Arctic Gas Research Articles

CAGE Final Report 2017–2023

After a successful decade as a Centre of Excellence funded by the Norwegian Research Council, the Centre for Arctic Gas Hydrate, Environment and Climate (CAGE) will draw to a close at the end of February 2023. In this final report, we reflect on the extraordinary accomplishments, impacts, and legacy from the second phase of CAGE (2017-2023). The first phase of the Centre (2013-2017) was reported in the CAGE Annual 2016 Report.

CAGE17-4 Cruise Report: Recovery of observatory and water column survey offshore Svalbard

The cruise was conducted from August 3rd to 5th 2017 as part of the Centre of Excellence for Arctic Gas Hydrate, Environment and Climate (CAGE) at UiT –The Arctic University of Norway. The main goal of the cruise was to recover the observatory K-Lander 2 deployed in October 2016 offshore Svalbard, at the same location where OS2 was deployed in June 2015 and recovered in May 2016. The present cruise also aimed at continuing the water samples and CTD survey on the shallow shelf and the shelf edge presenting extensive flares western Svalbard. The addressed scientific topics include quantification of methane concentration in the water column, temperature and salinity (via CTD casts), echosounder and multibeam signals and current (amplitude and direction). The cruise may be known as: CAGE17_4

CAGE17-1-Leg 2 cruise report

From the afternoon of May 19th to the early morning of June 2nd 2017, CAGE-WP6 at the Department of Geology Uit, the Arctic University of Norway, arranged a scientific cruise aimed at investigating sediment cores and porewater, and water masses, at the western Svalbard margin, Fram Strait, East Greenland Ridge, and Storfjorden Trough, visiting methane seep sites off Vestnesa Ridge, and in Storfjorden Trough on R/V “Helmer Hanssen”. Investigated areas were (in order of visiting sites on the cruise): Prins Karls Forland (PKF) (overlap with ‘leg 1’ 17th to 19th of May – see Leg 1 report), southern Yermak Plateau, Vestnesa Ridge, East Greenland Ridge, Storfjorden Trough and Storfjorden.
 The scientific sampling was done within the framework of several ongoing projects at the Department of Geology, University of Tromsø: “CAGE – Centre for Arctic Gas Hydrate, Environment and Climate”-WP6: “Methane Release, Ocean Acidification and CO2”. Planned surveys north of Svalbard was abandoned due to extensive sea ice cover and the East Greenland Ridge was surveyed instead. Sea ice over outer Vestnesa prevented surveys there and Storfjorden trough was also completely covered, but the sea ice broke up towards the end of the cruise and thus could be surveyed during the very last part of the cruise.
 A total of 15 gravity cores (c. 60 m), and 20 CTD (conductivity-temperature-depth) casts were performed along the western Svalbard margin (Vestnesa and PKF and Yermak). Data were also collected at East Greenland Ridge and in Storfjorden Trough and Storfjorden, brine overflow was detected. The CTD casts and chirp- and multibeam lines from PKF May 17-19th are reported in the cruise report for Leg 1.
 Chirp profiles and multibeam lines were acquired during transits and in surveys (mapping of East Greenland Ridge, moraine systems and basins in Storfjorden Trough, active and inactive pockmarks at Vestnesa Ridge and over and to find potential core sites.
 The cruise may be known as: CAGE17_1_leg2

CAGE17-1-Leg1 Cruise Report: Water column observation from CTD and water samples west of Prins Karls Forland, Svalbard

From the afternoon of May 15th to the afternoon of May 19th, CAGE-Centre for Arctic Gas Hydrate, Climate and Environment, the Department of Geoscience UiT, the Arctic University of Norway, arranged a scientific cruise to survey offshore Prins Karls Forland, Svalbard to perform CTD measurements and water sampling on R/V “Helmer Hanssen”. The purpose is to study the variations in methane release and its dependence on oceanographic changes. The area has been continuously surveyed for the last three years for methane concentration, and methane consumption by bacteria and other related data. Because of the good weather conditions time allowed survey of the outer part of the shelf west of Prins Karls Forland – the socalled ‘Masox area’. Here three CTD’s were taken and the area surveyed by echosounding (EK60), chirp and multibeam for combined flare survey (EK60) and geological recording of sedimentary environments (chirp and multibeam). A total of 69 CTD (conductivity-temperature-depth) casts were performed with 12 water bottles sampled for each CTD station. The cruise may be known as: CAGE17_1_leg1

CAGE15-1 Cruise Report : CAGE-CO2 Winter Cruise to the western and northwestern Svalbard margin and the Barents Sea

From the afternoon of April 1st to the morning of April 9th 2015, CAGE at the Department of Geology Uit, the Arctic University of Norway, arranged a scientific cruise aimed at investigating the western Barents Sea slope, western and northern Svalbard margin, methane seep sites at Vestnesa and Storfjorden Trough and the Barents Sea on R/V “Helmer Hanssen”. Investigated areas were (in order of visiting sites on the cruise): Malangen Trough, Bjørnøya Trough Mouth Fan south and mid, Storfjorden Fan, Vestnesa Ridge, the northwest Svalbard slope to north of Schmeerenburgfjorden. On the track towards Tromsø we sampled in Storfjorden Trough. The scientific sampling was done within the framework of several ongoing projects at the Department of Geology, University of Tromsø: “CAGE -Centre for Arctic Gas hydrate, Environment and Climate”, in which the sub-projects “Paleo-CIRCUS”, “OA-Ocean Acidification” is included.
 A total of 2 gravity cores, 8 plankton net casts and 22 CTD (conductivity-temperature-depth) casts were performed along the route to Northern Svalbard at the western Barents Sea slope. Data were also collected in Storfjorden Trough and the mouth of Storfjorden. In addition, CTD’s and a small chirp and multibeam survey was performed off Schmeerenburgfjorden, north of fjorden and in its northernmost part.
 Chirp profiles and multibeam lines were acquired during transits and during the survey of outer Schmeerenburgfjorden. The recording started from c. 71 N on the western Barents Sea slope and ended at 70.00 N.
 The cruise may be known as: CAGE15_1_CO2

CAGE14-4 Cruise Report: CAGE-CO2 Cruise and GEO3144 Teaching Cruise to the western Svalbard margin and the Barents Sea

From the afternoon of July 21st to the morning of July 29th 2014, CAGE at the Department of Geology Uit, the Arctic University of Norway, arranged a scientific cruise with teaching (GEO3144/8144- Arctic Marine Geology and Geophysics Cruise) aimed at investigating and teaching students about the western Svalbard margin, methane seep sites at Vestnesa and Storfjorden Trough and the Barents Sea on R/V “Helmer Hanssen”. Investigated areas were (in order of visiting sites on the cruise): Vestnesa Ridge, the west Svalbard slope, Storfjorden Trough, Storfjorden and western Barents Sea. The scientific sampling was done within the framework of several ongoing projects at the Department of Geology, University of Tromsø: “CAGE – Centre for Arctic Gas hydrate Environment and Climate”, in which the sub-projects “Paleo-CIRCUS”, “OA-Ocean Acidification” is included. A total of 11 gravity cores, 7 box-cores (with a total of 18 sub-samples retrieved), 9 plankton net casts and 16 CTD (conductivity-temperature-depth) casts were performed at Vestnesa Ridge, Storfjorden Fan, Storfjorden Trough, Storfjorden and the western Barents Sea, respectively. All gravity cores were logged onboard by magnetic susceptibility loop sensor for stratigraphical purposes and educational purposes. Chirp profiles and multibeam echo sounder lines were acquired during transits and during surveys of Storfjorden and several pockmarks at the Vestnesa Ridge. A total of 129 lines were collected during transits and during surveys. A total of six seismic lines were performed with the airgun. The cruise may be known as: CAGE14_4_CO2_GEO

CAGE16-3 Cruise Report: CAGE-PWC April Cruise to the western Svalbard margin

From the afternoon of April 22nd to the early morning of May 1st 2016, CAGE at the Department of Geology Uit, the Arctic University of Norway, arranged a scientific cruise aimed at investigating sediment cores and pore water, water masses, and planktonic faunas, at the western Svalbard margin and western Barents Sea slope, also visiting methane seep sites off Vestnesa Ridge, Prins Karls Forland (PKF) and in Storfjorden Trough on R/V “Helmer Hanssen”. Investigated areas were (in order of visiting sites on the cruise): PKF, Vestnesa Ridge, PKF again, Storfjorden Trough and Storfjorden. This cruise can be regarded as a continuance of the previous cruise February 8-15, 2016, where all seep sites at Vestnesa Ridge and PKF were abandoned because of bad weather conditions. In April we hope to reach Vestnesa and PKF to get the cores we missed in February. The scientific sampling was done within the framework of several ongoing projects at the Department of Geology, University of Tromsø: “CAGE -Centre for Arctic Gas hydrate, Environment and Climate”, in which the sub-projects Paleo-CIRCUS and “OA-Ocean Acidification” are included.
 A total of 10 gravity cores, 3 multinet casts and 14 CTD (conductivity-temperature-depth) casts were performed along the western Svalbard margin (Vestnesa and PKF). Data were also collected in Storfjorden Trough and Storfjorden, no brine overflow detected in April either.
 Chirp profiles and multibeam lines were acquired during transits and in small surveys at potential core sites over outer Vestnesa, PKF and in Storfjorden filling previous gaps in records from earlier cruises.

CAGE14-1 Cruise Report: CAGE research school in Arctic Marine Geology and Geophysics

Cruise CAGE 14-1 is one of several cruises in 2014 that will be carried out to collect cross-disciplinary data for addressing the objectives of the Norwegian Centre for Arctic Gas Hydrate, Environment and Climate, CAGE. The Norwegian Research Council funds CAGE for a period of 10 years to addressee main scientific questions about gas hydrate environments in Arctic regions. Cruise CAGE 14-1 was also hosting this year’s AMGG research school cruise with 14 PhD students participating, most of them from CAGE. The cruise focused on acquisition of seismic, oceanographic, atmospheric, geochemical and sediment and benthic fauna sampling data from three target areas: the shallow shelf and shelf edge methane seepage sites at Prins Karls Forelanda sediment drift on the western flank of the Knipovich Ridgethe Vestnesa Ridge Research objectives were planned long the goals of CAGE and its individual work packages, and the teaching would be organized along these goals. Scientific problems that are to be addressed in these two key target areas include the periodicity of seepage (i.e. time scales of active, inactive and reactivated systems), quantification of methane concentrations in surface sediments, water column and above the sea surface, gas and hydrates, the nature of gas sources, and the benthic communities occurring at the seep sites. Specific objectives of cruise CAGE 14-1 were as follows: Hydro-acoustic mapping of methane bubble plumes above shallow and deep-water vent fields.Seismic surveying and multibeam mapping across the contours of the Svyatogor Rise.Sediment sampling using gravity, box and multi-corer for sediment and pore-water geochemical analysesSampling of benthic fauna at several seep sites and reference stations in all three target areas.Acquisition of oceanographic data for measuring oceanographic conditions and methane concentrations in the water column, particularly at the shallow shelf sites. The cruise may be known as: CAGE14_1

CAGE16-7 Cruise Report: Deployment of observatories and water column survey in the Barents Sea and offshore Svalbard

The cruise was conducted from October 16th to 25th 2016 as part of the Centre of Excellence for Arctic Gas Hydrate, Environment and Climate (CAGE) at UiT – The Arctic University of Norway. The main goal of the cruise was to deploy two observatories in the pingo-crater area (“Yin Yang”) in the Barents Sea, and offshore Svalbard at the same location where OS2 was deployed in June 2015 and recovered in May 2016. The exact targeted location was determined according to multibeam analysis in order to deploy in the vicinity of bubble streams. The previously K-Landers called OS1 (black) and OS2 (grey) are now called K-Lander 1 and K-Lander 2. They contain a CH4 sensor, a CO2 sensor, a CTD, a pH meter, and a hydrophone. K-Lander 1 contains in addition a DVS (Doppler volume sampler) as the broken ADCP did not arrive on time for the deployment. K-Lander 2 contains in addition an ADCP, a transmissometer (for turbidity measurement) and an M3 (Multibeam echosounder). The present cruise also aimed at investigating an area of extensive flares western Svalbard, particularly the shallow shelf and shelf edge. The addressed scientific topics include quantification of methane concentration in the water column, temperature and salinity (via CTD casts), echosounder and multibeam signals and current (amplitude and direction) The cruise may be known as: CAGE16_7

CAGE16-4 Cruise Report: Recovery of observatories and water column survey offshore Svalbard

The cruise occurred from May 1st to May 9th 2016 and was part of the Centre of Excellence for Arctic Gas Hydrate, Environment and Climate (CAGE) at UiT – The Arctic of Norway. The main goal of the cruise was to recover two observatories that were deployed on June 30th and July 2nd 2015 during CAGE 15-3 (chief scientist Anna Silyakova). The sites were selected according to pictures taken during CAGE 15-2 cruise (chief scientist Giuliana Panieri) illustrating bacterial mats on the sea floor. The exact locations were decided just prior to deployment according to flare locations. The present cruise also aimed at investigating an area of extensive flares western Svalbard, particularly the shallow shelf and shelf edge. The addressed scientific topics include quantification of methane concentration in the water column, dissolved inorganic carbon, pH, microbial activity and identification, nutrients, DMSP, CDOM and current amplitude and direction. The cruise may be known as: CAGE16_4

CAGE19-3 Cruise Report: Calypso giant piston coring in the Atlantic-Arctic gateway – Investigation of continental margin development and effect of tectonic stress on methane release

CAGE 19-3 cruise with RV “Kronprins Haakon” to the Atlantic-Arctic gateway region is organized and funded through the Tromsø Forskningsstiftelse (TFS) and Research Council of Norway (RCN) supported SEAMSTRESS project and the Center of Excellence "CAGE – Centre for Arctic Gas Hydrate, Environment and Climate" at UiT-The Arctic University of Norway in Tromsø. SEAMSTRESS focuses on studies of the effect of tectonic stress on methane release at Arctic continental margins while CAGE studies the amount of methane hydrate and magnitude of methane release in Arctic Ocean environments on time scales from the Neogene to the present. CAGE 19-3 cruise is directed to the Atlantic-Arctic gateway region to provide necessary field data for these objectives. From previous cruises, we have identified key localities which will be main targets for this cruise. The cruise may be known as: CAGE19_3

CAGE 20-1 Cruise Report: K-lander recovery and water column survey offshore Svalbard and in the Barents Sea

The cruise was conducted from June 22nd to July 1th 2020 as part of the Centre of Excellence for Arctic Gas Hydrate, Environment and Climate (CAGE) at UiT – The Arctic University of Norway. The main objective of the research cruise was to recover the K-lander that was deployed offshore Prins Karls Forland on an extensive methane seepage area. The sub-objective was to performed single and multibeam surveys around the lander in order to locate the origin of the signal seen in the collected data, and map the seepages to compare with our horizontally-looking multibeam mounted on the lander. In addition, we collected water from Niskin bottles during CTD casts to measure methane concentration in the water column along and across the lander. Other areas of interest were the “MASOX” site, and other sites where methane seepages are suspected
 The cruise may be known as: CAGE20_1

CAGE19-2 Cruise Report: Hunting gas flares and launching seafloor observatory

The cruise was part of the Centre of Excellence(SFF) Centre for Arctic Gas Hydrate, Environment and Climate Climate (CAGE) at UiT – The Arctic University of Norway. It was partly supported by The Norwegian Petroleum Directory (NPD). The cruise had the following scientific objectives: Identification of gas seepage associated with assumed hydrocarbon reservoirs subcropping the sea floor due to erosion of overlying cap rocks.Identification of gas seepage related to leakage along faults breaching the seafloor.Acqusition of multibeam, subbottom profiler-, seismic data and samples of gas in water and sediments for cross disciplinary investigations by CAGEDeployment of seafloor observatory and oceanographic studies west of Prins Kars Forland The cruise may be known as: CAGE19_2

Annual Report 2013

Earth scientists at CAGE together with colleagues from The Geological Survey of Norway and Akvaplan-niva aim to assess the role of Arctic gas hydrate in past, present and future climate change. For past or present reconstructions we study samples from the sub seabed, the seabed, the water column and the atmosphere and for the future outlook we aim to use modeling with experts from atmospheric science. To accomplish these goals, CAGE contributes to enhanced collaborations and relationships with university and industry research teams at national and international levels.

CAGE13-2 Cruise Report: CAGE, OAFS and Paleo-CIRCUS cruise to Northwest Norway, Jan Mayen and East Greenland

From the morning of June 23rd to the morning of July 7th 2013, the Department of Geology of the University of Tromsø, Norway, arranged a scientific cruise aimed at investigating the western Northern Norwegian margin and the central Nordic seas and east Greenland margin| on R/V “Helmer Hanssen”. Investigated areas were (in order of visiting sites on the cruise): the northwestern Norwegian Sea margin to north of Jan Mayen, and the western Greenland Sea north and off Scorebysund. The scientific sampling was done within the framework of ongoing projects at the Department of Geology, University of Tromsø: “CAGE (CoE): Arctic Gas Hydrate, Environment and Climate”, hereunder the projects “OAFS-Ocean Acidification Fram Strait” and “Paleo-CIRCUS”.
 A total of 12 gravity cores, 5 piston cores and 9 multi-cores (with a total of 27 sub-coresretrieved), 15 plankton net casts and 20 CTD (conductivity-temperature-depth) casts were performed at the western Barents Sea slope, and the Barents Sea.
 >44 chirp profiles and multibeam echo sounder lines were acquired during transits and during surveys of potential core sites.
 -4 seismic lines using GI mini airgun
 The cruise may be known as: CAGE13_OA_PaleoCIRCUS

CAGE18-5 Cruise report : Remotely-operated vehicle (ROV) investigations of active gas seepage sites in the Barents Sea

Cruise CAGE18-5 was the first research expedition under the helm of UiT The Arctic University of Norway in Tromsø with the new ice-going research vessel R/V Kronprins Håkon. This new vessel provides new opportunities to collect cross-disciplinary data for addressing the objectives of the Norwegian Centre of Excellence for Arctic Gas Hydrate, Environment and Climate, CAGE. CAGE investigates Arctic gas hydrate and methane seepage systems in order to better understand the effects they may have on our oceans, ecosystems and global climate. The new research vessel and its facilities allows CAGE access to a state-of-art remotely-operated vehicle, the ROV Ægir 6000, opening a new domain for experimental work and acquisition of sample material from the seafloor. The overall goal of cruise CAGE18-5 therefore was to utilize the ROV in order to provide guided video imagery and to study active gas seepage systems at the gas-hydrate pingo (GHP) site located in the outer Storfjord Trough, and at Storbanken in the northeastern part of the Barents Sea. The cruise may be known as: CAGE18_5

Cruise CAGE-18-4

Cruise CAGE18-4 with UiT’s research vessel R/V Helmer Hanssen was carried out to collect cross-disciplinary data for addressing the objectives of the Norwegian Centre of Excellence for Arctic Gas Hydrate, Environment and Climate, CAGE. The cruise was split into two legs with a port call in Longyearbyen. Leg 1 targeted the Vestnesa Ridge on the western Svalbard margin and acquired 2D and 3D high-resolution P-Cable seismic data in close proximity to the Molloy Ridge in order to better understand tectonic impacts on fluid flow and gas hydrate accumulations. Leg 2 continued our investigations of the newly discovered gas seepage field in the Leierdjupet Fault complex (see CAGE17-3 cruise report) focusing on a better understanding of its complex leakage and source-to-sink plumbing system using seafloor photo and video imagery, water and sediment sampling, multibeam mapping and hydroacoustics. The cruise may be known as: CAGE18_4

CAGE-18-3 Cruise to the Barents Sea, Storfjorden Trough, East Greenland Ridge (Leg 1, 2), Arctic Ocean Vestnesa Ridge, and PKF, (Leg 3)

From the evening of June 29th to the evening of July 10th 2018, CAGE at the Department of Geology Uit, the Arctic University of Norway, arranged a scientific cruise aimed at investigating methane seep sites by surface sediment sampling, sediment core sampling, plankton sampling and water sampling. The areas for investigation were the Barents Sea (Crater area), Storfjorden Trough (Pingo area),East Greenland Ridge (non-seep, for IODP-proposal) (Leg 1 and 2) and the western Svalbard margin, Vestnesa Ridge, Arctic Ocean and Prins Karls Forland (Leg 3) on R/V “Helmer Hanssen”. The scientific sampling was done within the framework of several ongoing projects at the Department of Geology, University of Tromsø: “CAGE -Centre for Arctic Gas Hydrate, Environment and Climate”-WP6: “Methane Release, Ocean Acidification and CO2” hereunder ocean acidification impact on marine calcifiers (planktic foraminifera and pteropods, methane seeping impact on ocean acidification and productivity, the state of the inorganic and organic biological pump from foraminifera, bottom water temperature change and impact on release of methane, living benthic microfauna studies from seep sites for geochemical investigations for calibrations for paleostudies. A total of 15 gravity cores (c. 60 m),and 31 CTD (conductivity-temperature-depth) casts were performed, 11 plankton net (no. 12 failed because the net was torn completely), 22 boxcore samples x 6 surface samples for each. A total of 137 lines of acoustics and seismics together were performed. Chirp profiles and multi-beam lines were acquired during transits and in surveys mapping of new seep sites northeast of “Crater” area, seep sites in Storfjorden Trough, East Greenland Ridge, seeps in Hinlopen trough and Norske Banken, the east slope of Yermak Plateau, active and inactive pockmarks at Vestnesa Ridge and a small patch off PKF for WP4. All acoustic and seismic investigations were performed with soft-start of all instruments (Echo-sounders, deep-penetrating echosounder (‘Chirp’), Multi-beam echosounder and mini-air gun). The cruise may be known as: CAGE18_3_leg1 CAGE18_3_leg2 CAGE18_3_leg3

CAGE20-2 Cruise Report: Hunting flares in Hopendjupet and glacigenic sediments in Sentralbankrenna

The research cruise was part of the Centre of Excellence (SFF) Centre for Arctic Gas Hydrate Environment and Climate (CAGE) at UiT – The Arctic University of Norway. It was partly supported by The Norwegian Petroleum Directorate. From Tromsø, we visited Sentralbankrenna and Hopendjupet in the central Barents Sea in order to pursue the following scientific objectives: – Identify gas seepage associated with known and assumed sandstone reservoirs sub-cropping at the sea floor. – Identify gas seepage related to leakage along faults and geological structures breaching the seafloor. – Collect gravity cores, multibeam and sub-bottom data to establish how grounding zone processes impact marine-based ice sheet behaviour and trigger ice-stream retreat during deglaciation. The cruise may be known as: CAGE20_2

CAGE18-2 Cruise Report: LoVe site – exploration around node 7

The cruise was conducted from May 20th to 27th 2018 as part of the Centre of Excellence for Arctic Gas Hydrate, Environment and Climate (CAGE) at UiT – The Arctic University of Norway.
 The main goal of the cruise was to explore the area around Node 7 as part of the LoVe (Lofoten-Vesterålen) observatory. The first phase of the LoVe project was founded by Statoil in was first launched in 2013 to observe a cold coral reef. This area is known to be an oceanographic hotspot because the shelf is very narrow and northern drift of warm Atlantic water is concentrated and very dynamic in this area. It is also a biological hotspot because the large oceanic fish stocks are passing through or spawn in the area. It is finally an economic hotspot because the area is expected to hold large oil and gas resources but exploitation of these resources is controversial because of the importance for fish and fishermen in this region. The observatory has 12 sensors on the platform today including a camera looking at the coral reef and echosounders to study the biology.
 The second phase of LoVe was granted by the Research Council of Norway in 2015 through the Infrastructure programme, with a network of nodes crossing the main oceanographic and biological processes. The various nodes of the planned transect have specific objectives, and in particular, node 7 is located on top of methane seepages which CAGE is in charge.
 The present cruise aimed at performing echosounder and multibeam surveys as well as performing water samples and CTD casts around node 7 and known seepage area. The addressed scientific topics include quantification of methane concentration in the water column, temperature and salinity (via CTD casts), echosounder and multibeam signals and current (amplitude and direction)
 The cruise may be known as: CAGE18_2