The retreat of the summer ice cover in the Arctic Ocean allowed modern mapping surveys of the seafloor in the Canadian Beaufort Sea to be conducted in 2010. These surveys revealed a remarkable coalescence of seafloor morphologic features near the self edge and slope, which include submarine pingos, sinkholes, gigantic landslide scars and active mud volcanoes. To understand the development of these features we have participated in 8 expeditions  utilizing MBARI’s ROVs and AUVs. These tools provide extremely high resolution bathymetry of the seafloor as well as detailed ground truth observations and strategic samples from which the processes of formation can be established. By repeating the mapping surveys separated by as little as two years, we have shown that both the mud volcanoes and sinkholes are actively forming in this short time span.

The unusual coalescence of these morphological features may be unique to their Arctic settings. The continental slope here experienced extremely rapid deposition of sediment associated with Pleistocene ice ages, which leaves it susceptible to slope failures and the formation of mud volcanoes. In addition, the adjacent shelf is still underlain by a >600 m thick wedge of relict ice-bonded permafrost formed during the Pleistocene ice age. The shelf edge and slope are infused with brackish water, which geochemical analyzes show has come from the decomposition of relict permafrost. Apparently there is a large ground water circulation system that carries ground water, in part freshed by the decomposing permafrost to where it discharges at the self edge. The origin of the new sinkholes captured in our repeat mapping effort is especially interesting as they are attributed to surface collapse following the decomposition of relict submarine permafrost associated with the heat carried in this ground water.

MBARI’s Arctic ROV operations on the shelf and slope of the Beaufort Sea

MBARI has participated in five research cruises in the Canadian Beaufort Sea on the Canadian Coast Guard (CCG) Icebreaker Sir Wilfrid Laurier (SWL) and three cruises on the Korean Ice Breaker IBRV Araon. On each of these cruises an inspection class remotely operated vehicle (ROV) was utilized to visualize the seafloor and to collect samples. This work was conducted in collaboration with scientists at the Geological Survey of Canada and Fisheries and Oceans Canada and since 2016 the Korean Polar Research Institute

 

The ROV operations conducted from the SWL in 2010, 2012, 2013, and 2016 and the Araon in 2017 and 2022, are shown on the continental shelf of the Canadian Beaufort Sea. AUV surveys are outlined in white.

The locations of these dives are indicated in the map above and listed in this table.

ROV dive locations (.csv file)

Mini ROV Specs (.doc file)

MBARI provides these data “as is”, with no warranty, express or implied, of the data quality or consistency. Data are provided without support and without obligation on the part of the Monterey Bay Aquarium Research Institute to assist in its use, correction, modification, or enhancement.

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Team

Collaborators

Jong Kuk Hong (Korean Polar Research Institute), Young Keun Jin (Korean Polar Research Institute), Tae Siek Rhee (Korean Polar Research Institute), Scott Dallimore (Geological Survey of Canada). Mathieu Duchesne (Geological Survey of Canada)

Publications

Paull, C.K., S.R. Dallimore, Y.K. Jin, D.W. Caress, E. Lundsten, R. Gwiazda, K. Anderson, J.H. Clarke, C. Youngblut, and H. Melling. 2022. Rapid seafloor changes associated with the degradation of Arctic submarine permafrost. Proceedings of the National Academy of Sciences, 119: 1–8. https://doi.org/10.1073/pnas.2119105119

Kang, S.E., Y.K. Jin, U. Jang, M.J. Duchesne, C. Shin, S. Kim, M. Riedel, S.R. Dallimore, C.K. Paull, Y. Choi, and J.K. Hong. 2021. Imaging the P-wave velocity structure of Arctic subsea permafrost using Laplace-domain full-waveform inversion. JGR Earth Surface, 126: 1–15. https://doi.org/10.1029/2020JF005941

Lee, D.H., J.H. Kim, Y.M. Lee, J.H. Kim, Y.K. Jin, C. Paull, J.S. Ryu, and K.H. Shin. 2021. Geochemical and microbial signatures of siboglinid tubeworm habitats at an active mud volcano in the Canadian Beaufort Sea. Frontiers in Marine Science, 8: 1–16. https://doi.org/10.3389/fmars.2021.656171

Paull, C.K., S.R. Dallimore, D.W. Caress, R. Gwiazda, E. Lundsten, K. Anderson, H. Melling, Y.K. Jin, M.J. Duchesne, S.G. Kang, S. Kim, M. Riedel, E.L. King, and T. Lorenson. 2021. A 100-km wide slump along the upper slope of the Canadian Arctic was likely preconditioned for failure by brackish pore water flushing. Marine Geology, 435: 1–16. https://doi.org/10.1016/j.margeo.2021.106453

Lee, Y.M., H.J. Noh, D.H. Lee, J.H. Kim, Y.K. Jin, and C.K. Paull. 2019. Bacterial endosymbiont of Oligobrachia sp. (Frenulata) from an active mud volcano in the Canadian Beaufort Sea. Polar Biology, 42: 2305–2312. https://doi.org/10.1007/s00300-019-02599-w

Data

Beaufort Sea shelf edge morphologies

ROV dives along the shelf edge of the Beaufort Sea were conducted during the SWL cruises in 2010, 2012, and 2013. Two re-occurring morphologies were observed, including areas of slightly elevated rough topography and exposed gravel deposits.

(a) Areas of rough topography

ROV-observations of the seafloor near the shelf edge in the areas where gas venting was observed (Phantom Dives 1 to 7) documented patches of distinctive slightly elevated rough topography. These patches form isolated small mounds and ridges that are frequently accompanied by a white surface coating interpreted to be bacterial mats. The positive relief of these features may be due to differential erosion, that leaves these more erosion-resistant patches standing higher.

Arctic_2013_Combined_WebMap_2013Dive25 2010_Dive5_mounds

Mounds (Dive 5: 2010) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing an individual patch of rough topography near the shelf edge. This video clip starts when the ROV is hovering over smooth seafloor and shows the transition as it moves onto a patch of rough topography. Rough topography is composed of areas with a white surface coating and with exposed black colored sediment. These white and black colored areas outline subtle ridges that are slightly elevated with respect to the tan-colored sediments of the surrounding smooth seafloor. Field of view is estimated to be ~2 m.

Arctic_2013_Combined_WebMap_2010Dive3-01 2010_Dive_3_Polygonal_structure

Polygonal Structure (Dive 3: 2010) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip shows a patch of slightly elevated rough topography near the shelf edge.Within this patch there are ~20 cm wide <5 cm high white and black ridges that appear to be arranged in approximately polygonal patterns. Gas bubbles occasionally emanate from the white and black areas. Field of view is estimated to be ~2 m.

Arctic_2013_Combined_WebMap_2010Dive3-01 2010_Dive_3_Older_inactive_ridge

Older Inactive Ridge (Dive 3: 2010) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Ridge of slightly elevated and rough topography seen near the shelf edge. The ridge is estimated to be ~1 m across and have 10 cm to 20 cm of relief with respect to the surrounding smooth seafloor. Because the size and shape of this ridge, which lacks the typical white and black coloration, are similar to the elevated rough topography where gas venting is occurring nearby, this ridge is inferred to be of a similar origin, but older. Field of view is estimated to be ~2 m.

(b) Gravel deposits along the shelf edge

Gravel deposits were discovered near the shelf edge at a number of sites (2013 mini ROV Dives, 14, 17, 18, 19, 20, 25, 26, & 28 and 2012 mini ROV Dives 7, 9). These deposits are considered to be tills as they are composed of unsorted material containing boulders, cobbles, and pebbles of mixed lithologies, as well as fine sediment. The origin of these tills is the topic of on-going investigations.

Arctic_2013_Combined_WebMap_2013Dive18 2013_Dive18_Shelf_Edge_Gravel

Shelf Edge Gravel (Dive 18: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing extensive fields of gravel exposed on the seafloor near the shelf edge. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2013Dive25 2013_Dive_25_Shelf_Edge_Gravel

Shelf Edge Gravel (Dive 25: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing extensive fields of gravel exposed on the seafloor near the shelf edge. Note that sessile organisms are frequently attached to cobbles. Red dots are 8 cm apart.

 

Appearance of continental slope sediments

(a) Sediment covered areas

A mini ROV dive transect (mini ROV Dive 15) was conducted on the continental slope within a huge landslide scar. The seafloor was observed to be covered with fine sediment, which has apparently accumulated in place. Not a single rock was observed. This is in sharp contrast to areas at the shelf edge and on the headwall faces exposed by slide scars where pebbles, cobbles and even boulders are common.

Arctic_2013_Combined_WebMap_2013Dive15 2013_Dive15_background

Background Seafloor (Dive 15: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip shows part of an 867 m long transect between 667 and 592 m water depth up the slope of a sediment-draped landslide scar. Bottom has scattered sea pens (distinguished from tubeworms as they do not form clusters). The bottom was monotonously similar along the entire transect. Red dots are 8 cm apart.

(b) Outcrops exposed on the slope

Three mini ROV dives were conducted within slide scars or on the sides of gullies where older materials are exposed. These deposits are also considered to be tills as they are composed of unsorted material containing boulders, cobbles, and pebbles of mixed lithologies, as well as fine sediment. These dives demonstrated that that tills occur on the slope of the Canadian Beaufort Sea down to nearly 1 km water depth.

Arctic_2013_Combined_WebMap_2013Dive21 2013_Dive21_Scattered_Cobbles

Scattered Cobbles (Dive 21: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip shows the mini ROV’s mechanical arm collecting a cobble from the face of a slide scar in ~950 m water depths, where scattered cobbles were commonly observed during the dive. Some of these cobbles were plucked out of the wall formation. On most dives where cobbles were observed 8 to 14 samples were collected. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2013Dive29 2013_BouldersandCobbles

Boulders and Cobbles (Dive 29: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip from ~990 m water depths where the mini ROV conducted a transect up the steep sidewall of a slope-cutting gulley. An outcrop sequence ~100 m thick was observed, containing an extremely poorly sorted sequence that included boulders and numerous cobbles. Red dots are 8 cm apart.

(c) Water seepage on the slope

The mini ROV encountered six positive relief features within a slide scar in ~960 m water depths during dives 21 and 22, which were covered with a distinctive orange stain and/or chemical precipitate.These features occur on a steep slope where older strata might be exposed on the sole of the slide. These features are ~1 m high, 2-5 m wide, and appear to occur along the same isobath. They are believed to be present where fluid seeps onto the seafloor.

Arctic_2013_Combined_WebMap_2013Dive21 .wmv

Shimmering Water (Dive 21&22: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip shows shimmering water. This effect is created by the flow from the mound onto the seafloor of water with a different salinity than seawater. A brilliant orange color is seen on freshly exposed faces, where the mini ROV has broken off samples. 

 

Mud volcanoes

Multibeam bathymetric surveys conducted by the ArcticNet project in 2009 provided the first detailed bathymetry for a 100 km long section of the shelf edge and slope of the Canadian Beaufort Sea (Saint-Ange et al., 2014; Fig. 1). These data revealed the existence of large circular morphologic features in water depths of ~282 m, ~420 m, and a cluster of three closely-spaced structures in ~740 m water depths. Water column acoustic anomalies were identified over each of these features, indicating that they are sites of active gas venting and thus initially interpreted as being large mud volcanoes (Blasco et al., 2013; Saint-Ange et al., 2014). Six mini ROV dives focused on exploring and sampling gas from the tops and flanks of these expulsion features.

Arctic_2013_Combined_WebMap_2012Dive8-01 2012_Dive_8_Gas_Collection

Gas Collection (Dive 8: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip first showing gas bubbles escaping from the top of the mud volcano in 420 m water depth and then being captured into a transparent overturned funnel mounted on the front of the ROV. When a sufficient amount of gas was collected the ROV ascended to 400 m water depth and a heater within the funnel was turned on. The gas hydrate coated bubble mass decomposed over a couple of minutes, forming a gaseous headspace. This gas was later collected by withdrawing it into a pre-evacuated cylinder. 

Arctic_2013_Combined_WebMap_2012Dive5_11_12 2012_Dive5_TubewormBeds

Tubeworm Beds (Dive 5: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing a characteristic seafloor texture on a generally flat-topped mud volcano in ~282 m water depths on the continental slope of the Beaufort Sea. Clip begins with a close up of a starfish and surrounding tubeworm tubes, then zooms out as the ROV hovers over extensive tubeworm beds and lands to zoom on the worms and seafloor again. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2012Dive5_11_12 2012_Dive5_Moundand Furrow

Mound and Furrow (Dive 5: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing a characteristic fine-scale texture and topography on the top of a mud volcano in ~282 m water depths on the continental slope of the Beaufort Sea. Tubeworms are abundant and form parallel swaths with varying worm density. Clip begins with a view of an individual elevated mound with a small crack on its top that reveals black sediment rimmed by frosting of white mat. This pattern is interrupted by a distinct furrow which is ~5 cm across and has raised levee-like flanks. Similar furrows and gouges elsewhere have been attributed to excavation by marine mammals (Nelson et al., 1987; Woodside et al, 2006). Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2012Dive6 2012_Dive_6_dense_tubeworms

Dense Tubeworm Beds (Dive 6: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video transect across part of a large flat-topped mud volcano in ~740 m water depth. This transect starts in area of isolated clusters of tubeworms and moves into an area where the bottom is carpeted with tubeworms. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2012Dive6 2012_Dive6_Topof740mound

Top of 740 m Mound (Dive 6: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video showing area near top of a conical mud volcano in ~740 m water depths. This area is notably devoid of sessile organisms. The linear furrow crossed by the mini ROV is similar to furrows that have been observed elsewhere and attributed to excavation by marine mammals (Nelson et al., 1987; Woodside et al, 2006). Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2013Dive24 .wmv

Top of 420 m Mound (Dive 24: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing part of a mini ROV dive transect across the top of a mud volcano in 420 m water depths. Clip starts in an area believed to be a recent mud flow where the seafloor is characterized by its light gray color, rough texture and notable absence of sessile organisms. As the mini ROV moves towards the edge of the flow, the number of mobile organisms increases. The contact between the recent flow and the older surface is marked by a change to a tan color, a slight drop in the surface elevation, a change to a smoother surface texture, and the occurrence of sessile organisms (notably tiny tubeworms and white mats rimming burrows). A linear ridge seen on the older surface outside the flow appears to end where it was buried by the flow. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2013Dive24 2013_Dive24_Topof430Mound_youngwhitecontact

Top of 420 m Mound (Dive 24: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing part of a mini ROV dive transect over a recent flow across the top of a mud volcano in 420 m water depths. This clip starts at the edge of the what is interpreted to be a recent mud flow. Initially the surface is light tan color and has some sessile organism (small tubeworms and white rimmed burrows). The edge of the flow is associated with a change to a light gray color, slight rise in surface elevation, and rougher surface texture. The surface of the flow is notably lacking in sessile organisms. Red dots are 8 cm apart.

 

Seafloor excavation features

Seafloor excavation features were seen on most of the ROV dives on the Beaufort Sea shelf and slope. These excavation features are typically 2-10 m long and have slightly curving paths. In cross section these features are characterized by smooth rounded central troughs, which are consistently associated with upturned sediments on their flanks. These features occur as tear shaped gouges or longer furrows. The gouges are tapered at one end and get deeper towards the other end where they abruptly end in a semicircular depression. It is common to see clumps of obviously out of place sediments apparently dropped onto the seafloor at the end of these gouges. Similar furrows and gouges elsewhere have been attributed to excavation by marine mammals (Nelson et al., 1987; Woodside et al, 2006).

Arctic_2013_Combined_WebMap_2012Dive5_11_12 2012_Dive5_Whalemark

Whale Mark (Dive 5: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing an example of a large tear-shaped groove. This groove has clumps of sediment at its end that are lighter colored than the surrounding sediment. This suggests that these clumps were apparently dropped onto the seafloor and that this feature is comparatively fresh. Red dots are 8 cm apart.

 

Video annotation

The video recorded from the ROV dives in 2010, 2012, and 2013 are archived at MBARI. The video has been reviewed to document the major components of the visually identifiable benthic fauna using VARS (video annotation and reference system). Lists of the identified organism is tabulated here.

This research has been advanced in collaboration with scientists from the Geological Survey of Canada, Fisheries and Oceans Canada and MBARI. Future research cruises will include an expanded research network with participation by the Korean Polar Research Institute.

 

Published literature

Blasco, S., Bennett, R., Brent, T., Burton, M., Campbell, P., Carr, E., Covill, R., Dallimore, S., Davies, E., Hughes-Clarke, J., Issler, D., MacKillop, K., Mazzotti, S., Patton, E., Shearer, J., and White, M., 2013, State of knowledge: Beaufort Sea seabed geohazards associated with offshore hydrocarbon development Geological Survey of Canada Open File 6989, 307 p.

Paull, C.K., Ussler, W. III, Dallimore, S., Blasco, S., Lorenson, T., Melling, H., McLaughlin, F., and Nixon, F.M., 2007, Origin of pingo-like features on the Beaufort Sea shelf and their possible relationship to decomposing methane gas hydrates, Geophysical Research Letters, 34, L01603, doi:10.1029/2006GL027977.

Paull, C.K., Dallimore, S., Hughes-Clarke, J., Blasco, S. Lundsten, E., Ussler, W. III, Graves, D., Sherman, A., Conway, K., Melling, H., Vagle, S., and Collett, T., 2011, Tracking the decomposition of permafrost and gas hydrate under the shelf and slope of the Beaufort Sea, 7th International Conference on Gas Hydrate, 12 p.

Nelson, C.H., Johnson, K.R., and Barber, J.H. Jr., 1987, Gray Whale and Walrus Feeding Excavation on the Bering Shelf, Alaska, Journal of Sedimentary Research, v. 57, p. 419-430.

Saint-Ange, F., Kuus, P., Blasco, S., Piper, D.J.W., Hughes-Clarke, J., and MacKillop, K., 2014, Multiple failure styles related to shallow gas and fluid venting, upper slope Canadian Beaufort Sea, northern Canada, Marine Geology, v. 355, p. 136-149.

Woodside, J.M., David, L., Frantzis, A., and Hooker, S.K., 2006, Gouge marks on deep-sea mud volcanoes in the eastern Mediterranean; caused by Cuvier’s beaked whales?, Deep-Sea Research V. 53, p. 1762-1771.

Beaufort Sea shelf edge morphologies

ROV dives along the shelf edge of the Beaufort Sea were conducted during the SWL cruises in 2010, 2012, and 2013. Two re-occurring morphologies were observed, including areas of slightly elevated rough topography and exposed gravel deposits.

(a) Areas of rough topography

ROV-observations of the seafloor near the shelf edge in the areas where gas venting was observed (Phantom Dives 1 to 7) documented patches of distinctive slightly elevated rough topography. These patches form isolated small mounds and ridges that are frequently accompanied by a white surface coating interpreted to be bacterial mats. The positive relief of these features may be due to differential erosion, that leaves these more erosion-resistant patches standing higher.

Arctic_2013_Combined_WebMap_2013Dive25 2010_Dive5_mounds

Mounds (Dive 5: 2010) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing an individual patch of rough topography near the shelf edge. This video clip starts when the ROV is hovering over smooth seafloor and shows the transition as it moves onto a patch of rough topography. Rough topography is composed of areas with a white surface coating and with exposed black colored sediment. These white and black colored areas outline subtle ridges that are slightly elevated with respect to the tan-colored sediments of the surrounding smooth seafloor. Field of view is estimated to be ~2 m.

Arctic_2013_Combined_WebMap_2010Dive3-01 2010_Dive_3_Polygonal_structure

Polygonal Structure (Dive 3: 2010) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip shows a patch of slightly elevated rough topography near the shelf edge.Within this patch there are ~20 cm wide <5 cm high white and black ridges that appear to be arranged in approximately polygonal patterns. Gas bubbles occasionally emanate from the white and black areas. Field of view is estimated to be ~2 m.

Arctic_2013_Combined_WebMap_2010Dive3-01 2010_Dive_3_Older_inactive_ridge

Older Inactive Ridge (Dive 3: 2010) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Ridge of slightly elevated and rough topography seen near the shelf edge. The ridge is estimated to be ~1 m across and have 10 cm to 20 cm of relief with respect to the surrounding smooth seafloor. Because the size and shape of this ridge, which lacks the typical white and black coloration, are similar to the elevated rough topography where gas venting is occurring nearby, this ridge is inferred to be of a similar origin, but older. Field of view is estimated to be ~2 m.

(b) Gravel deposits along the shelf edge

Gravel deposits were discovered near the shelf edge at a number of sites (2013 mini ROV Dives, 14, 17, 18, 19, 20, 25, 26, & 28 and 2012 mini ROV Dives 7, 9). These deposits are considered to be tills as they are composed of unsorted material containing boulders, cobbles, and pebbles of mixed lithologies, as well as fine sediment. The origin of these tills is the topic of on-going investigations.

Arctic_2013_Combined_WebMap_2013Dive18 2013_Dive18_Shelf_Edge_Gravel

Shelf Edge Gravel (Dive 18: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing extensive fields of gravel exposed on the seafloor near the shelf edge. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2013Dive25 2013_Dive_25_Shelf_Edge_Gravel

Shelf Edge Gravel (Dive 25: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing extensive fields of gravel exposed on the seafloor near the shelf edge. Note that sessile organisms are frequently attached to cobbles. Red dots are 8 cm apart.

 

Appearance of continental slope sediments

(a) Sediment covered areas

A mini ROV dive transect (mini ROV Dive 15) was conducted on the continental slope within a huge landslide scar. The seafloor was observed to be covered with fine sediment, which has apparently accumulated in place. Not a single rock was observed. This is in sharp contrast to areas at the shelf edge and on the headwall faces exposed by slide scars where pebbles, cobbles and even boulders are common.

Arctic_2013_Combined_WebMap_2013Dive15 2013_Dive15_background

Background Seafloor (Dive 15: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip shows part of an 867 m long transect between 667 and 592 m water depth up the slope of a sediment-draped landslide scar. Bottom has scattered sea pens (distinguished from tubeworms as they do not form clusters). The bottom was monotonously similar along the entire transect. Red dots are 8 cm apart.

(b) Outcrops exposed on the slope

Three mini ROV dives were conducted within slide scars or on the sides of gullies where older materials are exposed. These deposits are also considered to be tills as they are composed of unsorted material containing boulders, cobbles, and pebbles of mixed lithologies, as well as fine sediment. These dives demonstrated that that tills occur on the slope of the Canadian Beaufort Sea down to nearly 1 km water depth.

Arctic_2013_Combined_WebMap_2013Dive21 2013_Dive21_Scattered_Cobbles

Scattered Cobbles (Dive 21: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip shows the mini ROV’s mechanical arm collecting a cobble from the face of a slide scar in ~950 m water depths, where scattered cobbles were commonly observed during the dive. Some of these cobbles were plucked out of the wall formation. On most dives where cobbles were observed 8 to 14 samples were collected. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2013Dive29 2013_BouldersandCobbles

Boulders and Cobbles (Dive 29: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip from ~990 m water depths where the mini ROV conducted a transect up the steep sidewall of a slope-cutting gulley. An outcrop sequence ~100 m thick was observed, containing an extremely poorly sorted sequence that included boulders and numerous cobbles. Red dots are 8 cm apart.

(c) Water seepage on the slope

The mini ROV encountered six positive relief features within a slide scar in ~960 m water depths during dives 21 and 22, which were covered with a distinctive orange stain and/or chemical precipitate.These features occur on a steep slope where older strata might be exposed on the sole of the slide. These features are ~1 m high, 2-5 m wide, and appear to occur along the same isobath. They are believed to be present where fluid seeps onto the seafloor.

Arctic_2013_Combined_WebMap_2013Dive21 .wmv

Shimmering Water (Dive 21&22: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip shows shimmering water. This effect is created by the flow from the mound onto the seafloor of water with a different salinity than seawater. A brilliant orange color is seen on freshly exposed faces, where the mini ROV has broken off samples. 

 

Mud volcanoes

Multibeam bathymetric surveys conducted by the ArcticNet project in 2009 provided the first detailed bathymetry for a 100 km long section of the shelf edge and slope of the Canadian Beaufort Sea (Saint-Ange et al., 2014; Fig. 1). These data revealed the existence of large circular morphologic features in water depths of ~282 m, ~420 m, and a cluster of three closely-spaced structures in ~740 m water depths. Water column acoustic anomalies were identified over each of these features, indicating that they are sites of active gas venting and thus initially interpreted as being large mud volcanoes (Blasco et al., 2013; Saint-Ange et al., 2014). Six mini ROV dives focused on exploring and sampling gas from the tops and flanks of these expulsion features.

Arctic_2013_Combined_WebMap_2012Dive8-01 2012_Dive_8_Gas_Collection

Gas Collection (Dive 8: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip first showing gas bubbles escaping from the top of the mud volcano in 420 m water depth and then being captured into a transparent overturned funnel mounted on the front of the ROV. When a sufficient amount of gas was collected the ROV ascended to 400 m water depth and a heater within the funnel was turned on. The gas hydrate coated bubble mass decomposed over a couple of minutes, forming a gaseous headspace. This gas was later collected by withdrawing it into a pre-evacuated cylinder. 

Arctic_2013_Combined_WebMap_2012Dive5_11_12 2012_Dive5_TubewormBeds

Tubeworm Beds (Dive 5: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing a characteristic seafloor texture on a generally flat-topped mud volcano in ~282 m water depths on the continental slope of the Beaufort Sea. Clip begins with a close up of a starfish and surrounding tubeworm tubes, then zooms out as the ROV hovers over extensive tubeworm beds and lands to zoom on the worms and seafloor again. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2012Dive5_11_12 2012_Dive5_Moundand Furrow

Mound and Furrow (Dive 5: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing a characteristic fine-scale texture and topography on the top of a mud volcano in ~282 m water depths on the continental slope of the Beaufort Sea. Tubeworms are abundant and form parallel swaths with varying worm density. Clip begins with a view of an individual elevated mound with a small crack on its top that reveals black sediment rimmed by frosting of white mat. This pattern is interrupted by a distinct furrow which is ~5 cm across and has raised levee-like flanks. Similar furrows and gouges elsewhere have been attributed to excavation by marine mammals (Nelson et al., 1987; Woodside et al, 2006). Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2012Dive6 2012_Dive_6_dense_tubeworms

Dense Tubeworm Beds (Dive 6: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video transect across part of a large flat-topped mud volcano in ~740 m water depth. This transect starts in area of isolated clusters of tubeworms and moves into an area where the bottom is carpeted with tubeworms. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2012Dive6 2012_Dive6_Topof740mound

Top of 740 m Mound (Dive 6: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video showing area near top of a conical mud volcano in ~740 m water depths. This area is notably devoid of sessile organisms. The linear furrow crossed by the mini ROV is similar to furrows that have been observed elsewhere and attributed to excavation by marine mammals (Nelson et al., 1987; Woodside et al, 2006). Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2013Dive24 .wmv

Top of 420 m Mound (Dive 24: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing part of a mini ROV dive transect across the top of a mud volcano in 420 m water depths. Clip starts in an area believed to be a recent mud flow where the seafloor is characterized by its light gray color, rough texture and notable absence of sessile organisms. As the mini ROV moves towards the edge of the flow, the number of mobile organisms increases. The contact between the recent flow and the older surface is marked by a change to a tan color, a slight drop in the surface elevation, a change to a smoother surface texture, and the occurrence of sessile organisms (notably tiny tubeworms and white mats rimming burrows). A linear ridge seen on the older surface outside the flow appears to end where it was buried by the flow. Red dots are 8 cm apart.

Arctic_2013_Combined_WebMap_2013Dive24 2013_Dive24_Topof430Mound_youngwhitecontact

Top of 420 m Mound (Dive 24: 2013) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing part of a mini ROV dive transect over a recent flow across the top of a mud volcano in 420 m water depths. This clip starts at the edge of the what is interpreted to be a recent mud flow. Initially the surface is light tan color and has some sessile organism (small tubeworms and white rimmed burrows). The edge of the flow is associated with a change to a light gray color, slight rise in surface elevation, and rougher surface texture. The surface of the flow is notably lacking in sessile organisms. Red dots are 8 cm apart.

 

Seafloor excavation features

Seafloor excavation features were seen on most of the ROV dives on the Beaufort Sea shelf and slope. These excavation features are typically 2-10 m long and have slightly curving paths. In cross section these features are characterized by smooth rounded central troughs, which are consistently associated with upturned sediments on their flanks. These features occur as tear shaped gouges or longer furrows. The gouges are tapered at one end and get deeper towards the other end where they abruptly end in a semicircular depression. It is common to see clumps of obviously out of place sediments apparently dropped onto the seafloor at the end of these gouges. Similar furrows and gouges elsewhere have been attributed to excavation by marine mammals (Nelson et al., 1987; Woodside et al, 2006).

Arctic_2013_Combined_WebMap_2012Dive5_11_12 2012_Dive5_Whalemark

Whale Mark (Dive 5: 2012) (Download movie file .wmv .mov. Depending on your web browser you may need to right click on link and save the file to download the clip.) Video clip showing an example of a large tear-shaped groove. This groove has clumps of sediment at its end that are lighter colored than the surrounding sediment. This suggests that these clumps were apparently dropped onto the seafloor and that this feature is comparatively fresh. Red dots are 8 cm apart.

 

Video annotation

The video recorded from the ROV dives in 2010, 2012, and 2013 are archived at MBARI. The video has been reviewed to document the major components of the visually identifiable benthic fauna using VARS (video annotation and reference system). Lists of the identified organism is tabulated here.

This research has been advanced in collaboration with scientists from the Geological Survey of Canada, Fisheries and Oceans Canada and MBARI. Future research cruises will include an expanded research network with participation by the Korean Polar Research Institute.

 

Published literature

Blasco, S., Bennett, R., Brent, T., Burton, M., Campbell, P., Carr, E., Covill, R., Dallimore, S., Davies, E., Hughes-Clarke, J., Issler, D., MacKillop, K., Mazzotti, S., Patton, E., Shearer, J., and White, M., 2013, State of knowledge: Beaufort Sea seabed geohazards associated with offshore hydrocarbon development Geological Survey of Canada Open File 6989, 307 p.

Paull, C.K., Ussler, W. III, Dallimore, S., Blasco, S., Lorenson, T., Melling, H., McLaughlin, F., and Nixon, F.M., 2007, Origin of pingo-like features on the Beaufort Sea shelf and their possible relationship to decomposing methane gas hydrates, Geophysical Research Letters, 34, L01603, doi:10.1029/2006GL027977.

Paull, C.K., Dallimore, S., Hughes-Clarke, J., Blasco, S. Lundsten, E., Ussler, W. III, Graves, D., Sherman, A., Conway, K., Melling, H., Vagle, S., and Collett, T., 2011, Tracking the decomposition of permafrost and gas hydrate under the shelf and slope of the Beaufort Sea, 7th International Conference on Gas Hydrate, 12 p.

Nelson, C.H., Johnson, K.R., and Barber, J.H. Jr., 1987, Gray Whale and Walrus Feeding Excavation on the Bering Shelf, Alaska, Journal of Sedimentary Research, v. 57, p. 419-430.

Saint-Ange, F., Kuus, P., Blasco, S., Piper, D.J.W., Hughes-Clarke, J., and MacKillop, K., 2014, Multiple failure styles related to shallow gas and fluid venting, upper slope Canadian Beaufort Sea, northern Canada, Marine Geology, v. 355, p. 136-149.

Woodside, J.M., David, L., Frantzis, A., and Hooker, S.K., 2006, Gouge marks on deep-sea mud volcanoes in the eastern Mediterranean; caused by Cuvier’s beaked whales?, Deep-Sea Research V. 53, p. 1762-1771.

Fauna Observation (.csv file)

Taxa
common name
 
Annelidaannelid worm 
Polychaetapolychaete worm 
Nereididaepolychaete worm 
Sabellidaefeather duster worm 
Serpulidaepolychaete worm 
Oligobrachiatubeworm 
Terebellidapolychaete worm 
Amphipodaamphipod 
Carideatrue shrimp 
Decapodacrab 
Lithodidaeking crab 
Majidaedecorator crab 
Pandalidaeshrimp 
Pasiphaeashrimp 
Euphausiaceakrill 
Isopodaisopod 
Mysidamidwater shrimp 
Copepodacopepod 
Calanuscopepod 
Scalpellidaebarnacle 
Pycnogonidasea spider 
Chionoecetes opiliosnow crab 
bacterial matbacterial mat 
Brachiopodalamp shell 
Bryozoabryozoan 
Chaetognathaarrow worm 
Tunicatasea squirt 
Osteichthyesbony fish 
Lophiiformesanglerfish 
Oneirodes acanthiasanglerfish 
Bythitidaebrotula fish 
Zoarcidaeeelpout 
Pleuronectiformesflatfish 
Agonidaepoacher 
CottidaeSculpin 
LiparidaeSnailfish 
Ophiodongreenling 
Sebastesrockfish 
Appendicularialarvacea 
Octacnemidaesea quirt 
Rajiformesray, skate 
Cnidariajelly 
Medusaejelly 
Calycophoraesiphonophorae 
Nanomiasiphonophorae 
Rhodaliidaebenthic siphonophore 
Siphonophoraesiphonophore 
Aeginajelly 
Actiniariaanemone 
Hormathiidaeanemone 
Antipathariablack coral 
Cerianthidaetube anemone 
Zoanthideazoanthid 
Octocoralliasoft coral 
Octocoralliasoft coral 
Gersemiasoft coral 
Pennatulaceasea pen 
Umbellulasea pen 
Ctenophoracomb jelly 
Cydippidacomb jelly 
Lobatacomb jelly 
Beroecomb jelly 
Asteroideasea star 
Henriciasea star 
Hippasteriasea star 
Solasteridaesea star 
Crossastersea star 
Solastersea star 
Pterasteridaesea star 
Comatulidinasea lilly 
Echinoideasea urchin 
Holothuroideasea cucumber 
Ophiuroideabrittle star 
Gorgonocephalusbasket star 
Echiuraspoon worm 
Bonelliidaespoon worm 
Bivalviaclam 
Pectinidaescallop 
Octopusoctopus 
Rossiabobtail squid 
Teuthoideasquid 
Gastropodasnail 
Nemertearibbon worm 
Phaeophyceaebrown algae 
Phoronidahorseshoe worm 
Platyhelminthesflatworm 
Poriferasponge 
Poeciloscleridasponge 
Cladorhizidaecarnivorous sponge

MBARI provides these data “as is”, with no warranty, express or implied, of the data quality or consistency. Data are provided without support and without obligation on the part of the Monterey Bay Aquarium Research Institute to assist in its use, correction, modification, or enhancement.