Eoghan P. ReevesUniversity of Bergen | UiB · Department of Earth Science
Eoghan P. Reeves
Ph.D.
About
48
Publications
8,432
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1,383
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Citations since 2017
Introduction
My hydrothermal research group aims to understand how high temperature and pressure geologic fluids in the Earth's crust acquire their inorganic-organic chemical compositions, using a variety of analytical techniques, specifically to determine how they interact with Earth's lithosphere and biosphere. I work within the Department of Earth Science and the Centre for Deep Sea Research at the University of Bergen, Norway, and conduct sampling expeditions on Arctic and global hydrothermal systems.
Additional affiliations
September 2015 - present
September 2013 - present
April 2010 - August 2013
Education
January 2005 - April 2010
January 2005 - April 2010
September 2003 - August 2004
Publications
Publications (48)
Evidence of hydrothermal venting on the ultra-slow spreading Gakkel Ridge in the Central Arctic Ocean has been available since 2001, with first visual evidence of black smokers on the Aurora Vent Field obtained in 2014. But it was not until 2021 that the first ever remotely operated vehicle (ROV) dives to hydrothermal vents under permanent ice cove...
The Aurora hydrothermal system, Arctic Ocean, hosts active submarine venting within an extensive field of relict mineral deposits. Here we show the site is associated with a neovolcanic mound located within the Gakkel Ridge rift-valley floor, but deep-tow camera and sidescan surveys reveal the site to be ≥100 m across—unusually large for a volcanic...
The methane-rich areas, the Loki's Castle vent field and the Jan Mayen vent field at the Arctic Mid Ocean Ridge (AMOR), host abundant niches for anaerobic methane-oxidizers, which are predominantly filled by members of the ANME-1. In this study, we used a metagenomic-based approach that revealed the presence of phylogenetic and functional different...
To investigate the origin of C–H bonds in thermogenic methane (CH4), a solvent-extracted sample of organic-rich Eagle Ford shale was reacted with heavy water (D2O) under hydrothermal conditions (350 bar) in a flexible Au-TiO2 cell hydrothermal apparatus at a water-to-rock ratio of approximately 5:1. Temperature was increased from 200 to 350 °C over...
Plain Language Summary
Deep sea hot springs are widespread along Earth's ∼60,000 km of mid‐ocean ridge crust. These systems host some of the planets most diverse geologic fluids, as well as extreme ecosystems that depend on chemicals supplied by these fluids for chemosynthetic energy. Hence, understanding the behavior and timing of hydrothermal flu...
Hydrothermal vents modify and displace subsurface dissolved organic matter (DOM) into the ocean. Once in the ocean, this DOM is transported together with elements, particles, dissolved gases and biomass along with the neutrally buoyant plume layer. Considering the number and extent of actively venting hydrothermal sites in the oceans, their contrib...
The HACON21 cruise was organized to re-visit the Aurora vent field and conduct a full multidisciplinary survey with a focus on observations and sampling of the hydrothermal vent habitat and ecosystem. The specific objectives of the cruise included the following:
1. Conduct exploratory ROV dives on the Aurora Vent Field.
2. Sample vent fluids with I...
![Figure 5: Keeling plot for δ 13 C-CH4 versus 1/[CH4] for the data...](publication/357551072/figure/fig5/AS:1108342701326338@1641260900177/Keeling-plot-for-d-13-C-CH4-versus-1-CH4-for-the-data-obtained-in-background-BG_Q320.jpg)
Hydrothermal vents modify and displace subsurface dissolved organic matter (DOM) into the ocean. Once in the ocean, this DOM is transported together with elements, particles, dissolved gases, and biomass along with the neutrally buoyant plume layer. Considering the number and extent of actively venting hydrothermal sites in the oceans, their contri...
Deep-sea hydrothermal vents are amongst the most extreme environments on Earth and represent interesting targets for marine bioprospecting and biodiscovery. The microbial communities in hydrothermal vents are often dominated by chemolithoautotrophs utilizing simple chemical compounds, though the full extent of their heterotrophic abilities is still...
Accumulation of molecular hydrogen in geologic systems can create conditions energetically favorable to transform inorganic carbon into methane and other organic compounds. Although hydrocarbons with a potentially abiotic origin have been proposed to form in a number of crustal settings, the ubiquitous presence of organic compounds derived from bio...
Abstract
The Manus Basin hosts a broad range of vent fluid compositions typical for arc and back‐arc settings, ranging from black smoker to acid‐sulfate styles of fluid venting, as well as novel intermediate temperature and composition ‘hybrid’ smokers. We investigated B, Li, Mg and Sr concentrations and isotopic compositions of these different fl...
SuSu Knolls is an area of ongoing magmatic activity and recent volcanism located in the back-arc spreading environment of the Manus Basin in the Bismarck Sea, Papua New Guinea. In 2006, hydrothermal fluids were collected from three areas of submarine hot-spring venting and analyzed for the chemical and isotopic composition of major and trace specie...
Abyssivirga alkaniphila strain L81T, recently isolated from a black smoker biofilm at the Loki’s Castle hydrothermal vent field, was previously described as a mesophilic, obligately anaerobic heterotroph able to ferment carbohydrates, peptides, and aliphatic hydrocarbons. The strain was classified as a new genus within the family Lachnospiraceae. H...
The composition of submarine hydrothermal vent fluids is affected by a variety of processes, such as interaction of heated seawater with rocks and sediments, addition of magmatic fluids, as well as phase separation and segregation. How these processes specifically affect the vent fluid composition is still poorly understood. In particular, the rela...
Hot-spring fluids emanating from deep-sea vents hosted in unsedimented ultramafic and mafic rock commonly contain high concentrations of methane. Multiple hypotheses have been proposed for the origin(s) of this methane, ranging from synthesis via reduction of aqueous inorganic carbon (∑CO2) during active fluid circulation to leaching of methane-ric...
In this study we present boron (B), lithium (Li) and strontium (Sr) concentrations and isotopic composition of submarine hydrothermal fluids collected in 2006 and 2011 from PACMANUS, DESMOS and SuSu Knolls vent fields located in the Eastern Manus Basin [1,2].
Hydrothermal vent fluids within the Eastern Manus Basin range from high-temperature black...
Hydrothermal vents are often enriched in arsenic, and organisms living in these environments may accumulate high concentrations of this and other trace elements. However, very little research to date has focused on understanding arsenic bioaccumulation and biotransformation in marine organisms at deep-sea vent areas; none to date have focused organ...
Deep-sea hydrothermal vents are highly dynamic habitats characterized by steep temperature and chemical gradients. The oxidation of reduced compounds dissolved in the venting fluids fuels primary production providing the basis for extensive life. Until recently studies of microbial vent communities have focused primarily on chemolithoautotrophic or...
The SuSu Knolls and DESMOS hydrothermal fields are located in the back-arc extensional transform zone of the Eastern Manus Basin. In 2006, highly acidic and SO4-rich vent fluids were collected at both sites and analyzed for the chemical and isotopic composition of major and trace species. Fluids exiting the seafloor have measured temperatures from...
Methane is a key component in the global carbon cycle with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply-substituted "clumped" isotopologues, e.g., (13)CH3D, has recently emerged as a proxy for determining methane-formation t...
Sulfide 'chimneys' characteristic of seafloor hydrothermal venting are diverse microbial habitats. (13) C/(12) C ratios of microbial lipids have rarely been used to assess carbon assimilation pathways on these structures, despite complementing gene- and culture-based approaches. Here, we integrate analyses of the diversity of intact polar lipids (I...
Significance
Simple alkyl thiols such as methanethiol are widely speculated to spontaneously form in seafloor hot spring fluids and are implicated in facilitating the emergence of protometabolism and microbial life in early Earth hydrothermal systems, the complexation of hydrothermally derived metals, and as fuels for microbial ecosystems. Existing...
Processes controlling the composition of seafloor hydrothermal fluids in silicic back-arc or near-arc crustal settings remain poorly constrained despite growing evidence for extensive magmatic–hydrothermal activity in such environments. We conducted a survey of vent fluid compositions from two contrasting sites in the Manus back-arc basin, Papua Ne...
Whereas the sulfur isotope effects during the abiotic disproportionation
of SO2 were thoroughly investigated in the last years, data on the
oxygen isotope signature of produced sulfate is scarce. To fill in this
gap in knowledge, we performed laboratory experiments which simulated
the abiotic SO2 disproportionation at temperatures ranging from
150°...
As part of an integrated study conducted at the Lucky Strike Seamount (Mid-Atlantic Ridge, 37°17′N) in 2008, gas-tight sampling devices were used to collect high-temperature (∼300 °C) hydrothermal fluids issuing from sulfide structures distributed throughout the vent field located in the summit depression. Compared with previous observations from 1...
To investigate the extent of hydrogen isotope (2H and 1H) exchange between hydrocarbons and water under hydrothermal conditions, we performed experiments heating C1–C5n-alkanes in aqueous solutions of varying initial 2H/1H ratios in the presence of a pyrite–pyrrhotite–magnetite redox buffer at 323°C and 35–36MPa. Extensive and reversible incorporat...
The Eastern Lau Spreading Center (ELSC) is the southernmost part of the back-arc spreading axis in the Lau Basin, west of the Tonga trench and the active Tofua volcanic arc. Over its 397-km length it exhibits large and systematic changes in spreading rate, magmatic/tectonic processes, and proximity to the volcanic arc. In 2005 we collected 81 sampl...
Two records of seawater sulfate isotope composition from the Early Jurassic demonstrate that large isotopic gradients existed between the European epicontinental sea and the open Tethys Ocean. These differences can be explained by the modifi cation of open-ocean sulfate isotopic compositions by water-mass isolation, sea-level rise, and the effects...
Stable isotopes are extensively utilized in studies of hydrocarbons in naturals fluids. However, factors controlling the hydrogen isotope (2H/1H) composition of dissolved hydrocarbons in hydrothermal fluids are still poorly understood despite interest in their 2H/1H signatures as indicators of abiogenesis. Due to its high activation energy for exch...
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2010 This thesis presents the results of four discrete investigations into processes governing the organic and inorganic chemical composition of seafloor hydrother...
Rare earth element (REE) concentrations are reported for a large suite of seafloor vent fluids from four hydrothermal systems in the Manus back-arc basin (Vienna Woods, PACMANUS, DESMOS and SuSu Knolls vent areas). Sampled vent fluids show a wide range of absolute REE concentrations and chondrite-normalized (REEN) distribution patterns (LaN/SmN∼0.6...
The formation of aqueous organic sulfur compounds in hydrothermal systems remains poorly constrained, despite their potential significance in 'prebiotic' chemistry and the origin of life. The simplest - methanethiol (CH3SH) - has been implicated as a critical abiogenic precursor to the establishment of primitive microbial metabolism in early Earth...
Here we present two records of marine SO4-O isotopes
derived from carbonate associated sulfate (CAS) across the
Toarcian anoxic event, one from a Tethyan open ocean margin
(Tibet) and the other from within the European Epicontinental
Sea (EES, Yorkshire, UK). Limestones from Tibet record
average SO4-δ18O of +13.1±1.3‰ across the interval with no
sy...
The Lau Basin is actively spreading along three major spreading centers: the Central Lau Spreading Center (CLSC) in the north, the Eastern Lau Spreading Center (ELSC), and the Valu Fa Ridge (VFR) to the south. A southward progression along these spreading centers reveals decreasing spreading rates, decreasing distance to the arc, and a correspondin...
A major objective of cruise MGLN06MV to the Manus Basin, north of Papua
New Guinea, was the use of vent fluid chemistry as a guide to
sub-seafloor processes occurring within four major areas of hydrothermal
activity. A broad spectrum of high and low temperature fluids were
sampled using gas-tight and syringe style "major" samplers from black
smoker...
ABSTRACTA record of the Early Jurassic mass extinction event is reported from eastern Tethyan (Tibetan) locations for the first time. In the Mount Everest region a thick Lower Jurassic carbonate formation, here named the Yungjia Formation, is developed within the predominantly clastic Triassic–Jurassic succession. Within the formation a sharp trans...
The Lau Basin is a back-arc spreading center characterized by widespread hydrothermal activity. High and low temperature vent fluids were collected from six vent fields along the Eastern Lau Spreading Center (ELSC) and the Valu Fa Ridge (VFR) using isobaric gas-tight samplers during R/V Melville cruise TUIM05MV. Fluids were analyzed for the abundan...
Projects
Projects (3)
HACON will push the frontiers of deep-sea and Arctic research, unraveling the physical, geochemical and ecological processes that shape faunal communities at the Aurora hydrothermal vents and test the hypothesis that the Gakkel Ridge provides a connecting pathway for gene flow between the Pacific and Atlantic oceans. HACON will provide the first comprehensive study of deep (4000 m) hydrothermal vent ecosystems under ice in the Arctic region. HACON targets a key missing piece of the global vent biogeographic puzzle in a region that remains mostly unexplored because of its remote and climatologically challenging location. The project will provide empirical robust data of a pristine system prior to expected climate-change variations and increased human activities in the Arctic.
DeepSeaQuence is an interdisciplinary project funded by the Norwegian Research Council, spanning microbial ecology, geobiochemistry, microbial interactions, bioinformatics, and supported by advanced Norwegian marine technology. Altogether, the knowledgebase provided by DeepSeaQuence will impact our understanding of the distribution, diversity, metabolic repertoire, and interactions of the vastly uncultivated, and thus far largely unknown, microbial biosphere in deep-sea hydrothermal systems.
