Go here and have a look at the best shrunken cups!

What is it? A foam cup, a polystyrene cup, a Frigolite cup, a Styrofoam cup … Or anything made of foam! They are designed, drawn, or/and signed (with waterproof pens) during a cruise.

Why? How ? This material is made of plastic and 95% of air.  When it dives into deepness,  the pressure exerted on the cup will shrink the material by diminishing the air space proportionally. At the surface, the atmospheric pressure is 1 bar. It increases of 1 bar every 10 meters. Therefore, at 10 meters, the pressure is 2 bars and at 30 meters, the pressure will be of 4 bars.  The air space in the cup is divided by 2 at 10 meters and by 4 at 30 meters! While reaching some depth, the pressure will be so intense, that the airspace could be considered as negligible and only the volume of the plastic material stays intact.

Finally, from about 10-15 cm tall cup, we obtain a ~4 cm tall cup without any air space.

It is always a great time on the cruise to relax at drawing on our cups. We all get exited  when they come back from depth, 1000 m, 3000 m, or even for the luckiest ones, going back from a trench at more than 5000 m! They were attached in a bag on any instrument/device going into water, such as the CTD rosette or the ROV (remote operated vehicle).

Some examples from scientists at the National Oceanography Centre!

David Price, PhD student, at the Whittard Canyon refers to the iconic Boaty McBoatFace:

Iain Stobbs, PhD student, from the TAG Hydrothermal Field on the Mid-Atlantic Ridge:

Dr Isobel Yeo, myself, and some colleagues on board the Celtic Explorer for the TOSCA expedition where we see before and after:

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From May 15^th to June 8^th, I was lucky enough to participate in my 10^th expedition at sea.  As part of the TOSCA Expedition composed of an international team of scientists, I boarded the RV Celtic Explorer in Galway, Ireland, and we left for the Charlie-Gibbs Fracture Zone, approximately 1,500 km away in the middle of the Norther Atlantic.  The main goal of the expedition was to understand the geology of the area, but I was really there to study the environmental conditions which affect the distribution of megabenthic species (organisms which live on the seafloor and are large enough to be captured in imagery from cameras).

A common concept in ecology is the idea of a species’ niche.  Very briefly, this represents the set of environmental conditions and resources which are needed for individual species to survive and reproduce.  Hence by looking at where species occur and do not occur, we can start to understand what kind on conditions are most suitable for each species.  For example, species attached to the seabed and which rely on food being delivered by currents (suspension- or filter- feeders such as cold-water corals or sponges), may prefer steep or elevated structures where currents may be slightly higher (Figure 1).  On the other hand, other species are deposit-feeders (such as sea cucumbers), and feed on food which ‘snowed’ down from the surface and accumulated at the surface of sediment.  These species will tend to occur in areas dominated by soft sediments (Figure 2).  Of course, it gets much more complicated than that and many other factors (e.g. temperature, salinity, pressure, orientation, type and frequency of food available, …) need to be taken into account to fully understand why species occur where they do.

Figure 1: Cold-water corals on small boulder on top of a ridge

Figure 2: Sea cucumber on soft sediment at ~2000m in depth

As part of my research, I am particularly interested in understanding the factors controlling the distribution of cold-water corals.  These are similar to tropical corals that can bee seen while snorkeling or scuba diving.  They are long-lived large colonies made up of many individual polyps, but instead of having symbiotic organisms that allow them to use the energy of the sun, cold-water coral polyps catch tiny food particles suspended in the water column, and as such, can occur in much deeper waters where there is no sunlight.  We often find many other species in close proximity to cold-water corals, and we believe that cold-water coral presence leads to higher biodiversity, possibly at it provides complex habitats for other species to utilize (e.g. protection for small fish or hard substrate for sea anemones to get higher up from the seafloor where more food might be available).  However, cold-water corals are at risk from activities such as trawling and potential impacts from climate change (e.g. ocean acidification).  The former removes large colonies which can take 100s of year to replace, while the latter is likely to affect the ability of corals to build their calcium carbonate skeleton.  Hence, my aim is to help understand where these species occur so we can minimize impacts and monitor responses to potential changes.

Katleen Robert

Fisheries and Marine Institute of Memorial University
St John’s, NL, Canada

Here are some pretty images from the seafloor during the TOSCA expedition (provided by the ROV Holland 1).

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Everything you always wanted to know – from A to Z about how to succeed a ROV (remotely operated vehicle) dive.

1)     Go to sea with a bunch of very talented ROV pilots: 6 is a minimum number (3 for each 12 hours shift).

2)      Set up the OFOP (ocean floor observation program) software on the computer to be able to record in real time any special features, biological or geological  (such as fish, scarp, boulder field, shimmering water, soft sediment, anemone garden, etc.).

A biologist, a geologist and a map wizard discuss locations (Katleen, Bramley and Oisin). © Adeline Dutrieux.

3)   Plan the dive according to your purpose and allowed time. Set up the planned track on the ROV monitors to help scientists and ROV pilots to follow it. Technically a dive could last forever. But ideally, a dive will last about 12 to 24h or until it had achieved its objectives.

4)      Start the dive. Watch the blue becoming darker and darker.

Start of a ROV dive. © Evi Nomikou.

5)    Two scientists join three ROV pilots in the ROV container, located on the back deck, close to the immersion platform of the ROV. Together they will watch the HD camera located on the front of the ROV and discuss the appropriate moves to make.

Isobel and Patrick (in the back) are in the ROV container, their eyes focused on the HD camera in front of them, the OFOP map and the planned track. © Maria Judge. All information we need in less than 2 meters square, and in front of our eyes: HD camera video, HD photography, positions of the ship and ROV with coordinates, time, and location on the geological map with the track line. © Adeline Dutrieux.

6)      One scientist is in charge of the camera joystick and capturing as many photographs as she/he can with a stills camera mounted on the ROV frame. Remember to zoom in close to the seafloor to allow animal species counting!

7)      The other scientist is in charge of recording and clicking as much as she/he can on the OFOP (ocean floor observation program) software along the track.

8)      Together identify locations for sampling and ask to stop the ROV for rock or biology sampling. Sometimes we cleaned the seabed of glass bottles.

Grabbing a green glass bottle, next to a squat lobster. Fortunately, we didn’t meet many of them.  © ROV Holland 1.

9)     See a crinoid, or a skate egg. Ask for “grabbing” or “sluuuuurping” the specimen (main biology goals during our mission). From the biology side, to get an idea of environmental conditions, we can look at the bathymetry (the shape of the seabed) and examine whether there are relationships between where species occur and different terrain characteristics (e.g. depth, slope, direction of slope, roughness of the terrain).

10)    On the geology side, look at the faults, scarps, fractures, change of sediment lithology, or boulders fields. Ask one of the ROV pilots to kindly sample some rocks at specified locations. He/She gently manipulates the arm and grabs with dexterity the rock. Sometimes that rock is bigger than expected – we call it “iceberg”!

11)    Decide which bucket or drawer compartment to drop the sample in. Very often, each compartment ends up with 2 to 5 samples. Remember to write down the sample location, the event number (sequence in which it’s collected), with their precise location and description so that we can identify them when they are brought on deck.

12)    Once in a while, when the terrain allows it, create a photo-mosaic. It consists of going from side to side on a steep scarp, and then moving up a level and repeating the process to obtain a full and very detailed surface of the scarp (like a close-up panorama).

13)    Every two hours, another buddy pair comes to take the lead. Fresh minds start over.

14)    A dive can continue as long as the weather stays fine. At the end of it, retrieve the ROV on deck.

A stalk yellow crinoid. © ROV Holland 1.

The arm gently detaches (at the top) the stalk yellow crinoid from the seafloor. © ROV Holland 1.

15)    On deck, once the ROV is secured by the technicians, start unloading the samples. It can be a puzzle with sometimes vague description (“black large rock”) and blurred pictures to identify which rock belongs to which event so be careful to provide better descriptions in the next dive. Similarly, collect the biological samples. Label everything!

Maria and Arne are unloading the biology and rock samples from the ROV on a night shift. © Maria Judge.

16)  Once all rocks have been identified to each event/sampling location, brush them from their saline and encrusted life cover.

Brushing rocks – they stink! © Evi Nomikou. 17)   Photograph the rocks with a correct label and measure the dimensions.   Steve, Elisa, Bramley and Adeline are describing the rocks.  ©  Bramley Murton. Pat is ready to unload the biological samples. Crinoids and skate eggs were our special dishes on this expedition. Oisin, Aggie and Katleen are taking care of the push cores. 18)   Chop a bit of rock and describe their textural and mineralogical features. 19)   Give a provisional name. 20)   Finally pack them in their bag. Make sure the label is legible and will stay. They will be described later in full details in labs by petrologists. Concerning the biology, scientists will look at the morphology in greater detail, and if possible, carry out molecular analysis (e.g. DNA, RNA).  Many deep-sea species are still unknown, so maybe one of the sample we collected will turn out to be a new species! 21)   Job done! Have a cuppa.

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Alright… If you’re not familiar with the seafloor topography, you probably don’t know where it is. So, a fracture zone is what we call a transform fault which will connect two segments of a spreading ridge (remember your lectures of tectonic plates?). In this case, the Charlie-Gibbs Fracture Zone connects the Reykjanes Ridge (the same one dividing Iceland in two halves) and the Mid-Atlantic Ridge, and crosses the deep-sea basin of the North-Atlantic about 50 degrees North, from Ireland to Newfoundland. Now you should be able to point out its location on the GEBCO map !

The purpose of this cruise is to improve our understanding of tectonic plates at divergent plate boundaries, like processes such as the effects of change in the magma melt supply at volcanoes, and what features they create, such as exposure of mantle outcrops on the seafloor.. The mantle is essentially made of peridotite and is found below the oceanic crust, but sometimes during the stretching of the crust, the mantle is exhumed, and brings with it a higher heat gradient. We call these phenomena oceanic core complexes (OCC).

So what are we going to do there? A bunch of things! We will map the seafloor with a multibeam swath sonar, we will undertake some seismic reflection geophysics surveys, and at the same time, acquire some sub-bottom acoustic profiles to understand the sediment cover infilling the troughs. We will also collect sediment by gravity coring to learn about mass wasting (rapid transport of sediments) and do some dredging (a metallic net pulled by the back of the ship scrapping the seafloor surface). Finally we will explore for hydrothermal plumes with CTD casts which will measure Eh, nephels and CH₄, and dive with a ROV (remotely operated vehicle) to sample seafloor outcrops or mineral deposits and vent fluids if we locate some hydrothermal vents! Hydrothermal vents are very often associated to oceanic core complexes. This is a similar case to the Von Damn Field on the Mid-Cayman trough that you have learned about in the Week 1 !  (Ok, I’ll tell you, I am most excited about finding hydrothermal vents!)

All of this is exciting, isn’t it? If you would like to hear week by week the news of the CE18008 expedition, then stay tuned on the blog and I’ll post some updates, and my colleagues on the ship will post few more as well on the official cruise blog ! By the way, this link has as well many other posts about other cruises of any different kinds: fisheries, ocean climate on the Irish Sea, micro-plastic … Check them out  :-).

PS: With my niece, we drawn some fine art on polystyrene cups, and hop direction to few thousands meters depth for an original souvenir !

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