Discovery of a chemosynthesis-based community in the western South Atlantic Ocean

Giongo, Adriana; Haag, Taiana; Simão, Taiz L. L.; Medina-Silva, Renata; Utz, Laura R. P.; Bogo, Maurı́cio Reis; Bonatto, Sandro L.; Zamberlan, Priscilla Mena; Augustin, Adolpho Herbert; Lourega, Rogério V.; Rodrigues, Luiz Frederico; Sbrissa, Gesiane Fraga; Kowsmann, Renato Oscar; Freire, Antônio Fernando Menezes; Miller, Dennis J.; Viana, Adriano R.; Ketzer, João Marcelo Medina; Eizirik, Eduardo

doi:10.1016/j.dsr.2015.10.010

Cited by 37 publications

(24 citation statements)

References 86 publications

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“…Spatial distribution of microorganisms in deep-sea habitats has been studied in several locations, such as Arctic sediments in the Pacific Ocean [5], Siberian continental margin [6], eastern South Atlantic sediments near Angolan coast [7] and pockmarks from Southwestern Atlantic close to the Brazilian coast [8]. Although there are few studies in deep-sea habitats from South Atlantic Ocean, the knowledge of how, what and where microorganisms inhabit is incipient compared with similar environments from North Atlantic or other better studied deep-sea basins.…”

Section: Introductionmentioning

confidence: 99%

Bacterial diversity in deep-sea sediments under influence of asphalt seep at the São Paulo Plateau

Queiroz

Bendia

Duarte

et al. 2019

Preprint

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Section: Introductionmentioning

confidence: 99%

Bacterial diversity in deep-sea sediments under influence of asphalt seep at the São Paulo Plateau

Queiroz

Bendia

Duarte

et al. 2019

Preprint

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“…Direct evidence of natural gas hydrate and gas seeps on the seafloor were found in the Rio Grande Cone [47] and in the Amazon deep-sea fan [48], in both areas in association with gas venting from the GHSZ. Living chemosynthesis-based communities in pockmarks in the Rio Grande Cone [51,52], in addition to acoustic disturbance caused by the presence of free gas at shallow depths (<10 m) below seafloor in sub-bottom profiles [53] are indicative of active methane seeps. Direct evidence of gas seepage was identified in the Amazon deep-sea fan by the presence of acoustic anomalies in the water column using multi-beam echo sounder backscatter data, which is also supported by the presence of remnants of chemosynthetic organisms at the seafloor [48].…”

Section: Gas Hydrate and Gas Venting Structures On Brazil's Continentmentioning

confidence: 99%

Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin

Ketzer

Praeg

Pivel³

et al. 2019

Preprint

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Gas hydrate provinces are present in at least in two areas along Brazil’s continental margin: (1) the Rio Grande Cone in the southeast, and (2) the Amazon deep-sea fan in the equatorial region. The occurrence of gas hydrates in these depocentres was first detected geophysically and has recently been proven by seafloor sampling of gas vents, detected as water column acoustic anomalies rising from seafloor depressions (pockmarks) and/or mounds, many associated with seafloor faults. The gas vents include typical features of cold seep systems, including shallow sulphate reduction depths (<4 m), authigenic carbonate pavements and chemosynthetic ecosystems. In both areas, gas sampled in hydrate and in sediments is dominantly formed by biogenic methane. Calculation of the methane hydrate stability zone for water temperatures in the two areas shows that gas vents occur along its feather edge (water depths between 510-760 m in the Rio Grande Cone and 500-670 m in the Amazon deep-sea fan) but also in deeper waters within the stability zone. Gas venting along the feather edge of the stability zone could reflect gas hydrate dissociation and release to the oceans, as inferred on other continental margins, or upward fluid flow through the stability zone facilitated by tectonic structures recording the gravitational collapse of both depocentres. The potential quantity of venting gas on the Brazilian margin under different scenarios of natural or anthropogenic change require further investigation. The studied areas provide a natural laboratory where these critical processes can be analysed and quantified.

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“…In Brazil, the Rio Grande Cone Gas Hydrate Province in the Pelotas Basin [13] is one of the main areas with gas hydrate deposits with associated chemosynthetic communities [14,15], and consists of the first discovery of gas hydrates in the western South Atlantic. The direct recovery of gas hydrate was performed through sediment sampling by piston coring and the results showed that the gas was mainly composed of methane of biogenic origin [13].…”

Section: Introductionmentioning

confidence: 99%

Molecular and Isotopic Composition of Hydrate-Bound, Dissolved and Free Gases in the Amazon Deep-Sea Fan and Slope Sediments, Brazil

Rodrigues

Ketzer

Oliveira³

et al. 2019

Geosciences

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In this work, we investigated the molecular stable isotope compositions of hydrate-bound and dissolved gases in sediments of the Amazon deep-sea fan and adjacent continental slope, Foz do Amazonas Basin, Brazil. Some cores were obtained in places with active gas venting on the seafloor and, in one of the locations, the venting gas is probably associated with the dissociation of hydrates near the edge of their stability zone. Results of the methane stable isotopes (δ13C and δD) of hydrate-bound and dissolved gases in sediments for the Amazon fan indicated the dominant microbial origin of methane via carbon dioxide reduction, in which 13C and deuterium isotopes were highly depleted (δ13C and δD of −102.2% to −74.2% V-PDB and −190 to −150% V-SMOW, respectively). The combination of C1/(C2+C3) versus δ13C plot also suggested a biogenic origin for methane in all analysed samples (commonly >1000). However, a mixture of thermogenic and microbial gases was suggested for the hydrate-bound and dissolved gases in the continental slope adjacent to the Amazon fan, in which the combination of chemical and isotopic gas compositions in the C1/(C2+C3) versus δ13C plot were <100 in one of the recovered cores. Moreover, the δ13C-ethane of −30.0% indicates a thermogenic origin.

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Discovery of a chemosynthesis-based community in the western South Atlantic Ocean

Cited by 37 publications

References 86 publications

Bacterial diversity in deep-sea sediments under influence of asphalt seep at the São Paulo Plateau

Bacterial diversity in deep-sea sediments under influence of asphalt seep at the São Paulo Plateau

Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin

Molecular and Isotopic Composition of Hydrate-Bound, Dissolved and Free Gases in the Amazon Deep-Sea Fan and Slope Sediments, Brazil

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Discovery of a chemosynthesis-based community in the western South Atlantic Ocean

Cited by 37 publications

References 86 publications

Bacterial diversity in deep-sea sediments under influence of asphalt seep at the São Paulo Plateau

Bacterial diversity in deep-sea sediments under influence of asphalt seep at the São Paulo Plateau

Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil&rsquo;s Continental Margin

Molecular and Isotopic Composition of Hydrate-Bound, Dissolved and Free Gases in the Amazon Deep-Sea Fan and Slope Sediments, Brazil

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Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin