Thursday 24 June 2010

Well only 5 days to go before we have to end science on this ECOMAR cruise and head for Vigo. However, just as we were getting into these last few days of work the weather once again reminded us who was in charge. So our plans to complete a 30 hour ISIS ROV dive to survey the seabead slopes and terraces of this South East mid Atlantic ridge site were put on hold. Although the weather was freshening it was still Ok to use the Megacorer. The Megacorer is deployed on a wire from the ship and takes a number of sediment corers from the sea floor. Once on deck these cores are sectioned and sieved to look for animals living in the sediment. The Megacorer is a robust piece of gear and is always the sampling instrument we turn too if the weather gets a bit marginal for other work. So with nothing else to do and the need for 3 Megacorers at this final site we set off to do three in a row.

Now that sounds easy but in reality it is  very difficult for the guys involved in processing the sediment. They have to go out on the aft deck and spend 2 to 3 hours in increasing winds and ship role to sieve and process the sediment.  Brrrr! So after the second Megagcorer in trepidation I headed out to the aft to see how the troops were doing. I needn’t have worried all the guys we working hard and still cheerful … amazing dedication, well done guys!

Grant, Debbie, Mark and Helena still smiling after processing two Megacorer drops

In the end the weather kept getting worse and we could not do the third Megacorer, a relief for the processing team, but a worry as this storm was predicted to carry on for 36 hours and we have only limited time left.

Phil Bagley

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Wednesday 23rd June 2010

Earlier today Isis provided us with a glimpse of what lives on a seamount located just a few miles from the SE Station. Estimates inferred through remotely-sensed altimetry data suggest that about 100,000 seamounts with an elevation higher than 1000m are spread throughout the world’s oceans. Because they are topographically isolated features, and are often associated with particular hydrographic processes that promote larval retention, it is believed that seamounts play a pivotal role in evolutionary divergence and speciation of deep-sea benthic fauna, contradicting the early view that they could increase connectivity by acting as stepping-stones for dispersal. Evidence, however, is not consistent across regions and taxa, which calls for further surveys to obtain a clearer picture of biogeographical patterns.

The seamount we visited rises from the abyssal plain at 4000m and has its summit around 700m below the surface. Due to time restrictions, the plan was to perform one video transect up a slope between 1050m and 850m depth, obtain high-definition video footage of benthic fauna and collect voucher specimens of the most representative species. The later part of the dive was to be devoted to finding and, if possible, retrieving an accoustic lander that had been lost during a previous cruise.

The diversity and abundance of benthic fauna were staggering. The more gentle slopes were mostly covered with gorgonian and sponge gardens with a diverse associated fauna including brittle-stars, crinoids and squat lobsters. Another significant feature of these areas was the presence of extensive layers of coral rubble (fragments of dead scleractinian corals which accumulate over hundreds of years or more).

Brisingid and coral rubble

Anemone and Acanthogorgia

Steeper slopes and vertical walls were densely inhabited by sponges, Gorgonocephalus sea stars, anemones, gorgonians, sea-pens and a few black corals. There were also numerous small colonies of reef-building scleractinian corals, probably Lophelia pertusa or Solenosmilia variabilis (not easy to distinguish through video). A closer look at the rock walls revealed a myriad of solitary scleractinian corals, as well as countless small sea stars and brittle stars.

Gorgoncephalus

Lophelia and Acanthogorgia

Gorgonocephalus and Acanthogorgia

So much to explore and so little time available. After a brief, yet fruitful, period spent at collecting specimens, we headed for the waypoint where the accoustic lander (hopefully) was. It showed up on screen, not far from its suspected location, turned upside down with a few floats missing, presumably because they have imploded. Unfortunately it was too risky to retrieve it during the night, and dawn was still a few hours away. Because the cruise runs on a tight schedule we could not afford waiting for suitable conditions so it was decided to leave the lander for now and come back for it later.

The last week of science has just begun. There’s still a lot to explore at the southeast station, so stay tuned for more news!

Pedro Ribeiro

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Tuesday 22nd June 2010

The main focus of today was the transit to the South Eastern station and the opportunity that it presented. During our transit we would pass over a seamount. These undersea mountains create boundaries, forcing currents to shift and different water depths to mix. These currents, and the hard substrate provided by the mount itself, support large populations of filter feeding invertebrates. These in turn support many other animals creating isolated hotspots of life. Usually the complex terrain makes only limited sampling possible but with the ROV we were able to closely explore these complex structures.

Life was abundant and diverse. Wolf fish, False Borfish, Codling, Orange Roughy and Chimera were just a few of the most striking fish species seen. Many were attracted to the lights of the ROV and would come to investigate us before we could move towards them.

Orange Roughy: This slow growing fish doesn’t even reach maturity until about 30yrs old and can live well into its hundreds. When relaxed they are a cream colour but flush this salmon pink when they feel threatened.

The rocks were coated with a variety of colourful invertebrates, the majority facing into the current with a variety of filtering appendages. The same biological problem had been solved in the development of many different forms.

Diverse filter feeding communities.

We were seeing some beautiful things and this moment served to take us out of ourselves. Most of us have ended up here through fascination with exactly this sort of thing. It’s easy to get too narrow sighted: will the new program work properly, will the housing fail and your equipment flood, is the data you have good enough, is there enough for statistical analysis?

For me and a few others in that room watching these images widened our view again. Suddenly we regressed to kids looking in rock pools and we realised how lucky we were to live this life and to witness these things first hand.

This has been a long and intense cruise but I know those few hours will hold significant for me, a little reminder of why I do it.

A full house in the ROV control room.

Thom Linley

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Monday 21st June 2010

What is Isis?

Today we had another successful ROV day. We got a good collection of specimens up in the morning, after a very successful 12 hour collection dive during the night.

I am going to take the opportunity to talk a little about the ROV. ROV stands for Remotely Operated Vehicle and is, according to a member of the ROV team (who wishes to stay anonymous), ‘the best thing since sliced bread’. The ROV is basically a big robot designed to go into the deep sea to explore and to collect samples. Our ROV lives in the National Oceanography Centre, Southampton, and spends about half the year sailing the Atlantic from pole to pole. Isis is being looked after and cared for by a crack team of 8 technicians. Using a 12 hour shift system, she gets 24h care from a team of 3 at a time.

Isis being prepared for a dive

Isis is connected to the ship via a 10km umbilical cable which allows her to dive down to depths of 6000m.  She has her own 128multibeam and 200kHz sonar, which gives a 120° swath angle for producing very detailed swath images of the seabed. Flying Isis at about 30m from the seafloor gives a swath width of about 70m. The sonar is not only used for swath but also for obstacle avoidance and target detection, it has been particularly helpful when looking for lost landers (DOBO, amphitrap etc).

Isis being depoloyed for the test dive

Onboard the ship we have the ROV control centre, from here Isis is sent commands from the ship. The core team for every dive consists of 3 members of the ROV team sitting in the front operating Isis and communicating with the ship’s bridge, 2 scientists who sit in the back logging and recording, and finally a mission scientist who is responsible for whatever mission we have during that dive… may that be collection, observation or something else.  Everyone gets rotated in order to maximise the work output.

A logger's view inside the ROV control room

In order to see the deep sea, we rely on 10 cameras, 2 of which shoot in high definition. The feed from these cameras is sent to the ship via the umbilical cable and displayed on nice big flat screens in the ROV van. All footage is also recorded for later reference and analysis. Lasers affixed to the ROV provide a reference point for judging distance when looking at footage; it would be very difficult to judge the sizes of specimens without these.

In terms of sampling and storage devices, Isis has a biobox and push cores, a slurp gun, and most importantly two functional manipulators, also known as arms, which have being used for sample collection and lander rescue operations. She has her own hydraulic power unit that operates the swing arms, forward drawer manipulators, the slurp pump and the carousel rotation (one of the storage options). As well as the carousel it also has bio-boxes on either side, so we have plenty of space to store samples. The configuration of tools and storage can be altered depending on requirements.

Back at the surface after a night dive

Potentially, Isis could stay in the water indefinitely, provided all systems remain functional. Normally the time she stays down is limited by either storage capacity or leakage of hydraulic fluid. It takes quite some time to get her down to the seafloor, in our case it takes about 2 hours to reach a target depth of about 2500m.

Oh and on a completely different matter we made the astounding discovery today that Grant’s legs have gotten shorter, the good news is that they are still expandable when pulled hard enough.

Claudia Alt and Dave Edge

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Sunday 20th June 2010

Rock ‘n Roll Again

At this writing, we’re heaving up and plunging down, leaning port then careening starboard, over and over again.  Yep, the sea surface is definitely lumpy and bumpy.  Monty Priede, our intrepid cruise leader, will be modifying yet another daily activity schedule.  He continues to scheme and dream, sifting through the daily weather forecasts and shifting the research tasks to maximize what we can learn about the deep, dark and hyperbaric realm in the time available.  

Expect the unexpected is one way of describing the variability in faunal diversity, distribution and abundance we experience each time we enter King Neptune’s domain.  Diving the ISIS ROV continues to be exciting and always provides a surprise or two about life in the deep sea.  A pelagic plunge begun yesterday afternoon landed back on deck in the wee hours this morning.  During a journey through the water column, a vast fluid world comprising about 99% by volume of the inhabitable space on this planet, we’re always surrounded by a soup of particles, some living and some detrital, some suspended and some sinking.  The various mixtures nurture the drifters, crawlers and burrowers below.  On this journey to 2600 m we searched for elusive gelatinous carnivores (ctenophores, siphonophores and medusae) and puffy detritus feeders (appendicularians).  Finding and collecting these so-called jellyfishes can be challenging because such animals are soft-bodied and easily fragment unless sampled very gently. Consequently, their presence, persistence and ecological roles continue to be underrated, and often unknown.  Last night the “hottest” sectors above the Mid-Atlantic Ridge, in terms of the numbers and kinds of various jellies, occurred in the lower mesopelagic (700 to 1000 meters down) and in the benthic boundary layer (just centimeters above the seafloor).  High-def video records highlighted gossamer ctenophores, stringy siphonophores, and whispy medusae.  We also encountered a slender, 30-cm long squid with feathery-looking arms, seemingly sleeping in mid-water.  Attempts to collect wily, undescribed appendicularians were unsuccessful but ROV pilots, David Edge, Bob Keogh, James Cooper, Simon Dodd and Peter Mason, did scoop and slurp delicate dark red blobs (unknown trachymedusae and cydippid ctenophores) and translucent holothurians (two different species) that cruised close to the bottom.   Shortly before ascending, Andy Gooday and Andrey Gebruk, directed sampling with several coring tubes, which were pushed into the sandy, pteropod-rich sediments to collect giant forminiferans.

A relatively huge (ca. 2 cm diameter), amoeboid protozoan called a formaminiferan. This representative of an encrusting deep-sea animal (Discospirina) is characterised by a very thin, discolidal test having chambers incompletely subdivided by internal septa. Knowledge of the assemblage composition of large benthic foraminiferans in relation to environmental conditions provides information needed to interpret fossil records.

Once the ROV was on deck, the planktonic animals were offloaded and waltzed to the “cold room” where David Shale spent several bone-chilling hours digitizing their contrasting colors and swimming antics in aquaria and a specially-designed kriesel. 

One of the mysterious trachymedusa (possibly Crossota, ca. 35 mm wide) that occur near the bottom of the deep sea in all the oceans. The plethora of tiny tentacles around the umbrella must allow this animal to capture and consume small bottom-living crustaceans, but its feeding behavior has never been observed

An enigmatic holothurian (Peniagone) that meanders close to the sea floor. The translucent body (ca. 10 cm long) is gelatinous with a broad, anterior brim overlying a mouth connected to a spiral, transverse gut filled with sediment. The posterior feet are fused into fan-shaped lobes that aid in locomotion.

 The next shipboard activity was the deployment of the mega-multi-coring platform by the Stig and crew.  Shortly after retrieval of this gear and the cartridge loads of sediment, strong winds commenced and further over-the-side activities were suspended. 

We’re not finished yet; there’s still more sampling and observing to accomplish.  Stay tuned.

“After all, I guess it doesn’t matter whether you look down or up, as long as you look.”

[Ed ‘Doc’ Ricketts – in John Steinbeck’s novel, Sweet Thursday]

Marsh Youngbluth

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Saturday 19th June 2010

Day 24 in the James Cook house…

Today was a good day; we were only a couple of hours behind schedule when I got up for my shift at 12:30 this morning and everything was working and going well. Of particular success was Jess’s light box (aptly nickname HALO, though we don’t know what this stands for yet, but it is a much cooler name than PARSNIP which Grant is still petitioning for), after a bumpy start HALO produced some interesting results…. and great screen saver material.

The ROV dive was also successful in catching a number of species of interest to Marsh and David, a few of which they had never seen or been able to photograph before due to their delicate nature. As they were caught at the beginning of the dive there was some worry that when they finally surfaced some 33hrs later they would not be in good condition. But the cold of the deep and the containers on the ROV protected them and they were the cause of excitement and curiosity when they finally arrived on deck. This site has previously been an area of contention having ripped nets and lost trawls due to the rocky terrain, which we encountered ourselves on an ROV dive which was supposed to be relatively flat and ended up with the ROV having to scale cliff faces and dodge huge boulders, but it also gave the first real look into what was living in the south-west of the ridge.

Predictably the Megacorer was also successfully deployed bringing up more of the dense sandymud sediment that seems to dominate this area and the thick layer of pteropod shells on the sediment surface in most cores at this site. The CTD also went providing more data from one of the least sampled sites of the ECOMAR project.

Amphipod trap with a successful catch

I had my first experience of helping sample and sort the amphipod trap, which had been down for almost 72hrs collecting the little beasties. There were some huge amphipods in the trap, but the ones you have to look out for are the smaller ones who, once they figure out the bait (which is very neatly wrapped) is difficult to get into turn on the larger amphipods often leaving only the carapace behind.

A large amphipod

Another large amphipod

Tonight the ROV is going down to do more collecting so hopefully tomorrow will bring some interesting new creatures from the deep.

Debbie Crockard

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Friday 18th June 2010

Tracks, cracks and pteropods! (or where have all the sponges gone?)

Now we are (relatively) safely ensconced at the southwest ECOMAR station we can get our first look at the seabed below and more importantly the animals living there. A combination of tumultuous terrain and poor weather on previous cruises has resulted in us having absolutely no samples from this region….so it is now even more of a voyage of discovery!

Descending to the seabed we expected Isis to find some similar seabed structures to those we had seen in the northern sites. Bathymetric data indicates that here in the south we are again surrounded by basalt cliffs and terraces interspersed with soft sedimented valleys. However, a dramatically different sight awaited us on arrival at the seafloor.

The flat areas of sediment look dramatically different to those in the north, gone were the long, languid meandering trails of echinoderms about their business…replaced with large ripples and riffles in the seabed, shaped by the passage of strong currents. In the hollows between these structures the seabed was carpeted with never-ending swathes of pteropod shells. The pteropod is a pelagic mollusc found high up in the water column, far from the seabed. Its shell has become much reduced and is located internally within the soft body parts of the animal. These pteropods drift and swim on the ocean currents feeding on smaller members of the plankton. However, as with all things in the sea when they die they will sink to the seafloor (getting to be a common theme isn’t it? Whales, algae, bits of Thom’s mackerel!) and over time these pteropod shells contribute to the biogenic oozes that make up large parts of our ocean floors. The shells of pteropods contain large amounts of aragonite and carbonate, however, these deposits are often rare, compared to the biogenic oozes made up of planktonic foraminiferans, as the aragonite dissolves much more readily than the calcite of foraminiferan shells.

pteropod shells

Pteropod Clione limacina

As Isis traversed her way across the seafloor we saw huge cracks, hollows and mounds in the seabed, often full of fluffy marine snow just waiting to be devoured by a hungry sea-cucumber! It is unclear what could have made these massive earthworks, feeding fish? busy shrimps tunnelling away? What was clear was that we are dealing with something completely different to the habitats north of the Charlie-Gibbs Fracture Zone.

Surely the cliffs shouldn’t spring too many surprises? Same depth, similar topography, lots of hard substrate……

southwest cliffs

The first thing we became acutely aware of flying along the cliff faces of the southwest station was, well nothing really….in that it all looked fairly barren. Where were all the crinoids, soft corals and sponge gardens we had got so used to in the north? They had been replaced with tumbling boulders and outcrops of ancient pillow lava, sediment-filled gullies and the odd whip coral every now and then. Occasionally we may bump into a familiar funnel sponge or golden crinoids but long sections of cliff wall appeared devoid of life…even the intrepid mountaineering sea-cucumbers were missing from the sedimented screes and ledges.

northwest cliffs

So, much to ponder on as we progress to more dives to collect what characteristic species we can find and all on board now wait with baited breath for the first use in anger of Marsh’s fabled pelagic D-samplers….ctenophores and appendicularians beware!!

 Ben Wigham

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Thursday 17th June 2010

Today has been a bit of a slow day in terms of science, we had a successful megacore in the early hours and Jess’ yoyo CTD went into the water too, but it currently remains there due to bad weather making recovery impractical. This has also meant that plans to recover the amphipod trap and deploy the ROV are also on hold. When everything is on hold due to bad weather, us students come into our own and put our powers of procrastination to good use. As the youngest and most junior scientists onboard, Debbie and myself like to consider ourselves the masters of this, which is especially useful when we’re on the night shift and the ROV cannot go in water because of the weather.

Here is our top 10 (in no particular order):

Noughts & Crosses: A classic.

Fish-Wrapping: While the fish Thom attracts to his PAL lander are happy with a crucified mackerel, amphipods are far more tricky, so the bait we use requires wrapping neatly in muslin. After some practice I’ve gotten this down to an art form, defrosted mackerel never looked so good!

Naming Equipment: After the colour and shininess, the name of a piece of kit is most important. Much effort has gone into naming Jess’ new light box-thingamajig, which following standard practice must have a long-winded name that tells you limited information about the equipment but has a cool acronym. The name is yet to be finalised but so far we’ve gone through all of the Norse gods (FREYA, LOKI etc), Star Wars ships (DEATH STAR), and foodstuffs (RAVIOLI, and my personal favourite PARSNIP – we even went so far as to make a logo).

Parsnip logo

Sorting Amphipods: The new amphipod trap is both shiny and efficient at catching amphipods, this means there are a few thousand of the little darlings to sort every time we get a new catch, which takes a fair bit of time.

Making Paper Snowflakes: We were sat in the ROV van filling time between transects and someone had left scissors on the desk, making snowflakes was the least destructive thing we could think of, although Debbie has mentioned she wants a haircut…

Singing Songs from Muppet Treasure Island: This needs no explanation.

Learning to Tie Knots: Theoretically we should be learning how to tie useful nautical knots, but Dan showed us that you can make juggling balls out of ‘monkey fists’ so that is the main focus for the time being.

Megacoring: While we don’t get involved in the complicated analysis bit, Mark always appreciates a hand with cutting and sieving cores, which basically means playing with mud, which is always fun! We still haven’t gone down the mud sculpturing route though…at least not yet.

Mud from the megacorer

Speaking Latin: Scientific names are always Latinised or Greekified, really useful for identification but really hard to remember (thank you Linnaeus!). Unfortunately referring to a worm as ‘that one with the round swirly poo’ is frowned upon by the scientific community, so learning a dead language is the only option. Draco Dormiens Nunquam Titillandus!

The Opposites Game: Pick anything you want and try to determine it’s opposite. The opposite of salt is sugar, therefore adding sugar to seawater would make it palatable (this may not be true, sea survival 101: never drink seawater!). Pepper’s opposite is cinnamon, and bleach and vinegar are mortal enemies!

Grant Duffy

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Image upload problems

Please note that we are having problems uploading photographs to the blog due to intermittent internet access. As soon as this has been resolved we will post photographs.

Mark Shields

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Wednesday 16th June 2010

We arrived at the SW station at 3.30am this morning. As with every station, the first job was to deploy the CTD, then to recover the mooring line. We were a bit worried that we might have problems finding the mooring line on the surface as there was dense fog all around. The best way to locate the mooring line when it has surfaced is to look out for the orange flag that is mounted at the top. Luckily, the fog began to disperse in time and the mooring was easily found. The fog dispersed so much in fact that it turned into quite a sunny day… yay! A few of us even grabbed a short sunbathing session out on the forecastle deck, at the front of the ship. Meanwhile, the ROV was deployed for a video survey of the slopes and flat areas.

But, I had another mission… to build a new ‘observation tool’… in all honesty, this mission was born out of a bit of desperation, but will hopefully turn out to be very useful! There’s an important thing to accept when you do deep sea science: you might not get all the data that you planned to get. This is particularly true of deep sea science because you only have a limited time to do what you need to do, and if the weather or your instruments (or your whale bones) fail to co-operate you probably won’t get another chance. So, you have to be resourceful and take full advantage of what is possible when other options may not be possible.

The new ‘quadrat with light box’ - codename HALO

 Getting back to my mission… I am on this cruise to study the deep-sea bioluminescence at the Mid Atlantic Ridge. One focus of my studies is bioluminescent fauna (animals) in the water column. In deep waters, below 500 m, there are estimates that up to 90% of the animals are bioluminescent. These include swimming animals (nekton) such as fish and squid, as well as slower moving animals (zooplankton) such as crustaceans including shrimp, amphipods and ostracods, as well as gelatinous animals like medusa, ctenophores and siphonophores. I measure the abundance of bioluminescent zooplankton using the ICDeep profiler. The ICDeep is an ultra sensitive video camera that is mounted on the CTD frame, focussed downwards onto a rectangular mesh. As the CTD moves down from the surface to the seafloor, the zooplankton in that column of water are stimulated to bioluminesce as they impact on or pass through the mesh (nekton can avoid the mesh). Then, from the video I can calculate the density of bioluminescent zooplankton from the surface to the seafloor. But on this cruise, with the ROV, I have also been able to adapt the system to study the abundance of bioluminescent zooplankton horizontally above the seafloor. This means I can study the distribution of bioluminescent animals at different heights above the seafloor at different sites on the Mid Atlantic Ridge. The ‘observation tool’ that I mentioned earlier, is part of this study and will enable me to get images of the animals and particles in the water above the seafloor. It is essentially a square frame (quadrat) that is moved horizontally through the water with a high definition camera filming everything that passes through it. But, if you use the big front lights of the ROV then it is nearly impossible to know what is passing through the screen and what is in the distance. So, to make sure that we only film the particles and animals that pass through the quadrat the only light that is used is a shaft of light shining across the quadrat area. This light comes from a box with a slot on the side of the quadrat. Hopefully, we can test it soon and see how well it works!

Fingers crossed,

Jessica Craig

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