoblamiento y cultivo del alga), aportando información taxonómica.
The Sargassum genus (Phaeophyceae, Fucales) is distributed in different parts of the world, predominating in tropical and subtropical areas. It inhabits from the middle littoral zone to the sublittoral zone on rocky substrates and reefs. Some species of the genus are capable of developing adaptations to avoid colonization and herbivory, in addition to emitting chemical signals to induce the settlement of other organisms, so they are considered to play an important role as regulators of biodiversity in some ecosystems. There are numerous studies that have provided information about Sargassum, however, despite its abundance, it has been scarcely studied in Rapa Nui, here two species have been described: S. aquifolium and S. obtusifolium, however, there is a large gap in terms of descriptive characters, life cycle and reproductive aspects of the genus in the island. This study aimed to evaluate morphological and reproductive characters of Sargassum, including taxonomic characters such as holdfast size, thallus size, blades and receptacles. For this, samples of Sargassum collected in March 2023, at 5 sampling sites around Rapa Nui Island were analyzed. Through a principal component analysis (PCA), it was determined that the most important morphological characters and those that showed the greatest variation among the samples, were the length and diameter of apical aerocysts, number of main and secondary axes, holdfast diameter, characteristics of conceptacles and oogonia. All the collected samples presented reproductive structures, the receptacles were mostly dioecious (80%) while the remaining 19% corresponded to monoecious receptacles and 1% of the receptacles were found senescent. The importance of this work is based on its contribution to the morphological aspects and reproductive characters of the Sargassum genus, as a baseline for future studies (such as repopulation and cultivation of the algae), providing valuable taxonomic information.
The Sargassum genus (Phaeophyceae, Fucales) is distributed in different parts of the world, predominating in tropical and subtropical areas. It inhabits from the middle littoral zone to the sublittoral zone on rocky substrates and reefs. Some species of the genus are capable of developing adaptations to avoid colonization and herbivory, in addition to emitting chemical signals to induce the settlement of other organisms, so they are considered to play an important role as regulators of biodiversity in some ecosystems. There are numerous studies that have provided information about Sargassum, however, despite its abundance, it has been scarcely studied in Rapa Nui, here two species have been described: S. aquifolium and S. obtusifolium, however, there is a large gap in terms of descriptive characters, life cycle and reproductive aspects of the genus in the island. This study aimed to evaluate morphological and reproductive characters of Sargassum, including taxonomic characters such as holdfast size, thallus size, blades and receptacles. For this, samples of Sargassum collected in March 2023, at 5 sampling sites around Rapa Nui Island were analyzed. Through a principal component analysis (PCA), it was determined that the most important morphological characters and those that showed the greatest variation among the samples, were the length and diameter of apical aerocysts, number of main and secondary axes, holdfast diameter, characteristics of conceptacles and oogonia. All the collected samples presented reproductive structures, the receptacles were mostly dioecious (80%) while the remaining 19% corresponded to monoecious receptacles and 1% of the receptacles were found senescent. The importance of this work is based on its contribution to the morphological aspects and reproductive characters of the Sargassum genus, as a baseline for future studies (such as repopulation and cultivation of the algae), providing valuable taxonomic information.
Description
Tesis presentada para optar al título de Bióloga Marina
Keywords
Phaeophyceae, Biodiversidad, Rapanui