Victor Gallardo

Victor Gallardo
University of Concepción · Departamento de Oceanografía

Ph.D.,U.S.C., L.A.; Ms. Mar. Aff., U.R.I., R.I.

About

122
Publications
18,236
Reads
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6,962
Citations
Introduction
With Carola Espinoza and Alexis Fonseca, we continue working on the giant, filamentous, multicellular, motile macrobacteria living in the large Humboldt Sulfuretum off Chile. A manuscript is being prepared on the recently detected presence of "cable bacteria" in our metagenomic data base and most exciting is the recent finding of filamentous multicellular macrobateria in Atacama Desert Region saline lakes, opening a new line of reseach with potential implications to Astrobiology

Publications

Publications (122)
Poster
Full-text available
Here we describe new findings of osseous skeletal material in marine sediments under the Oxygen Minimum Zone off northern and central Chile which, combined with previous reports for the study area, lead us to suggest the existence of a benthic band of bone accumulation extending at least twenty degrees in latitude (18°-38° S). Future studies should...
Article
Full-text available
The Humboldt Current, one of the most productive waters in the world, flows along the Chilean coast with high primary production level. However, living marine resources in these waters are declining due to overexploitation and other anthropogenic and environmental factors. It has been reported that deploying artificial reefs in coastal waters can i...
Article
Full-text available
The Humboldt Sulfuretum (HS), in the productive Humboldt Eastern Boundary Current Upwelling Ecosystem, extends under the hypoxic waters of the Peru-Chile Undercurrent (ca. 6°S and ca. 36°S). Studies show that primeval sulfuretums held diverse prokaryotic life, and, while rare today, still sustain species-rich giant sulfur-oxidizing bacterial commun...
Data
Phylogenetic analysis for the amino acid sequence of phytoene synthase identified in “Ca. V. ishoeyi”. The aligning of the amino acid sequence of the phytoene synthase (ps) identified in “Ca. V. ishoeyi” and 25 amino acid sequences of the Squalene/Phytoene synthase (Sps) and Phytoene synthases taken from the top 50 blastp match, and a sequence of A...
Data
S5A. Gene and product names of the Terpene type gene cluster. S5B. Gene and product names of the gene cluster, related with the potential biosynthesis of a non-classified secondary metabolite. (PDF)
Data
Genes identified in “Ca. V. ishoeyi”: S3A. In the tricarboxylic acid cycle; S3B. Involved in glycolysis; S3C. Involved in the Calvin-Benson-Bassham cycle. (PDF)
Data
S4A. List of CRISPR repeats identified in “Ca. V. ishoeyi”. The table shows: scaffolds containing start and end of CRISPR repeat regions, Direct Repeat (DR) sequences, length of the DR, and number of spacers. S4B. CRISPR-associated protein encoding genes identified in “Ca. V. ishoeyi”. (PDF)
Data
Amplification products of 16S rDNA genes and whole genome amplification (WGA) from seven bacterial filaments (MDA1-7) isolated by micromanipulation and visualized using agarose gel electrophoresis. The top of the figure shows the amplification products of the full length (~1.5 kbp) 16S rDNA PCR products of the seven micro-manipulated bacterial fila...
Data
Identification of amplified filaments by SeqMatch function (Ribosomal Database Project, RDPII). (PDF)
Data
Genes coding for sulfur oxidation enzymes in “Ca. V. ishoeyi”. (PDF)
Article
Full-text available
The so-called “surf diatoms” constitute a small group of species that are present with great abundance in the surf zones of some sandy beaches where often the accumulations are dominated only for one of these species. They adhere to air bubbles generated by wave action forming green or brown patches that float in the surf zone, remaining as long st...
Article
Full-text available
We used amplicon sequencing of the 16S rRNA gene to characterize the diversity and assess temporal and spatial patterns of Actinobacteria operational taxonomic units (OTUs) extracted from sediments of the Humboldt Sulfuretum located off the coast of central Chile. The sediment of this zone is rich in sulfur compounds and organic material and suppor...
Article
In a benthic macrofaunal survey of the continental shelf of northern Chile a peculiar filamentous material was collected in grab and dredge samples of greenish, foul smelling sediment from depths of 50 to 280 m (ref. 1). In reporting the results emphasis was placed, however, on the fact that a virtually iazoic* bottom had beenfound between depths o...
Article
Full-text available
The next generation sequencing (NGS) tools available today, i.e., 454 Roche pyrosequencing (Shendure and Ji 2008) allow metagenomic studies on the composition and structure of microbial communities in a way that it was not possible before (Handelsman 2004). In the field of macroecology, early studies showed that fresh water and marine benthic inver...
Article
Full-text available
We thank Dvořak et al. for their comment (1) on our paper (2), in which we compare sulfur-cycling ∼1.8- and ∼2.3-Ga fossil communities with their modern counterparts and report that the community fabric of the fossil and modern microbes, as well as their organismal and cellular morphology, their interlinked energy-production via anaerobic sulfate-r...
Article
Full-text available
The recent discovery of a deep-water sulfur-cycling microbial biota in the ∼2.3-Ga Western Australian Turee Creek Group opened a new window to life's early history. We now report a second such subseafloor-inhabiting community from the Western Australian ∼1.8-Ga Duck Creek Formation. Permineralized in cherts formed during and soon after the 2.4- to...
Conference Paper
Full-text available
Un tema fundamental en el campo de la ecología microbiana es la identificación de la biodiversidad presente en comunidades bacterianas. En la actualidad muchos marcadores genéticos, entre ellos el gen 16S ARNr, se han utilizado para resolver esta situación. En el presente trabajo se presentan los resultados del análisis filogenético de un filamento...
Article
Full-text available
The current study describes the taxonomic and functional composition of metagenomic sequences obtained from a filamentous microbial mat isolated from the Comau fjord, located in the northernmost part of the Chilean Patagonia. The taxonomic composition of the microbial community showed a high proportion of members of the Gammaproteobacteria, includi...
Data
Hierarchical clustering of the Comau microbial mat metagenome with related datasets. All the metagenomes were selected from the IMG-MER website [9], and the hierarchical clustering was done using the tools available on the website. (PDF)
Data
KEGG pathway for nitrogen metabolism. The pathway was generated using the KEGG website [19], and the color intensity reflects the number of proteins associated with a particular enzymatic activity. (PNG)
Data
KEGG pathway for sulfur metabolism: reduction and fixation. The pathway was generated using the KEGG website [19], and the color intensity reflects the number of proteins associated with a particular enzymatic activity. (PNG)
Data
Full-text available
Assembly statistics. (PDF)
Data
KEGG pathway for carbon fixation pathways in prokaryotes. The pathway was generated using the KEGG website [19], and the color intensity reflects the number of proteins associated with a particular enzymatic activity. (PNG)
Data
List of genes in the C. psycherythraea genome that had coverage of the metagenomic reads. (TXT)
Data
Classification of metagenomic reads into viral families.Reads were classified into viral families using MG-TAXA [16]. (PDF)
Data
Full-text available
Count of predicted open reading frames (ORFs) in the assembled contigs. Gene prediction was done using the IMG-MER platform [9]. (PDF)
Data
Full-text available
Nutrient analysis from water samples, October 2012. (PDF)
Data
List of reads mapped to the C. psycherythraea genome. (TXT)
Data
Assembled and unassembled proteins that had hits against the Phantome viral database [44]. (TXT)
Data
KEGG pathway for carbon fixation in photosynthetic organism. The pathway was generated using the KEGG website [19], and the color intensity reflects the number of proteins associated with a particular enzymatic activity. (PNG)
Data
Count of the viral genomes in the Phantome database [44], with hits to the Comau microbial mat metagenome, indicating the total number of hits and the average sequence identity. (TXT)
Data
Taxonomic classification of all the proteins in the KEGG pathways that were predicted to be present in the Comau microbial mat metagenome. (TXT)
Data
Full-text available
Classification of 16S rRNA reads with Greengenes. (PDF)
Data
Full-text available
Classification of all the metagenomic reads using MGTAXA. (PDF)
Data
List of reads mapped to the M. marina genome. (TXT)
Data
List of genes in the M. marina genome that had coverage of the metagenomic reads. (TXT)
Article
Full-text available
Citation: Gallardo VA, Fonseca A, Musleh SS, Espinoza C (2013) Extrapolations of Standing-Stocks of Big Bacteria in Humboldt Eastern Boundary Current Ecosystem (HEBCE). Oceanography 1: 110. doi:10.4172/ocn.1000110 Copyright: © 2013 Gallardo VA, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution Lic...
Article
Macplocimine A (1), a rare naturally occurring 18-membered macrolide, was isolated from the marine-derived filamentous sulfur bacteria Thioploca sp. The structure was determined by a combination of spectroscopic techniques, including HRESIMS, 1D and 2D NMR analyses. 1 features a thymine group, which is attached to an aromatic fused 18-membered macr...
Article
The sublittoral seafloor of the Humboldt Eastern Boundary Current ecosystem (HEBCE) is characterized by sediments rich in sulfur compounds and extensive and sometimes massive benthic bacterial mats. This sulfur-based sublittoral ecosystem is maintained by the very high input of organic matter from the productive surface waters and the concurrence o...
Article
Full-text available
During the first national study of the oxygen minimum zone (OMZ) and the animal macrobenthos off northern Chile (1962), a benthic community mainly composed of giant filamentous multicellular bacteria was discovered in the highly reduced shelf bottoms between 50-182 m depth. Totally unexpected were the great abundance of massive and visible filament...
Article
Full-text available
During the first national study of the oxygen minimum zone (OMZ) and the animal macrobenthos off northern Chile (1962), a benthic community mainly composed of giant filamentous multicellular bacteria was discovered in the highly reduced shelf bottoms between 50-182 m depth. Totally unexpected were the great abundance of massive and visible filament...
Conference Paper
Full-text available
Las nuevas herramientas moleculares de alto rendimiento como la pirosecuenciación 454 de Roche permiten conocer la abundancia relativa de los taxa bacterianos y estudiar la estructura de comunidades procariónticas como nunca antes. Presentamos los resultados de su aplicación al sulfuretum de Humboldt (SH) de Chile central. En función de los niveles...
Article
Full-text available
Orbital and in situ analyses establish that aerially extensive deposits of evaporitic sulfates, including gypsum, are present on the surface of Mars. Although comparable gypsiferous sediments on Earth have been largely ignored by paleontologists, we here report the finding of diverse fossil microscopic organisms permineralized in bottom-nucleated g...
Conference Paper
Full-text available
In February 27 2010, Chile mega earthquake (M=8.8) occurred at the Maule area in middle of Chile. The epicenter location is 115 km, NNE direction (35.9° S, 72.73° W) from Concepción, the second biggest city in Chile. The main shock, in which the focal depth is about 35 km, is a thrust - type subduction earthquake where the Nazca Plate subduct/colli...
Conference Paper
Full-text available
2010 February 27, Chile Mega Earthquake (M=8.8) occurred at the Maule area in middle of Chile. In 1960, Chile stroke by the largest earthquake of human ever recorded event, with a magnitude of 9.5. In the west coast of Chile, it is a convergence plate boundary between the Nazca and South American plates. The Nazca Plate subduct toward northeast dir...
Article
Thioploca araucae and Thioploca chileae from the sublittoral soft bottoms of the coastal upwelling ecosystem off central Chile were examined by scanning and transmission electron microscopy. Except for filament diameter (30–43 and 12–20 μm, respectively) and slight differences in other dimensions and surface topology, the details of fine structure...
Article
Archaea are important potential candidates in astrobiology as their metabolism includes solar, inorganic and organic energy sources. Archaeal viruses would also be expected to be present in a sustainable archaeal exobiological community. Genetic sequence Shannon entropy and fractal dimension can be used to establish a two-dimensional measure for cl...
Article
Full-text available
Benthic megafaunal and demersal fish assemblages were sampled in three areas off Chile during the German–Chilean Expedition PUCK (SO-156) onboard the R/V Sonne from March to May 2001, at depths ranging from 120 to 2201 m. These samples, taken with an Agassiz trawl, are among the deepest ever taken in Chilean waters. A total of 147 species were reco...
Article
Full-text available
A new component of the benthic Thioploca mat microbial ecosystem on the Chilean continental shelf was detected by epifluorescence microscopy: filamentous, bacterial endobionts of 4-5-mum filament diameter and length sometimes exceeding 1 mm. These filaments were identified as growing within Thioploca sheaths located between the sediment surface and...
Article
Full-text available
Among prokaryotes, the large vacuolated marine sulphur bacteria are unique in their ability to store, transport and metabolize significant quantities of sulphur, nitrogen, phosphorus and carbon compounds. In this study, unresolved questions of metabolism, storage management and behaviour were addressed in laboratory experiments with Thioploca speci...
Article
Full-text available
Analog examples of what primeval oceans might have looked in the Precambrian are probably extant in various regions and at various size scales in present day oceans albeit they have not been sufficiently recognized and/or studied. The Eastern Boundary Current Ecosystems (EBCEs), with their characteristic high productivity-inducing coastal upwelling...
Article
Population density, nitrate turnover, and oxygen respiration of benthic foraminiferans were investigated in the oxygen minimum zone (OMZ) off the Chilean coast. Live foraminiferans were found predominantly in the upper 3 mm of the sediment, and the nitrate accumulating species Nonionella cf. stella and Stainforthia sp. dominated with a combined sta...
Article
The International Census of Marine Microbes (ICoMM), together with the South American and Caribbean Steering Committees of the Census of Marine Life program (CoML), supported the initiative of launching a regional ICoMM node (LACar ICoMM). This network aims at promoting discussions among scientists currently involved in marine microbial studies car...
Article
Full-text available
The International Census of Marine Microbes (ICoMM), together with the South American and Caribbean Steering Committees of the Census of Marine Life program (CoML), supported the initiative of launching a regional lCoMM node (LACar ICoMM). This network aims at promoting discussions among scientists currently involved in marine microbial studies car...
Article
In the soft reduced sediments of the continental shelf, below the oxygen minimum zone (OMZ) of the eastern South Pacific (ESP), peculiar microbial communities have been disclosed which include a variety of large prokaryotes, protists and small metazoans. Dominant among the prokaryotes are large multi-cellular filamentous bacteria which, according t...
Article
Full-text available
New complex communities of morphologically diverse and sometimes abundant large, multicellular, filamentous bacteria were discovered in the oxygen-deficient, organically laden, shelf sediments under the oxygen minimum zone off the coast of the eastern Pacific, i.e., off the coasts of central and northern Chile; central and northern Perú; Roca Redon...
Article
Full-text available
The aerobic and anaerobic metabolism of Paraprionospiopinnata were estimated under laboratory conditions. Paraprionospiopinnata is a widely distributed, often dominant polychaete inhabiting sublittoral sediments on the continental shelf off central Chile, where there is a pronounced oxygen minimum zone (OMZ). The aerobic respiration rates ranged fr...
Article
Full-text available
The world's oceans contain a complex mixture of micro-organisms that are for the most part, uncharacterized both genetically and biochemically. We report here a metagenomic study of the marine planktonic microbiota in which surface (mostly marine) water samples were analyzed as part of the Sorcerer II Global Ocean Sampling expedition. These samples...
Article
Full-text available
The world's oceans contain a complex mixture of micro-organisms that are for the most part, uncharacterized both genetically and biochemically. We report here a metagenomic study of the marine planktonic microbiota in which surface (mostly marine) water samples were analyzed as part of the Sorcerer II Global Ocean Sampling expedition. These samples...
Article
A review of the latest findings relating big filamentous sublittoral bacteria of sediments under the oxygen minimum zone (OMZ) of the eastern Pacific, and, on the basis of associated morphological and environmental factors, an analysis and comparison of extant and Precambrian similar benthic microorganisms is performed. Based on the similarity betw...
Article
Full-text available
To a certain degree, Eastern Boundary Current (EBC) ecosystems are similar: Cold bottom water from moderate depths, rich in nutrients, is transported to the euphotic zone by a combination of trade winds, Coriolis force and Ekman transport. The resultant high primary production fuels a rich secondary production in the upper pelagic and nearshore zon...
Article
The significance of whale falls for the study of the biogeography, evolution and biodiversity of deep-sea biota has been recently recognized by international programs since large carcasses are known to give rise to biogenic chemosynthetic ecosystems. However, the plain accumulation of smaller bone material in the shallower settings of the continent...
Article
Full-text available
COML field projects will extend our understanding of ocean diversity, distribution and abundance from the nearshore to the abyssal plains. In nearshore, coastal and the upper ocean zones where diversity is reasonably well known it will add details about ranges, migrations and population size, but in the deep ocean there are still likely millions of...
Article
Full-text available
COML field projects will extend our understanding of ocean diversity, distribution and abundance from the nearshore to the abyssal plains. In nearshore, coastal and the upper ocean zones where diversity is reasonably well known it will add details about ranges, migrations and population size, but in the deep ocean there are still likely millions of...
Article
Full-text available
A quantitative study of macrobenthos was carried out on three transects on the shelf and continental slope off Chile (22° to 42°S; from 100 to 2000 m water depth) within and beneath the oxygen minimum zone (OMZ). Macrobenthos mean densities ranged from 104 to 13 808 ind m−2, with highest values off Concepción ([similar]36°S), where highest chloropl...