When most land lubbers look out of their window first thing in the morning, they are likely to spot a blackbird, sparrow or blue tit bouncing around the backyard or bickering on a bird-feeder. When we here on the James Cook awake and peer out of our cabin’s portholes, the first thing that we’re likely to encounter, are a flock of Great Shearwaters majestically negotiating the storm-induced swells that have either gently rocked us to sleep or violently thrown us out of the scratcher. As you can probably gather from the ornithological introduction, I am the ship’s bird watcher. I am also responsible for the visual and acoustic records of those whale, dolphin and porpoise (collectively known as cetaceans) populations that inhabit the offshore waters of the Mid-Atlantic Ridge, although we haven’t caught sight of any blubbery beasts for a few days now!!

This Monday morning was a particularly fine Monday morning. Clear sky, flat sea and little wind – a bird observer’s dream day out. The James Cook had been making steady progress at 4 knots since 5.15am, trawling the sea-floor for specimens that would keep Nikki’s scalpel-bearing troops busy for the afternoon. David also had his camera primed and ready for any unique-looking beastie that survived the ascension from darkness to daylight. I too prepared myself for a busy morning, surveying the ocean ahead positive in the belief that something big was going to break the surface soon. The survey started brightly when a small group of Great Shearwaters crossed the bow and landed no more than 100m from the ship – a rare sight indeed. While taking a couple of photos of this elegant pelagic seabird, I noticed that the settled flock appeared to be keeping pace with the ship’s progress. When the seated birds began to overtake the vessel I knew something was awry. Alas, the net had got itself snagged, and in an effort to free it from the basement the second mate, Rob, had slipped the ship into reverse.

Second Mate, Rob, enjoys a good Force 9 storm.

After nearly six hours of careful maneuvering the gear remained firmly attached to the ocean floor, so the decision was made at 15.00 hours to employ the ship’s muscle to persuade the net free from the ocean floor. From 2600m below the surface the benthic trawl gear, or what was left of it, should have taken about an hour to surface. Unfortunately, due to the great strains placed on the gear during the tug-o-war haul, the cable snapped rendering the gear, and its contents lost.

Once the residual cable was back on deck, CTD number 42 was deployed down to 150m to collect samples for Gavin’s chlorophyll analysis and Victor’s optical cast was also sent into action. Chlorophyll levels are used to estimate variations in phytoplankton biomass through the water column and supplies a measure of how productive a body is at any given time. Gavin indicated that the chlorophyll levels for the northwestern stations have been surprisingly low. Gavin believes that we have arrived at the tail-end of an algal bloom, which is currently senescing. He also indicated that the water column in this region (54 10N, 36, 06W) has a mixed layer down to 40m, which was probably driven by the recent Force 9 storm.

CTD 42 comes up for air.

The Force 9 storm also impacted on Gavin’s Reflectance Radiometer, which resides on the meteorological platform at the pointy end of the ship. Together with Viv, Gavin repaired the cable, which frayed and broke during the storm. This instrument measures the reflectance of sunlight from the sea surface, which in turn, validates the remotely sensed data generated from ocean colour satellites (e.g. SeaWIFS, MODIS, MERIS).

Gav & Viv at work on the Reflectance Radiometer.

The NOCS Shrimp that was deployed last night commenced recording images of the ocean floor at 23.30 last night. The two and half hours of recordings that resulted included images of brightly-coloured Holothurians (i.e. sea cucumbers) and tall columnar sponges. Some of the images generated from Nikki’s PAL lander’s most recent outing included Cusk Eels, Pycnogonids (i.e. Sea Spiders), Rabbit Fish, Blue Hake and Grenadiers.

While I have your attention, I may as well give you a 3-week summary of some of the seabirds and cetaceans that we have observed to date:

Seabirds:
Sixteen species of seabird have been observed since James Cook left Bantry Bay, Ireland on July 15th. The most frequently encountered species is the Northern Fulmar, particularly in the north western sector of the survey region. The Great Shearwater (pictured) has consistently been observed in moderate concentrations together with the odd Sooty Shearwater, as they migrate north from their island breeding grounds off the east coast of South America. Both juvenile and adult Arctic Terns were observed in small groups of up to seven birds over the south western station during their southward migration to Antarctic waters. All four skua species commonly observed off Ireland and Britain have been noted over the MAR. The Arctic Skua has been frequently recorded harassing the flock of Great Shearwaters that constantly hover behind James Cook like a child’s balloon at a town fair.

The identity of the most interesting seabird “sighting” for the trip thus far has yet to be confirmed. While investigating a group of pilot whales, I photographed a passing Great Shearwater. On examining the photograph later that evening, I noticed another bird flying alongside the shearwater. This bird may be a Zino’s Petrel (Pterodroma maderia), Europe’s rarest breeding seabird!! Formerly believed to be extinct during the 1960’s, Zino’s Petrel is now classified as Critically Threatened with a current population of 250 to 400 birds. Unfortunately, I didn’t see the petrel – I just photographed it.

The Great Shearwater.

Cetaceans:
Seven species of dolphin and whale have been recorded during the survey’s first three weeks. The most commonly sighted species has been the aptly named Common Dolphin, although the Long-finned Pilot Whale (pictured) also became a regular visitor once the James Cook reached the southwestern stations. Occasional sightings of Striped Dolphins and Atlantic White-sided Dolphins have been punctuated by regular distant encounters with adult and juvenile Sperm Whales. The most significant sightings of the survey involved a single Northern Bottlenose Whale and a pod of five Sowerby’s Beaked Whales.

A tight family group of Long-finned Pilot Whales.

A day that began with bright skies and flat seas has suddenly deteriorated this bleak Monday evening into thick sea mist and Force 10 winds – time to down tools and hove too.

Mick Mackey
University College Cork

We woke up this morning with a little sunshine (at last), and in this bright morning, there was also a bright start: dozens of fish and hundreds of invertebrates from a deep trawl were coming to surface. I must say I had high expectations for this trawl to come up, not only because of the obvious scientific curiosity, but also because a much more mundane reason: I was expecting to taste some of them!
After the trawl captures came in the boys and girls from Aberdeen, Durham and East Anglia got themselves to separate out the fishes, the team from Southampton to take apart the invertebrates and … me , I was trying to smuggle some fish out of their sampling and some “gambitas rojas”(red shrimps). However my attempts were discouraged by two facts: firstly the actual fishes (don’t ask me the long and latin name) were very ugly, and so I found it hard to imagine that they could taste nice; secondly, after the scientific processing of the “samples”, there was very little remaining of the original fish (although Antonio, the captain, was suggesting to do a nice broth with them…). But thanks to the encouragement of Monty: “…the aspect of these fishes is a wrong criterion to judge their taste…” I will try to be more courageous next trawl and see if I can get hold of one of those fishes and take it to the ship’s kitchen…
Apart from the trawl and the culinary curiosity, a lot of other interesting science was going on during the day: a shallow CTD and an optics cast were done in the morning and the PML group got on to filter seawater and do the primary production incubations. Also an EK60 survey of the area was duly done during the afternoon. In the evening the activity even increased: a sediment sampler went to the bottom and collected some “mud samples” (again, I am unsure of the technical word to use here, but I did taste some of those, and I can report that they actually taste like cheese…), the PAL lander was recovered (this activity always impresses me, not the actual recovery manoeuvre, but seeing the lander coming back to surface!), and the amphipods trap was sent to the sea floor.
And just as I am writing these lines, the NOCS Shrimp is going down to 2500m and tonight there is another deep trawl planned. Not a bad day of work for a Sunday….
PS: I’ll leave it here as I would like to take a place in the Main Scientific lab, to see tonight’s movie: “Shrimp 2: return to the deep ocean” … Pity we lack pop corn!

Victor
PML

Following two days of a force 9 storm with the RRS James Cook being thrown around by an angry sea, we resumed our position at a station to the North West of the Charlie Gibbs Fracture Zone at 03:00 GMT where the sediment traps were deployed on 01 August. We are now at the same latitude as Northern Scotland, at the end of the Reykjanes Ridge, an underwater lava sea mount that extends from the tip of Iceland and separates the North American and European tectonic plates.

Today saw a hive of activity; much to the relief of the scientists and crew after a few days of literally holding on!!!! Shortly after 03:00 the CTD (see Colin’s blog of 28 July for a description of the CTD) was deployed to 2.5 km depth so that Jane and Andy could characterise the dominant water types in this area from the temperature, salinity and oxygen profiles and from water samples collected at specific depths to determine the nutrient contents. This was followed by another three hour CTD at 06:00 at a station further to the North to not only look at the temperature, salinity and nutrients, but also to identify the dominant phytoplankton and to determine how much carbon they are fixing through photosynthesis. With the CTD still in the water, there was an optics cast at 08:30 to determine how much light the phytoplankton are absorbing during photosynthesis and how much they are scattering back to the sea surface which can be detected by satellites (see Williams blog of 30 July).

Shortly after lunch, the Southampton group lead by Alan Hughes deployed the MEGA-CORER. This instrument consists of a number of 10 cm diameter Perspex cylinders that are lowered onto the sea floor by a wire to collect sediment cores from the seabed. As the mega corer nears the seafloor, it is hydraulically dampened so as not to disturb the tiny benthic animals that live in the uppermost surface layer of the sediment, which would otherwise be disturbed and washed away. Once dampened, the instrument is activated automatically using a series of levers that thrust the Perspex tubes into the soft muddy substrate and then seals the tubes with a metal plate on the bottom and o ring on the top. This ensures that the mud does not fall out of the tubes when it is being hauled back onto the ship. The resulting cores can be anything from 20 to 30 cm deep. Today the sediment consisted of a 10 cm light brown top layer overlying dark brown and grey mud. Once back on board they are fixed in a preservative and stored for analysis back in the laboratory, which can take up to three months. Alan’s group are studying the abundance and diversity of Benthic Formanifera, single celled animals that live in the sediments that are formed from the raining down of detrital material from the upper ocean. There have been very few studies of these tiny creatures and with each mega-core there is a high chance of discovering new species.

Next to be launched from the deck at 15:00 were BATHYSNAP and PALANDER (described in Tom’s blog of 26 July). BATHYSNAP consists of a time lapse camera mounted on a stainless steel frame. The instrument is weighted to the sea floor with an iron anchor and is equipped with a series of buoys which carry it back to the surface when an acoustic release mechanism is activated. BATHYSNAP is left on the sea floor for one year, taking photographs every 12 hrs onto 35 mm Cinema film and records the seasonal changes on the sea floor. Instruments like this have revolutionised our understanding of how the deep oceans change over time and season.

Last, but by no means least, SHRIMP was deployed at 18:00. SHRIMP stands for Seafloor High Resolution Imaging Platform and was originally developed in the early 1990’s and has been updated at regular intervals since, most significantly with the addition of a fibre optic link giving scientists a real-time view of the seafloor. It is now part of the NMFSS deep platforms group lead by Ian Rouse, who is running it on this cruise. It consists of a very heavy duty stainless steel frame (approximately 1 meter high and wide and 3 meters long) loaded with very powerful high intensity lights (400w), underwater CCD colour video and photographic cameras which relay real time footage of life on the deep sea floor back to the scientists and crew through a fibre optic cable. As it was lowered through the water column, myriads of tiny copepods rushed past us like shining stars, skeletal jellyfish ambled by and the occasional fish darted from view. There was a moment of suspense at 200 metres from the bottom when something seemed to hit the instrument making the cameras shake and causing momentary loss of the lights and images. Ian fortunately managed to regain communications!! The instrument was suspended at 2.5 mts above the seafloor guided by Charlie, Bob and Steve, the Winch men who use a downward facing camera focused on a weighted target to guide the instrument as it is towed at 0.5 knots. The atmosphere on board was electric as we witnessed for the first time images 2.5 kms below us of the deep ocean floor on the Northern Mid Atlantic Ridge plateau. As the instrument neared the bottom it caused small plumes of sediment creating interest for the carnivorous Blue Hake and disturbing Snail fish and Rats tails. As it moved along the plateau and eventually down the slope of the ridge we saw Brittle Stars, Sea Cucumbers, Sea Urchins, Sponges and Grenadieres gliding past us. We spotted the elusive Dragon Fish (Bathyosaurus Ferox) which has an array of massive front teeth and lies in wait for unsuspecting prey. We also saw the Spiral Poo Worm, which until 3 years ago on a voyage to the same area, was only known in fossil records. The suspense and excitement in the scientists’ faces captured it all. The deep sea truly is an incredibly exciting and undiscovered world!!!!!

Gavin Tilstone
Plymouth Marine Laboratory, UK.

We continue to ride out the bad weather which has once again prevented all scientific work. The storm, which reached its peak on Thursday morning, has passed. However, although the wind has dropped significantly, a considerable swell still remains.

Last night most had a poor nights sleep owing to the roll of the ship in the 7-8 metre swell and
occasional larger waves. A popular method of preventing yourself being thrown out of bed is to put a life jacket under one side of the mattress. I tried this last night and had a relatively sound sleep though I did wake this morning to find my floor littered with the contents of my shelves and much of what was on my desk!

As there is no scientific work to report on I thought I’d write about the storm and the strategy of riding it out. The first signs of the approaching storm came on Tuesday 31st July when we experienced a long low swell from the south west which wasn’t accompanied by any wind or rain. This swell was being generated by a depression (a region of low pressure) to our north. Officers on board began monitoring this depression via synoptic charts (weather maps), provided by the Ocean Prediction Centre (updated every 6 hours), and data from satellites. Using this information the path of the storm was tracked and its course predicted. The swell continued to increase in size and on the Wednesday 1st August the Barograph started to decrease rapidly. The Barograph (see Fig.1) plots barometric pressure over time. A rapid decrease in pressure indicated we were moving under the depression. At midnight on Wednesday wind speeds began to increase from about 10 knots to 15-20 knots as pressure decreased further.

Fig.1, Barograph of the storm

The pressure “cusped” on Thursday morning at about 09:00hr (it curved and started to increase again). During storms the strongest winds come as the pressure “cusps” and is accompanied by a change in wind direction. The wind changed from SSW to WSW accompanied by winds of 35-40 knots and then 50 knots with occasional gusting of 55-57 knots (~65 mph). As the pressure continued to increase through Thursday and during the course of today, wind speeds died away and are now (Friday afternoon) about 25 knots.

Fig.2, Satellite image of the depression relative to the RRS James Cook (Thursday 2nd August, 13:33:40 GMT)

Fig.3, Satellite image of the depression relative to the RRS James Cook (Friday 3rd August, 15:00:34 GMT)

Fig.4, Synoptic chart of the North Atlantic (Friday 3rd August)

High wind speeds generate large waves; in this case the swell was about 8 metres on Thursday with occasional 10-12 metre waves. The strategy of riding out a storm is to point the bow in to the dominant wave direction. The ship then moves as slow as possible whilst maintaining speed enough to turn (a rate of ~3-4 knots). This allows control of the ship whilst preventing the vessel from hitting waves too hard and causing damage. As the depression moves and the wind direction changes, officers change the direction in which the ship travels to maintain the wave direction on the bow. Fig.5 shows a plot of the direction in which the ship has travelled since 03:00hr this morning showing adjustments to compensate for the changing wind direction.

Fig.5, Chart of the direction in which RRS James Cook has travelled since 03:00hr Friday 3rd August

Due to changes in wind direction and the persistence of waves in deep water, swell often comes from different directions. This is known as “confused swell” and can cause the vessel to roll…something which it has been doing quite a lot of…soup for lunch was definitely a bad choice!

The duration of the storm and the strategy of riding it out means we have travelled 67 miles from the north eastern station. This evening at 18:30hr we shall turn and steam for this station, arriving sometime before midnight. We will immediately deploy the semi balloon otter trawl (OTSB) and start fishing…at last!!!

Andrew Oliphant
University of Newcastle

At 6 a.m. this morning the barometer displayed a drop in pressure which has unfortunately put a temporary halt to all scientific work. In anticipation of an approaching low pressure zone and the bad weather associated with it the CTD surveys were stopped last night in order to allow adequate time for deploying the northwest mooring which consists of sediment traps and current meters amongst various other pieces of equipment. In addition we also needed to use the swath bathymetry system in order to map the topography of the seabed at this site. Data acquired from the swath surveys is required to plan for the subsequent deployment of other equipment - for example the identification of suitable flat areas which can be sampling using the OTSB trawl, so it was important for us to complete as much work as possible before the bad weather hit.

Today’s weather has seen a between gale force 9 and 10 on the Beaufort scale. For those of you wondering the Beaufort scale was introduced in 1806 by Sir Francis Beaufort – an admiral of the British navy, who devised a system of measuring wind speed. The system is still in use today and consists of 12 stages, each one with an associated range of wind speeds in knots and water surface characteristics such as wave height. 0 on the Beaufort scale is classed as calm with wind speed of 0-1 knots (0 miles per hour) and characterized by a flat, mirrored surface, whereas 12 is classed as a hurricane with wind speeds of 64 knots (75 miles per hour) or higher and a wave height of 14m. Today we typically experienced an average wind speed of 40-50 knots and a wave height of 7m – not exactly a hurricane but more than enough to produce some impressive waves and a ban on setting foot on deck!

For the bulk of the scientific staff bad weather means a lot of free time which is generally taken up by reading, catching up on sleep, watching DVDs or having a few drinks in the bar- possibly even working up samples in the lab. What many of us don’t take into consideration is that the crew of the James Cook still have to keep the ship running (not to mention afloat!) in these conditions so I decided to find out how the crew and the ship itself cope with a rough spell.
During bad weather the wind and waves cause the ship to pitch up and down and roll. The side to side rolling is counteracted by the ship’s stability tank which uses displaced water to cushion the effects of the waves. The up and down pitching is controlled by sailing on the most comfortable heading into the oncoming waves at a minimal speed. The downside of this is that the ship is basically riding the bad weather out and may not maintain the correct heading, as we saw during a previous spell of bad weather when we ended up 50 miles off course.
From the crews standpoint a priority is placed on properly securing all equipment and supplies so that won’t come loose, which could lead to serious injury, damage to the ship or to the equipment itself – in short personal safety is the prime consideration. Generally work is undertaken only when absolutely necessary, this could include restarting the engine which may become blocked with water which is normally immiscible in the fuel but may temporarily mix due to the rolling of the ship. The galley staff still have to prepare meals- fried food is obviously not an option and I can’t imagine its all that easy to cook with your ingredients rolling around. All in all its a pretty incredible feat and not one I would like undertake as I certainly don’t possess the required balance let alone patience, so well done and thank you to all the crew of the James Cook!

Ian Cross
NOC, Southampton, UK

Today has seen the James Cook pressing ever northwards and we have been surrounded by fog for most of the day. There is now a distinct chill in the air since crossing the Charlie-Gibbs fracture zone and it will soon be time to break out the extra jumpers!

Our long CTD transect is now almost over and we have succeeded in collecting huge amounts of data that will no doubt keep many of us busy in our labs over the coming winter months.

Our first task on arriving at our northern working stations is to again make some detailed maps of the seabed terrain using the multibeam swath bathymetry system. This is a vital part of this first ECOMAR cruise as many of the areas we are studying have not been visited before. As well as providing us with a means to target suitable trawling grounds and locations for the landers and long-term moorings, these bathymetric maps will be invaluable for planning future Isis ROV dives in 2009.
As these surveys are so important to our project is probably a good idea to give you an insight into how we can visualise what lies 3miles beneath the ship.

Echo sounding is the key method scientists use to map the seafloor today. The technique, first used by German scientists in the early 20th century, uses sound waves bounced off the ocean bottom. Echo sounders aboard ships have components called transducers that both transmit and receive sound waves. Transducers send a cone of sound down to the seafloor, which reflects back to the ship. Just like a torch beam, the cone of sound will focus on a relatively small area in places where the ocean is shallow, or spread out over the size of a football pitch when water depths reach greater than 3000 metres. The returned echo is received by the transducer, amplified electronically, and recorded on graphic recorders. The time taken for the sound to travel through the ocean and back is then used to calculate water depths. The faster the sound waves return, the smaller the water depths and the higher the elevation of the seafloor. Echo sounders repeatedly “ping” the seafloor as a ship moves along the surface, producing a continuous line showing ocean depths directly beneath the ship.
This single-beam echo sounding is very useful for showing the depth of the seabed beneath the ship and it can give some limited information of the seafloor topography, but it is limited to a narrow strip and it would take many passes of the ship to build up a map of the seabed.

So how can we visualise a greater area of seabed beneath the ship? Well, the concept is simple really…..more beams = more area covered. The entire concept of multibeam bathymetry is based on the simple fact that more beams are better than one. Instead of just one transducer pointing down, “multibeam bathymetry systems” have arrays of 12 kHz transducers, sometimes up to 120 of them (we are using a Kongsberg-Simrad EM 120 on the James Cook), arranged in a precise geometric pattern on ships’ hulls. The swath of sound they send out covers a distance on either side of the ship that is equal to approximately two times the water depth. The sound bounces off the seafloor at different angles and is received by the ship at slightly different times. All the signals are then processed by computers on board the ship, converted into water depths, and automatically plotted as a bathymetric map with an accuracy of about 10 metres.

In this way, the James Cook travelling at speeds of up to 10 knots (11.5mph/18.5km hr-1) can produce a swath, rather than a line, of water-depth information. Multibeam bathymetry systems are now routinely used during research cruises to map areas of seafloor as large as thousands of square kilometres.

So tonight will be spent producing the best maps we can of our working area so hopefully by tomorrow we will have identified some good, clear, trawling grounds, a site for the long-term mooring and of course some interesting features that will warrant closer inspection with the ROV!

Ben Wigham
University of Newcastle, UK

We are continuing to steam and do regular CTDs along the transect to reach the two northerly stations on either side of the Mid Atlantic Ridge. We have now reached the Charlie Gibbs Fracture Zone (incidentally there was no-one called Charlie Gibbs). Here we are deploying the DOBO Lander Mooring– the Deep Ocean Benthic Observatory. This device is a large titanium frame packed with equipment. DOBO will remain on the sea floor in the CGFZ for one year. It will be recovered by R.R.S. Discovery when she visits the area for further research as part of the ECOMAR project next year. It is designed to collect data on scavenging fish over a period of 12 months by recording the attraction of fish and other animals to bait, in this case mackerel. The frame carries 8 tubes each containing a single mackerel in artificial seawater; the first mackerel is exposed at the start. These are sealed to prevent access by any animals. A stepper motor and controller release a mackerel at predetermined times, i.e. one every 30 days over the period of deployment.

A CCD camera takes photographs illuminated by 2 LED lights. The camera will record for a total of 24 hours over 9 months onto a Hard Drive. It initially records the bait release and then records over varying intervals until the next release in 30 days. The camera records for one minute every 15 minutes for the first 12 hours, then for one minute every 30 minutes for the next 12 hours and finally for one minute every 5 days. The process restarts with the release of the next fish. An ADCP current meter is also fitted to the lander to measure ocean current.

Mounted above the DOBO at a depth of is a MARU pop-up whale listening device. This piece of equipment consists of 2 glass spheres; the bottom one housing a battery and the upper is the recording device and a peizo-hydrophone. It is suspended 42.5m above the seabed and above the DOBO. This is part of an experiment by Henrik Skov a MarEco scientist from Denmark. It will gather data on cetaceans (whales and dolphins) in the CGFZ for one year.

Ballast weights consisting of two iron bars keep the DOBO on the sea floor at a depth of 3688m. In 12 months two releases will be triggered, the weights released and DOBO will float to the surface to be recovered and the data downloaded.

As we were continuing to do CTDs I was assuming that there would not have been a lot of new information to impart. I was not sure when we were to have arrived at the CGFZ so I have prepared a different addition to our life at sea.

Oceanography today relies a lot on new technology, much of which we take for granted and as such we use acronyms for systems we don’t fully understand and which are quite complicated but make our lives easier. Take for example the much-used CTD. We assume that out here in the middle of the Atlantic we can suspend a piece of highly technical and valuable equipment over the side of the ship to a depth of 3700m. That it will reach the bottom of the ocean and be where we want it to be. There are many variables at sea. Wind and ocean currents, which move in different directions and can seriously affect working conditions at sea. If something is suspended over the side the assumption is it will go straight down with a vertical wire. In the past, not so, however, today on ships like the “James Cook” we have “D.P.”

So what is “D.P.” and how does it work?

D.P. stands for Dynamic Positioning- a text book description is ‘ An integration of systems and sub-systems combined that automatically control a vessel’s surge, sway and yaw by means of active thrust’ This means that it controls the vessel’s position and heading using position references by propulsion only.
Most ships, you assume have one or two propellers, the James Cook has 6! There are the two main propellers, which have fixed pitch and variable speed. Also at the rear are two stern thrusters of 800 and 600 KW power. These are mounted across the ship. Forward there are two more propellers, one tunnel thruster of 1200 KW power and a fully retractable azimuth thruster. This one can be lowered below the hull and can turn through 360 degrees. These systems are all designed for maximum quietness, which is also very important for the underwater acoustic systems.
There also 2 High Lift rudders, which improve low speed manoeuverability.

The D.P. system is totally automatic with no hands on control by anyone on the bridge.
All the computer, which controls it needs, is information.
The information it requires is heading input, provided by 2 gyrocompasses;
Position reference provided by gps with differential correction;
Satellite and terrestrial signals
Hydro acoustic position reference
Vertical reference sensor information

With all this information the computer adjusts for pitch and roll and calibrates the ships position to an accuracy of ± 2-3m

There are also wind sensors - sonic anemometers that also provide a live input to the ships positioning.

All in all this sophisticated technology means that equipment that operates on a vertical wire such as CTDs, corers, optical sensors do remain vertically below the ship and if equipment needs to be placed on the sea floor it goes exactly where it should with pinpoint accuracy.

We can do amazing things at sea now but the one element we cannot control is the weather. If it gets too rough to work then we have to heave to and stop.

David Shale

Hello. My name’s Will. I’m one of the marine ecologists on this trip and about to start my PhD at Newcastle University. I’m here to examine deep sea food webs on ocean ridge systems. To do this I’m heading to two very remote locations in the world- East Scotia Ridge (ESR) in the Antarctic and to the Mid Atlantic Ridge (MAR). These sites are very different and have been chosen for very special reasons. The sites on the ESR are hydrothermal vents while the stations selected as part of the ECOMAR programme are areas that are believed to contain none or limited hydrothermal activity.

So, my first stop is here over the MAR with my samples approximately 2500 metres below me. That is the equivalent of 25 football pitches or 7.5 Eiffel Towers. Which begs the question how am I going to get at them? Well, I’m going to be collecting material in two different ways. Firstly with the semi-balloon otter trawl (OTSB) during the first three cruises and secondly the UK’s deep sea remotely operated vehicle ISIS on the final cruise in 2009. These two pieces of equipment will allow me to collect different types of animals. The OTSB captures mobile megafauna that live on the sea floor, and has been written about in previous blog instalments, while ISIS will collect suspension feeders that live in areas that the OTSB cannot reach- mainly attached to rocks and steep surfaces. Once the catch is on board and sorted, a small tissue sample is removed from the specimens, which I will take back to Newcastle for biochemical analysis. This will give me an idea of the position or trophic level of each species within the food web. Ultimately, I will compare the food webs of the MAR (non-vent) and the ESR (vent) to determine the relative importance of chemosynthetic and photosynthetic sources of energy at vent sites under strongly seasonal and very productive waters in the Antarctic, and examine the range of influence and incorporation of chemosynthetic energy into the food-webs of ‘non-vent’ ridge fauna at the MAR.

For now we are still on the CTD transect, heading north, which means no sampling for me. But as the blog has already mentioned there a series of scientists who are currently working around the clock. Andy wrote about the work Jane Read from NOC was conducting in relation to the CTD transect yesterday. So today I’m going to write about the work currently being undertaken by the scientists from Plymouth Marine Laboratory (PML). Their current aim is to collect data that will validate ocean colour satellites. Ocean colour is literally the colour of the sea, which is caused by whatever is in the surface layer that absorbs light. In the open ocean the main absorbing particles are phytoplankton (Fig. 1) or in other words the plants of the ocean. There are millions of these in a single droplet of sea water. So in the upper 100 metres you have a dense forest of phytoplankton which collectively are bigger than the tropical rainforest. Phytoplankton forms the base or foundations of the food web. They capture the energy from the sun and use carbon dioxide (CO2) to produce their own food in a process known as photosynthesis. This energy is passed to the next level when they are eaten by zooplankton and so on up to higher levels of the food web to animals like fish and whales.

Fig. 1 As you can see from the above images, phytoplankton comes in many different shapes and sizes.

The phytoplankton can be observed form space by ocean colour satellites. There are currently three ocean colour satellites that orbit the earth. These are SeaWIFS, MODIS and MERIS (Fig 2). When sunlight shines on the sea a proportion is absorbed by the phytoplankton and some of it is reflected back to these satellites. Each satellite carries a radiometer that can detect sunlight reflected from the sea surface. From this signal the scientists are able to get an idea of the amount (or biomass) of plant life in the oceans. They can compare these satellite images of phytoplankton biomass against sea water samples collected by the CTD rosette (mentioned in Colin’s blog). Phytoplankton plays a crucial role in regulating the earth’s atmosphere. Their role can not be understated as they absorb more carbon dioxide (CO2) from the atmosphere than land plants. Therefore, phytoplankton plays an important part in regulating CO2 concentrations and in turn our climate.

Fig 2 Satellite image taken by MODIS-AQUA over the MAR on 30 July 2007 showing chlorophyll concentration of phytoplankton. Our sample sites are marked by the white boxes.

The guys form PML are also conducting experiments on the photosynthesis and carbon fixation by phytoplankton. Using light, phytoplankton biomass and sea surface temperature, which can be derived from satellite data, they are able to produce global maps of carbon fixation by the phytoplankton and compare this with the experiments that are done on board. Satellite measurements of carbon fixation are being used to monitor the health of the oceans and how much CO2 phytoplankton is drawing down from the atmosphere. These measurements are crucial in understanding the seas role in reducing global warming.

So for me I’m going back to reading scientific papers, books and watching DVDs until I get a chance to start fishing once more! And finally a big HELLO to all my friends and family back home. See you all soon.

Will

PS Did you know that a cod cannot hear the James Cook when she passes 20 metres above it!

We have spent much of today in fog, edging to the northwest, making vertical profiles every 15 miles as we go. The focus for the time being is on ocean circulation. We will gradually be crossing the Subpolar Front, a major boundary between warm southern waters and cool northern waters. Along this boundary flows the North Atlantic Current, a continuation of the Gulf Stream and the supplier of the warm water that keeps the climate of Western Europe relatively mild. The Subpolar Front crosses the Mid-Atlantic Ridge close to the twin east-west gashes of the Charlie-Gibbs Fracture Zone. The valleys also provides a deep connection between the eastern and western basins of the North Atlantic via which deep water of Arctic origin seeps to the west. So the topography of this area makes it a crossroads of the North Atlantic circulation.

Our present route follows the track of an orbiting satellite, TOPEX/POSEIDON, which carries an altimeter able to accurately measure the elevation of the ocean surface. At first glance, it appears that the ocean’s surface is flat – at least, if you look beyond the effect of waves and tides. Of course the ocean is curved because the planet is curved, but this can still be regarded as flat if the surface is not tilted when compared with the direction of gravity. In fact the ocean is not flat and the shape of its topography tells us about ocean currents in just the same way that a pressure chart of the atmosphere tells us about winds and weather systems. When the ocean surface is elevated, the weight of this extra water creates high pressure about which currents at the surface flow in a clockwise direction (in the Northern Hemisphere). As our ship track takes us across the North Atlantic Current, the ocean surface will drop by about half a meter. It’s not much! We can neither see nor measure this directly, but by making our shipboard measurements of currents and profiles of density we can infer the slope of the surface and compare this with the satellite measurements. We will also see the deeper structure that is invisible to the satellite. This comparison is the research focus for Jane Read of NOC, Southampton who is leading this aspect of our work

So for now it’s one profile after another as we slowly piece together a transect revealing the structure of the currents and differing water types of this region. There’s not much to be seen as we push forward into the fog.

Andy Dale
SAMS, Oban

Midnight Position N48º 51.5’ W029º 35.3’

We are now heading towards the northern sites. On the way we will be working a hydrographic section comprising 26 CTD stations. The first station on the section was back inboard at 0142. The section is just over 400 nautical miles long. The casts are roughly an hour and a half apart and the average water depth is 3500m. Terry, Darren, Paul, Jane, Andy, Ian and myself make up the CTD team. We are split into three shifts working four hours on and eight hours off. I’m fortunate, I’m working the 8>12 & 20>24, so I can have a normal nights sleep. The other two watches are more disruptive to normal sleeping patterns and it takes your body clock a while to readjust.
There was a torrential downpour around 5 o’clock just before the 2nd CTD of the day. The working pattern for the next 5 days has now been set, each watch will have a single CTD cast. The St Andrews team have also gone onto a watch system to monitor the EK60 during the transit between CTD stations. Monty, Jessica & Rhys are working on the CTD whilst it’s aboard to prepare a mounting for one of the Oceanlab cameras.
Victor and Gavin have taken extra water from the first CTD after breakfast and performed an optical cast at the same time.
Steve is working on the after deck preparing all the ropes and various other components which make up the two northern moorings. These will be full depth moorings with far more instrumentation than the two moorings deployed at the southern sites. Terry and I will be working on setting up the instruments in between the CTD casts over the next couple of days. In total we have 27 instruments to prepare for the two moorings, an assortment of current meters, temperature/salinity loggers, acoustic releases, sediment traps, beacons & lights.
Nikki & Ben are preparing one of the Oceanlab landers which will be deployed before the end of the section. This lander, as well as all four moorings, will be recovered during next summer’s ECOMAR trip aboard
RRS Discovery.
Mick is not having much success today with the binoculars, all in all a miserable day, no sun at all and visibility is very poor indeed.
Highlight of the day, dinner, even more so on a Saturday, it’s curry night. The ship operates a self service cafeteria system, great restraint must be shown, otherwise it’s down to the gym for payback time.
The late CTD watch passes without incident and then it’s time for bed.

CTD cast displayed in real time on one of the monitors in the main laboratory. Water bottles are closed during the upcast as required for subsequent nutrient, chlorophyll, oxygen & salinity analyses.

The CTD at the start of a cast. The package is lowered on an armoured cable with a central conducting core. The instrument is powered from the ship and the data is sent back to the ship in real time.

Colin Griffiths
Scottish Association for Marine Science, Oban.