Perseverance paid off in the final hours of this NC Fall Cruise: 12 hours before having to transit home, the waves subsided just enough to attempt one last very important dive. On the ambitious agenda (14-page dive plan) for this Main Endeavour vent Field (MEF) dive were: deployment of Tempo-Mini and a Benthic And Resistivity Sensor (BARS) instrument plus the sampling of fluids and gas. To complicate matters, these operations required synchronized international collaboration. The deployment of Tempo-Mini required online presence of our French colleagues from IFREMER in Brest, and BARS needed the cyber presence of our Seattle colleague Marv Lilley who just happened to be in Zurich, Switzerland that night.
If you haven't followed our previous blogs involving weather (Weather, ROCLS, Food), here's a quick review of how it came to such a tight call for our last dive. Consider the Endeavour itinerary after we finished our Barkley Canyon work with Wally and Barkley Benthic Pod 3 (see blog post):
We steamed post haste back to Endeavour because the weather pattern indicated a chance for deploying a cable drum to the Mothra site before arrival of an impending storm. We went directly to Endeavour without stopping for the planned bottom pressure recorder (BPR) deployment at ODP 1027.
A whole day with 8+ m swell; no dive or deployment, but we used the time to finish building our MEF extension cable.
With inclement conditions at Endeavour, we returned to ODP 1027 and deployed autonomous BPRs via the ship's winch (ROPOS wasn't required for this, so we could deploy in higher waves). After that, we steamed straight back to Endeavour.
In the wee hours we were able to sneak in a real dive to deploy ROCLS (see blog post) with ROPOS near the Endeavour node. But due to strengthening winds (35+ kts) and some issues with a ROPOS manipulator, we were forced to abandon the dive, leaving ROCLS on the seafloor (see ROCLS blog post). With unpredictable weather, we had no choice but to hold out and hope.
Luck came in the morning, when a change in wind direction resulted in such a confused sea-state that the total wave height was actually low enough to dive! This was such a surprise that it was difficult to find the shore support required for this dive. But everything ended in success, the cable was connected, MEF got power, and our previously installed instruments all sprung back to life! But alas, when coming up from the dive, the weather worsened once again.
Hoping for better weather...
Hoping for better weather...
Yes, better weather! Now the swell has to subside quickly...
OK, let's do it!
So all in all we'd spent 7 days on site (plus two days at ODP1027 in between), and finally we were getting our third dive in, but only just!
Excitement took over quickly, but also a foreboding sense of time pressure, as our return to port could not be delayed. And weather conditions could, of course, worsen again. The deck crew loaded Tempo-Mini and BARS onto the ROPOS tool basket, ROPOS latched on, and down they went. Watching blue water and monitoring the pressure gauges while descending, the dive log read: "Strong surface swell is visible in the video as a reversal of direction."
Keith Tamburi (CSSF) monitors ROPOS deployment with tool basket attached and loaded with Tempo-Mini, connection cable, base platform and (hidden) BARS, 28 September 2011
Two hours later, ROPOS reached the seafloor. A place to put down the tool basket was found near the instrument platform, and BARS installation was the first order of business. At this time it was 5 a.m. in Europe; a short night for our scientific colleagues in France and Switzerland. But everyone involved was suddenly wide awake because something was unusual: Far more black smokers than were seen there before came into view! Marv Lilley Skyped from Zurich to say that this area is "pretty active" – a comment that made it into the dive log.
The vent for BARS was certainly active enough, but we also checked with a poker that the vent was deep enough, too. Then, gas samples were taken using so-called gas tights. After everything was deemed good, ROPOS zoomed back and forth, first fetching BARS from the tool basket, placing the BARS canister, then connecting its cable at the IP. While flying back to the vent, BARS was powered on and data began streaming immediately.
BARS on the seafloor, ready to detach the probe that's still strapped to the pressure cylinder, 28 September 2011
BARS, which stands for Benthic And Resistivity Sensor, measures fluid resistivity (yielding chloride concentration), temperature and redox potential. Its sensor is located directly inside an active vent.
In order to avoid shock heating of the probe by inserting it directly into the hot vent, the wand was carefully preheated for several minutes while moving it gradually closer to the plume and down into the vent opening. When the temperature stabilized at 150°C just above the vent, ROPOS inserted it fully into the vent where it measured 325°C. Some like it hot! Marv Lilley could then proceed with his remote testing and set-up.
Temperature curve of the BARS probe from the moment of powering it up, carefully pre-heating it to 150°C, and then inserting it into a ~325°C hot vent
BARS probe finally inserted into the very active vent opening, already measuring 325°C, 28 September 2011
Since larger patches of level seafloor right next to an active vent are sparse, the chosen placement for Tempo-Mini happened to be right next to the RAS (Random Access water Sampler). Tempo-Mini's installation procedure included a 3D site survey. If the RAS anchorage was in the way, we intended to move and then re-deploy RAS; not a trivial operation. But, with a time running low, this step was quickly skipped.
Instead, ROPOS placed a checkerboard calibration target against the vent wall, and flew back and forth at various depths and distances, while we photographed the site from all angles. These pictures can later be used for a 3D reconstruction.
RAS anchor (at right) and the checkerboard plate used for the 3D survey of Tempo-Mini's new home, the only flange structure large and flat enough to host Tempo-Mini, 28 September 2011
By this time, 5 hours had lapsed and we were making good progress. The next step was to install Tempo-Mini 's base platform. The base platform has 4 adjustable legs so it provides a horizontal base even on a slanted uneven seafoor. Adjusting the base plate was no small feat, when you consider it was done by a two-armed remotely operated vehicle flying 2.3 km below stormy seas, working on a cramped, yet fragile hot vent flange structure! 90 minutes and a shift change later, the base platform was adjusted and ready for Tempo-Mini.
Meanwhile, in France, morning coffee had arrived at the IFREMER conference room where a dozen scientists gathered to watch the drama live via streaming video. Much to their delight, they witnessed ROPOS skillfully install Tempo-Mini on the base plate with very little room to operate. The French were certainly impressed when Skyping "Wow!"
Scientists and technicians at IFREMER in Brest, France, watched streaming video and collaborated via Skype, as Tempo-Mini was deployed. Pictured left to right are Julien Legrand, Jozée Sarrazin, Yves Auffret, and pointing at he screen Gilles Youenou (communications), 29 September 2011
As night turned to morning, more IFREMER staff from the RDT-EIM unit (Technological Research and Development – Electronics, Informatics and in-situ measurements) followed the installation, helped along by (probably good French) coffee, 29 September 2011
The cable was inspected and adjusted, then Tempo-Mini was switched on from shore. Breathless, IFREMER logged on to test the camera, and it began streaming clear images of the hot vent tubeworm community!
Tempo-Mini on its platform next to RAS. The lights of Tempo-Mini were already working but its light arms still needed to be unfurled, 29 September 2011
Tempo-Mini, by the way, is a benthic observation platform that includes an HD camera with lights and temperature, oxygen and ion sensors. These several metres long sensor strings were unfolded from Tempo-Mini and placed on the benthic field. Plenty of twirling and untwisting was necessary to disentangle the mess.
In the end, all sensors worked properly, a happy conclusion that drew joyful applause from our French collaborators. After years of planning, building, testing and testing, Tempo-Mini had finally become a reality!
ROPOS switched its lights off for this side view of Tempo-Mini's benthic field, illuminated only by Tempo-Mini's six LED light clusters, 29 September 2011
By now, 10 hours had elapsed and time was running out, so we quickly fired two Niskin bottles above the vent to sample its plume water, turned and followed the MEF cable to pick up the ROCLS grating, zoomed back to the tool basked, threw the grating in and began our last the ascent of this cruise
No doubt, our perseverance riding out the waves was paid off. It was absolutely worth it to get this final dive done!
PS: In case you wondered: tempo rubato ~ time robbing, a musical term.
Last picture from ROPOS emerging from the sea at sunrise, 29 September 2011
The days on the ship can get long and dreary when the weather is bad and the sea is too rough for ROPOS to dive. During this cruise, we even had days when the decks were "secured" – i.e. it was too dangerous to go outside because of the swell height. Waves were crashing over the side of the ship, and there was nothing to do but wait for the wind to die down and the weather to pass. What can one look forward to, trapped inside a rocking ship with un-deployed equipment and grumpy co-workers?! Dinner, of course!
The meals on a ship are of crucial importance for keeping the spirits of the crew and passengers up and meals serve as a key social time on the boat. The galley crew serves three meals a day:
- breakfast from 7:15-8:00
- lunch from 11:30-12:15
- dinner from 17:00-18:00
On this cruise, 3 men kept a crew of 21, and science party of 23 people well fed and happy (at least for as long as they were sitting in the mess!) Meet Dan, Tony and Mike!
Dan chops parsley (left), Mike washes up (centre), and Tony cleans the galley
Dan, the ship steward is one of the longest serving members on the R/V Thompson crew; he has been with the ship since it was first commissioned in 1991. Tony, the second cook, started cooking in his home town of New Orleans, and has been faithfully serving up chow on the Thompson for the last 10 years. Mike, the mess attendant from San Francisco, brings good cheer and hard work to the mess hall, cleaning up after everyone.
Every day, breakfast preparation begins at 5:30am. A typical feast includes eggs, French toast, sausage, bacon, fresh fruit, yoghurt, warm homemade muffins, cream of wheat and sometimes even specials like breakfast burritos.
Mexican day is a popular lunch, with enchiladas, tacos, Mexican rice, and all the toppings including homemade guacamole. Some in the science party especially appreciated the spicy food on board! No bland cooking here. Dinner could include everything from steak to ribs to salmon to stuffed peppers with sides of potatoes and vegetables, and a well-stocked salad bar.
Tasty food at the salad bar
Planning for the day's meals happens in the morning, when the galley crew "go shopping" in the storeroom where all the food is kept and decide on-the-fly what to cook for the day. The menu for each meal is posted on a whiteboard, along with announcements such as "Happy Birthday, Andy!" (The galley crew are responsible for the all-important job of baking you your birthday cake, should you have the good fortune to celebrate at sea.)
So, how much food do you need for hungry people spending days at sea? When the cabins are filled to capacity on the ship, 1000lbs per month of meat alone are consumed!
You might be wondering what happens to what remains uneaten after everybody has taken seconds and had dessert. Don't worry, the food doesn't disappear. Just like your kitchen at home, you can find a well-stocked leftover fridge on the ship, perfect for a midnight snack. This is crucial, since operations on the ship continue 24/7.
Leftovers for a midnight snack
The amazing thing about the cooks in the galley is that they keep cooking in any weather, and the food is still delicious. Thanks for cheering us up with food, no matter how strongly the wind was blowing and how high the waves were! Cheers!
The location and strength of the Aleutian low is the major controlling factor for weather in the Northeast Pacific. During the summer months it retreats poleward and weakens allowing a high to develop in the region. This tends to deflect passing storms northward, resulting in warm sunny weather on Vancouver Island weather.
World map marked with ocean currents and winds moving around semi-permanent high-pressure cells typical for the month of January. Aleutian Low marked.
This year, the Aleutian low stayed strong well into summer and now appears to be making an early comeback. When the low is in place, we typically expect a 4-day cycle of storms, steadily propagating one after the other across the northeast pacific. As they approach, these storms generate waves from the southeast, which back to the west-southwest after storm passage. The result is a seemingly perpetual high sea state, with waves criss-crossing in multiple directions.
However, during the fall transition period, there is a lot of variability as the winter regime develops. I think we still have good reason to expect breaks in the weather pattern before the Aleutian low establishes itself.
That is where we find ourselves now, waiting for a weather window to deploy our heavy spool of cable to the seafloor, so we can connect the Mothra hydrothermal vents to Endeavour node and the rest of our network.
The 8km spool, which weighs in at about 3200kg, is fastened into ROCLS, light aluminum frame and mechanical apparatus for cable laying beneath ROPOS. ROCLS is lowered first to the seafloor independently of ROPOS, then ROPOS descends and latches onto ROCLS at the seafloor to lay cable.
Two ROCLS frames at the CSSF/ROPOS facility in Sidney, BC, 6 September 2011.
ROCLS with the 8km Mothra-Endeavour Node cable spool, September 2011.
On an oceanographic research vessel like the R/V Thompson, there are two options for deploying ROCLS:
- off the stern through the A-frame, or
- off the side utilizing the ship's crane.
The first option is, I think, much safer for crew; however, wave-induced pitching is substantially greater at the stern of the ship, which further limits seas in which we can successfully deploy. With this in mind, we have already positioned ROCLS on the starboard side within reach of the crane, just aft mid-ship where pitching is minimized. With the wave field we are riding on now we would not be able to move it safely over other equipment back to the A-frame, so this positioning was done in anticipation of deteriorating weather. The question now is, when will the sea state be calm enough to launch?
There are two major areas of consternation for deploying ROCLS, getting it off the ship into the surface waters, and landing it on the bottom. Moving a 3200kg object on a heaving, pitching, rolling ship, is no mean feat. Our launch procedure involves roping tag-lines to all four corners and placing cleats in appropriate multiple locations to attempt to control the load. But how many wraps are needed on the cleats for human power to hold 3200kg in rough seas? If you have too many wraps, you can't release the load properly and risk losing control, but with too few wraps you have no control over this enormous load. Wrapping and unwrapping a heavy load is dangerous, only experience can guide you.
The deployment procedure also includes inserting an acoustic release (more about this below) between the ship's wire and ROCLS. In order to mitigate damage to the cable by the acoustic release after ROCLS is dropped, we attach floats to the acoustic release so it rises up and away. The floats are made of syntactic foam, which does not compress under pressure, and weigh about 14kg in air. For this operation, we need 12 of them (weighing 160kg) strung along a line. These floats are hand balmed over the side concurrently with the launch of ROCLS. During the previous launch of ROCLS in calm weather conditions, we needed 11 people on deck for this operation.
As ROCLS goes over the side, our main concern, after safety, is keeping ROCLS from smashing into the side of the ship. It is an aluminum frame and is quite fragile when fastened to a 3200kg cable spool. So the deployment crew try to get it into the water quickly once it's overboard.
After ROCLS enters the water, our main concern is snap loading on the ship's wire and the ROCLS attachment point. With 8m waves that are often out of phase with the ship's heaving, there will be times when the phase mismatch can put sudden extreme strains or "snap loads" on the cable. Snap loads, not static loads, are the times when cables snap and equipment typically breaks.
Once ROCLS is lowered into the water to depth where we can control it and snap loads are reduced, we need to attach a transponder to the line. To do this, the ship's wire needs to be brought to the side of the ship, where some brave people are required to attach a transponder to the wire that is part of the USBL (Ultra Short Base-Line) navigation system we use for positioning ROCLS at the seafloor.
The second area of concern occurs when we have navigated to the surveyed landing location and lowered ROCLS to the bottom. The acoustic release holds fast while ROCLS is lowered, until an acoustic signal is sent to it from ship and it unfastens. We try to release ROCLS just above the seafloor.
Currently, measurements indicate a trough-to-crest wave height of about 8m. So we need to estimate our distance from the bottom carefully and time the waves so we minimize the free fall and potential damage to ROCLS and our $300,000 cable.
And again, the key question is what sea state/ship dynamics make this achievable? At present, the sea state we are confronting is too rough to risk deployment.
A further confounding consideration is making sure we will be able to lay the cable. Before we can lay cable between the Mothra hydrothermal vent fields and Endeavour node, ROPOS must be deployed with the Mothra Instrument Platform. Such a dive and the subsequent cable lay are also weather-dependent, but it is imperative that they be done if ROCLS is deployed. ROCLS is made out of aluminum, stainless steel and ferrous materials (basically a large battery in seawater) and if left at the seafloor would rapidly corrode over the winter, becoming structurally unsound by next summer. If we deploy ROCLS now but are unable to lay the cable this cruise, both ROCLS and our $300,000 cable will be lost.
So as you can see, there is a high level of complexity to installing a subsea cabled network. Not only are good weather and relatively calm seas required, but also a well-equipped and expertly staffed research vessel like the R/V Thompson is essential. A little good luck doesn't hurt, either!
(NOTE: No facts have been verified in the writing of this blog post, it is based strictly on the author, Steve Mihály's opinions.)
While the study of storms is interesting to many, those of us on the R/V Thompson prefer to investigate our study areas when the wind is in the 0-20 knot range. Nasty weather is triply bad because (1) not only is it hard on those who have to find their sea-legs on the ship and get used to being thrown back and forth while trying to work but also (2) for ROV operations, which have a certain threshold beyond which people and equipment are outside their safety zone, and finally (3) the work schedule has to be constantly adjusted in order to account for the weather so that it becomes difficult to plan coordinated operations with shore support.
We spent some time in Trevor Channel, off the coast of Diana Island and Bamfield, evading bad weather and taking the opportunity to pick up some spare parts. We are now waiting at Endeavour for the weather to calm, as we continue to make preparations for the upcoming dives on deck. Everything is tied down including buckets, chairs and milk crates. Those still working in their chairs narrowly missed being tied down themselves. The crew is in good spirits but unfortunately this weather puts a bit of a damper on our plans.
Instruments and equipment all tied down to prevent movement during rough weather.
The view from the ship in Trevor Channel while evading the storm.
Our highly reputable ROV partner, ROPOS, operates happily in wind speeds up to ~25 knots (46 km/h) under the condition that the sea state is not worse than typical for this wind speed (wave height approx. 3 m). Lower thresholds come into play when ROPOS is required to carry payloads such as instrument platforms or ROCLS, the Remotely Operated Cable Laying System. This upper threshold wind speed of 25 knots corresponds to a 6 on the Beaufort Scale, called a "strong breeze"; slightly stronger winds are called "gales", a 7 on the Beaufort Scale. Other ROVs often have limits in the lower 20 knots. However, ROPOS can draw on their considerable crew experience and the fact that the most critical operations, launch and recovery, are performed using their LARS (Launch And Recovery System) crane which is self-stabilizing and extremely reliable.
CSSF's Launch and Recovery System (LARS) with ROPOS.
For this cruise, ROPOS thresholds are not coming into play for some crucial cruise operations. One example is our deep-sea mooring installation, which required flat seas. See our mooring magic blog post for details.
Some statistics regarding this cruise: We planned a total of 59 cruise operations, including 21 ROPOS dives. Here's a summary of the weather requirements:
very good weather and daylight
good weather and daylight
no special weather requirements
install short-period seismometer
If only we could synch our schedule with Mother Nature!
Weather conditions at Endeavour while diving with ROCLS.
While waiting out the weather in Trevor Channel, we busily prepared POD 3 for redeployment at Barkley Canyon, which was a success. The sonar was affixed and the camera was removed as the new one has its own little tripod. We've also been tying up the cable (or "juting" as we call it here) with twine which becomes difficult when the fibres are blowing off and the twine won't go anywhere voluntarily except horizontally into your face, but we're managing. Our wait at Endeavour continues and we are building cables and preparing instruments. So, when this tempest finally blows past, we'll be ready to go!
Sunset at sea.
Wally the Crawler underwent the ultimate stress test on Sunday. After entering the water tethered beneath ROPOS, strong waves apparently sprung Wally loose. He took an 870m free dive from the sea surface to the seafloor at Barkley Hydrates.
Wally the Crawler dangles below ROPOS just prior to entering the ocean at Barkley Hydrates, 18 September 2011.
Shortly after entering the water, we checked for Wally in the downward-looking camera, and he was gone. As the dive logger described it, "The hook came off, Wally is by himself." Onlookers both on ship and shore drew a collective gasp.
Wally's creator, Laurenz Thomsen of Jacobs University was watching the events live from Bremen, Germany. He remarked, "Hoppla, that could imply that Wally took his own dive with 40kg weight."
Free-fall deployment is not new to ocean research, and has been used for many years. In fact, we used this method to successfully deploy our Seafloor Compliance apparatus at ODP 889 in 2009. But, Wally was not designed and built to be dropped from the surface, although we wouldn't put it past our German partners to have designed some extra toughness into their little crawler.
As we watched ROPOS descend, the sense of dismay was palpable. Could Wally survive such a plunge? Could his extremely sensitive instruments and microprocessors?
When ROPOS arrived at the bottom, Wally was not there. To make matters worse, a sudden glitch in our positioning system complicated our efforts. ROPOS began running sweeps, using sonar to search for Wally. Gas hydrate mounds in the area presented a couple of false targets. But, after a relatively short search, the ROPOS pilots found Wally, resting on his treads on a steep submarine slope. Just like a cat, Wally had landed on his feet!
Wally's position on the steep submarine canyon slope where we found him after his "cat-like" landing.
We were relieved to find Wally, but the question on everyone's mind was whether he and his instruments were intact. ROPOS carried him back to his regular haunts in "Wallyworld", unfurled his umbilical cable and plugged him in to the Barkley Hydrates instrument platform.
Fingers crossed, we turned on the power and asked Laurenz to go ahead and activate Wally. ROPOS hovered nearby as everyone watched and waited. At first, nothing happened. The ROPOS crew Skyped Laurenz, "we are 2m away, don't run us over."
There a sudden shout and rapid flurry of Skyped "Yee-Haws" erupted when Laurenz switched on the lights and began driving Wally. No problems with left turn, right turn, forward or backward movement.
Wally does the Hokey-Pokey after surviving his great fall, 18 September 2011.
We were happy to see Wally's lights, camera and wheels still functioning. The next concern was the state of his instruments:
- methane sensor
- conductivity-temperature-depth (CTD) instrument
- current meter
- turbidity meter
- sediment micro-profiler
Some of the instruments installed on Wally II, 18 September 2011.
Upon visual inspection, all appeared intact, although Wally's lights were somewhat askew.
One-by-one we powered and quickly tested the instruments. After troubleshooting a couple of device driver problems, we were able to confirm all instruments to be working. However, there appear to be problems with two of the delicate probes on Wally's sediment micro-profiler. There are also some lingering data offset issues, which we're still trying to resolve, but Wally appears to be well enough to leave deployed at Barkley Hydrates for the winter.
Needless to say, everyone's happy Wally was able to "take such a licking and keep on ticking". But, we're not planning to use free-diving as our favoured method of deployment for Wally anytime soon!
Plot of methane concentrations from Wally II METS methane sensor, 19 September 2011.
While the study of storms is interesting to many, those of us on the R/V Thompson prefer to investigate our study area in the 0-20kt range. Currently, we are in Trevor Channel off the coast of Diana Island and Bamfield evading bad weather and taking the opportunity to pick up some spare parts. Everything is tied down including buckets, chairs and milk crates. Those still working in their chairs narrowly missed being tied down themselves. The crew is in good spirits but unfortunately this weather puts a bit of a damper on our plans.
NEPTUNE Canada, its Highland Technology contractors, the IOS mooring team, and the fabulous R/V Thompson crew co-operated Tuesday in a complex deployment of the Northwest Regional Circulation Mooring (RCM-NW) in the axial valley of the Endeavour segment of the Juan de Fuca Ridge. The RCM-NW mooring is part of a planned 4-mooring array at Endeavour designed to establish a big picture view of currents and water column characteristics in the axial valley of this hydrothermally active spreading centre. Each mooring consists of a large anchor and a suite of tethered instruments suspended above the anchor on cables connected to floats.
NEPTUNE Canada research theme integrator Steve Mihaly with a mooring anchor, 13 September 2011.
The North-East mooring was deployed on our Fall 2010 NEPTUNE Canada installation/maintenance cruise thanks to a combined effort from our team on the R/V Thompson and a DFO team on the CCGS Tully: the Tully crew deployed the mooring itself while ROPOS (deployed from the R/V Thompson nearby) waited for the mooring at depth. This setup proved very efficient as the mooring could be guided within 1m of its planned landing site and connected as soon as it landed.
This year, the deployment was performed entirely from the R/V Thompson. The plan involved carefully lowering floats and instruments one by one off the aft deck, using the ship's crane and A-Frame. Once strung out behind the ship, the 750kg anchor was lowered into the water on the A-Frame, pulling the instruments into a vertical configuration. Then, the entire assembly was lowered to the seafloor where it was detached using an acoustic release. The process was very delicate – working on the aft deck with incredibly heavy objects, ropes and cables strung everywhere, two cranes overhead, and sensitive scientific instruments in between was like performing a ballet in hardhats and lifejackets! Deck operations alone took over six hours, not including the days of planning and preparation beforehand, and the ROPOS dive to connect the instrument afterwards. The pictures below show the step-by-step operations as they took place.
The deployment plan had three main phases:
- First, there was a lot of preparation.
- Second, the mooring was lowered into the water. At the end of that phase, the mooring would be standing freely in the water column supported at the surface by two large deployment floats.
- Third, these two floats would be removed and the mooring transferred to the deep-sea winch cable so it could be slowly lowered to the seafloor at a depth of 2300m.
As a first step, floats, instruments and cables for the 270m tall mooring had to be arranged and secured on the deck so that they would be accessible in order of deployment without risk of tangling. The engineering team did this work the previous day, then the night shift reviewed the set-up and added some safety artefacts.
Top float of the mooring (left) and two floats used in the deployment.
Orange floats on the cable, the acoustic release used in the deployment (silver cylinder in the centre), the L-Box (orange canister at right) and the concrete anchor.
Overhead view of the entire setup.
The first step in the deployment was to lower the three large spherical floats to the water using the ship's crane. The top float for the mooring, which is made of material that will not compress under immense pressure at depth, weighs over 350kg in air!
The first float is lowered off the aft deck.
Three floats bobbing with a cormorant observing.
Next, the instruments on the long mooring cable were deployed off the deck one-by-one. An upward-looking Acoustic Doppler Current Profiler (ADCP) was slowly lowered into the water via crane. Then, 3 tandem instrument packages (Acoustic Current Meter (ACM) + conductivity-temperature-depth (CTD) gauge) with interspersed floats were lowered into the water.
The upward-looking ADCP goes over the edge.
A float at the surface with an instrument package below.
The final ACM/CTD package goes out.
Next, the anchor and L-box (electronics canister) were carefully raised up and over the edge using the A-Frame on the R/V Thompson.
The mooring anchor and L-box are lifted over the water.
The anchor was then lowered and released to assume its natural position at the bottom of the mooring line. Doing this also pulled the entire assembly into vertical configuration.
The anchor is lowered on the winch cable.
At this point, the second phase of the deployment began. The crew used a pole to hook the floats and pull them around to the aft deck. The top two floats were removed and lifted back on deck using the A-Frame. This left only the main mooring float atop the array in the water.
A beacon was attached to the anchor before it was deployed, and a second beacon was secured to the mooring float. The first beacon reports the position of the mooring during the descent and helps position it on the seafloor. The second beacon is a precautionary measure: should the cable snap, or some other mishap occur (e.g. the anchor falling off and instruments floating away), the mooring can be tracked and retrieved.
An acoustic release was used to connect the float to the winch cable. This release is triggered from the ship by sending a "ping" through the water, telling the release to unlatch when the mooring reaches its target depth.
The top float of the mooring with beacon and acoustic release.
The deck operations were a successful co-operative effort on this bright sunny day at sea. Our mooring was deployed and sent off down through the water.
As the float disappeared from view, we all waited anxiously for the next ROPOS dive to see how it would look on the seafloor, and more importantly, whether it would start sending data on connection.
The top float of the mooring disappears below the surface.
As it turned out, the mooring was successfully deployed. When ROPOS went down to inspect, the mooring was found intact, and upon connection, we discovered that all 9 connected instruments activated and began sending data!
Mooring anchor and L-box with cable connection at the seafloor (depth: 2145m).
Plot of data from four temperature sensors on the mooring.
When NEPTUNE Canada prepares to sail, quite a bit of preparations are necessary to get all necessary equipment out to sea. Mobilization (a.k.a. "mob") encompasses three tasks:
- getting things to the ship
- loading the ship
- tying things down so that everything stays put in rough seas on a swaying ship
For our September 2011 cruise, we had quite a lot of equipment to deal with:
- 3 instrument platforms (IPs)
- Wally II (deep-sea crawler)
- Tempo-mini (new integrated platform from France)
- 4 large cable drums
- 3 250m moorings, each with 9 scientific instruments
- 1 array of 4 temperature probes
- 3 short-period seismometers
- 2 sonars
- 2 Benthic And Resistivity Sensors (BARS)
- 4 bottom-pressure recorders
- 1 high-definition camera platform
- and a partridge in a pear tree (just kidding)
Three IPs and Wally II await loading on a flatbed truck at Esquimalt Graving Dock, 9 September 2011.
In addition to these major items, were numerous bits and pieces including SPARES, which you just don't want to forget when there is no convenience store nearby or a seeming insignificant but crucial adapter on the shelf in your lab is totally out of reach for three weeks.
It was like setting up a rock concert to move all that gear from our MTC lab in Patricia Bay (near the Victoria airport) to the Graving Dock in Esquimalt where the R/V Thompson berthed. We packed five large trucks (two 54-foot step decks, two 45-foot and one 30 foot flat deck), using one 60-ton mobile crane and three forklifts (one 7000 kg, one 6000 lb and one 5000 lb). Unloading them at the Esquimalt Graving Dock required one rig to shuffle trailers and two ship cranes.
Wally the Crawler at Esquimalt Graving Dock, 9 September 2011.
The R/V Thompson arrived on time and loading commenced without any delay. The major challenge for smoothly transferring all the equipment from shore to the deck is to stow each load without delay after it lands on deck. Otherwise, we quickly run out of open space to drop the next crane load. Almost all of the large plastic containers full of small items could go straight into the main lab, rolled along by a jack lift. Finding space for all the bulky parts like the IPs, Wally and cable drums was more difficult. Bulky things can't just be stashed anywhere on deck or they start getting in the way. Sometimes we had to find passages for the gear using a tape measure.
NEPTUNE Canada and ROPOS crew members help load a large cable drum onto the R/V Thomas P. Thompson, 9 September 2011.
Meanwhile, the operations lab computers were set up and networked. These include laptops for the chief scientists and loggers, a dedicated laptop for conductivity-temperature-depth (CTD) measurements, a printer, and our video encoder. At the same time, the R/V Thompson crew installed a block onto the A-frame for us.
R/V Thomas P. Thompson crew members install a block onto the ship's A-frame 9 September 2011.
Loading continued right into a beautiful sunset, unfortunately missed by those who were working inside, tying down boxes, bits and pieces or setting up the computer network.
NEPTUNE Canada science staff member Steve Mihaly (centre) and contractor Adam Cavanagh during mobilization work, 9 September 2011.
NEPTUNE Canada systems integration engineer Jonathan Zand seeks deck space for three mooring floats aboard the R/V Thompson, 9 September 2011.
Unfortunately at some stage the ship's crane stopped working with two trucks still needing to be unloaded. Unfazed, the mobilization crew switched to the Esquimalt Graving Dock crane and was able to finish all loading work by 11:00PM.
But the ship's crane needed a spare part, forcing a delay in our departure time until 11:00 a.m. the next day (Saturday September 10, 2011). This gave our crew a good reason to enjoy one last beer onshore and a steady bed for one more night before finally setting sail into another three week adventure.
R/V Thomas P. Thompson crew member signals to the crane operator, reflecting the mood on deck when the crane broke down, 9 September 2011.
NEPTUNE Canada scientists and engineers are sailing again, aboard the R/V Thompson for 3 weeks. The cruise's dive plan is an ambitious one, with Endeavour being the focal point of repairs and new installations.
R/V Thompson at Esquimalt Graving Dock, 10 September 2011.
A new cable into Main Endeavour vent field (MEF) will be installed (the old cable one stopped working last October and had to be chopped up and retrieved by ROPOS during our July cruise). Once reconnected, our MEF instruments (COVIS, RAS water sampler, short-period seismometer) can be reactivated and new instruments installed. These will include Tempo-mini and benthic and resistivity sensors (BARS), which had its connector cable fried by molten lava.
Tempo-mini, designed and developed by our French collaborators IFREMER, is a unique instrument platform, which integrates a video camera, oxygen sensor, dissolved iron sensor and temperature probes in one compact platform. We're eager to install Tempo-mini, after a series of delays.
Tempo mini, September 2011.
A new cable will connect Endeavour node to the dynamic Mothra hydrothermal vent field, where we hope to deploy a second BARS and a short-period seismometer (SPS).
If the weather gods smile on us, new Regional Circular Moorings (RCMs) will be deployed. The first mooring was successfully installed last year with the assistance of the CCGS John P. Tully; however, due to scheduling conflicts this year's deployment of the RCMs will be attempted by the R/V Thompson alone. This complex and risky procedure will therefore likely be a slower process than previous RCM deployments and is further complicated by being highly dependent on good weather and very calm seas.
Our plans call for replacement of the northeast RCM and installation of two more at the northwest and southwest corners of the mooring "box" we intend to build around Endeavour ridge. Each of these moorings includes three different types of instruments affixed at varying depths along a cable extending upward from the seafloor. The uppermost instrument is an Acoustic Doppler Current Profiler (ADCP) which is able to estimate currents up to 800m above the sea floor. Below this are four instrument pairs positioned at different locations down the mooring line. Each pair includes a Conductivity Temperature and Depth (CTD) sensor and an Acoustic Current Meter (ACM). Working together, these instruments measure deep-sea current velocity in three-dimensions as well temperature and salinity of the water. The top of the mooring line is kept vertical at all times by a large buoy while the base of the RCM is anchored to the sea floor by a 650kg weight.
If all goes well, we also hope to install a short-period seismometer at Endeavour node.
Pacific Geosciences Centre technician Bob Meldrum (left) describes short-period seismometer preparations to NEPTUNE Canada contractor Kim Wallace, 6 September 2011.
A stop at ODP 1027 will be made to install three bottom pressure recorders (BPRs) for the "Tsunami-meter" experiment. While these instruments will not be connected to the network until 2012, they will be recording data autonomously. They will be deployed to new sites, 25km distant from the central node, which will help scientists improve their ability to detect and model tsunamis in the northeast Pacific.
We also hope to diagnose and repair a problem with our piezometer, installed during the July 2011 cruise.
Wally the Crawler made it back just in time from Germany where the team at Jacob's University Bremen and the Max Planck Institute for Marine Microbiology worked feverishly to get him ready for his next adventure in Barkley Canyon. This time, Wally is equipped with a webcam, a sediment micro-profiler, methane sensor, current meter, fluorometer, turbidity sensor and a CTD device.
NEPTUNE Canada instrument manager Reece Hasanen with Wally II, September 2011.
Additionally, Barkley Benthic Pod 3 will be retrieved, refitted with a new Kongsberg sonar and redeployed. Collection bottles on the sediment trap will be swapped out and a new stand-alone video camera system will also be connected to Pod 3.
The new HD camera slated for Barkley Benthic Pod 3.
On such a tight schedule, hopefully there will be time to revisit ODP 889 and install a refurbished Imagenex multibeam sonar (a.k.a. "Kraki"), which will hopefully be used to observe methane bubble plumes. We then need to retrieve the seismometer auxiliary platform, which developed a ground fault and was disconnected earlier this month. We also hope there will be time to download the data from the IODP Circulation Obviation Retrofit Kit (CORK) 1364A to be sure the CORK is healthy and our work last cruise was successful.
DMAS (Data Management and Archive System) has been preparing for the cruise since the end of July! They have tested approximately 60 instruments for the upcoming cruise. Each instrument had to be put through an extensive testing procedure. The testing procedures include:
- Preparing meta-data
- Prepare the correct parameters for the instruments
- Retrieve raw data
- Pair and calibrate the raw data to be readable by people rather than just computers
- Prepare a camera control page for camera users to operate the device
- Prepare a final data product in order to allow a user to search and download data
NEPTUNE Canada quality assurance specialist Daisy Qi meets with DMAS staff during final preparations for the cruise.
DMAS, NEPTUNE Canada scientists and engineers have been working tirelessly to ensure that the cruise has an excellent chance of success. Hopefully, the weather will be on our side as well.
It almost felt like going home. Two weeks through our cruise we were heading for land, but only to take on two pilots for our work at Folger Passage at the head of Barkley Sound. Larger ships are not allowed close to shore unless they have local navigators with sufficient experience on the bridge; therefore, a Zodiac was sent to Bamfield from the R/V Thomas G. Thompson to pick up the two pilots who were waiting and ready to jump in, not even the zodiac pick-up crew set foot on land. At least we were close enough to shore for cell phone coverage, a rare treat on these open ocean voyages.
Zodiac from R/V Thompson going to pick up pilots from Bamfield.
Our aim at Folger Passage was to conduct maintenance on the instrument platform at a site called Folger Deep. It has a staggering water depth just under 100 metres, so really, the name only makes sense when compared to our nearby site Folger Pinnacle at 30 metres depth. By the way, Folger Pinnacle is actually the only active NEPTUNE Canada site that we did not visit during this cruise. The three main research objectives at Folger Passage are to:
- identify factors controlling biological productivity both within the water column and at the seafloor
- evaluate the effects that marine processes have on fish and marine mammals, and
- provide learning opportunities for students, researchers and the public, many of whom will be working and studying at the nearby Bamfield Marine Sciences Centre.
We were ready to dive as soon as the zodiac and the pilots came aboard, but dinner time had also arrived, and so it was decided to delay the dive by 15 minutes. That verdict caused the longest line in the mess-hall that we've ever had!
Following dinner, everyone was keen to get down to the ocean floor. Once ROPOS submerged into the water it only took eight minutes to reach bottom (really quick compared to the three hour descent at NEPTUNE Canada's deepest node ODP1027 at 2660 metres). Unfortunately, Folger Passage waters are murky and it was really hard to see anything. Thus, ROPOS navigation relied heavily on its accurate positioning system and sonar scans. ROPOS sonar looks like a radar screen where you can see bright reflections of the instrument platform (IP). When you can finally see the IP on the visual, it is already close enough to grab with ROPOS' arms.
Maintenance of an IP happens on deck, so the IP was disconnected from the main cable, its bottom pressure recorder, and its hydrophone (usually sitting approximately 15 metres away from the platform). Then, ROPOS attached the instruments to itself and the IP, respectively, before it hopped on top of the IP to latch on and ascend.
Nine minutes later ROPOS was on the surface again. What came into our view was an IP that looked like it had seen much better days, as it was all completely covered in mud, algae and animals. Once the platform was secured on deck, some kind souls onboard started collecting crabs, fish and anemones to cast them back into their natural environment.
ROPOS swinging by with the dirty Folger Deep instrument platform.
Bold attempts with power hoses and brushes were made in order to get the IP nice and shiny again, and the improvement was considerable. Had you not seen the IP just before, though, you would think it could still do with a good bath. However, the important parts were good again, and the IP was refitted with a new CTD (Conductivity, Temperature, Depth (pressure) Sensor), ADCP (Acoustic Doppler Current Profiler), Hydrophone and Bottom Pressure Recorder.
Meanwhile, the ship cruised slowly along a survey line to measure water depths and currents with its own multi-beam sonar and ADCP. If it hadn't been the middle of the night, we could have seen some stunning sights of the coastline. At the end of this survey, the ship also performed a CTD cast with water sampling.
Towards sunrise, the IP looked quite respectable again. All instruments were checked to see if they successfully responded through a test cable when talked to, and final touches were applied to ensure that everything was ready for redeployment.
ROPOS lifting off with cleaned and overhauled IP to redeploy at Folger Deep.
Redeployment on the seafloor went smoothly, and after connecting the IP back to the main cable, our shore team confirmed that data were streaming in again. For calibration of the echo sounder, ROPOS hovered 40 metres above it at for awhile. After taking several mud and water samples in the murky waters, ROPOS returned to deck, and the two pilots were relieved of their duties, departing via another ride in the Zodiac. We used the opportunity of our journey back out to deep sea to conduct another survey with the ship's multi-beam echo sounder and ADCP at Barkley Canyon. Hopefully, we will set foot on land the next time we come so close to shore.
Admittedly, the seafloor around Barkley Canyon is perhaps not quite as versatile and exciting as the Endeavour site. Nevertheless, considering that the Barkley seafloor consists mostly of grey mud with a thin layer of more recent brown deposits, it is not at all boring: Flora and fauna are plentiful on the seafloor, and even the water column often seemed to sparkle from many small fish reflecting ROPOS' lights during descent and ascent. And so, during the dives, sometimes the dive video loggers could not keep up with describing what came to view.
Shellfish remains and tiny crabs on the Barkley Canyon seafloor.
As normal with NEPTUNE Canada's maintenance missions, many dives were planned to recover, redeploy or newly install our ocean floor hardware. But this time was a little unusual as we were not entirely sure what to find on the seafloor. This was because in February the two instrument platforms (IPs) at the upper slope (400 m water depth) stopped talking to us, and some instruments equipped with tilt meters inside reported some extreme turning before they stopped (indicating a potential fishing trawler encounter). It seemed clear that we would find some damage. And so, our first dive was to inspect how it looked around the locations of the upper slope IPs and their attached instruments. See Barkley Upper Slope blog for a description and pictures of our seafloor findings.
Sediment trap standing happily upright next to the overturned Barkley Benthic Pod #2.
While the images from the Upper Slope inspection dive were being analyzed and a clean-up and recovery procedures were being established, we moved a little further down the slope to our other Barkley Hydrates site (800-900 m water depths). Here, we continued with more typical maintenance and deployment where damage was not an issue and we knew where things should be and in what state we would find them. Among other things, we recovered Wally II, the seafloor deep-sea crawler from Jacobs University in Bremen, Germany, for maintenance. Wally normally crawls around a gas-hydrate mound, where natural gas (mostly methane) is bound in ice-like crystals just below the seafloor; hence, we call this site Barkley Hydrates. Wally II takes pictures and various measurements along its path throughout the whole year. But like most vehicles, Wally II needs servicing once in a while, and after some inspection on deck it is now coming with us to shore.
Wally II being loading into the ROPOS tool basket on the seafloor.
Wally II emerging from the water for servicing.
The images from Barkley Hydrates clearly showed us just how active gas-hydrate structures are. We saw some bubbling from dissolved gas, drops from oil leaking out of the seafloor, and the continuous hydrocarbon feast around these natural resources benthic community, an enjoyable prospect to researchers.
A shark glides by Wally's tracks near a couple of way markers in "Wallyland."
We also took plenty of mud samples (read mud blog to find out why grey can be exciting) in the form of push-cores, filled plenty of water bottles attached to ROPOS, and scooped up some mussel shells for scientific sampling. And when ROPOS returned onto deck, we even lowered the ship's CTD (conductivity, temperature, depth (pressure) sensors) attached to a rosette of more water bottles to sample the water column.
Push-core sampling on the seafloor and a hagfish lingering by the flipped Instrument Platform.
Our sediment trap after recovery to deck, as viewed from below.
James Stephaniuk and Kira Homola carefully extracting water for oxygen analysis from the CTD and water sampling rosette with its grey Niskin bottles.
After the initial inspection dive was analyzed, the scene was set for the clean-up that followed. The over-turned IPs were put on their feet again, instruments and cables were collected and recovered on deck, cleaned and partially dismantled. We are bringing them home for more thorough inspection and re-fitting. The detached main cable was repaired by bringing its broken end on deck while leaving the rest of the cable dangling 500 m down to the seafloor. A clean cut and proper termination put the cable back into a working condition, to be re-fitted with a new connector and hooked up to the main cable hopefully during our next cruise in September.
Cutting and preparing broken cable, for refit and reconnection on a future cruise. From left to right: Steve Mihály, Kim Wallace, and Jonathan Zand.
Not everything worked out perfectly though, for example, a heat sensor and a temperature probe array we deployed on the seafloor did not perform as we hoped, so we had to recover them. But at the end of the Barkley Canyon leg of our cruise, we left the seafloor instrumentation bright and sparkling, and our shore colleagues confirmed nice data streaming in again. Good news, and so we allowed ourselves to enjoy a stunning sunset that one can only admire at sea.
Sunset over the Pacific Ocean.
My name is Rénald Belley and I'm a PhD student in marine biology at the Memorial University of Newfoundland. I'm part of the Canadian Healthy Oceans Network (CHONe), a partner of NEPTUNE Canada. This partnership gave me this great opportunity to come aboard the R/V Thompson to sample some of the NEPTUNE Canada sites. Using the remotely operated vehicle ROPOS, I collect and study deep-sea soft-sediments, a.k.a. mud. For this reason, I'm now known on board as the Mudman.
Kira Homola and Rénald Belley with a glorious sample of mud.
The main reason why I'm interested in the animals that live within the sediment (a.k.a. infauna) is that approximately 70% of Earth's surface is covered by oceans and that most seafloor areas are soft-sedimentary habitats. This means that soft-sedimentary habitats are the largest on Earth! This being said, deep-sea soft-sedimentary habitats lying below 200+ meters of water are heavily under-studied. We know very little about the animals that live in this mud and most of the species living there remain unknown to science. In fact, most estimates show that 99% of the bottom-living (benthic) species are still unknown. Therefore, these soft-sedimentary habitats represent a large pool of unknown biodiversity and one of my goals is to extend our knowledge of these species a step further. To do that, I'm studying the interactions between these animals and their environment, in other words, how the species living in the mud influence their environment. By doing so, I hope to shed some light on the importance of these animals to their ecosystems and for the well-being of humans. This study will ultimately help us to better protect and sustainably use our oceans.
A skate, nudibranch, sea pig, and some brittle stars
If this interests you, stay tuned to the NEPTUNE Canada blog. I'll tell you more about these amazing creatures living in the sediment and how we collect them with ROPOS, one of the world's most advanced remotely operated vehicles.
Do you enjoy large amounts of delicious food three times a day? Playing ping-pong when the floor is moving beneath you? Watching movies and playing games with your friends? Reading a relaxing novel while staring out over the beautiful ocean?
Then life aboard a research vessel is for you!
Fine company for the R/V Thomas G. Thompson.
In between shifts of logging, piloting, fixing, navigating, and sampling, the shipboard residents of the Thomas G. Thompson still find time for fun, relaxation, and, occasionally, laundry. We live two to a room, four to a bathroom. Each room is equipped with ample cabinet space, chairs, a sink, a mirror, and two lovely bunks with individual reading lights. Between every two rooms is a bathroom that includes a toilet and shower, difficult to use during rough seas, but thankfully there is an emergency handle handy.
Kim Wallace prepares the temperature probe array for deployment at Barkley Hydrates.
On board, we are divided into three groups: crew, science party, and the ROPOS team. The crew is in charge of keeping us on course, helping with the launch and recovery of instruments, and making sure the ship is running perfectly. The science party can be divided into the engineers and the ROPOS lab team. The engineers are stationed in the main lab and spend their time preparing instruments for deployment, and repairing, maintaining, and downloading data from the instruments we recover. The ROPOS lab team, the chief scientists and us loggers, communicates with shore, logs events during the dives, streams video life to the internet, and takes photos. We are also the ones who take and process samples, including everything from boxes of sediment to bottles of water to tubes of mud. The ROPOS team spends their time maintaining, deploying, recovering, navigating, and piloting the ROV. Overall, the sheer amount of activity on board is amazing: you can walk into any lab in the middle of the night and there will still be a group of tired people working away. Our 24-hour operations keep us very busy, but watching the dives and handling the samples is fascinating work, so I don't mind.
Maryann with samples of mud.
Personally, rocking boats put me to sleep, so I'm rarely wide-awake during my actual working hours. My leisure time is about half sleep, but that still leaves a bit of free time for socializing. While on board, I have had my rear end handed to me playing scrabble against the head cook and other members of the crew, science team, and ROPOS team. I have also been taught Cribbage, a bad game to learn while only half awake: it's very hard to add to 15 sometimes, people.
As everyone on board is very friendly, the ruling ping-pong champions have taken the underling players (such as myself) under their wing. After my first few days of falling, tripping, hitting myself in the face with the ball, and serving like a girl, I have been transformed into a hard-core, intense, spin-balling ping-pong champ. Not really, but I can actually get the ball into the right box most of the time, so that's quite an improvement. I especially enjoy the occasional doubles game, played to the intoxicating sound of our Chief Scientist's accordion. A very difficult instrument to play, I now realize, but one that is very fun to listen to.
Ping pong and accordions: What could be better?!
We are not lacking for musical talent on board, as a matter of fact. In addition to our accordion queen, we have a stunning flute-playing Able Bodied Seawoman on board, who can also spell better than anyone except the cook, as well as a guitar playing chief engineer. Satellite radio is always blaring from the ROPOS corner of the ship, accompanied by the sometimes questionable singing voices of the ROPOS team and, from time to time, myself.
For those of us that work in the ROPOS lab, we spend 8-12 hours a day staring at more screens than I've seen in the same room my entire life, including the TV store. Apparently watching undersea footage just can't compare to Talladega Nights, though, as everything from Will Ferrell to old westerns are playing around the clock upstairs in the lounge. Not counting the VHS movies, there are exactly 1008 numbered DVD's in every genera available for viewing. Across the hall in the library are 5 floor-to-ceiling bookshelves full of novels ranging from Ann Rice and James Patterson to an autobiography by a Country-Music-Singer/Comedian and a tour book about Tahiti.
The Control Room.
In conclusion: being on board and unable to walk down a hallway without feeling like a yo-yo is a complete blast. Though everyone on board slightly resembles a zombie at this point in the cruise, we are all enjoying our science and our play, but most of all, our food and our sleep!
On July 12, 2011, the R/V Thompson arrived at Barkley Canyon. The much anticipated first dive was dedicated to inspecting and assessing the damage at Upper Slope (Dive R1431), one of over 15 study areas on the NEPTUNE Canada network. Communications were lost from Barkley node to the Upper Slope and Pod #2 instrument platforms and all connected instruments on February 18, 2011, and since then, the state of the equipment was completely unknown - staff members at NEPTUNE Canada were not even sure we would find our equipment on the sea floor!
Barkley, a submarine canyon, is an important region for studying nutrient and sediment transport between the shelf break and the deep sea. Scientists are studying benthic (seafloor) ecology using instrument suites at four "Pod" sites on the upper slope away from the canyon (400m), mid-canyon wall (900m), and canyon axis (1000m). Long-term monitoring will allow scientists to follow the seafloor response to pulses of food from the phytoplankton blooms of the surface waters, and observe changes in seafloor communities related to seasonal patterns of sediment transport and nutrient upwelling.
Overview map of Barkley Canyon
Overview map of Barkley Upper Slope
The upper slope location was home to two instrument platforms. The Barkley Upper Slope instrument platform, host to an acoustic current profiler (ADCP) and a conductivity, temperature, depth gauge (CTD), and was additionally was connected 3 satellite instruments: a broadband seismometer, bottom pressure recorder (BPR), and a hydrophone.
Barkley Upper Slope Instrument Platform - as installed
The Pod #2 instrument platform (the upper slope pod mentioned above), had a rotary sonar for acoustic seafloor imaging, an acoustic current profiler (ADCP), an aquadopp current profiler and a black & white video camera on board, and was connected to a satellite sediment trap.
Barkley Upper Slope Pod #2 - as installed
When ROPOS arrived at the bottom, it was immediately evident that something was wrong. The first pieces of equipment we saw were cables. The 9.875km cable which connects the Upper Slope platform to the Barkley node had obviously been disturbed - it is normally buried in the sediment to protect it from fishing trawlers, but it was laying on top of the sea floor. ROPOS followed the cable and discovered that the end had been pulled out of the termination can. A second cable was also visible which was also broken off from its end.
Next, ROPOS followed the extension cable to the bottom pressure recorder (BPR), part of the NEPTUNE Canada tsunami array. The BPR was still connected to its cable, but was laying on its side. An octopus had taken up residence and layed her eggs on it as well.
A Small Snuggly Octopus and Her Eggs on a BPR
We followed the cable toward the instrument platform, and found that the other end of the BPR had also been ripped out of its termination can. At this point, it was time to try to find the instrument platform itself. In Victoria and around the world, NEPTUNE Canada staff and scientists were gathered around monitors after hours to watch this spectacle unfolding. As the Barkley Upper Slope instrument platform came into view, it looked more like a rock fish habitat than a piece of scientific equipment! It was lying on its side with one foot missing and disconnected cable ends beside it. The legs were serving as an octopus condo, with a resident in 3 out of 4 legs!
Barkley Upper Slope Instrument Platform - as inspected
We continued the survey, and the next instrument brought a bit of optimism. The broadband seismometer was still buried, the sediment above it looking undisturbed. We have not been able to test it, but our engineers are hopeful that it might still be operational.
The Pod #2 instrument platform was not so lucky. We found it upside-down, with the normally downward facing benthic camera looking into the water column. Amazingly, the sediment trap was standing upright beside the platform as if nothing had happened.
Barkley Upper Slope Pod #2 - as inspected
Over the course of several subsequent dives, the damaged equipment was brought on board the R/V Thompson. Righting the upturned platforms, necessary so that ROPOS could connect to them and ascend, was challenging. Engineers on board have brought the damaged cable end on deck to better assess damages and stop any water ingression inside the cable structure and ensure its integrity in anticipation of the eventual repair. This necessitated unburying approximately 700m of cable so that the end could be raised to the surface. ROPOS achieved this by spending over 8 hours vacuuming sediment to expose the cable in a trench.
One very disappointing consequence of the damage at Barkley Upper slope was that we are not yet able to deploy the Vertical Profiler System (VPS). The VPS is a custom designed instrument which consists of a seafloor platform and a motorized tethered float which is host to a collection of instruments for monitoring processes in the water column such as the transport of productivity from the surface to the deep sea. It will periodically scan the entire water column by raising and lowering the float several times per day. The VPS was successfully tested at the Ocean Technology Test Bed in Saanich Inlet earlier this year, and is ready for deployment.
So far, we have lost 5 months of valuable data from the site, and it is unclear how long it will be before the site can be brought back to operation. Right now, the biggest question is whether the almost 10km cable to the node is reparable, but the state of most of the other equipment is still unknown. In addition to the scientific cost, the monetary cost is significant. Equipment will need to be repaired and replaced; days of ship time which could otherwise be used for connecting new instruments were sacrificed; and significant staff time has gone into the planning and execution of the recovery operations.
On a positive note, we did find all the "silent" equipment on the sea floor. We are hoping some of it might be salvageable, and that it will be redeployed and transmitting data again in the near future.
One of the most exciting accomplishments of the Fall 2010 installation and maintenance cruise on the R/V Thompson was the successful deployment of instruments at the Main Endeavour Vent Field (MEF). After laying a 6 km cable across the precipitous mid-ocean ridge terrain from the node to the instrument platform site, five unique instruments were deployed: a short-period seismometer, BARS (Benthic and Resistivity Sensor), RAS (Remote Access Water Sampler), COVIS (Cabled Observatory Vent Imaging System) and an HD video camera. The HD camera developed problems shortly after deployment and had to be retrieved, but the other instruments were fully operational, providing researchers with unprecedented real-time data and a new perspective on this fascinating region.
Example of data from COVIS.
Unfortunately, the month of October brought an unwelcome development. On October 20th, communication from the shore to the junction box on the MEF Instrument Platform was lost, and the instrument data streams stopped. One of the principal objectives of the July 2011 installation and maintenance cruise was to visit MEF and perform some underwater detective work to determine what went wrong at Main Endeavour.
Engineers developed a test plan with several contingencies: The first step was to test the junction box using a specially-designed testing kit which was sent down with ROPOS. If the junction box was found to be faulty, a new junction box and instrument platform was ready on the ship for replacement. If it was found to be operating properly, then some diagnostics on the cable would be performed. If communication could not be restored through the cable, then the individual instruments would be tested using test protocols supplied by the researchers responsible for the instruments. A test result showing a faulty cable would mean that MEF could not be brought online until September due to the necessity of installing a replacement cable. Unfortunately, this turned out to be the conclusion of our engineers.
On visual inspection, one of the cables which was supposed to be oil filled appeared very flat, which could put pressure on the optical communication fibres.
We punctured the oily to see if seawater would seep into the cable and relieve some pressure on the wiring.
In a last ditch attempt to salvage the cable, we tried poking hole in the "oily," to allow water to seep in and relieve pressure on the fibres. We tried puncturing the oily in several places with an awl, but unfortunately nothing happened. Based on these results, the installation of Tempo-mini will have to be postponed to September when we will have a new cable to replace the one currently installed. However, the good news from the tests is that the existing junction box, RAS and COVIS have all been confirmed to be working, and are ready to begin streaming data again whenever communications are restored.