It’s the last day of the cruise!  I can’t believe it!  The time on board has flown by and – as we throw ourselves into packing and report writing – it’s also important to take a few moments to reflect on the last seven weeks.  It’s been a fantastic couple of months, and we’ve had a lot of successes and a lot of fun at the same time, thanks to a great science and technical team, and all the ship’s crew.

In total, we collected literally thousands of water samples, biology samples, fossil corals, and sediments!  And terabytes of video and mapping data! Phew!  I think some world records must have been broken there somewhere…

Thanks for reading our blogs!  We hope you enjoyed them!

Kate

I’ve had a few requests (mostly from other sponge enthusiasts!) for an update after my blog earlier in the cruise.  I can confirm that we’ve been successful in sampling lots of types of sponge from the different locations, all the way from tiny blobs growing on corals, all the way up to giants shaped like ear and fans!  Here are a couple of photos from Isis showing some of the different sponges we found at our last sample site, Vayda Seamount.

Fan-shaped Sponge. Photo taken by: ROV ISIS.

Ear-shaped sponge. Photo by: ROV ISIS.

Blog Written By: Kate Hendry  

We have just left Vayda Seamount and are now sampling on another seamount in the Researchers’ Seamount Chain.  The wonderful sampling that occurred at Vayda, inspired Mrs. Robinson to write an amazing poem:

The Vayda Seamount.

Four thousand metres to the sediment

picked out by the ROV’s beam against

the cliff side, a curious sponge, then space

And more space where the waters press

In prehistoric layers, compressed and chill

incomprehensibly down and down until

the valley floor, the deepest part

the underwater mountain range’s foot.

Paleologically quaternary?

Aeons and aeons, and a wary

Unknown sort of fish

Creeps by and slides, slowish

Past the camera’s eye,

while on the surface the scientists try

To follow on their multi-screens

An age of ages never seen .

Sarah Robinson, November 2013

This is the second part of the questions asked by school children from London.

2)   Corals and Climate

• What kinds of coral are there?

This question could take a long time to answer so I will try my best to keep it short! The word coral actually covers a few different groups of creatures. They are all part of one large group (phylum) called Cnidaria (pronounced ny-dairy-a), which also includes jellyfish. Then you have the hard corals and soft corals (including big sea fans) which are the most common types and make up coral reefs. You can find them living alone or in big colonies. These are a particular kind of Cnidarian called Anthozoa. Other types of Anthozoan include gold corals, black corals, bamboo corals and sea anemones. They can live in warm or cold water and from the very surface of the ocean to some of the deepest places. You can even find them around the south coast of England! On this cruise we are looking mainly at hard corals because we can analyse their hard skeletons to work out what the ocean was like in the past. There are other types of coral (fire coral and lace coral) that belong to a kind of Cnidaria called Hydrozoa. Some of these also have hard skeletons that we can analyse when we get home.

Pete Spooner

• I would like to know how many corals you predict to find.

We have already found a huge amount. I was surprised at how many there can be in the deep-sea. We are aiming for areas where we think they might live (like seamounts) in the hope that this will mean we will find more. However, we have already seen big differences between the first two seamounts we have visited, with different species and amounts of creatures. We are some of the first to thoroughly explore these areas so it is difficult to predict exactly what we will find, but that is part of the fun!

Pete Spooner

• How many corals have you seen so far?

Thousands! Corals are really prolific here. They like the habitats that you can find on a seamount (underwater mountain), because there are fast currents to provide food and sweep away sand that would otherwise cover up the delicate corals. Sometimes the currents are so strong that they can sweep the ROV along! The ones that live in colonies usually live on rock faces or big boulders, and the ones that live on their own seem to like to grow where the sea floor is a bit sandy. We have seen lots of both types.

Pete Spooner

• What have you found out about coral so far?

It has been really interesting to see where the corals live! When we are watching the screens in the ROV control room we can get a good idea about where the corals like to live best. For example, the big fan-shaped ones like to live on big rocks or cliffs, but some of the small solitary corals live in the sand. We have also seen that some species of coral like to live only at certain depths, but we haven’t worked out why yet!

Most of our investigations will happen when we get back home though, because we can’t bring entire labs on the ship with us. I will be testing the chemistry of the coral skeletons; in particular how much magnesium is present compared to lithium (two kinds of metal that can be found in small amounts in the skeletons). We think that this is related to the temperature of the water that the skeleton grew in. If it is, we will be able to work out how warm the deep-sea was thousands of years ago by measuring the skeletons of fossil corals. This could help us understand how climate has changed in the past, as well as in the future.

Pete Spooner

• Have you been to the Seychelles? If you haven’t you better go because Seychelles has the 2^nd largest amount of coral in the world.

Neat! I haven’t been to the Seychelles but I have been to the Great Barrier Reef in Australia which also has a lot of coral. In both the Seychelles and the Great Barrier Reef most of the corals you see while snorkelling are shallow water corals that only live in warm water. On this cruise we’re actually looking at deep water corals. Otherwise we would have loved to go to the Seychelles!

Allison Jacobel

• In your studies have you found out what happens to the corals due to climate change?

Most studies so far have focussed on how climate change may affect shallow water corals. Climate change is likely to affect these corals in two main ways:

1)     Ocean warming: Corals that live in warm water have algae that live inside them that can photosynthesize like plants. These help to give the coral energy. If the water gets too warm these algae don’t like it and leave the coral. This is known as coral bleaching. If it happens too much the algae don’t return to the coral and it will die.

However, the deep sea corals that we are studying don’t have these algae, because there is no light in the deep sea for them to use for photosynthesis. Also, the temperature of the deep sea will get warmer much more slowly than the surface water, because it takes a long time for the heat to get down into deep water. So it is unclear how much effect ocean warming will have on deep-water corals.

2)     Ocean acidification: This happens when we burn fossil fuels and add carbon dioxide to the atmosphere, because carbon dioxide can dissolve in water, making the water more acidic (you can do this experiment yourself by blowing through a straw into water and measuring the change in pH). Coral skeletons are made of calcium carbonate, which dissolves in acid. Most people think that if the ocean becomes more acidic corals will find it harder to make their skeletons. However, this is likely to affect different species in different ways, so it is very difficult to predict what will happen to whole coral ecosystems, especially for the deep-water ones because we know much less about them.

From studying deep sea fossil corals from around Antarctica we know that as the Earth got warmer after the last Ice Age and the oceans changed, certain species of coral completely changed where they lived. We hope to do the same studies for the corals we find in this cruise to see what happened to the corals in the Atlantic Ocean as well.

Pete Spooner

• What kind of affect does the coral have on the sea to change the climate?

This is a very interesting question! Mostly we think about the effect of climate change on corals but you’re right that corals can affect the climate too. The chemistry involved can be quite complex and would take a long time to describe here, but the basic idea is that when corals grow they use up some elements carried by the seawater to make their hard skeletons. This slightly changes the chemistry of the seawater, which can affect how much carbon dioxide the seawater contains. Because the concentrations of carbon dioxide in the ocean and in the atmosphere are linked, this means that coral growth or death can affect the level of carbon dioxide in the atmosphere. Carbon dioxide is an important greenhouse gas so changing how much there is in the atmosphere can change the climate.

One of the best known scientific hypotheses about this is called ‘The Coral Reef Hypothesis’. During the last Ice Age, sea level was about 120m lower than today, because lots of water was stored in ice sheets on land rather than in the ocean. This meant that there was much less warm, shallow ocean floor area for coral reefs to grow. Because there were fewer corals, the chemistry of the ocean may have changed allowing more atmospheric carbon dioxide to be absorbed by the ocean. This may have helped to cause the low atmospheric carbon dioxide levels and cold temperatures of the Ice Age. It is known as a feedback process which made cold ice age temperatures even colder (see below).

Coral reef hypothesis feedback process:

Colder temperatures -> Ice sheets grow -> Sea level falls -> Less area for coral reef -> Fewer corals -> Less carbon dioxide in atmosphere -> Even colder temperatures.

However, we don’t know how much effect changing sea level would have had on deep sea coral, or how deep sea coral populations changed during the Ice Age. This is something we can start to discover from the fossil corals we are collecting on this cruise.

Pete Spooner

• How long did you practice for?

 You could say that being at sea is unlike any other experience and that none of us practiced for the cruise! However, all of us have been going to school for a very long time and ‘practicing’ science every day.

Allison Jacobel

A few weeks ago, a class from a school in London got together to think up some questions to ask the scientists on board. Topics range from how a polystyrene cup shrinks when sent to the bottom of the ocean to how corals can affect the climate. Allison and I have done our best to give these some answers which you can find below.

1)   Pressure and Polystyrene

• How deep are you going to make the cup go and how long are you going to keep the cup under water? (p.s. can you shout my name out when you drop my cup?)

So far the deepest we’ve sent cups down is 5 thousand meters. Those cups went down when we lowered an instrument called a CTD which we use to measure the properties of sea water like temperature and salt and nutrient content. The CTD also takes water samples from various depths.  Because we want to be very careful with our equipment we lower everything to the bottom at a gradual pace instead of just dropping it straight down. Our last CTD went down to the bottom at 4am and reached the surface four hours later at 8am.

Ps. The speed of sound in water is about 1400 m/s which is much faster (about 15x) than the speed of sound in air.  Unfortunately, sounds made in the air largely bounce off the surface of the water so your cup probably didn’t hear us.

Allison Jacobel

• How does the polystyrene cup get crushed and how do you pick up the cups from the bottom of the sea?

We send the cups down very deep; some of them have been more than four kilometres to the bottom of the ocean. The pressure created by all that water is very high. Imagine sitting on the sea bed with 5km of water on your head! You may have experienced the pressure caused by the weight of water if you’ve ever dived to the bottom of a deep swimming pool and felt an uncomfortable feeling in your nose and ears.  That’s because the pressure is squeezing the air behind your eardrums and your nose. If you can feel the effects of pressure at the bottom of a swimming pool imagine how much greater the effect is at the bottom of the ocean! As you can imagine that’s not a very good environment for people, so we send the cups down in nets attached to the wires used to lower scientific equipment.  The air in the cups all gets squeezed out by the pressure of the water and so the cups get smaller. When we bring the equipment back up to the ship the cups come up too.

Allison Jacobel and Pete Spooner.

• How long does it take for water pressure to crush something big?

No matter how big the object the pressure at the bottom of the ocean will crush it instantly (assuming it can be crushed).  The ROV ISIS isn’t crushed because it’s intentionally made of materials that are pressure resistant.

Allison Jacobel

• Is the pressure of the ocean different in some areas and what is the different to the mass of the ocean and the weight of the pressure?

An excellent, thoughtful question. Yes, the pressure of the ocean is different in different areas. The pressure is dependent on the amount of water, the temperature of the water and the salinity (salt content) of that water. Mostly we think of depth as the primary control on pressure and say that the deeper the water at a given location the greater the pressure.  However, if you have a column of warm, fresh water and a column of cold, salty water of an equal height the column of cold salty water will have a greater pressure at its base because it is heavier! If you keep the temperature and salinity of the water constant (let’s say fresh water at ~4^oC), and if the column of water has an area of 1m², for every additional cubic meter of water you add to your column the pressure at the base of the column will increase by ~10,000 Pa!

Allison Jacobel

• Is the pressure in the Atlantic stronger than other seas and oceans?

From the answer to the previous question we know that the pressure of a column of water will vary with temperature and salinity.  On average the Atlantic Ocean is saltier and colder than the Pacific so if you were to take a package of water of 4000m from the Atlantic and one from the Pacific, you would expect the pressure at the bottom of the one from the Atlantic to be higher.

Allison Jacobel

Sometimes we find pieces of sea urchin amongst the fossil coral rubble. Most often we get spines or fragments of exoskeleton (its round ‘shell’), but we did find one large whole exoskeleton and recently some tiny whole ones as well. We’ve seen a few different species of sea urchin on the cruise. One of them has relatively big spines and is called a pencil urchin, and another is a bright white sphere and nicknamed a golf ball urchin, and there are tiny green pea urchins as well. You can see a video of Isis picking up a sea urchin on the cruise YouTube page (http://www.youtube.com/user/JC094TROPICS). Sea urchins (echinoids) are echinoderms, the phylum that starfish (asteroids), brittle stars (ophiuroids), sea cucumbers (holothurians) and sea lilies (crinoids) also belong to.

Small Pea Urchin Exoskeletons

Large Urchin Exoskeleton

Urchin Spines

Blog Written By: Stephanie Bates

Seven weeks is a long time at sea. However, I feel like it’s gone really very quickly! It’s amazing to think that we’ve got less than a couple of weeks left on our expedition. I asked a number of the science team about what they miss, and what they’re really pleased to have brought with them. There are some interesting answers [with my edits]… there seems to be some confusion over temperature control…

What did you bring that you haven’t used?

Seasickness pills – Marcus

Smart shoes – Kate

A bikini – Melanie

Rain trousers – Torben

[along a common theme…] Umbrella – Allison

A hairdryer – Vanessa

Ginger chews [not shoes] – Laura

Tattoo transfers – Michelle

“too many warm jumpers” [see below] – Veerle

Shorts – Lucy

Tea – Steph

Shampoo and books – Maricel

Movies – Hong Chin

Leather shoes – Paul [with you on that one, Paul]

[Jesse has used everything that she brought!]

What do you wish that you’d brought?

Flip flops – Marcus

More Berocca – Kate

A bath – Melanie

A paddling pool and a sunbed – Torben

Peanut butter  – Allison

An updated version of iTunes – Vanessa

Rhian – Laura

A giant Toblerone – Michelle

Nail varnish – Veerle

A rugby ball – Jesse

Another woolly sweater [talk to Veerle about that one…] – Lucy

More snacks – Maricel

Headphones and raingear [talk to Torben]- Kais

A little microphone and a double bed – Paul

A hammock – Steph

Slippers and hot sauce- Shannon

More socks – Hong Chin

What are you SO glad that you did bring?

A boiler suit – Marcus

A book of the unabridged Monty Python scripts – Kate

Flip flops – Torben [who, as it turns out, brought two pairs and should possibly should talk to Marcus]

A jumper [again, should probably talk with Lucy about that one] – Melanie

A yoga mat – Allison

A water bottle – Vanessa

An [awesome] coffee machine – Laura

A woolly hat – Michelle

A mug [it’s already seen a lot of tea, that mug…] – Veerle

A camera and warm clothes – Jesse

A thermal mug for tea – Lucy

A Kindle – Steph

A Tablet and a passport – Kais

200 glow bracelets and water pistols- Shannon

And Maricel was just pleased that Torben had brought his speakers…

Blog Composed by: Kate Hendry

Kate

I am of average height. I am well aware that I am dwarfed by many animals, like elephants and giraffes. In the oceans, organisms can even grow bigger than terrestrial animals as they are not limited by gravity like land critters; the water carries their body weight. As a result, whales are one of the biggest animals that ever lived on the Earth. Body size is an interesting phenomenon, as it varies with many other aspects of a species. For example, number of offspring in a lifetime, energy use per unit weight, oxygen consumption, abundance, etc. all relate to body size.

In the deep sea, most animals are small as food availability is limited in the deep sea. This is because even down here, most organisms depend on photosynthesis, the process of producing new organic material by using the sun’s energy. This material is produced by the phytoplankton in the upper water layers. However, dead organisms, excreted material and other debris will sink to the ocean floor and serve as a food source for the organisms living here. This flux will get smaller with depth; thus the deeper you go down the less food there is. Being small means you are more likely to find a meal that is big enough to sustain you and your species.

However, that does not mean that there cannot be giants here. These giants grow at a very slow pace, patiently waiting for food to come by. And they can live for hundreds of years, if not thousands! Bamboo coral is one of these giants, being able to grow several meters high. We had the luck and opportunity to find a very large one and bring it up. It barely fitted in the tool tray of ISIS, our Remotely Operated Vehicle. And when we finally got it in our hands, it towered even above the tallest of us! It was amazing, such an old creature dwarfing the whole team. And do not be deceived by the smiles and think that it was a nice thing to handle – it fights back with its tiny, but sharp, spines!

Blog Written By: Jesse van der Grient

We have visited two seamounts and successfully sampled for fossil and live corals, as well as a lot of seabed mud and water from different depths. It is great to have so many really valuable samples on board.

There is a little time, while we are relocating to our next sample site, to reflect on some of the amazing deep sea habitats that we have seen with the ISIS HD video (31^st October). You may have already taken at look at the fantastic array of marine life that is both easy (shark- 21^st October) and less easy to identify (pyrosome – 2^nd November). We have collected so many samples and recorded so much video, the time between sample locations is very important: we can check our catalogued samples and place them into boxes so that they can be sent to the correct scientists once we are back on land.

When we do not have any sampling gear in the water doesn’t mean that we are not seeing any wildlife though. In addition the the life we have found at depth, we have also seen flying fish (18^th October), squid and turtles. However not all species seen have been those living in the water. We have been a rest place for at least three types of birds and many butterflies and moths.  The birds have rested in the shade, where they have been provided with food and water, then set off again on their way. Tonight the ocean is the roughest it has been so far (but still not very bad), so provides a perfect opportunity for securing myself in the lab with a nice hot drink and my computer so that I can start to analyse the diversity of life that we have found.  I hope that you have all enjoyed the images from the deep as much as I have!

Blog Written and Photos taken by: Lucy Woodall

Moin moin Vema!

After a 4-day transit which included a small bonfire festivity we arrived just this morning at our next sampling location: the Vema transform fault. This transform fault displaces the Mid-Atlantic Ridge (MAR) axis by about 300 km (i.e. more than Ireland’s W-E extension). The MAR is a volcanic spreading axis in the Atlantic Ocean, separating the African and South American plates. The entire fracture zone extends over >2000km from east to west with a full spreading rate of about ~27 mm/yr, i.e. the two plates move apart with a “speed” of 27 mm/year. The geological evolution in time and space was accompanied by the formation of a spectacular submarine V-shaped transform valley. The southern wall of this valley is the result of the uplift of a single block of mantle material starting about 50 million years ago and currently erecting up to >4 km from bottom to top being one of the highest and longest ridges in the entire MAR system – and it may even have reached the sea surface in the past! The northern wall consists of exposed (oceanic) crust of 2-3 km thickness being slightly less spectacular compared to its southern counterpart.

Besides spectacular geology the Vema frature zone is also very interesting from an oceanographic point of view. It acts as a channel for deep and bottom water masses between the western and the eastern Atlantic basins allowing northwards flowing bottom water masses from Antarctica to pass the MAR and enter the deep East Atlantic Ocean.

Hence, during the next few days we will run the full range of equipment we have onboard the James Cook in order to collect (hopefully) loads of precious samples: starting off with a deep CTD profile this morning we aim to deploy the ROV and to raise some sediment cores in order to shed some light on this spectacular key deep-sea location in the equatorial Atlantic Ocean!

Blog Written by: Torben Struve