Wyville Thomson Ridge survey summary

Now we have returned from the stormy seas of northern Scotland and got our land-legs back, we have been able to look back over the work we achieved. During our 15 day survey of the Wyville Thomson Ridge and Faroe-Shetland channel we were able to employ a wide variety of data collection techniques and cover a large area within the two survey areas.

Some summary statistics of what was accomplished during our time is shown below:

• Sidescan: ~307 km of Sidescan Sonar on the slopes of Wyville Thompson Ridge and in south-west of the Faroe-Shetland Channel.
• Mulitbeam: In excess of 170 km of multibeam on Wyville Thompson Ridge and Noss Head.
• Video tows: 61 completed – 29 on Wyville Thompson Ridge and 32 in Faroe Shetland Channel
• Grab samples: 5 successfully completed in Faroe-Sheltand Channel and Noss Head
• Rock dredge: 1 sample taken in the north of Faroe-Shetland Channel

Wyville Thomson Ridge survey map

We would like to thank the captain and crew of the MRV Scotia, our partners from Marine Scotland Science, Rebecca and Gillian for their help and assistance during this survey.

As this cruise has come to an end another is just about to begin with colleagues from JNCC due to depart onboard CEFAS Endeavour on 17th November heading to the Braemar Pockmarks and Scanner Pockmark SCIs, which contain the Annex I feature ‘Submarine structures made by leaking gas’ as well as the Scottish offshore Nature Conservation MPA proposals within the Fladen Grounds.

High tailing it back

After yesterday’s weather and equipment setbacks, lunchtime comes around and we’re able to hit the ground running once again. With a further eight video tows planned in our mission to map deep sea sponge aggregations and to hopefully collect some samples for analysis later, we certainly had an ambitious work plan laid on the table. Luckily we weren’t disappointed, with sponge grounds out in force. Particular highlights include massive sponges such as the cathedral sponge (pictured below with pencil urchins either side) and the general high diversity of different sponge species observed.

Cathedral sponge with pencil urchins

Sponge grounds of the Faroe-Shetland Channel



Sponges, red banded fish and sea cucumber on boulder

Once we’d completed our camera work in the Faroe-Shetland Channel the weather finally started to creep in and it was time to high tail it back to port. With time on our hands we used an opportunity en route back home to conduct some further survey work in an area of interest for a Marine Protected Area in Scotland known as Noss Head. Here the feature of interest is beds of the horse mussel (Modiolus modiolus).

We conducted multibeam sounding over the area of interest to try and get a feel for the extent of horse mussels in the area, followed by some grab sampling work so we could assess the biodiversity associated with the beds. Unfortunately, our grab samples were a bit hit and miss but we still got some interesting stuff such as many different types of worms and clams.

Suited and booted ready for grab work

Hamon grab sampling at Noss Head

Grab sampling

After a brief period of calibrating our multibeaming equipment in the Moray Firth on the way back home we finally arrived back into Aberdeen at 19:30 hours on 8th November 2012, weary but satisfied with the achievements we’ve made on the cruise.

The search for ‘cheesy bottoms’ continues...

With our towed video camera back up and running it was time to kick into gear and continue our search for aggregations of deep sea sponges on the seabed of the Faroe-Shetland Channel. Keeping an eye out for the aptly named ‘Ostebund’ or ‘cheesy bottoms’ as they are known by Faroese fishermen due to their appearance, we continue to move eastward towards previously identified records of the habitat.

Along our journey we came across some oil industry installations, the first sign of other civilisation we’ve had all trip barring the odd trawler vessel in the distance. After some frantic waving and observing it was back to the video surveys. What beheld us was some pretty interesting animals, including a range of lamellate, lobose and encrusting sponges, a fireworks anemone or two, some vivid red sea cucumbers, pencil urchins and several species of fish. A taste of the diversity of species identified are provided below.

Cerianthid anemone

Sea cucumber, pencil urchin and lamellate sponge on coarse sediments

Sponge communities on rock

All was going well, and we were moving towards completing some repeat surveys from data on sponge grounds collected over six years ago, but unfortunately camera problems once again struck. This time the camera tow cable had become wrapped around the transponder unit that tells us the position of the camera on the seabed. So, it was back to the angle grinder to cut out the now kinked piece of cable and a 2 hour repair job at 1am in the morning. With the camera back up and running it was now time for the weather to foil our plans. We now sit waiting for a weather window to continue with our camera work.

Back to sidescan whilst the camera takes a well-earned ‘rest’

Well, unfortunately our camera was in a slightly worse condition than everyone thought, leaving two options: a) a DIY repair, or b) heading into Scrabster to pick up and replace the damaged parts – a 20 hour round trip...

Whilst we wait to see what the very capable engineers on board can do, we hooked up the sidescan to continue surveying the lumps and bumps of the Faroe-Shetland Channel seabed. Sidescanning around the clock certainly took it out of the scientists on board, but reaped some reward.

By processing the sidescan before continuing with video camera work we have been able to target key areas of interest. These include particularly rough grounds dominated by boulders and cobbles, sediment wave fields that appear as large expanses of ripples on the seabed, and areas where trawl marks may be present. This presents the opportunity to sample communities of the Faroe-Shetland Channel in a range of environmental conditions. 

Sidescan interpretation

With sidescanning and interpretation complete, it was time to take the plunge with the DIY repair on the camera. A tube of araldite later and we were ready to go. Everyone stood nervously on deck and bridge waiting for a fuse out. Luckily hovering at 100m depth seemed to cause no problems and so we cautiously lowered the camera to the depths we would be using it at – between 450-500m. So far so good, the DIY repair job seemed to have done the trick!

Testing the repair job on the towed camera

Vivid blue sponge encrusted rock with lamellate sponges, branching sponges,

squat lobsters and pencil urchin

With camera work back on track it was back to 12 hour rotas and a continuation of mapping the extent and distribution of deep sea sponge grounds in the Faroe-Shetland Channel.

Sunrise on a day of survey work

Riding the sponge belt

A short transit from the Wyville Thomson Ridge saw us at our second and final study area – the Faroe-Shetland Channel which is of particular interest to Marine Protected Areas work in Scotland. The ‘Faroe-Shetland sponge belt’ MPA proposal has been identified primarily for its aggregations of vivid yellow and white deep sea sponges, known to Faroese fishermen as ‘ostebund’ or ‘cheesy bottoms’.

These dense sponge aggregations, which can reach numbers of up to 4-5 individual sponges per m2, are thought to be situated around the 400-600m depth mark and often found in association with iceberg ploughmarks which provide settlement points for the sponges. We have records of the deep sea sponge aggregations habitat towards the eastern extent of the MPA proposal, but want to see if these numbers are present towards the west of the channel.

Video tow work began in quite an exploratory fashion, with 1km long video tows planned at approximately 5km intervals between sampling stations selected randomly between 400-600m in depth. Unfortunately, just as occasional sponges were starting to appear on the video feed , the camera took a bit of a turn for the worse and needed some maintenance before it went anywhere near the water again. Fingers crossed for a quick repair!

Sponges

Coarse and shelly sediments

Sediment ripples

Featherstars and anemones on rock

In the meantime, we’ve been using the onboard grab sampling equipment to take some samples of the seabed at previously video surveyed locations. These samples will be used for analysis of the sediment types present and the animals living within the seabed. We’ve also been setting up the sidescan sonar device for deployment to help us generate a picture of the lumps and bumps of the seabed we're videoing and taking grab samples of. This will help us to better identify the iceberg ploughmark zones previously mentioned where sponges like to settle and hopefully better target our camera work.

Rockin’ and a rollin’

Excellent sea conditions have enabled camera work to continue around the clock. At the Wyville Thomson Ridge we have been busy surveying the stony reef communities at various depth zones right across the south-western part of the site. Adding to the 10 video tows from yesterday, we have now completed a further 19 giving a total of 29 tows.

The type of beasties we’ve seen at the Wyville Thomson Ridge are considered largely typical of stony reef communities at these depths, and have included the bizarrely shaped pencil urchin, more squat lobsters than you could shake a stick at, and masses of vivid coloured encrusting sponges. We’ve also had a few fishy visitors, including chimeras, ling and a red banded fish chilling out on the rocks.

Chimera with rocks and yellow encrusting sponges

A few particularly special video tows came at the end of the day shift today when we visited some locations within the Wyville Thomson Ridge SAC surveyed by other scientists several years ago. We wanted to do some repeat work here to see if similar communities were still present. We certainly weren’t disappointed, with beds of cup corals, sponges, countless featherstars and the delicate framework building cold water coral reef Lophelia pertusa all present in force.

Cold water corals and sponges

Having ended our time at the Wyville Thomson Ridge on a high, it was now time for a short steam to hopefully have similar luck at our second and final study area – the Faroe-Shetland Channel.

Sidescanning within the SAC is finished

We’ve been really lucky with the weather so far, considering the forecast at the beginning of the week. Bad weather is all around us (Force 11 in the Faroes not that far North of us) but we are still in (relatively) calm water in the eye of the storm.

Having finished the sidescan sonar lines on Wednesday 31st October at 10:30pm, we spent the night checking sea conditions as it had become too rough for camera work. By morning the wind and swell had calmed enough for us to start the first of the camera tows, lowering the video and stills cameras on their frame to the seabed, between 400m and 800m below us.  The aim is to hover the camera frame at about 1.5m off the seabed whilst the boat drifts slowly along. 

Towed camera deployment

Once the ship’s crew have got the camera to the seabed, in our office below decks, three or four people watch the video monitor.  One person makes fine adjustments to the height of the frame off the seabed with the winch as the boat drifts along – but in the 3-4m swells we have been experiencing, this is just about impossible. One person presses a button on the laptop to take still photos approximately every 20 seconds.  However, as there is a slight delay between pressing the button and the camera at the seabed responding, you need to press the button a couple of seconds before the camera is at the right height, and before it hits the bottom as a result of the boat rocking in the swell – not as easy as it sounds! The third person writes on a form what they see on the video, and the fourth records the position of the start and end of the tow and each still photo.  Each video tow is 500m long, which takes about half an hour.  The scientific staff  work in shifts of 12 hours on, 12 hours off during video work, so the work continues 24 hours a day.

Selecting video tow sites

Camera clicking on a video tow



We’ve completed 10 video tows today on the south side of Wyville Thomson Ridge, at different depths from 400m down to 800-900m, in some areas where we know trawling has been carried out in the past, and areas where trawling has not been carried out.

Trick or treat on the high seas

Halloween marks the continuation of sidescan sonar work in a south-western strip of the Wyville-Thomson Ridge. In keeping with the date, we were certainly in for some tricks and treats...

As we headed into greater water depths, it became evident that there were signs of fishing pressure on what appeared to be softer sediment communities, though unfortunately our time investigating these depths was cut short with the loss of the tow fish device fins…AGAIN!


However, the equipment downtime did attract some attention from some neighbouring critters. Bobbing around we began to see large numbers of seabirds settling on the water; suddenly, a dark fin shape and back appear from the water and as if from nowhere we were greeted with pilot whales some 70ft away from the ship.

Pilot Whales

After some whale watching it was back down below deck to prepare for the last few tows of side scan in our current location, and to start developing plans for camera work to investigate and identify the kinds of animals you find at different depths on the Wyville-Thomson Ridge.

Sidescan data processing

Sidescan sidescan everywhere but not a drop to drink

With the weather remaining thankfully calm, the sidescan sonar work continues in strips south west of the ridge. We have been lucky enough to find ourselves in the eye of a storm that we were originally expecting to hit us and continue the uncomfortably high sea state we experienced at the start of the survey.

Eye of the storm

The current calm seas over Wyville-Thomson ridge have allowed us to both recover from seasickness and continue the sidescan sonar work around the clock to get a large area surveyed, with only a short stop to reattach the tow fish fins again (and again). We have now started to plan where to place further video work in order to groundtruth selected areas.

In other news, a week in and we have now exhausted what remained on the Sky TV box, resorting to such classics as ‘Fish tank kings’, and have all become keen ornithologists seeing fulmars, kittiwakes, gannets, Manx shearwaters, black-backed gulls, and a cheeky waxwing on his last legs/wings.

Feathery offerings

We are now also preparing for a high-seas Halloween. Join us tomorrow for our next ghoulish tale!

Sidescan a go-go!

A (fairly) promising weather window provided us with the opportunity to deploy the side-scan sonar; a piece of equipment that is used to identify seabed features, such as iceberg ploughmark zones.

After some promising test runs of the sidescan sonar, we set out to build up a picture of seabed features heading down the southern slope of Wyville-Thomson Ridge between approximately 400 and 650m. The resulting sidescan sonar image revealed some fairly extensive areas of iceberg ploughmarks, ridges, furrows and rises between 400 and 550m, and what appeared to be finer sediments in the deeper depths.

After one successful tow of the sidescan sonar, the fin of the tow fish became loose and fell off, this resulted in a nail biting 120 degrees swing of the device in the water column! However, after recovering the sidescan sonar back on deck, the fins were quickly replaced and secured.

The plan going forward is to process the raw sidescan sonar data that has been collected, and to use this processed data to help select the locations where we will undertake video and camera tows.

Charlotte undertaking coordinate conversions

Side scan sonar feed from the Wyville-Thomson Ridge showing iceberg ploughmarks

Rainy deployment of the side-scan sonar

Weekend break for the ridge

After a rocky nights sleep we eventually made it to the Wyville Thomson Ridge at 01:00 hours on 27th October 2012. With relatively calm weather at dawn, calibration and testing of the on board kit began. This included lowering of the camera frame onto the ridge and testing the lasers and lights. A Sound Velocity Profiler was then lowered through the water column to find out the speed of sound at different water depths. This is very important to help us when calibrating the mutibeam system – a piece of kit that produces a depth image of the seabed and enables us to then pick out features of interest such as pinnacles and furrows.

Blowing a gale

With the forecast not looking particularly encouraging over the next few days, we have decided to focus on using multibeam to generate a picture of the seafloor bathymetry in the northern part of the Wyville Thomson Ridge study site on a relatively shallow part of the ridge at c350m. This is in the hope that there will also be time to get some video and camera tows included in the same area before the bad weather arrives.

The majority of Saturday and the early hours of Sunday morning were spent multibeaming the shallow part of the ridge feature. Despite the fairly rough sea conditions, the pictures on screen were of reasonable enough quality and resolution to help guide the decision on which areas might be of interest to collect data using towed video and camera transects.

Initial multibeam outputs

Using multibeam outputs to select areas for towed video transects



At 08:00 hours on 28th October we deployed our first towed video transect. Attached to the frame was a HD camera, supplied and run by Plymouth University PhD student Rebecca Ross. This was the camera’s first outing and is already starting to produce results.

In five hours we had three transect lines worth of data, but the bad weather came creeping back halting any further progress today. Fingers crossed for another weather break soon!

Deployment of towed video camera

High definition camera frame image from Plymouth university with size calibration lasers   

Munida rugosa (Squat lobster) on stony reef at Wyville Thompson Ridge

Cidaris cidaris (Pencil urchin) on stony reef at Wyville Thompson Ridge

All hands on deck and bon voyage

Progress so far has been slow, with the acoustic equipment requiring some final checks before departure. Once we finally left the harbour at 14:30 hours on 25th October 2012 it was a frantic wave to our colleagues in the JNCC Aberdeen office before steaming on to our first destination – The Southern Trench. The intention was to test and calibrate some of our on board kit, but unfortunately due to the Force 8 winds and big sea swell, we haven’t managed to do any calibration yet.

MRV Scotia

Then weather conditions took a turn for the worse and it wasn’t long before many of the staff on board were turning a little green. A tour of the ships facilities and getting to know the ins and outs of the sampling equipment has kept us all busy so far. We are due to arrive at the first of our study sites the Wyville-Thomson Ridge at 10pm on 26th October 2012. Fingers crossed for good weather!

Trying on an immersion suit

MRV Scotia to survey Wyville Thomson Ridge SCI

Four members of JNCC staff have joined the Marine Scotland research vessel ‘MRV Scotia’ for the next two weeks to undertake a detailed survey of the Wyville Thomson Ridge candidate Special Area of Conservation. The Wyville Thomson Ridge is a rock ridge situated in the Atlantic Ocean at the northern end of the Rockall Trough approximately 150km north-west of Cape Wrath, Scotland. The site was submitted to the European Commission in 2010 for its reef features and has since been made a Site of Community Importance (SCI).

Wyville Thomson Ridge  © Crown Copyright

Wyville Thomson Ridge rises from 1000m at its deepest point to 400m at the summit. Along the ridge there are large areas of stony reef, thought to have been formed by the ploughing movement of icebergs through the seabed at the end of the last ice age. Bedrock reef is present on the flanks of the ridge and, due to the differences in water masses, there are different species compositions on either side.These reef communities comprise sea urchins, sea spiders, sea cucumbers, dense beds of featherstars and brittlestars, a range of colourful sponges and both cup and soft corals.

The main aim of this survey is to obtain evidence to facilitate fisheries management discussions in relation to Wyville Thomson Ridge SCI.  In addition, the survey provides an opportunity to improve our understanding of habitat distribution and community composition within the site and develop methods for future site monitoring.

After surveying Wyville Thomson Ridge, the vessel will transit to an area near the Faroe-Shetland Channel to investigate the extent of deep-sea sponge aggregations for the Scottish Marine Protected Area Project.