JNCC Offshore Survey to Anton Dohrn Seamount and East Rockall Bank

Offshore Survey Diary - July 2009

 

On 1^st July four members of JNCC's Marine Protected Sites team headed to sea on a three week survey off north-west Scotland. Neil Golding, our Offshore Survey Manager, is sending back a diary to keep us up-to-date with the new discoveries as they happen. The team will be using state of the art technology to explore and map the seabed in what is one of the least studied areas of our seas. They will be visiting Anton Dohrn Seamount (an underwater mountain rising from the seabed at a depth of 2,100 m) and East Rockall Bank and are hoping to discover deep sea biogenic and rocky reef communities that might be suitable for selection as offshore Special Areas of Conservation (SACs).

 

The team have previously visited many other areas of sea around the UK undertaking surveys to find out what habitats and species are present. Several of these places, such as the Dogger Bank, have since been recommended to UK Government for selection as SACs.

 

See a map of where the team have got to.

 

 

 

 

 

Day 28 - Tuesday 28^th July

 

We were woken this morning by the sound of the anchor coming up and the engines starting, so we knew we were leaving our sheltered spot in St. Kilda. Neil had stayed up until 2am this morning to await the most up-to-date weather forecast. Sadly, the low pressure area that has been plaguing us for days showed no signs of moving away, so we had to accept defeat - a return to Anton Dohrn was not possible.

 

Ironically, during the first part of the journey home we had some warm sunshine, though the winds were still brisk and the waves still relatively high. The process of packing up the equipment and storing all the data appropriately began - a sure sign that the survey was now officially winding to a close. We set about organising our travel home from our arrival port of Scrabster. There was time for a final photograph with the crew before finally arriving at 10pm - the survey was over! All that remained was the long journey south home to Peterborough and the knowledge that the easy part was over – the working up and reporting of the data would continue for many months to come!

 

   

 

Day 27 - Monday 27^th July

Alas…a new dawn brought more wind! The vessel moved around to Village Bay on the south side of the island to get some cover from the wind. Although the wind had changed direction round to the north west, the weather remained too foul to leave the protection of St Kilda. Some of the crew ventured ashore to download data from a tide gauge positioned on the jetty. Whilst there, they were informed by some of the islanders that the strong winds (up to 60 knots) meant that they could not drive their vehicles up to the weather station on the hill. Even on the MV Franklin sheltered within the bay, the weather station up on the bridge was recording wind speeds almost that strong! Unfortunately, we were approaching the time when a decision would need to be taken as to whether to continue the survey or head home. There was a possibility that we could take advantage of a lull in the weather and head back to Anton Dohrn. However, it was unclear whether the weather window would be long enough to make this a viable option. The alternative was to accept defeat and to run for port before the next band of poor weather arrived, forecast for around Tuesday lunchtime. We went to bed awaiting the arrival of a fresh weather forecast which would make the decision for us.

 

       

 

Day 26 - Sunday 26^th July

The team woke up to an unusual sight through their cabin portholes. Instead of a great expanse of ocean, we were greeted by the spectacular cliffs of St. Kilda draped in cloud. We had travelled from Anton Dohrn to St. Kilda overnight; with an average wind speed at the end of our transit of 55 knots (the bridge informed us that this was almost a "Violent Storm" on the Beaufort Scale!). Though we all had a good nights sleep, evidence of our well-developed sealegs, we were still relieved to find shelter from the wind in Glen Bay, on St Kilda's main island (Hirta).

 

Later in the afternoon, we crept out of the shelter of the bay to see if conditions had improved. At the same time, we were treated to incredible views of the dizzyingly sheer cliff faces and their resident seabirds. Throughout the journey, gannets, skuas, kittiwakes and gulls soared and dipped in the wind, flying in and out of their colonies. We also spotted some Soay sheep teetering on the edge of the steep green hillsides.

 

Despite this wonderful spectacle, it was disappointing that we were unable to be out at sea collecting more data. We will continue to monitor the weather situation overnight and tomorrow morning to assess whether there will be any opportunity to return to Anton Dohrn to complete our camera work.

 

 

Day 25 - Saturday 25^th July

Today was a race against the storm - we had to be on our way to shelter by the evening. We worked furiously throughout the night and day to try to get through as many camera tows as possible before the weather closed in. Our feelings were a combination of delight at what we found and frustration that the weather would prevent us from doing more. During the very early morning, the night shift team conducted a tow down a parasitic cone off the north western flank of Anton Dohrn seamount. We discovered a large and pristine 'garden' of gorgonians with a truly incredible diversity of species and colour. These remarkable discoveries continued into the day shift, when two further tows, one along a ridge and one across a series of mounds revealed dense Lophelia pertusa reefs. All the habitats we filmed were in excellent condition, and showed little or no evidence of human damage - an increasing rarity in today's world.

 

We finally had the call that we were dreading. The master made the decision to head for cover as the winds were picking up. We turned tail and steamed towards the nearest shelter (a mere nine hours away!) - the small isolated archipelago of St Kilda. Although it was disappointing to cut our work short, we were comforted by the fantastic images we had managed to collect and were looking forward to seeing the iconic World Heritage Site of St Kilda.

 

 

Day 24 - Friday 24^th July

Today was our last day of survey on East Rockall Bank. We completed four video tows in total today, covering a variety of different features, including a deep canyon. From the acoustic data we observed escarpments on the edge of Rockall Bank. With the camera equipment we discovered that these escarpments were primarily steep rocky cliffs, with solitary corals and sponges. From our images, we also observed marks on the seabed made by fishing gear, along with several observations of discarded fishing gear.

 

Before departing for Anton Dohrn we completed a plankton tow for the Sir Alister Hardy Foundation for Ocean Science. During the transit in the late evening the JNCC team took advantage of the free kitchen to prepare some tasty treats for the weekend - including apple crumble and chocolate crispy cake.

 

As midnight approached the night shift team prepared themselves for our first camera tow on the north western side of Anton Dohrn.

 

 

Day 23 - Thursday 23^rd July

Camera work continued throughout the night and into the early morning in good weather. From the acoustic data, we had spotted some mounds on the seabed, which we thought warranted further investigation with the camera equipment. A camera tow over the area in the early morning revealed a dense cold-water coral reef on the top of the mound. Other video footage showed evidence of fishing activity - we could see the marks made by trawl gear on the seafloor.

 

We were accompanied for most of the day by a large flock of fulmars and storm petrels sitting on the water around the boat. They seemed to be under the mistaken impression that we were a fishing boat and that some free supper might be coming their way at any moment - sadly this was a waste of their time!

 

The weather forecast is looking good for the next 48 hours or so, but then is due to deteriorate quite dramatically on Sunday, with an average wave height of 7m predicted. Therefore we have had to plan our work around this by prioritising the most important areas and features for data collection.

 

 

Days 21 and 22 - Tuesday 21^st July and Wednesday 22^nd July

On Tuesday we continued our transit out to Rockall and were met by the 40kt winds on the way. Thankfully, the situation improved and we were out on deck enjoying the warm sunshine by the early afternoon. We spent much of the rest of the day reviewing the multibeam and sidescan data and selecting the camera tow locations for Rockall

 

We arrived on station very early on Tuesday morning and the night shift consisting of Neil and Emma were ready to go! With the bottomless supply of tea and coffee helping to keep us awake, we got our first glimpse of the seafloor at the northern end of East Rockall Bank. At 6am the day shift arrived to relieve the bleary eyed night crew and a further three tows were completed over the course of the day. We were all very excited to find large areas of cold-water coral reef, which was home to lots of strange and beautiful species. We got some great video footage and still images of these areas.

 

 

However, all the action has not just been happening on the seafloor. Despite the rough seas, whales were spotted by the crew several times on Monday and Tuesday, but sadly we've been too busy looking at the seafloor to think what might be happening on the surface! Some of the crew managed to see a basking shark very near the boat early on Monday morning, but our excuse this time is that we were all in bed following a rough transit!

 

 

Day 20 - Monday 20^th July 2009

Today was a day of change. We arrived into Stornoway in the early morning to find the camera equipment awaiting our arrival. Following a stock up of provisions for the ship, we waved goodbye to Therese, Dave and some of the crew that had accompanied us for the previous three weeks. Ken Hitchen from British Geological Survey joined us to replace Dave as Scientist in Charge. After a quick walk, followed by lunch in a local café, we arrived back on board to meet the new crew. We had a short meeting where we introduced each other and outlined the survey aims for the next 10 days.

 

 

We steamed out to sea in the early evening, testing the camera equipment just outside Stornoway harbour. We then continued south through the Minch towards Barra, nervously awaiting the 40 knot winds that have been promised once we reach the Atlantic.

 

 

Day 19 - Sunday 19^th July 2009

There were a few tired heads on Sunday morning after spending the night hanging onto our bunks. Last night the sea was pretty rough – those down in the lower cabins were kept awake by the banshee like screaming of the vessel stabilising equipment struggling to keep the boat on an even keel (and failing)! During the day when we went over particularly large waves, the sound of crashing plates could be heard from the kitchen. This was the type of weather during which we didn’t envy the cook as he prepared meals for everyone.

 

Therese spent several hours reviewing video data to see if some of the unusual deepwater fish species could be identified. We also had the chance to select possible camera transects for East Rockall Bank. We were excited by the sheer number of interesting features shown by the acoustic data.

 

Despite the weather we made good progress steaming to Stornoway, heading round the southern end of the Outer Hebrides. As we steamed into the Minch, we collected multibeam over Mingulay cold water coral reef complex, first discovered by the Victorians. We expect to arrive in port around 6am on Monday morning.

 

 

Day 18 - Saturday 18^th July 2009

Today was the last day of multibeaming. Progress was good, and a draft chart of south-east Anton Dohrn was produced. The crew have been flat out trying to process all the acoustic data…. they are certainly getting through the coffee. We now have coverage all along the steep cliff on the east side of Rockall, with survey lines branching out from this into deeper water, where we have identified features such as canyons, escarpments and pinnacles. We also have a block of acoustic data on the top of Rockall Bank where we are investigating an area known as the iceberg ploughmark zone. Many thousands of years ago, the bases of icebergs scraped along the surface of the bank, creating a complex seabed topography.

 

After lunch, a few of us were watching a large flock of fulmars…..but these were quickly abandoned when Therese spotted three Ocean sunfish (Mola mola) right next to the boat.  Later in the afternoon, Neil joined some of the crew in the kitchen to bake a dessert for Sunday dinner. Cimmy the chef kept a watchful eye on proceedings.

 

We started the steam back to Stornoway in the evening with poor weather predicted for the rest of the night. We were all warned to secure fragile items such as laptops and cameras before going to bed.

 

 

Day 17 - Friday 17^th July 2009

We made good progress steaming south down the eastern flank of Rockall Bank, collecting multibeam bathymetry and sidescan sonar data as we went. Over 200km of data were acquired, showing some very interesting seabed features that will warrant further investigation when we return with the underwater camera equipment. In particular, the multibeam backscatter and sidescan sonar line that we completed on the top of Rockall Bank showed marks up to a metre deep across the seabed; some were straight while others meandered. Work also started on producing the survey charts that will showcase the data collected during the survey.

 

 

On the route down we saw a fishing vessel in the distance off to our starboard side. We also saw a sailing yacht, which looked very small and exposed in the vast expanse of ocean. Hopefully they will find some shelter before the bad weather that is forecast, reaches us at the weekend.

 

We read in the news that the ferry due to bring the replacement camera equipment across from mainland Scotland to Lewis had broken down, creating a large backlog of passengers and cargo in Ullapool. A replacement (albeit smaller) ferry had been organised to resume normal service.  Hopefully this won’t significantly delay the arrival of the camera equipment, but it serves as a reminder that while you can plan a survey to the ‘n^th degree’, you still need to be prepared for the unexpected!

 

 

Day 16 - Thursday 16^th July 2009

Acoustic seabed mapping continued along the underwater cliff on the east side of Rockall Bank. We gathered data along this cliff all the way up to the northern end of Rockall Bank then steamed back on a parallel course. In addition to the acoustic survey, the analysis of the Anton Dohrn underwater camera tows have almost been completed.

 

The weather conditions have been very good and have allowed us to gather lots of good quality data. However, we have been watching the weather forecast with trepidation, an area of low pressure that could create gale force winds have been forecast for the weekend and into next week. This may coincide with when we are planning to start the camera work. With a bit of luck most of the bad weather will happen whilst we are in Stornoway for a crew change on Monday.

 

Thursday brought us a traditional Swedish lunch of yellow pea soup followed by pancakes, jam and cream for dessert.  Apparently, this is served everywhere in Sweden on a Thursday. Beth’s eyes were too big for her tummy, and she had to admit defeat half way through her stack of pancakes…

 

A pod of pilot whales were spotted in the morning very close to the boat. Although we missed them first time around, they made a second appearance a few hours later. After a shout from the bridge and a mad dash for the cameras, we managed to get a few pictures, phew!

 

 

Day 15 - Wednesday 15^th July 2009

In the early hours of the morning, we completed multibeam work at Anton Dohrn and began steaming towards East Rockall. On the way to Rockall, the sea was pretty rough, which caused some to almost fall out of their bunks! We had now reached our furthest point away from land and it was exciting to begin work in a new study area.  Multibeam data collection began just after breakfast, continuing until the late afternoon and the sidescan sonar was also deployed later in the day. This sidescan sonar equipment was different to the deep-tow system (seen in Day 3 photo) – it has an autopilot mode which allows it to maintain a fixed height above the seabed. Analysis of the mutlibeam and sidescan data suggested that there might be areas of hard substrate (possibly with coral) on a shallow area of East Rockall.  From previous work we have a good idea of where fishing activity takes place and the data we have collected so far allows us to clearly see trawl marks on the seabed. These appear as two parallel straight lines which are distinct from iceberg ploughmarks, which are also easily identifiable in acoustic images but appear in more irregular patterns. We hope to investigate this further with the camera equipment later in the survey. The team are working their way through the video data already collected, and are continuing to find interesting fauna.

 

The weather has been very generous to us over the past few days, with plenty of sunshine and light winds. The team were entertained by some low-flying acrobatic fulmars, who spent the afternoon racing alongside the boat. The bridge reported spotting pilot whales, but they had gone by the time we had got on deck.

 

 

Day 14 - Tuesday 14^th July 2009

We arrived at Anton Dohrn seamount early on Tuesday morning, when multibeam data collection began. As the day progressed and the data built up, the complex geomorphology of the north-western flank of the seamount was revealed.

 

 

Meanwhile, analysis of video footage collected earlier in the survey continued. The videos and images showed a diversity of habitat types, as well some unusual species including previously unreported anemones and sponges. In the evening, the team got together to plan the next few days of multibeam data collection over East Rockall, where we expect to begin working tomorrow morning.

 

 

Day 13 - Monday 13^th July 2009

Hoorah! We left Stornoway this morning and set sail for Anton Dohrn seamount once again. Our plan was to reach the seamount by the time the reported 6 metre waves had subsided. Flowers were hung over the bow of the boat to attract good spirits; a traditional practice of Thai fishermen. On the way out, we glimpsed the Flannan Isles and St Kilda in the distant haze. We were also joined by a pod of common dolphins and this time we got out on deck in time to see them! This definitely lifted our spirits which had become quite deflated with the extended periods of equipment down time that we had experienced over the last week. We should be on station in the very early hours of tomorrow morning, ready to start the acoustic survey of north-west Anton Dohrn.

 

 

Day 10 - Day 12 - Friday 10^th July - Sunday 12^th July 2009

We discovered that getting spares to a remote Scottish island on a summer weekend is a logistical nightmare!  However, despite all the ferries being fully booked the replacement parts for the camera system eventually arrived but the communications problems we had experienced with the camera kit persisted.  Whilst repairs were ongoing, the crew and scientists took the opportunity to stretch their legs and see some of the local area. Perhaps unusually for the west coast of Scotland, the sun shone all day long on Saturday, and we were able to appreciate the standing stones of Callanish in their full glory.  By Sunday evening, crucial repairs had been completed and we prepared ourselves for an early morning departure on Monday.

 

 

Day 9 - Thursday 9^th July 2009

The engineers were up most of the night working on the winches and we left Stornoway harbour in the late morning to test the repairs.  During the testing of the main winch, a pod of dolphins was spotted playing on the bow wave.  Hearing this, we all rushed on deck but unfortunately they had already moved on.  Once the testing of the winches was complete, the hydraulics engineer was dropped back on shore using the small safety boat. Meanwhile we started testing the camera system and it became clear that the gremlins from last week were meddling again; a communication problem had developed between the underwater camera and the ship.  There was nothing else for it - for the second time that week, we found ourselves steaming back into Stornoway.

 

 

Day 8 - Wednesday 8^th July 2009

Today, a specialist hydraulics engineer arrived and repairs continued on the main winch (used to deploy the deep-tow sidescan sonar) and camera winch.  During this period of downtime, we took the opportunity to catch up with work that we would have been doing back at the office – it's then that you appreciate having a vessel with wireless satellite broadband!   We also made a start on preliminary analysis of some of the underwater video footage.  As dusk fell, work continued on the winches, and into the night.  If all goes according to plan, we should be leaving in the morning to test the equipment, before transiting back to the survey area around Anton Dohrn seamount.

 

 

Day 7 - Tuesday 7^th July 2009

The journey from Anton Dohrn towards the Outer Hebrides continued through the early hours of this morning through lively seas. At midnight, Therese and Emma spotted the lighthouse on Flannan Island, about 28 nautical miles away from us. We rounded the Butt of Lewis at approximately 5am and we were alongside in Stornoway by 10am.

 

Despite some cloud, it was a lovely mild day in Stornoway and the first task for the team was to help load a large delivery of food onto the vessel (thankfully including a large consignment of teabags, which had run out!). This was achieved by means of a chain gang - proper teamwork! The replacement camera arrived at about 1pm and preliminary testing looked extremely promising which was a relief. The new kit is due to be fully tested tomorrow morning to ensure that it is all in fine working order. The team took advantage of the brief time on dry land to explore Stornoway; a few even braved a swim at a small rocky beach near the town! We were lucky enough to do some seal watching from the dock just before returning to the vessel for tea. A local Stornoway fishing vessel - The Kaylana - began assisting the Franklin crew to re-spool the winch and work on this task continued into the late evening.

 

 

Day 6 - Monday 6^th July 2009

Day breaks early this far north. For those on the night shift there seems to be the briefest of nights before that clear, morning light once more streams in through the portholes. The day began well with another successful camera tow under our belts in a somewhat more gravelly/coral rubble area. We then steamed to the next station and deployed the gear for another transect. Over the last few camera transects, we'd had problems with the video quality from the drop frame; halfway down this tow, the video screen suddenly went black, promptly followed by all the other camera systems. It didn't look good! Once on board, a malfunction was identified with the control module. A replacement was needed, so a steam back to Stornoway became essential. Before departing the area, a multibeam transect was conducted over the top of the seamount, and this was continued until such time that departing the area would mean arriving into Stornoway first thing in the morning. We suspect this area to be vastly different from the flanks, more of a sandy environment with perhaps some chance of Lophelia coral. We have continued to have unbelievably calm seas but as we turned for the Hebrides, the sea lifted and showed us a little of what she can do.

 

 

Day 5 - Sunday 5^th July 2009

We completed our first camera tow in the very early hours of the morning, and started to winch the drop frame back to the boat. It takes a long time to winch in 1500m cable and the drop frame didn't get back to the boat until breakfast! However, it was quickly back in the water, and for the second tow we were expecting a mixture of soft and hard sediment. The tow began in a boulder strewn environment before moving back into a silty environment.

 

A third tow was completed in the afternoon and we had a nerve racking moment at the beginning, as on reaching the seabed we noticed a discarded fishing net, which could have easily become tangled up in the drop frame. Fishing nets are discarded at sea for various reasons, and can remain extremely dangerous to marine life as the nets continue to 'fish' - this phenomenon is termed ghost fishing. We observed this effect with a crab tangled up in the discarded net. The third tow revealed yet another environment with large boulders acting as hotspots for life in the middle of sandy sediment. Every boulder was packed with colourful life, including bright blue sponges, orange anemones and even the occasional Lophelia coral colony.

 

 

A fourth tow was completed in the early evening along a very steep ridge that extends out from the main seamount. We dropped down immediately onto a deep coral reef with large Lophelia colonies, gorgonian fans, encrusting sponges and featherstars!

 

 

Day 4 - Saturday 4^th July 2009

The sidescan towfish made it back on deck in the very early hours of the morning, and it was quickly apparent as to why we had lost communication. The cable connecting the towfish to the winch on the boat is made up of extremely strong steel wires but the forces twisting the cable had been so great that several of them had snapped exposing the electronic wires inside! However, all is not lost - repairs were carried out quickly and the sidescan towfish is functional again. In the meantime we continued to collect multibeam data for the south-east of Anton Dohrn and processing began to get a better idea of what the seabed looks like.

 

 

The weather was lovely in the afternoon with bright blue skies and only a gently rolling swell. As such, JNCC staff took the opportunity while off shift to complete some circuit training on the front deck so we can remain fit and healthy. By late on Saturday evening we were ready to do our first camera tow using the drop frame. The drop frame holds both a video camera, so we can record real-time, and a stills camera, so we can take high-resolution photographs. During the deployment of the camera frame, a downpour of rain had started, and everyone was startled when a lightning bolt hit the sea 500m off our port side.  You could see a big spark where it hit the water, followed by a tremendous crackle! On the first camera tow we lowered the drop frame to nearly 1500m before reaching the seabed. From the acoustic data we were anticipating a soft substrate at first followed by a rock cliff with harder substrate at the bottom. We were rewarded with a very silty environment at first, followed by a chalky cliff and finally a gravel substrate at the bottom, which had seapens and brittlestars. We also spotted a few deep sea fish such as chimeras.

 

 

Day 3 - Friday 3^rd July 2009

Today was the final leg of the transit to Anton Dohrn seamount, and we arrived at the south-eastern flank in the late afternoon. En route, we undertook some calibration testing of the dynamic positioning (DP) system of the vessel. DP allows the vessel to move along a predetermined course, generally regardless of direction of currents, tide and wind. On this survey cameras will be dropped into depths in excess of 1500m, directly below the ship. Due to the long lengths of camera cable, underwater currents can force the camera system a long way from this position. Acoustic 'pings' are sent from the vessel to talk to the submerged camera, identifying its location. The camera can then be manoeuvred along the chosen transect by the vessel, allowing us to record images of the seabed along our desired route.

 

Once we arrived at Anton in the late afternoon we began collecting data for the same area with the deep-tow sidescan and multibeam, to allow comparison of the two different techniques. The sidescan towfish (see photo below) is flown approximately 50m above the seabed, almost 5 km behind the vessel. However, problems were experienced when communications were lost with the towfish just before it reached the seabed, and it was still being winched back at midnight...

 

We also had an unusual visitor on board today - a crossbill. Named MJ by Beth and Emma he was pretty exhausted and tried to drink water from rain puddles on deck.

 

 

Day 2 - Thursday 2^nd July 2009

We completed preliminary wet-testing of the camera drop frame equipment early on Thursday morning, before beginning the long transit to our first Area of Search, Anton Dohrn seamount. It was time to catch a few hours sleep before breakfast. All scientific personnel went on a safety briefing and familiarisation tour of the vessel. By lunch, we were steaming through the Pentland Firth and making good time. A fire drill was held mid-afternoon, when we had to assemble on the aft deck at the muster station and try and get into sea survival suits. As we were out on the aft deck, a bank of enormous grey clouds appeared; as they passed overhead, the wind started howling...and then the rain started! Luckily the squall passed over quickly. We saw a pod of bottlenosed dolphins passing. We also carried out some final modifications to the camera drop frame equipment, to try and improve the quality of the images we were getting, while the sea was shallow enough to get the camera down to the seabed quickly to test it; it can take over an hour to get the camera down to the seabed in the deep sea! The first set of acoustic lines were plotted for Anton Dohrn. We should arrive tomorrow afternoon to start surveying, fingers crossed the weather stays good...

 

 

Day 1 - Wednesday 1^st July 2009

We arrived on vessel first thing in the morning. It was a hive of activity; engineers were setting up the drop-down camera frame and other bits of equipment, while other supplies were being loaded. We departed Regents Quay, Aberdeen at around dinner time and after refuelling (which took a staggering 3 hours - that's a lot of diesel!) headed out of the harbour before commencing the wet testing of the equipment. The pilot guided the vessel out of the harbour and we were on our way.