Browsing by Author "Castro Nallar, Eduardo"

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    A First Insight into the Microbial and Viral Communities of Comau Fjord-A Unique Human-Impacted Ecosystem in Patagonia (42 degrees S)
    (2023) Guajardo Leiva, Sergio Eduardo; Mendez, Katterinne N.; Meneses Araya, Claudio Antonio; Diez Moreno, Beatriz; Castro Nallar, Eduardo
    While progress has been made in surveying the oceans to understand microbial and viral communities, the coastal ocean and, specifically, estuarine waters, where the effects of anthropogenic activity are greatest, remain partially understudied. The coastal waters of Northern Patagonia are of interest since this region experiences high-density salmon farming as well as other disturbances such as maritime transport of humans and cargo. Here, we hypothesized that viral and microbial communities from the Comau Fjord would be distinct from those collected in global surveys yet would have the distinctive features of microbes from coastal and temperate regions. We further hypothesized that microbial communities will be functionally enriched in antibiotic resistance genes (ARGs) in general and in those related to salmon farming in particular. Here, the analysis of metagenomes and viromes obtained for three surface water sites showed that the structure of the microbial communities was distinct in comparison to global surveys such as the Tara Ocean, though their composition converges with that of cosmopolitan marine microbes belonging to Proteobacteria, Bacteroidetes, and Actinobacteria. Similarly, viral communities were also divergent in structure and composition but matched known viral members from North America and the southern oceans. Microbial communities were functionally enriched in ARGs dominated by beta-lactams and tetracyclines, bacitracin, and the group macrolide-lincosamide-streptogramin (MLS) but were not different from other communities from the South Atlantic, South Pacific, and Southern Oceans. Similarly, viral communities were characterized by exhibiting protein clusters similar to those described globally (Tara Oceans Virome); however, Comau Fjord viromes displayed up to 50% uniqueness in their protein content. Altogether, our results indicate that microbial and viral communities from the Comau Fjord are a reservoir of untapped diversity and that, given the increasing anthropogenic impacts in the region, they warrant further study, specifically regarding resilience and resistance against antimicrobials and hydrocarbons.
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    Composition and structure of the skin microbiota of rorquals off the Eastern South Pacific
    (OXFORD UNIV PRESS, 2021) Toro, Frederick; Alarcon, Jaime; Marquez, Sebastian; Capella, Juan; Bahamonde, Paulina; Esperon, Fernando; Moreno Switt, Andrea; Castro Nallar, Eduardo
    Recent advances in high-throughput sequencing have enabled the large-scale interrogation of microbiota in the most diverse environments, including host-associated microbiota. This has led to the recognition that the skin microbiota of rorquals is specific and structurally different from that of the ocean. This study reveals the skin microbiome of 85 wild individuals along the Chilean coast belonging to Megaptera novaeangliae, Balaenoptera musculus and Balaenoptera physalus. Alpha diversity analysis revealed significant differences in richness and phylogenetic diversity, particularly among humpback whales from different locations and between blue and humpback whales. Beta diversity was partially explained by host and location but only accounting for up to 17% of microbiota variability (adjusted VPA). Overall, we found that microbiota composition was dominated by bacterial genera such as Cardiobacter, Moraxella, Tenacibaculum, Stenotrophomonas, Flavobacteria and Pseudomonas. We also found that no ASVs were associated with the three rorqual species. Up to four ASVs were specific of a location, indicating a great variability in the microbiota. To the best of our knowledge, this is the first report on the composition and structure of the skin microbiota of whales off the coast of Chile, providing a foundational dataset to understand the microbiota's role in rorquals.
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    Spatially and Temporally Explicit Metagenomes and Metagenome-Assembled Genomes from the Comau Fjord (42°S), Patagonia
    (2023) Castro Nallar, Eduardo; Berríos Farías, Valentín; Diez Moreno, Beatriz; Guajardo Leiva, Sergio; Cameron Thrash, J.
    Microbes play an important role in coastal and estuarine waters. We present 93 metagenomes and 677 metagenome-assembled genomes (MAGs) from Comau Fjord, Patagonia (42°S), to further understand the microbial dynamics and their response to anthropogenic disturbances. These data represent a spatially (35-km transect) and temporally (2016 to 2019) explicit data set.