Wednesday, 27 February 2013

18 - The final word from team biology

Sampling west shrimp gully at Beebe Vent Field
The Isis  ROV has captured the last glance of the seabed on our final dive at the Beebe Vent Field and we’ve collected our last batch of samples from the distant reaches of the deep ocean, where sunlight is a stranger and pressure exerts a tight grip. The cold, black waters revealed on the ascent unveil nothing of the marvels of life we leave behind and whose secrets we are endeavouring to unlock.

A final glimpse of the deepest vents
During the last few weeks we’ve collected hundreds of hours of video footage and thousands of stills of the creatures inhabiting the Von Damm and Beebe vent fields, and of the halo of life surrounding these island-like oases. We’ve catalogued, processed and photographed a diverse array of animal life, including abundant blind vent shrimp and elusive echindoderms, elongate tubeworms and squat lobsters, fragile sponges and corals, and exquisite anemones. One of our objectives has been to elucidate the biodiversity at the deepest vents and our final species list is still in preparation as we collate the data we’ve accumulated and begin to analyse what we’ve found. At the time of writing we don’t know if we’ve discovered any new species…but as you read this we’ll be working hard to find out!

Jon Copley using skype to show his SOES1006 class
our discoveries from the deep
The biologists have got a tremendous amount of new information and samples from this expedition and we’ll be kept very busy for the foreseeable future. I hope none of us will ever forget the wonders we’ve had the privilege to see and experience, captured by the cameras on Isis  and viewed through the eyes of awed human beings.

Jon Copley has been an inspirational principal scientist; in addition to leading on science he has made several daily Skype calls to schools across the UK and even taught his first year marine ecology practicals via Skype from the ship.

Paul Tyler
It has been a pleasure to sail with such a great team of scientists, technicians, officers and crew. And finally we raise a glass to Professor Paul Tyler, without whom none of this would be possible. His vision and commitment to deep sea biological exploration has shaped UK marine science. This is Paul’s last voyage and many of us have sailed with him on his 60+ expeditions – cheers Paul, here’s to a long and happy (semi) retirement.

By Verity Nye, Rachel Mills and Team Biology

Monday, 25 February 2013

17 - Geostrauphic wonders

A rare fish at the vent site
As our time at the deepest vents draws to a close, we reflect on what we have learned during these past nights. I say ‘nights’ as this is how it feels; immersed in the perpetual darkness of the abyssal depths, cameras for our eyes, the only light is that being reflected back as Isis picks out the colourful hues and dark shadows of the Beebe Vent Field.

The colours at the vent site are stunning
As geologists, we have wandered the furthest from the main vent site, mapping the surrounding hills and valleys. Here, we have found a landscape of volcanoes and lavas. Pelagic sediment sits like a recent snow-fall, picking out the texture and detail of the rocky surface in brilliant white filaments of chalk. Striking like dark streaks across this alpine scene are black fissures: cracks forming the plate boundary where the seafloor drops vertically away into the darkness below. Not even our most powerful lights can penetrate here, leaving the bottom a mysterious realm of shadows and gloom.

At the astonishing depth of 5080 metres, in the bottom of the deepest valley, we find a carpet of bright orange mud. Such a startling contrast in colour means only one thing: even down here, the minerals falling out from the distant vent field are having a profound impact. The orange colour is the result of iron. Spewed from the hydrothermal waters at over 400°C, the iron oxidises rapidly and falls as rust onto the seabed below. The accumulations here speak of thousands of years of fall-out.

Up slope, the seafloor shows signs of past catastrophes. Sink holes appear where earthquakes have shifted the rocks below and the rusty sediment has sunk to fill the resulting holes. A little further up the slope we are met by huge blocks of sulfide perched precariously on top of each other, teetering on the brink of the abyss. Some are as large as a bus, massive blocky lumps, with rusty scree in between, from which shimmering water seeps.

The colours here are amongst the most amazing sights: oranges and reds from the abundant iron, but also peacock hues of green, blue and purple: sure signs that copper is also in abundance. In places, green ‘stalagmites’ cling precariously to the rocky overhangs. Formed from a copper mineral called ‘atacamite’, here the copper is literally leaking out of the rock. This is an amazing sight to us as it confirms one of the hypotheses that bought us here: that the hydrothermal minerals at these depths and high temperatures will be rich in copper. Back on the ship, these rocks are indeed like peacocks: their vibrant colours attract everyone’s attentions and, for the first time, compete on an even footing with the biology for being the most photogenic.

The science party relaxing at sunset on deck after completion of dives.

Sunday, 24 February 2013

16 - This is only the beginning…

Will, Diva and Leigh in relaxed mode!
Team Chemistry have finished sampling and are wrapping up the analyses in the shipboard laboratories. We have stunk the ship out with hydrogen sulphide collected in the water samplers used by Valerie and Alain. We have measured huge amounts of this smelly gas in the hot, metal-rich vent fluids, along with other gases such as methane. We have traced this methane up through into the ocean, transported with the buoyant plume of material gushing from the vents. We have filtered over a tonne of sea water to extract the particles of different sizes to understand how the metals are dispersed in the ocean. We have probed the seafloor to measure temperature and collected mud to extract the fluids that ooze through the edges of the sulphide mounds. This is just the start of our work to understand the impact of these deepest vents on the ocean.

Detailed analysis of samples back at the National Oceanography Centre and the Geosciences Environment Toulouse laboratory will enable us to relate the chemistry in the local vent environment to discoveries made by the geology and biology team on the distribution of different rock types and organisms across the Beebe and Von Damm vent fields. This allows us to see how different species survive and tolerate different chemical environments. The micro-organisms that survive in these harsh, toxic conditions are an example of how life can survive in the most inhospitable places and may be our best model to search for life in other parts of our solar system.

On this expedition, biologists, geologists and chemists have collaborated to generate new views of the deepest known vents on the planet.

Team Chemistry: Alain Castillo, Valerie Chavagnac, Jeff Hawkes, Will Homoky, Aly Lough and Rachel Mills

Rachel on deck

Friday, 22 February 2013

15 - Vent energy and chocolate cake

We’ve just had a few birthdays on board, meaning great quantities of delicious chocolate cake for everyone. We’ve also been sampling the fantastic Beebe Vent site fluids, and so it seems a good opportunity to make some food comparisons.

The vents are furiously spewing out an estimated 300 kg of water every second, and that water contains about 12 millimoles (mM) of hydrogen sulfide, the main food for the bacteria which feed the shrimp. We’ll say 12 mM is about 1.25 Calories (kcal; after great calculations by McCollom and Shock in 1997).

Our chocolate cake, which is ginormous, is probably at least 15000 kcal – so a little maths tells us that our vents are serving up about a slice of cake every second – and more than 2,000 delicious chocolate cakes each day. Plenty of food for bacteria – if only they can get to the fluids – which (unfortunately for them) are more than 400°C. It’s probably safer for them to stay in the diffuse areas, which have less hydrogen sulfide, but much more comfortable temperatures around 50°C. Funnily enough, this is where we find the majority of the shrimp – which carry the bacteria in their gills and other convenient parts of their bodies. Personally, I prefer chocolate cake to rotten-egg smelling hydrogen sulfide – but each to their own!

By Jeff Hawkes

Jeff taking a sample from the CTD carousel to analyse methane – another great food source for bacteria

Wednesday, 20 February 2013

14 - Geo team at the Beebe Hydrothermal Vent Field

Beebe black smoker image from previous HYBIS expedition
Looking over the side of the ship into the deep blue of the Caribbean Sea, it is hard to believe that directly below us, almost 5 km (3 miles) down, lies the Beebe Hydrothermal Vent Field, the deepest of its kind yet discovered, and by a team from the National Oceanography Centre. The site is named after William Beebe, the first ecologist to observe deep-sea animals in their natural habitat. Today, we will be diving at the site for the geo team’s first sampling on JC82 with the Isis  ROV.

The extraordinarily high pressure (of 500 x atmospheres) at the Beebe site, situated at nearly double the normal depth of most known hydrothermal systems, is important due to the physical changes that seawater undergoes at extremely high pressures and temperatures. Instead of being a liquid or vapour, the vent fluid becomes supercritical. These supercritical fluids are very reactive, dissolve metals at depth in the Earth’s crust, and transport them to the seafloor where they form spectacular hydrothermal vents and mineral deposits.

The Beebe site is also fascinating because it contains a history of hydrothermal activity represented by a series of older mounds. Sampling them will give us an idea of how the deposit has changed through time. The mineral deposits oxidise (like rusting) to a bright red colour, a process that greatly increases the concentration of valuable metals: a process known as ‘supergene enrichment’.

We are studying the Beebe site because it is a natural laboratory in which to study the effects of temperature and pressure on the composition of hydrothermal mineral deposits. Studying modern day hydrothermal systems like the Beebe Field allows us better to understand the formation of land-based ore deposits from which humankind gets all its essential metals.

By Matt Hodgkinson

Verity teaches Matt a lesson

Tuesday, 19 February 2013

13 - Dinner in the Cayman Deep

The majority of the deep sea is very food poor. The main source of sustenance that reaches the deep seafloor arrives in the form of dead plankton from the sea surface. Occasionally however, larger packages of food drift down into the abyss…

These packages are termed organic falls and can be anything from a school of jellyfish to a coconut tree. The two most studied types are wood (wood falls) and the carcasses of whales (whale falls, see picture below). Because of the scarcity of food, when organic falls reach the seafloor, they prompt a feeding bonanza. Deep-sea creatures gather from hundreds of metres away to gorge on the new food source. Organic falls are not only extremely important in fulfilling the nutritional needs of many deep-sea species but they also provide shelter and substratum for many animals.

What we would have liked to find! A whale skeleton in the enrichment-opportunist stage off California. Note the yellow and white bacterial mats covering the vertebrae of the skeleton. A rattail fish can be seen in the foreground. Photo courtesy of Craig Smith.
As scientists visit the deep sea so infrequently, the chances of us stumbling across an organic fall are very low. There is no sure way of finding these bonanzas of life apart from driving straight over them with an underwater vehicle!

We will leave down colonisation experiments including bone, wood, and different types of surfaces, which can be compared with identical experiments around the world. This will allow us to observe what larvae settle on these substrates in the Cayman deep sea and whether they are specialised to do this or just opportunistic. Our experiments will be collected from the seafloor by our Japanese colleagues in July with their Human-Operated-Vehicle, Shinkai 6500, to provide those answers.

So why is this important you might ask? Organic falls are some of the more poorly-studied environments in the deep sea. In previous deployments, many of the species found using and colonising organic falls were new to science. Experiments like these have never been done in the Cayman Trench and should give us the chance to document the biodiversity in this part of the deep sea.

Many of these species and families also overlap with those at other chemosynthetic ecosystems like hydrothermal vents and cold seeps. It is thought that organic falls act as stepping stones for deep-sea chemosynthetic fauna dispersing between vents and seeps and vice versa because of the similarities between the habitats. Our deployments will enable us to look at the dispersal of fauna between these isolated deep-sea environments and also perhaps provide us with insight into how these fauna are able to find and settle on these packages in such a vast expanse of ocean. We should also be able to put the fauna observed into an evolutionary context helping us to understand better how they fit into the tree of life and also perhaps how life originated, as many scientists believe, in the deep sea at chemosynthetic ecosystems.

By Diva Amon

Monday, 18 February 2013

12 - The devil is in the detail - trace metal sampling and contamination

A lot of people especially such as those working in the pharmaceutical industry or hospitals, as well as people in their own homes like to keep things clean to avoid different kinds of contamination. In most cases a contamination problem can be cleaned up. For the trace metal samples that the chemistry team are collecting during this research cruise this is not the case and there are numerous potential contaminant sources that need to be avoided otherwise all the hard work and money that went into preparing for this cruise to get these samples could be wasted.

High concentrations of trace metals in the environment can be deadly to life but most life cannot thrive without small quantities of elements such as iron and zinc. This is why we study the chemistry of these metals in the ocean.

Iron is an essential nutrient for phytoplankton growth in the ocean. Phytoplankton are at the base of the food chain in ocean ecosystems but also photosynthesise and use up carbon dioxide in the ocean so the amount that these organisms can grow has important implications for the linked ocean-atmosphere system. Knowing how iron is supplied to the oceans and how this has changed in the past will help us to make better predictions about how our environment may change in the future.

Iron is only present in extremely small concentrations in the ocean due to its low solubility in oxic seawater. This means that in some regions of the ocean the lack of iron limits phytoplankton growth. In order to understand why some regions of the ocean are iron-limited, the potential sources of iron need to be sampled to examine how this element behaves in the environment.

The rear view of the ROV with
the niskin bottles mounted on the
port side. We use these to sample
water close to the vents.
One potential source of iron to the oceans is hydrothermal venting. Vents emit hot metal rich fluids to the ocean which mix with and become diluted by seawater to form a plume. As this mixing occurs, iron in the vent fluid forms iron oxide and sulphide minerals and the larger mineral particles fall to the ocean floor. During this process some of the iron forms smaller nano scale minerals or can become associated with organic matter, and it is these smaller particles that can be transported away from the vent by currents providing a source of iron to the ocean.

Due to the low concentrations of iron we are dealing with, samples are very easily contaminated. Certain precautions have to be taken to make sure we are measuring the actual concentration of iron in the water that was sampled.

The first step to prevent contamination of any samples begins weeks before any research cruise starts. The plastic bottles used to store samples may look clean and new, but they can contain particles which may spoil samples, and to remove absolutely everything the bottles need to be washed in baths of acid for weeks. Washing hundreds of plastic bottles in acid was my very first task upon starting my PhD last October.

The second of these precautions is the titanium frame the 10L niskin bottles are mounted on. A stainless steel frame would be the obvious choice when designing this type of equipment, however this would introduce the possibility for sample contamination.

Aly sampling the CTD
The RRS James Cook  has a clean lab on board and any processing of samples to be analysed for trace metals has to be done in this lab. As iron can be present as different particles of different sizes down to the nano-scale, sample processing involves taking several sub-samples from the niskin bottles and filtering those samples through different types of filters in different ways. I spend most of my time in the clean lab trying to keep track of all this but also trying to do it as quickly as possible as the longer samples are left in the niskin bottles the more likely that the samples chemistry will change as more particles may form in the niskin bottles over time. So not only am I trying to prevent my samples from outside sources of contamination but I'm also trying to minimise natural processes occuring in the samples that change their original composition. Unfortunately the clean lab is also up one deck, so the heavy 10L niskin bottles have to carted up and down the stairs before the sample can be removed.

Left to right: filtering from niskin bottles under pressure from nitrogen line., vacuum pump filtering, pre-rinsing of 0.02┬Ám filters for in-line filtering
I spend the vast majority of my time on the ship in the clean lab, which can be a bit strange at first as the lab is constantly moving around with the ship, there are no windows and the environment inside the lab is very different to that outside. So it can be a surprising but nice shock after hours of sample processing in the cold dry clean lab to come back outside into the real world and remember you’re in the middle of the Caribbean Sea!

By A.J. Mackenzie Lough

Sunday, 17 February 2013

11 - The Graduate School at Sea

Aboard the James Cook  we have 6 current students (Verity, Matt, Diva, Jeff, Aly and Leigh) and 4 graduates (Will, Alex, Adrian and our principal scientist Jon Copley) from our Graduate School of the National Oceanography Centre Southampton. NERC funds these researchers, who make up nearly half of the science contingent aboard. They are studying the different core disciplines of our subject (geology, chemistry and biology) in this exciting interdisciplinary environment.

Matt and Bram inspect the rocks
Shipboard fieldwork is an integral part of the PhD research and on-the-job training for most of our graduate students. Our PhD students have the opportunity to go to sea, either directly as part of their PhD research or to broaden their skills and experiences. Onboard, they are immersed straight into the work patterns of the ship. This involves standing a watch, planning dives, overseeing the logistics of sample collection, learning how to acquire data and quality control complicated and large data sets before lodging them in the data repository and locating them in our GIS system, working in a team under very different and sometimes harsh conditions. They experience the immense satisfaction of discovering new and unexplored areas of the ocean and communicating this excitement to the world via social media and, of course, their research talks and publications. These are the skills employers and funders of our PhD graduates tell us they want; and our graduates get great jobs all over the world.

Seagoing friendships and experiences last a long time whatever career trajectory is chosen; we will all go home changed and with a refreshed view of the world.

By Rachel Mills

Will setting up one of the ROV baskets for a dive

Saturday, 16 February 2013

10 - It’s Geological Mapping – Only different!

Geological mapping of the sea floor using the ROV is an incredible experience. To be able to drive around investigating geological locations, with almost as much freedom as a field geologist on land is pretty special. Indeed, we can begin to construct a geological map just as you would in the field, although because we don't get to hammer or put our hand lens to the rock , the blackened and stained rocks we see through the high resolution cameras sometimes turn out to be not quite as expected when the ROV returns to the surface with samples! But this is the other great thing about using the ROV, which is its capacity to return to the surface with a substantial geological payload. These ‘hand-picked’ samples can be split, hammered and sawn open, and the fresh interiors revealed allowing us to “ground truth” our region of interest.

Following two dives of 24 hour duration the Geoteam has been able to dramatically revise and enhance our understanding of the geology underpinning the Von Damm hydrothermal vent system developed on the flank of the Mt Dent ocean core complex. Oceanic core complexes are the result of tectonic processes that expose the lower crust and even the upper mantle. These rocks are quite different from the volcanic rocks that are usually at spreading ridges; one of the hypotheses we are testing is that these unusual rocks influence the type of hydrothermal mineralisation.

The ROV sea floor operations and sampling has enabled us to gain a clearer understanding of the host rocks and their geographical extent. This has allowed a more detailed picture of the geological processes controlling the location and formation of past and present vent systems in the area. This has revealed a history and extent of past venting across the Von Damm site that has been quite a surprise.

The discovery and study of an active hydrothermal system developed on an oceanic core complex represents something of a first, and we are really looking forward to further advancing our understanding of these unique geological systems.

By Steve Roberts

Steve and Alex examine a rock sample recovered from the ocean floor

Friday, 15 February 2013

9 - Confessions of a Benthic Mercenary – It’s all about connectivity

Modern deep-sea science is built on broad international collaborations. We share resources, expertise, and ship time. These exchanges allow scientists from around the world to benefit from a global research fleet that includes dedicated oceanographic platforms like the RRS James Cook  or the R/V Atlantis  as well as novel vessels-of-opportunity that could include Norwegian container ships, North Carolina ferries, or Papua New Guinea tug boats. There are small differences between the operation of vessels from different nations - new acronyms, different power supplies, and an enduring disagreement regarding what constitutes a proper biscuit (ask a North Carolinian to take you to Bojangles sometime) - but the rhythm of a ship at sea is dictated, above all else, by the ocean.

The international and interconnected network of deep-sea scientists is how I now find myself, as an American, sailing aboard a British ship, in a role that could best be described as a Benthic Mercenary. Just as the international marine scientific community is connected by a shared passion for ocean exploration, deep-sea communities are connected by evolutionary heritage, ecologic dependence, and dispersal potential. Connectivity is the personal mission of this benthic mercenary. My role aboard the James Cook  is to help identify distinct populations at the Von Damm and Beebe vent fields and investigate how these populations are connected to each other.

A sensor probe delicately measures the temperature of a vent
as the curious local population looks on
Are the shrimp at Beebe from the same population as those at Von Damm? Do different snail aggregations at Von Damm represent different cohorts? To what extent do these populations vary from generation to generation?

To answer these questions, I use a suite of genetic tools to investigate the underlying processes that shape population structure. By determining how frequently certain mutations appear in groups of organisms and comparing how those mutations spread within different groups, I can determine what constitutes a distinct population, how those populations are connected, how often migration happens between populations, and in what direction that migration occurs. I can also estimate the effective size (a measurement of the smallest a population could be to support the level of observed genetic diversity) of each population.

One form of connectivity - the collaboration of deep-sea scientists throughout the world - provides the opportunity to explore another form of connectivity - the population structure of deep-sea hydrothermal vent species at the Mid-Cayman Spreading Center. Yet another form of connectivity - the willingness of cruise participants to share this adventure with the world—allows you to follow along with us at this blog and on twitter, using the #DeepestVents hashtag (

Thursday, 14 February 2013

8 - Mud - a love story

Feb 14th 2013

Isis measuring the temperature of sediment around one of the areas of diffuse flow on the seafloor. The sediment at 2300 metres depth is riddled with small depressions, some of which shimmer with warm water. We sample the sediment and characterise this diffuse flow.
If mud could talk, it would tell a tale of devotion to the ocean.

The heart can think of no devotion, 
Greater than being shore to ocean; 
Holding the curve of one position, 
Counting an endless repetition.

Robert Frost's iconic love poem identifies with the seashore, a parallel that extends literally deeper than Frost intended; Sediment and seawater sit side by side, far beyond the shoreline, where sinking material expelled from the waters above rests enduringly on the seabed. Since it is St. Valentine’s Day, I'm going to tell you why this material and its relationship to the waters above it fascinate me.

Natural organic and mineral waste collecting on the seafloor is chemically altered over time; Microbes living near the surface of the seafloor feed off the rain of organic matter and exhaust their available oxygen, such that life underground has to switch to alterative metabolites, like nitrate and metals, to survive. In doing so, they accelerate the making and breaking of chemical bonds in the sediments, dissolving some minerals and precipitating others - a process with potential to return dissolved constituents back to the ocean, and nourish its water for life thriving in the sunlight far above.

The sediment corer (centre) on the Isis  rack ready for deployment
During our "Geo" dives with Isis, we're collecting a series of sediment cores (intact sections of the ocean floor) from which we are sucking the fluids dispersed between the sediment grains, and analyzing their chemical composition down through the seafloor. Using this approach, we will be able to measure gradients between the dissolved constituents of seawater and the sediments to understand the direction and magnitude of chemical exchanges between them. We will compare samples from different locations around the Von Damm and Beebe Vent Fields to learn how these deep hydrothermal vents impact the give and take of chemical constituents between sediments and the oceans.

By Will Homoky

Sample processing in the ship's controlled-temperature laboratory. We filter the sediment fluids in a cold and oxygen-depleted environment, much like they are accustomed to beneath the sediment surface.

Tuesday, 12 February 2013

7 - Go Team Biology!

The first biology dive took place over the weekend. It was a fantastic opportunity for Team Biology to observe the fauna of the Von Damm Vent Field and collect samples for future analyses back on dry land. We used this opportunity to conduct video surveys of the vent field to reveal the spatial distribution of the animals, and we hope that in the future we can determine if the patterns we observe now change over time.

We also collected a variety of animals from the vent field. These included fish, snails and shrimp. Although it was wonderful to watch the animals in situ the best bit of the dive was when the ROV returned to the ship and we got to see the animals for real.

Snails, fish and shrimp at Von Damm vent
The deep Cayman vent fields are really exciting for the biologists onboard because of their depth and isolation. Most of the species we’ve collected so far are known only from these vents, and we have already found and described several new species.

On future dives we aim to collect and examine more species to gain a better understanding of the colonies of creatures living here and to compare them with those living at different vents around the world. This will really help us to comprehend the dispersal and evolution of species in the deep sea. We’ll also be comparing what lives at the Von Damm and Beebe Vent Fields, seeing whether animals disperse between them, and investigating their life cycles in the deep ocean.

By Verity Nye.

Monday, 11 February 2013

6 - First Geo-dive mission

The first geo-dive went ahead from yesterday into today and the mission was simple. Collect as many different types of rock as possible! We want to really understand the geology of the area and in order to do that we need rocks. But there is a problem - under the sea all rocks look the same. They are dark, blocky looking, often covered in biology and sediment, and often too large to pick up with the robotic claws. However, occasionally luck is on our side and something unusual catches our eyes.

Mysterious purple rock near a vent
This is a picture of a mysterious purple rock taken near hydrothermal venting. By chance, a fresh face has been revealed and we can see an unusual veiny purple interior. Under the water we can only guess at what this is, and often our guesses turn out to be badly wrong, but once we get this sample up on deck we can have a proper look. Other rocks we have seen so far have varied greatly in their composition. We've collected peridoties, which originate in the mantle, gabbro, which forms the lower part of oceanic crust, and basalt, which forms the upper part of the oceanic crust. Together, these rocks represent a section through the crust and will help us understand the setting and chemistry of the hydrothermal venting.

By Alex Webber.

The action in the ROV van during the Isis  Geo-dive 199

5 - Nature Live event on at 14.30 today, 11 Feb!

The 11 Feb event is now over - please return to this post for updates, or look out on the 28 Feb when the Natural History Museum hope to make the next live link-up.

The scientists on this expedition will be broadcasting live to the Natural History Museum Attenborough Studio today at 14.30.

From the NHM Nature Plus web page:

Life in the depths of the Caribbean - 14.30 GMT, Monday 11 February

At 14.30 on Monday 11 February, watch an exciting discussion event about hydrothermal vents and join us as we live link to the RRS James Cook  in the Caribbean.

We'll be talking to mineralogist Richard Herrington in the studio about the creatures that survive around hydrothermal vents, and whether all life on Earth could stem from the bacteria living at the bottom of our oceans.

Go to:

Sunday, 10 February 2013

4 - Shrimp at the Von Damm

These abundant shrimp from the Von Damm vent are Rimicaris hybisae. They belong to the genus Rimicaris  because they are related to shrimp found at vents in the Atlantic and Indian Oceans, and Verity Nye named this new species hybisae  in honour of the HyBIS vehicle with which we saw and sampled the vents for the first time during Voyage 44 of the RRS James Cook.

Rimicaris hybisae shrimp

Saturday, 9 February 2013

3 - Chemistry Team at Von Damm

Water sampling bottles are
lowered over the side of the ship.
The Chemistry Team got up early for a midnight deployment of the water sampling system. They use this to take up to 24 individual samples of water from the deep ocean and can filter up to a tonne of seawater through pumps mounted on the frame. All this water only yields a few grams of solid which is analysed later back in Southampton. Jeff Hawkes is leading the watch; he has spent the last three years using chemical sniffers to find hydrothermal plumes in different ocean environments.

The Von Damm plume is exciting and unusual because the fluid is rich in reduced gases but poor in metal-rich particles. Usually, hot hydrothermal vents emit particle-rich fluid (hence their name ‘black smokers’) but here the hot fluids are clear. Jeff directs delicate manoeuvres of the 5800 tonne ship so the water bottles, dangling two kilometres below us, stay in the plume while he snaps the bottle closed to capture the water.

These samples are key to our understanding of the dispersion and fate of the hydrothermal effluent in the deep ocean. Jeff and the team will be working on the samples for the next few years; analyzing a suite of elements and isotopes. These data will ultimately help us to understand how hydrothermal activity affects the highly sensitive ocean-climate system because these metals may fertilise life in the upper ocean.

By Rachel Mills

Aly Lough sets up the water filtration rig in the clean van. Aly wears blue nitrile gloves to keep the rig clean, the van is positively pressurized to stop airbourne contaminants entering the lab.

Friday, 8 February 2013

2 - High-resolution sonar mapping

Where are we? This is not an easy question to answer deep under water. On the surface we use GPS and maritime charts to navigate. But underwater we need to make our own maps. Our first ROV mission, therefore, is high-resolution sonar mapping of the VDVF. We already have sonar maps made from the ship’s echo-sounders, made when we discovered the vents back in 2010. These maps cover the entire 110 kilometres length of the Mid-Cayman Spreading Centre and adjacent parts of the Cayman Trough.

With a resolution of 50 square metres, these maps provide a geological context for the vent fields. However, for our sampling of both the rocks and animals, we need much higher resolution maps. Again, we already have high-resolution maps of the vent fields, acquired from our Autonomous Underwater Vehicle (AUV), Autosub6000. These have a resolution of a few metres and reveal faults, fissures and the texture of the mound. But to get close enough to image the vent structures requires sonar mapping from the ROV. Using our new 300kHz RESON multi-beam echo sounder, we will get a map with centimetre resolution. We will have to hug the seafloor, at an altitude of 20 metres. At this altitude, we will be careful to avoid the chimneys and their hot vent fluids.

Our new multibeam echosounder will map both the shape of the seafloor and make sound images – like black and white photographs – of the different sediments and rocks. We hope the new maps will allow us to better understand how these hydrothermal mounds are formed and guide the following sampling and visual surveys. The mission will cover an area of half a square kilometre with a line spacing of 50 metres and take 36 hours.

By Bramley Murton

A high-resolution image of the Von Damm Vent Field and its surrounding seafloor. The vent field forms a 75 metre diameter cone-shaped hill in the centre of the image. At this resolution we can see the mound shaped mineral deposits. The new map will show the individual chimneys.

Wednesday, 6 February 2013

1 - The voyage begins

No post for the first entry, but we had the collected tweets leading up to the beginning of the expedition. Now you can continue following the ongoing tweets updated regularly on our media page.