Estructura y composición de la comunidad bacteriana del Sulfureto de Humboldt bajo dos condiciones enso “la niña”: 2007-2009 & 2011-2012.
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Date
2025
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Publisher
Universidad de Concepción
Abstract
Desde finales de 2007 hasta principios de 2009, y durante los años 2011 y 2012, se observaron condiciones oceanográficas de gran intensidad, denominadas “La Niña” (LN), frente a la costa de Chile central. Durante ambos periodos y en esta zona, se realizaron muestreos bentónicos en el denominado Sulfureto de Humboldt (SH), frente a las costas de Chile central, analizándose mediante pirosecuenciación Roche 454 el material genético procarionte presente. La información genética resultante fue procesada y depositada públicamente en la base de datos pública del NCBI. Las muestras de cada crucero fueron secuenciadas mediante OTUs (Unidades Taxonómicas Operacionales) y ASVs (Variantes de Secuencia de Amplicón), respectivamente. Con el objetivo de evaluar la estabilidad temporal de la comunidad bacteriana, se compararon las poblaciones muestreadas para analizar taxones compartidos durante ambas, junto con una comparación estadística a través de análisis de diversidad α y β por medio de un Índice de Shannon (H’), y test ANOSIM, PERMANOVA y escalamiento no métrico multidimensional (NMDS) respectivamente; estos tres últimos basados en la “matriz de similitud de Jaccard” para presencia/ausencia de especies. Este estudio reveló que ambos muestreos comparten una alta proporción de taxones y que, cuando se analizaron por separado, tanto la diversidad α (riqueza observada e índice de Shannon) como la diversidad β (ANOSIM y PERMANOVA) no mostraron diferencias significativas entre estaciones ni temporadas. Un análisis conjunto, sin embargo, revela diferencias significativas en las métricas de diversidad β, principalmente por la variable temporal. Una comparación tanto cualitativa como estadística, por tanto, requiere de trabajos futuros realizados no solo en condiciones meteorológicas similares, sino que con metodologías constantes; en concreto, mismas técnicas de secuenciación de material genético, como también acceso a datos crudos para asegurar métricas estadísticas tanto confiables como robustas.
From late 2007 to early 2009, and during the years 2011 and 2012, intense oceanographic conditions known as “La Niña” (LN) were observed off the coast of central Chile. During both periods and in this region, benthic samples were collected at the so-called Humboldt Sulfuretum (SH), off the coast of central Chile (BC), and the prokaryotic genetic material present was analyzed using Roche 454 pyrosequencing. The resulting genetic data was processed and made publicly available through the NCBI database. Samples from each expedition were sequenced using OTUs (Operational Taxonomic Units) and ASVs (Amplicon Sequence Variants), respectively. In order to assess the temporal stability of the bacterial community, the sampled populations were compared to analyze shared taxa across both periods, along with statistical comparisons through alpha and beta diversity analyses. Specifically, Shannon’s Index (H’) was used for α-diversity, and ANOSIM, PERMANOVA, and non-metric multidimensional scaling (NMDS) were applied for β-diversity — all three based on the “Jaccard similarity matrix” for presence/absence of species. This study revealed that both sampling events shared a high proportion of taxa, and when analyzed separately, neither α-diversity (observed richness and Shannon Index) nor β-diversity (ANOSIM and PERMANOVA) showed significant differences between stations or between seasons. A combined analysis, however, revealed significant differences in β-diversity metrics, primarily due to the temporal variable. A meaningful comparison, both qualitative and statistical, therefore requires future work to be conducted not only under similar meteorological conditions, but also with consistent methodologies; specifically, the same genetic sequencing techniques and access to raw data in order to ensure both reliable and robust statistical metrics.
From late 2007 to early 2009, and during the years 2011 and 2012, intense oceanographic conditions known as “La Niña” (LN) were observed off the coast of central Chile. During both periods and in this region, benthic samples were collected at the so-called Humboldt Sulfuretum (SH), off the coast of central Chile (BC), and the prokaryotic genetic material present was analyzed using Roche 454 pyrosequencing. The resulting genetic data was processed and made publicly available through the NCBI database. Samples from each expedition were sequenced using OTUs (Operational Taxonomic Units) and ASVs (Amplicon Sequence Variants), respectively. In order to assess the temporal stability of the bacterial community, the sampled populations were compared to analyze shared taxa across both periods, along with statistical comparisons through alpha and beta diversity analyses. Specifically, Shannon’s Index (H’) was used for α-diversity, and ANOSIM, PERMANOVA, and non-metric multidimensional scaling (NMDS) were applied for β-diversity — all three based on the “Jaccard similarity matrix” for presence/absence of species. This study revealed that both sampling events shared a high proportion of taxa, and when analyzed separately, neither α-diversity (observed richness and Shannon Index) nor β-diversity (ANOSIM and PERMANOVA) showed significant differences between stations or between seasons. A combined analysis, however, revealed significant differences in β-diversity metrics, primarily due to the temporal variable. A meaningful comparison, both qualitative and statistical, therefore requires future work to be conducted not only under similar meteorological conditions, but also with consistent methodologies; specifically, the same genetic sequencing techniques and access to raw data in order to ensure both reliable and robust statistical metrics.
Description
Tesis presentada para optar al título de Biólogo/a Marino/a.
Keywords
Océano, Bacterias marinas Chile, Bahías Chile