scholarly journals Methane oxidation in permeable sediments at hydrocarbon seeps in the Santa Barbara Channel, California

2010 ◽  
Vol 7 (2) ◽  
pp. 1905-1933 ◽  
Author(s):  
T. Treude ◽  
W. Ziebis
Keyword(s):  
Oil And Gas ◽  
Water Area ◽  
Convective Transport ◽  
Anaerobic Oxidation Of Methane ◽  
Sediment Layer ◽  
Santa Barbara Channel ◽  
Santa Barbara ◽  
Oxidation Of Methane ◽  
Methane Seepage ◽  
High Concentrations

Abstract. A shallow-water area in the Santa Barbara Channel (California), known collectively as the Coal Oil Point seep field, is one the largest natural submarine oil and gas emission areas in the world. Both gas and oil are seeping constantly through a predominantly sandy seabed into the ocean. This study focused on the methanotrophic activity within the surface sediments (0–15 cm) of the permeable seabed in the so-called Brian Seep area at a water depth ~10 m. Detailed investigations of biogeochemical parameters in the sediment surrounding active gas vents indicated that methane seepage through the permeable seabed induces a convective transport of fluids within the surface sediment layer, which results in a deeper penetration of oxidants (oxygen, sulfate) into the sediment, as well as in a faster removal of potentially inhibiting reduced end products (e.g. hydrogen sulfide). Methanotrophic activity was often found close to the sediment-water interface, indicating the involvement of aerobic bacteria. However, biogeochemical data suggests that the majority of methane is consumed by anaerobic oxidation of methane (AOM) coupled to sulfate reduction below the surface layer (>15 cm), where sulfate is still available in high concentrations. This subsurface maximum of AOM activity in permeable sands is in contrast to known deep-sea seep habitats, where upward fluid advection through more fine-grained sediments leads to an accumulation of AOM activity within the top 10 cm of the sediments, because sulfate is rapidly depleted.

scholarly journals Methane oxidation in permeable sediments at hydrocarbon seeps in the Santa Barbara Channel, California

2010 ◽  
Vol 7 (10) ◽  
pp. 3095-3108 ◽  
Author(s):  
T. Treude ◽  
W. Ziebis
Keyword(s):  
Water Area ◽  
Coastal Sediments ◽  
Deep Penetration ◽  
Anaerobic Oxidation Of Methane ◽  
Advective Transport ◽  
Santa Barbara Channel ◽  
Santa Barbara ◽  
Methane Consumption ◽  
Oxidation Of Methane ◽  
Hydrocarbon Emission

Abstract. A shallow-water area in the Santa Barbara Channel, California, known collectively as the Coal Oil Point seep field, is one of the largest natural submarine hydrocarbon emission areas in the world. Both gas and oil are seeping constantly through a predominantly sandy seabed into the ocean. This study focused on the methanotrophic activity within the surface sediments (0–15 cm) of the permeable seabed in the so-called Brian Seep area at a water depth of ∼10 m. Detailed investigations of the sediment biogeochemistry of active gas vents indicated that it is driven by fast advective transport of water through the sands, resulting in a deep penetration of oxidants (oxygen, sulfate). Maxima of microbial methane consumption were found at the sediment-water interface and in deeper layers of the sediment, representing either aerobic or anaerobic oxidation of methane, respectively. Methane consumption was relatively low (0.6–8.7 mmol m−2 d-1) in comparison to gas hydrate-bearing fine-grained sediments on the continental shelf. The low rates and the observation of free gas migrating through permeable coastal sediments indicate that a substantial proportion of methane can escape the microbial methane filter in coastal sediments.

scholarly journals A Synthesis Review of Emissions and Fates for the Coal Oil Point Marine Hydrocarbon Seep Field and California Marine Seepage

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-48 ◽  
Author(s):  
Ira Leifer
Keyword(s):  
Oil And Gas ◽  
Oil Spills ◽  
Marine Ecosystem ◽  
Anthropogenic Sources ◽  
Shallow Waters ◽  
Santa Barbara Channel ◽  
Santa Barbara ◽  
Run Off ◽  
Spatial And Temporal Heterogeneity

Anthropogenic oil in the ocean is of great concern due to its potential immediate and long-term impacts on the ecosystem, economy, and society, leading to intense societal efforts to mitigate and reduce inputs. Sources of oil in the ocean (in the order of importance) are natural marine seepage, run-off from anthropogenic sources, and oil spills, yet uncertainty and variability in these budgets are large, particularly for natural seepage, which exhibits large spatial and temporal heterogeneity on local to regional scales. When source inputs are comparable, discriminating impacts is complicated, because petroleum is both a bioavailable, chemosynthetic energy source to the marine ecosystem and a potential toxic stressor depending on concentration, composition, and period of time. This synthesis review investigates the phenomena underlying this complexity and identifies knowledge gaps. Its focus is on the Coal Oil Point (COP) seep field, arguably the best-studied example, of strong natural marine hydrocarbon seepage, located in the nearshore, shallow waters of the Northern Santa Barbara Channel, Southern California, where coastal processes complicate oceanography and meteorology. Many of our understandings of seep processes globally are based on insights learned from studies of the oil and gas emissions from the COP seep field. As one of the largest seep fields in the world, its impacts spread far as oil drifts on the sea surface and subsurface, yet much remains unknown of its impacts.

scholarly journals Anaerobic oxidation of methane alters sediment records of sulfur, iron and phosphorus in the Black Sea

2016 ◽  
Author(s):  
Matthias Egger ◽  
Peter Kraal ◽  
Tom Jilbert ◽  
Fatimah Sulu-Gambari ◽  
Célia J. Sapart ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Pore Water ◽  
Black Sea ◽  
The Black Sea ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Fe Oxide ◽  
Fe Oxides ◽  
Oxidation Of Methane ◽  
High Concentrations

Abstract. The surface sediments in the Black Sea are underlain by extensive deposits of iron (Fe) oxide-rich lake sediments that were deposited prior to the inflow of marine Mediterranean Sea waters ca. 9000 years ago. The subsequent downward diffusion of marine sulfate into the methane-bearing lake sediments has led to a multitude of diagenetic reactions in the sulfate-methane transition zone (SMTZ), including anaerobic oxidation of methane (AOM) with sulfate. While the sedimentary cycles of sulfur (S), methane and Fe in the SMTZ have been extensively studied, relatively little is known about the diagenetic alterations of the sediment record occurring below the SMTZ. Here we combine detailed geochemical analyses of the sediment and pore water with multicomponent diagenetic modeling to study the diagenetic alterations below the SMTZ at two sites in the western Black Sea. We focus on the dynamics of Fe, S and phosphorus (P) and demonstrate that diagenesis has strongly overprinted the sedimentary burial records of these elements. Our results show that sulfate-mediated AOM substantially enhances the downward diffusive flux of sulfide into the deep limnic deposits. During this downward sulfidization, Fe oxides, Fe carbonates and Fe phosphates (e.g. vivianite) are converted to sulfide phases, leading to an enrichment in solid phase S and the release of phosphate to the pore water. Below the sulfidization front, high concentrations of dissolved ferrous Fe (Fe2+) lead to sequestration of downward diffusing phosphate as authigenic vivianite, resulting in a transient accumulation of total P directly below the sulfidization front. Our model results further demonstrate that downward migrating sulfide becomes partly re-oxidized to sulfate due to reactions with oxidized Fe minerals, fueling a cryptic S cycle and thus stimulating slow rates of sulfate-driven AOM (~ 1–100 pmol cm−3 d−1) in the sulfate-depleted limnic deposits. However, this process is unlikely to explain the observed release of dissolved Fe2+ below the SMTZ. Instead, we suggest that besides organoclastic Fe oxide reduction, AOM coupled to the reduction of Fe oxides may also provide a possible mechanism for the high concentrations of Fe2+ in the pore water at depth. Our results reveal that methane plays a key role in the diagenetic alterations of Fe, S and P records in Black Sea sediments. The downward sulfidization into the limnic deposits is enhanced through sulfate-driven AOM with sulfate and AOM with Fe oxides may provide a deep source of dissolved Fe2+ that drives the sequestration of P in vivianite below the sulfidization front.

scholarly journals Methane emission and consumption at a North Sea gas seep (Tommeliten area)

2005 ◽  
Vol 2 (4) ◽  
pp. 1197-1241 ◽  
Author(s):  
H. Niemann ◽  
M. Elvert ◽  
M. Hovland ◽  
B. Orcutt ◽  
A. Judd ◽  
...  
Keyword(s):  
North Sea ◽  
Oil And Gas ◽  
Salt Diapir ◽  
Anaerobic Oxidation Of Methane ◽  
Cold Seeps ◽  
The North ◽  
Oxidation Of Methane ◽  
Phylogenetic Cluster ◽  
Carbonate Formation ◽  
Gas Seepage

Abstract. The North Sea hosts large coal, oil and gas reservoirs of commercial value. Natural leakage pathways of subsurface gas to the hydrosphere have been recognized during geological surveys (Hovland and Judd, 1988). The Tommeliten seepage area is part of the Greater Ekofisk area, which is situated above the Tommeliten Delta salt diapir in the central North Sea. In this study, we report of an active seep site (56°29.90'N, 2°59.80'E) located in the Tommeliten area, Norwegian Block 1/9, at 75 m water depth. Here, cracks in a buried marl horizon allow methane to migrate into overlying clay-silt and sandy sediments. Hydroacoustic sediment echosounding showed several venting spots coinciding with the apex of marl domes where methane is released into the water column and potentially to the atmosphere during deep mixing situations. In the vicinity of the gas seeps, sea floor observations showed small mats of giant sulphide-oxidizing bacteria above patches of black sediments and carbonate crusts, which are exposed 10 to 50 cm above seafloor forming small reefs. These Methane-Derived Authigenic Carbonates (MDACs) contain 13C-depleted, archaeal lipids indicating previous gas seepage and AOM activity. High amounts of sn2-hydroxyarchaeol relative to archaeol and low abundances of biphytanes in the crusts give evidence that ANaerobic MEthane-oxidising archaea (ANME) of the phylogenetic cluster ANME-2 were the potential mediators of Anaerobic Oxidation of Methane (AOM) at the time of carbonate formation. Small pieces of MDACs were also found subsurface at about 1.7 m sediment depth, associated with the Sulphate-Methane Transition Zone (SMTZ). The SMTZ of Tommeliten is characterized by elevated AOM and Sulphate Reduction (SR) rates, increased concentrations of 13C-depleted tetraether derived biphytanes, and specific bacterial Fatty Acids (FA). Further biomarker and 16S rDNA based analyses give evidence that AOM at the Tommeliten SMTZ is mediated by archaea belonging to the ANME-1b group and Sulphate Reducing Bacteria (SRB) most likely belonging to the Seep-SRB1 cluster. The zone of active methane consumption was restricted to a distinct horizon of about 20 cm. Concentrations of 13C-depleted lipid biomarkers (e.g. 500 ng g-dw-1 biphythanes, 140 ng g-dw-1 fatty acid ai-C15:0), cell numbers (1.5x108 cells cm-3), AOM and SR rates (3 nmol cm-3 d-1 in the SMTZ are 2-3 orders of magnitude lower compared to AOM zones of highly active cold seeps such as Hydrate Ridge or the Gulf of Mexico.

First direct evidence of methane seepage and associated chemosynthetic communities in the bathyal zone off Chile

2004 ◽  
Vol 84 (5) ◽  
pp. 1065-1066 ◽  
Author(s):  
Javier Sellanes ◽  
Eduardo Quiroga ◽  
Víctor A. Gallardo
Keyword(s):  
Preliminary Data ◽  
Direct Evidence ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Oxidation Of Methane ◽  
Methane Seepage ◽  
First Time ◽  
Shell Fragments

The occurrence of an area of methane seepage off Chile is reported for the first time. Shell fragments of two species of bivalves of the genus Calyptogena and one species of Acharax were retrieved in dredge hauls from 651 to 934 m depth off Concepción (≈36°S). A large quantity of carbonate blocks was also collected, indicating anaerobic oxidation of methane in the sediment. The accompanying, non-chemosynthetic fauna from one of the hauls was diverse, containing some species new to science. Our preliminary data suggests an assemblage similar in structure to those reported elsewhere, albeit with an important endemic component.

scholarly journals Anaerobic Oxidation of Methane in Freshwater Sediments of Rzeszów Reservoir

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 398
Author(s):  
Dorota Szal ◽  
Renata Gruca-Rokosz
Keyword(s):  
Electron Acceptors ◽  
Small Scale ◽  
Anaerobic Oxidation Of Methane ◽  
Sediment Layer ◽  
Anaerobic Oxidation ◽  
Freshwater Sediments ◽  
Oxidation Rates ◽  
Oxidation Of Methane ◽  
Dam Reservoirs ◽  
The Impact

The anaerobic oxidation of methane (AOM) is an important sink of methane that plays a significant role in global warming. However, evidence for the AOM in freshwater habitats is rare, especially in dam and weir (small-scale dam) reservoirs. Here, the AOM process was examined in freshwater sediments of a small-scale dam reservoir located in Rzeszów, SE Poland. The AOM rate was determined in the main experiment with the addition of the 13CH4 isotope marker (He+13CH4). Sediments were collected three times: in spring (in May, 15 °C), in summer (in July, 20 °C) and in autumn (in September, 10 °C). Further analysis considers the impact on AOM rate of potential electron acceptors present in pore-water (NO2−, NO3−, SO42−, and Fe3+ ions). The work suggests that an AOM process does take place in the studied reservoir sediments, with this evidenced by the presence in the headspace of an increased 13CO2 concentration deemed to derive from 13CH4 oxidation. Rates of AOM noted were of 0.36–1.42 nmol·g−1·h−1, with the most intensive oxidation in each sediment layer occurring at 20 °C. While none of the potential electron acceptors considered individually were found to have had a statistically significant influence on the AOM rate, their significance to the dynamics of the AOM process was not precluded.

scholarly journals Distribution of Nereilinum murmanicum (Annelida, Siboglinidae) in the Barents Sea in the Context of Its Oil and Gas Potential

2021 ◽  
Vol 9 (12) ◽  
pp. 1339
Author(s):  
Nadezda Karaseva ◽  
Madina Kanafina ◽  
Mikhail Gantsevich ◽  
Nadezhda Rimskaya-Korsakova ◽  
Denis Zakharov ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Oil And Gas ◽  
Barents Sea ◽  
Arctic Basin ◽  
Gas Production ◽  
The Arctic ◽  
Depth Range ◽  
Oxidation Of Methane ◽  
The Barents Sea ◽  
High Concentrations

Frenulate siboglinids are a characteristic component of communities living in various reducing environments, including sites with hydrocarbon seeps. High concentrations of hydrocarbons in the sediments of the Arctic basin seas, including the Barents Sea, suggest the presence of a rich siboglinid fauna there. This reflects the fact that microbiological oxidation of methane occurs under reducing conditions, generating high concentrations of hydrogen sulfide in the sediment. This hydrogen sulfide acts as an energy source for the sulfide-oxidizing symbionts of siboglinids. Here we report on the findings of the frenulate siboglinid species Nereilinum murmanicum made between 1993 and 2020 in the Barents Sea. These data significantly expand the range of this species and yield new information on its habitat distribution. The depth range of N. murmanicum was 75–375 m. The species was most abundant from 200 to 350 m and was associated with temperatures below 3 °C and salinities from 34.42 to 35.07. Most of the findings (43 locations or 74%) fall on areas highly promising for oil and gas production. Twenty-eight locations (48%) are associated with areas of known oil deposits, 22 locations (37%) with explored areas of gas hydrate deposits. N. murmanicum was also found near the largest gas fields in the Barents Sea, namely Shtokman, Ludlovskoye and Ledovoye.

scholarly journals Electron Acceptor Availability Shapes Anaerobically Methane Oxidizing Archaea (ANME) Communities in South Georgia Sediments

2021 ◽  
Vol 12 ◽  
Author(s):  
Annika Schnakenberg ◽  
David A. Aromokeye ◽  
Ajinkya Kulkarni ◽  
Lisa Maier ◽  
Lea C. Wunder ◽  
...  
Keyword(s):  
Community Composition ◽  
Electron Acceptor ◽  
Electron Acceptors ◽  
Anaerobic Oxidation Of Methane ◽  
Atmospheric Methane ◽  
Environmental Filters ◽  
South Georgia ◽  
Oxidation Of Methane ◽  
High Concentrations

Anaerobic methane oxidizing archaea (ANME) mediate anaerobic oxidation of methane (AOM) in marine sediments and are therefore important for controlling atmospheric methane concentrations in the water column and ultimately the atmosphere. Numerous previous studies have revealed that AOM is coupled to the reduction of different electron acceptors such as sulfate, nitrate/nitrite or Fe(III)/Mn(IV). However, the influence of electron acceptor availability on the in situ ANME community composition in sediments remains largely unknown. Here, we investigated the electron acceptor availability and compared the microbial in situ communities of three methane-rich locations offshore the sub-Antarctic island South Georgia, by Illumina sequencing and qPCR of mcrA genes. The methanic zone (MZ) sediments of Royal Trough and Church Trough comprised high sulfide concentrations of up to 4 and 19 mM, respectively. In contrast, those of the Cumberland Bay fjord accounted for relatively high concentrations of dissolved iron (up to 186 μM). Whereas the ANME community in the sulfidic sites Church Trough and Royal Trough mainly comprised members of the ANME-1 clade, the order-level clade “ANME-1-related” (Lever and Teske, 2015) was most abundant in the iron-rich site in Cumberland Bay fjord, indicating that the availability of electron acceptors has a strong selective effect on the ANME community. This study shows that potential electron acceptors for methane oxidation may serve as environmental filters to select for the ANME community composition and adds to a better understanding of the global importance of AOM.

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