The Geology and Biogeochemistry of Hydrocarbon Seeps

Annual Review of Earth and Planetary Sciences, Journal Year: 2020, Volume and Issue: 48(1), P. 205 - 231

Published: Jan. 6, 2020

Hydrocarbon seeps, deep sea extreme environments where deeply sourced fluids discharge at the seabed, occur along continental margins across globe. Energy-rich reduced substrates, namely hydrocarbons, support accelerated biogeochemical dynamics, creating unique geobiological habitats. Subseafloor geology dictates surficial expression of generating hydrocarbon (gas and/or oil) brine and mud volcanoes. Biogeochemical processes redox spectrum are amplified seeps due to abundance diversity reductant; anaerobic metabolism dominates within sediment column since oxygen is consumed rapidly near surface. Microbial activity constrained by electron acceptor availability, with rapid recycling required observed rates consumption. Geobiologic structures, from gas hydrate solid asphalt authigenic minerals, form as a result associated fluid discharge. Animal-microbial associations symbioses thrive diverse dense oases that provide nutrition mobile predators. ▪ abundant immense biodiversity specialization adaptation create extraordinary lifestyles. shapes defines geochemical nature seepage regulates flux regime, which dictate surface expression. High oxidation methane require coupling multiple promote in methanotroph microbial community. The recent discovery novel phyla possessing potential signals aspects seep biogeochemistry geobiology remain be discovered.

Language: Английский

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Global Biogeographic Analysis of Methanogenic Archaea Identifies Community-Shaping Environmental Factors of Natural Environments

Frontiers in Microbiology, Journal Year: 2017, Volume and Issue: 8

Published: July 18, 2017

Methanogenic archaea are important for the global greenhouse gas budget since they produce methane under anoxic conditions in numerous natural environments such as oceans, estuaries, soils, and lakes. Whether how environmental change will propagate into methanogenic assemblages of remains largely unknown owing to a poor understanding distribution patterns drivers this specific group microorganisms. In study, we performed meta-analysis targeting biogeographic controls communities using 94 public mcrA gene datasets. We show pattern that is more associated with habitat filtering than geographical dispersal. identify salinity control on community composition at scale whereas pH temperature major non-saline soils The importance structuring also reflected biogeography lineages physiological properties isolates. Linking alpha-diversity reported values emission identifies estuaries most diverse habitats with, however, minor contribution budget. With salinity, our study facing drastic changes many moment. However, consequences production remain elusive lack studies combine rate analysis.

Language: Английский

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Methane-metabolizing microbial communities in sediments of the Haima cold seep area, northwest slope of the South China Sea

FEMS Microbiology Ecology, Journal Year: 2017, Volume and Issue: unknown

Published: Aug. 9, 2017

Cold seeps are widespread chemosynthetic ecosystems in the deep-sea environment, and cold seep microbial communities of South China Sea poorly constrained. Here we report on archaeal communities, particularly those involved methane metabolization, sediments a newly discovered (named 'Haima') northwest slope Sea. Archaeal diversity, abundance distribution were investigated two piston cores collected from area (QDN-14B) non-seep control site (QDN-31B). Geochemical investigation QDN-14B core identified an estimated sulfate-methane transition zone (Estimated SMTZ) at 300-400 cm below sea floor (cmbsf), where high anaerobic methane-oxidizing archaea (ANME) occurred, as revealed by analysis 16S rRNA gene (mcrA) encoding α-subunit key enzyme methyl-coenzyme M reductase. ANME-2a/b was predominant upper middle layers SMTZ, whereas ANME-1b outcompeted ANME-2 sulfate-depleted bottom SMTZ methanogenic zone. Fine-scale phylogenetic further divided group into three subgroups with different patterns: ANME-1bI, ANME-1bII ANME-1bIII. Multivariate analyses indicated that dissolved inorganic carbon sulfate may be important factors controlling composition methane-metabolizing community. Our study ANME niche separation interactions other groups improves our understanding metabolic diversity flexibility ANME, findings suggest have evolved diversified/specified capabilities than syntrophic oxidation coupled reduction marine sediments.

Language: Английский

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Anaerobic Degradation of Non-Methane Alkanes by “ Candidatus Methanoliparia” in Hydrocarbon Seeps of the Gulf of Mexico

mBio, Journal Year: 2019, Volume and Issue: 10(4)

Published: Aug. 19, 2019

Crude oil and gases in the seabed provide an important energy source for subsurface microorganisms. We investigated role of archaea anaerobic degradation non-methane alkanes deep-sea seeps from Gulf Mexico. identified microscopically ethane short-chain alkane oxidizers "Candidatus Argoarchaeum" Syntrophoarchaeum" forming consortia with bacteria. Moreover, we found that sediments contain large numbers cells archaeal clade Methanoliparia," which was previously proposed to perform methanogenic degradation. "Ca. Methanoliparia" occurred abundantly as single attached droplets without apparent bacterial or partners. Metagenome-assembled genomes encode a complete methanogenesis pathway including canonical methyl-coenzyme M reductase (MCR) but also highly divergent MCR related those alkane-degrading pathways oxidation long-chain alkyl units. Its metabolic genomic potential its global detection hydrocarbon reservoirs suggest is degrader environments, producing methane by disproportionation organism.IMPORTANCE Oil-rich Mexico were diverse groups archaea. The symbiotic, consortium-forming are likely responsible alkanes, help sulfate-reducing occurs associated droplets. These two phylogenetically different reductases may allow this organism thrive methanogen on substrate alkanes. Based library survey, show frequently detected be key agent transformation methane. Our findings evidence roles alkane-rich marine habitats support notion significant functional versatility methyl coenzyme reductase.

Language: Английский

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Biotechnological conversion of methane to methanol: evaluation of progress and potential

AIMS bioengineering, Journal Year: 2018, Volume and Issue: 5(1), P. 1 - 38

Published: Jan. 1, 2018

Sources of methane are numerous, and vary greatly in their use sustainable credentials. A Jekyll Hyde character, it is a valuable energy source present as geological deposits natural gas, however also potent greenhouse released during many waste management processes. Gas-to-liquid technologies being investigated means to exploit monetise non-traditional unutilised sources. The product identified having the greatest potential methanol due robust, commercially mature conversion process from its beneficial fuel characteristics. Commercial requires high temperatures pressures, an intensive costly process. In contrast methanotrophic bacteria perform desired transformation under ambient conditions, using monooxygenase (MMO) enzymes. Despite great these number biotechnical difficulties hindering progress towards industrially suitable We have five major challenges that exist barriers viable that, our knowledge, not previously been examined distinct challenges. Although biotechnological applications reviewed part, no review has comprehensively covered for industrial perspective. All published examples date methanotroph catalysed collated, standardised allow direct comparison. focus will be on by whole-cell, wild type, cultures, application relevant recent shift research community mainly biological angle overall engineering approach, offers methanotrophs gas-to-liquid Current innovations future opportunities discussed.

Language: Английский

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