A5030514785- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Arctic and Antarctic ice dynamics
- Hydrocarbon exploration and reservoir analysis
- Geology and Paleoclimatology Research
- Oceanographic and Atmospheric Processes
- Geological Studies and Exploration
- Marine and coastal ecosystems
- Coastal wetland ecosystem dynamics
- Coastal and Marine Dynamics
- Geological formations and processes
- Microbial Community Ecology and Physiology
- Environmental Monitoring and Data Management
- Ocean Acidification Effects and Responses
- Marine and environmental studies
- Marine Biology and Ecology Research
- Oil Spill Detection and Mitigation
- Marine and fisheries research
- Analytical Chemistry and Sensors
- Peatlands and Wetlands Ecology
- Climate change and permafrost
- Offshore Engineering and Technologies
- Seismic Imaging and Inversion Techniques
- Aeolian processes and effects
- Spectroscopy and Laser Applications
UiT The Arctic University of Norway
2012-2025
Centre for Arctic Gas Hydrate, Environment and Climate
2015-2024
University of Copenhagen
2022
United States Geological Survey
2010-2018
Woodwell Climate Research Center
2010-2018
Ifremer
2017
Bellevue College
2017
Usman Institute of Technology
2015
Centre National de la Recherche Scientifique
2003-2008
Université de Perpignan
2003-2008
Methane hydrate is an icelike substance that stable at high pressure and low temperature in continental margin sediments. Since the discovery of a large number gas flares landward termination stability zone off Svalbard, there has been concern warming bottom waters have started to dissociate amounts resulting methane release may possibly accelerate global warming. Here, we corroborate hydrates play role observed seepage gas, but present evidence Svalbard ongoing for least 3000 years seasonal...
Abstract Borealis is a recently discovered submerged mud volcano in the Polar North Atlantic, differing from numerous methane seepages previously identified region. Here we show situ observations remotely operated vehicle (ROV), capturing release of warm (11.5 °C) Neogene sediments and methane-rich fluids gryphon at Borealis. The surrounding seafloor within features extensive carbonate deposits, indicating prolonged diffuse migration. Sampling imagery reveal that supports unique habitats...
Abstract We find that summer methane (CH 4 ) release from seabed sediments west of Svalbard substantially increases CH concentrations in the ocean but has limited influence on atmospheric levels. Our conclusion stems complementary measurements at seafloor, ocean, and atmosphere land‐based, ship aircraft platforms during a campaign 2014. detected high dissolved above seafloor with sharp decrease pycnocline. Model approaches taking potential emissions both bubble‐released larger region into...
The potential impact of future climate change on methane release from oceanic gas hydrates is the subject much debate. We analyzed World Ocean Database quality controlled data Norwegian‐Svalbard continental margin past 60 years to evaluate effect ocean temperature variations hydrate reservoirs. Bottom water temperatures in were significant cooling until 1980 (by ∼2°C offshore NW‐Svalbard and Barents Sea) followed by a general bottom increase 2010 (∼0.3°C deep‐water areas mid‐Norwegian...
Research Article| May 01, 2015 Abiotic methane from ultraslow-spreading ridges can charge Arctic gas hydrates Joel E. Johnson; Johnson * 1CAGE–Centre for Gas Hydrate, Environment, and Climate, Department of Geology, UiT The University Norway, Dramsveien 201, N-9037 Tromsø, Norway2Department Earth Sciences, New Hampshire, 56 College Road, Durham, Hampshire 03824, USA *E-mail: joel.johnson@unh.edu Search other works by this author on: GSW Google Scholar Jürgen Mienert; Mienert Norway Andreia...
Abstract. We describe and demonstrate algorithms for treating cohesive mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST Subversion repository revision 1234). These include following: floc dynamics (aggregation disaggregation water column); changes characteristics seabed; erosion deposition of (combination non-cohesive) sediment; biodiffusive mixing bed sediment. routines...
We present a novel instrument, the Sub-Ocean probe, allowing in situ and continuous measurements of dissolved methane seawater. It relies on an optical feedback cavity enhanced absorption technique designed for trace gas coupled to patent-pending sample extraction method. The considerable advantage instrument compared with existing ones lies its fast response time order 30 s, that makes this probe ideal 3D-mapping water. could work up 40 MPa external pressure, it provides large dynamic...
Abstract The Arctic Ocean subseabed holds vast reservoirs of the potent greenhouse gas methane (CH 4 ), often seeping into ocean water column. In a continuously warming as result climate change an increase CH seepage from seabed is hypothesized. Today, largely retained in column due to activity methane‐oxidizing bacteria (MOB) that thrive there. Predicted future oceanographic changes, bottom and increasing release may alter efficacy this microbially mediated sink. Here we investigate...
Abstract A newly discovered cold seep from the Lofoten-Vesterålen margin (Norwegian Sea) is dominated by chemosymbiotrophic siboglinid Oligobrachia haakonmosbiensis like other high latitude seeps, but additionally displays uncharacteristic features. Sulphidic bottom water likely prevents colonization cnidarians and sponges, resulting in fewer taxa than deeper seeps region, representing a deviation depth-related trends seen among elsewhere. O. was present carbonate barite crusts, constituting...
Abstract Seabed gas and oil emissions appear as bubble plumes ascending through the water column in various environments. Understanding characteristics—size, rise speed—is important for estimating escape rates of fluids like methane, oil, carbon dioxide. However, measuring underwater bubbles is challenging, often requiring expensive specialized equipment. This study presents a novel methodology using two calibrated consumer‐grade cameras to estimate size distribution, velocities,...
Borealis is a newly identified underwater mud volcano located in the Polar North Atlantic, distinct from many methane emissions previously found area. In this study, we present direct observations remotely operated vehicle (ROV), documenting emission of warm (11.5°C) Neogene sediments and methane-laden fluids gryphon at Borealis. The seafloor around covered with extensive carbonate formations, suggesting long history diffuse flow. Our sampling imagery indicate that hosts unique...
Cold-water corals in the Hola area off coast of Vesterålen (N. Norway), thrive on a substrate made methane-derived carbonate and are closely associated with microbial mats. High resolution seafloor imagery sediment samples collected during EMAN7 expedition June 2022 allowed us to reconstruct spatial relationships between methane seepage habitats gain insights into subsurface biogeochemical processes directly influencing benthic ecosystems. Here, we present fine-scale orthomosaics...
Abstract Cold seeps and cold‐water corals (CWCs) coexist on Northern Norway's continental shelf at the Hola trough between Lofoten Vesterålen. Here, cold release methane from seabed, yet none reaches sea surface. Instead, dissolves disperses in ocean where it is ultimately consumed by methane‐oxidizing microorganisms. These microorganisms metabolize carbon dioxide dissolved organic matter (DOM), which may impact biogeochemical habitat of CWCs close vicinity seeps. We investigated...
Abstract. Understanding the fate of gas seeping from seafloor is crucial for assessing environmental impact natural and anthropogenic seep systems, such as CH4 cold seeps or leaks wells future carbon capture projects. We present a comprehensive modelling framework that integrates physical, biological chemical processes to estimate 3-dimensional dissolved concentration total atmospheric flux seeps. The consists two main steps: 1) A phase model estimates free dissolution direct at site, 2)...
Abstract. Methane (CH4) is a powerful greenhouse gas. Its atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH4 sources essential for effective climate change mitigation. Here we report observations the measured at Zeppelin Observatory (Svalbard) in Arctic and aboard research vessel (RV) Helmer Hanssen over Ocean from June 2014 to December 2016, as well long-term trend 2001 2017. We investigated areas European identify possible hotspot regions emitting...
Abstract This study investigates the temporal variations in methane concentration and flare activity Hola trough (offshore Norway) during May 2018 June 2022. Between these time periods, seep exhibits 3.5 times increase, as evidenced by hydroacoustic measurements. As area is constantly within hydrate stability zone, observed increase cannot be attributed to migration of its shallow boundary due temperature increase. However, a combination low tide conditions resulting lower sediment pore...