DOE/NETL Methane Hydrate Projects
 
Assessing the Response of Methane Hydrates to Environmental Change at the Svalbard Continental Margin Last Reviewed June 2017

DE-FE0013531

Goal
The project goal is to study the biogeochemical response of gas hydrates to environmental change at the Svalbard Continental Margin. 

Performer
Oregon State University, Corvallis, OR 97339-1086

Background
More research is needed to better understand the role gas hydrates play in the global carbon cycle and their potential as a future energy resource. This includes determining

  • the residence time of gas hydrates near the seafloor and deeper within the sediment column,
  • the sources and pathways of methane transport,
  • the nature and driving mechanisms for flow,
  • methane distribution in the water column, and
  • the changes in the (above) variables over time.

Characterizing carbon cycling in the critical zone on the upper continental slope will increase our knowledge of the hydrate stability transition at/near the seafloor. The upper edge of gas hydrate stability defines one of the most climate-sensitive boundaries and represents a potential “window” to fluid and gas migration from below the seaward-deepening bottom simulating reflector. Hydrate transformations can be documented through analyses of geochemical data, modeling efforts to quantify each process and its associated rate, and obtaining ground truth data of these geochemically-derived inferences through analyses of microbial communities.

Impact
German and Norwegian colleagues have ongoing programs focusing on characterizing gas hydrate abundance, distribution, and the effect of environmental changes on gas hydrate stability at the western Spitsbergen continental margin. In cooperation with those programs, Oregon State researchers will explore the role of biogeochemical processes in the region via pore water and sediment geochemical analyses, microbiological analyses, and kinetic modeling. The roles of microbial methane generation and oxidation will be constrained at and below the sulfate-methane transition zone, enabling researchers to quantify the amount of methane as it escapes, moves, or is consumed. These fundamental data are needed in order to constrain models for assessing the residence time of carbon in various methane-rich reservoirs as well as the dynamic response of these systems to environmental change and the resulting effect in the overlying water column. The proposed research has the potential to increase our understanding of the response and impact of gas hydrates to changing environmental conditions.

Accomplishments (most recent listed first)

  • Researchers participated in five research cruises off Svalbard where they collaborated with Norwegian and German scientists to collect samples for geochemical and microbiological analyses using a variety of tools (geophysical data, conventional coring and water sampling, video-guided sampling, ROV surveys, seafloor drilling). In addition, researchers participated in another DOE-funded cruise to the Cascadia margin, where they collected additional samples for microbiological analyses, which will complement the principal investigator’s geochemistry data.
  • Modelling of methane dynamics and evaluation against data collected at seep sites in the Ulleung Basins (DOE co-funded project off Korea) was completed, and two papers have been published in Transport in Porous Media. The results were also presented at a methane gas conference in Taiwan in September 2014.
  • Results from the various expeditions off Svalbard document: 1) widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden ; 2) evidence for the presence of gas hydrate pavements near the seafloor in a pockmark location on Vestnesa Ridge; and 3) presence of gas hydrate mounds in Storfjordrenna, at the southern tip of Spitsbergen that may reflect a long history of methane venting in the region.

Current Status (May 2017)
Geochemical and microbiological samples from the past expeditions are being analyzed. The researchers have demonstrated the ability to extract DNA using two Svalbard cores from the past October expedition (GC-09 and GC-12) from depths ranging from 0 to 220 cm below seafloor, as well as amplification of the 16S rRNA. The research team established collaboration with Fengping Wang (State Key Laboratory of Microbial Metabolism at Shanghai Jiao Tong University in Shanghai, China) and funding for Scott Klassec (via a National Science Foundation summer fellowship) to use samples collected from the most recent Svalbard expedition for incubation experiments at high pressures to elucidate microbial response to changes in methane content. Building on the experience from the visit to Shanghai, Klassec has implemented sediment incubations for time-series experiments at situ temperatures and pressures under different methane concentrations. Methane consumption, sulfate reduction, and sulfide and dissolved inorganic carbon production will be measured. In addition to microbial community analysis, the team plans to quantify cell abundances and functional genes and transcripts associated with anaerobic methane oxidation and sulfate reduction. This work is partially supported by a Deep Carbon Observatory Deep Life Cultivation Internship grant to enrich or cultivate carbon-cycling microbes from subsurface environments. Preliminary results from these studies were presented at the AGU Fall Meeting in San Francisco, CA (Dec 2015), and at the Gordon Research Conference on Gas Hydrates in Galveston, TX (Feb-March 2016). Long-term high pressure incubations of marine sediment samples are now well underway. A stainless steel pressure vessel was constructed with the help of CEOAS’s machine and technical development facility to increase throughput of high-pressure incubations. Thirty-day incubations were sampled in March, while 4- and 8-month incubations will end in mid-June. Upon depressurization, sampling consists of preserving and measuring headspace methane. Media samples are stored for measurement of sulfide, sulfate, DIC, and nutrients. Sediment is frozen for nucleic acid analysis and fixed for fluorescent microscopy. Consumption of methane and production of sulfide was noted over the first three months of the 8-month incubation, when media was replaced and new methane was added. Additional chemical measurements and conversions to rates are forthcoming. Extracted microbial community DNA from incubations will be sequenced on an Illumina Miseq run that will be scheduled this summer. We plan to complete the experiment by July 2017. Molecular analyses will be conducted during August-September 2017 , with a manuscript planned for early 2018.

Geochemical characterization of samples recovered from the various expeditions is underway. The first manuscript describes the gas hydrate dynamics and associated geochemical response at newly discovered gas hydrate mounds off the shore of Svalbard. Modelling of the non-steady-state porewater profiles and the observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. Results of temperature modelling suggest limited impact of short-term warming on gas hydrates deeper than a few metres in the sediments. The research team concludes that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site. This manuscript was recently published in the Journal Nature Geoscience. Results were also presented at the Gordon Research Conference on Gas Hydrates in Galveston, TX (Feb-March 2016). Ongoing studies focus on the geochemical signals to elucidate fluid sources feeding these gas hydrate mounds. Preliminary interpretations were presented at the Gas in Marine Sediment conference in Tromso (Norway), September 2016.

Samples for the water column component document a much broader seepage area than previously reported, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometers in length. Data collected in the summer of 2015 revealed that 0.02-7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading the team to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.Preliminary results were presented at the 2016 Gordon Research Conference on Natural Gas Hydrate (Galveston, TX, March 2016), and a manuscript has been recently published in the journal "Scientific Reports," also published by the Nature consortium with an impact factor of ~5. An abstract detailing these results was submitted to the upcoming International Conference on Gas Hydrates to be held in Denver, June 2017, and it is the subject of an article to be published in the Fire in the Ice magazine July 2017.

Another collaborative effort with scientists from Norway, which include results from expeditions to the Svalbard margin in the context of this grant resulted in another paper, is now in press in the Journal Marine Geology. Preliminary results from the cruise using a video-guided camera to the vestnesa pockmarks were presented in an article in the FITI magazine in 2016. The manuscript resulted from integration of available information to date and reports on the first detailed seafloor imaging and camera-guided multicore sampling at two of the most active pockmarks along Vestnesa Ridge, named Lomvi and Lunde is now in press in the Journal Marine Geology. The research team correlate seafloor images with seismically defined subseafloor structures, providing a geological and ecological context to better understand pockmark formation and water column observations. Subbottom and seismic surveys, water column imaging, geochemical data and seafloor observations indicate ongoing fluid flow at these pockmarks. Visual inspection and sampling using a high-resolution deep-sea camera and multicorer system show exposed gas hydrate and authigenic carbonate in association with biota within two of these pockmarks. Distributed methane venting at both Lomvi and Lunde supports extensive chemosynthetic communities that include filamentous sulphide-oxidizing bacteria and Siboglinid tubeworms, all of which utilize chemical energy provided by the seeping fluids. Focused venting forms shallow gas hydrate, and sustains localized gas discharge from 50-m wide pits within the pockmarks. Cycles of carbonate precipitation and/or exhumation of carbonate deposits are indicated by scattered blocks of various size, pavements, and massive carbonate blocks up to 5 m in diameter. Consistent with other observations along continental margin settings, the research team show that the extensive authigenic carbonate deposits in the Vestnesa pockmarks represent an important and prolonged methane sink that prevents much of the upwardly flowing methane from reaching the overlying ocean.

Products:

Peszynska, M., Medina, F.P., Hong, W.L. and Torres, M.E., 2015. Reduced Numerical Model for Methane Hydrate Formation under Conditions of Variable Salinity. Time-Stepping Variants and Sensitivity. Computation, 4(1), p.1.

Peszynska, M., Hong, W.L. Torres, M.E., and Kim, J-H., 2015. Methane Hydrate Formation in Ulleung Basin Under Conditions of Variable Salinity: Reduced Model and Experiments. Transport Porous Media DOI 10.1007/s11242-016-0706-y

Mau, S., Römer, M., Torres, M.E., Bussmann, I., Pape, T., Damm, E., Geprägs, P., Wintersteller, P., Hsu, C.W., Loher, M. and Bohrmann, G., 2017. Widespread methane seepage along the continental margin off Svalbard-from Bjørnøya to Kongsfjorden. Scientific Reports, 7.

Hong, W-L, Torres, M.E., Carroll, J-L, Crémière, A., Panieri, G., Yao, H. and Serov, P. 2017. Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming. Nature Communications, 8:15745 | DOI: 10.1038/ncomms15745

Panieri, G., Bünz, S., Fornari, D. J., Escartin, J., Serov, P., Johnson, J. J, Jansson, P., Hong, W-L., Sauer, S., Torres, M. E., Garcia, R., Gracias, N. 2017. An integrated view of the methane system in the pockmarks at Vestnesa Ridge, 79°N. Marine Geology, in press.

Project Start: November 1, 2013
Project End: October 31, 2018

DOE Contribution: $645,724
Performer Contribution: $180,000

Contact Information:
NETL – Joseph Renk (Joseph.Renk@netl.doe.gov or 412-386-6406)
Oregon State University – Marta Torres (mtorres@coas.oregonstate.edu or 541-737-2901)

Additional Information:

Quarterly Research Progress Report [PDF-396KB] Period Ending - June, 2017

Quarterly Research Progress Report [PDF-773KB] Period Ending - March, 2017

Quarterly Research Progress Report [PDF-1.98MB] Period Ending - December, 2016

Quarterly Research Progress Report [PDF-565KB] Period Ending - September, 2016

Quarterly Research Progress Report [PDF-2.77MB] Period Ending - June, 2016

Quarterly Research Progress Report [PDF-3.39MB] Period Ending - March, 2016

Quarterly Research Progress Reportt [PDF-14.4MB] Period Ending - December, 2015

Quarterly Research Progress Report [PDF-11.1MB] Period Ending - September, 2015

Quarterly Research Progress Report [PDF-1.65MB] Period Ending - March, 2015

Quarterly Research Progress Report [PDF-11.2MB] Period Ending - December, 2014

Quarterly Research Progress Report [PDF-540KB] Period Ending - September, 2014

Quarterly Research Progress Report [PDF-4.93MB] Period Ending - June, 2014

Quarterly Research Progress Report [PDF-868KB] Period Ending - March, 2014

Quarterly Research Progress Report [PDF-168KB] Period Ending - January, 2014

Quarterly Research Progress Report [PDF-173KB] Period Ending - December, 2013