Equipment

ROV

Remotely operated underwater vehicles (ROVs) are unoccupied, highly maneuverable underwater robot, which are operated by a person aboard a ship, the pilot. They are linked to the ship by cables that carry electrical signals back and forth between the operator and the vehicle, allowing the pilot to control the actions of the various arms and thrusters. On this cruise, we will be using the Holland I Deepwater ROV, which can dive to 3000 m and has high definition video cameras, lights, a manipulator or cutting arm, water samplers, and instruments that measure water clarity, light penetration, and temperature. For more information click here 



CTD
A CTD is an instrument which measures the saltiness (Conductivity) and Temperature at specific Depths in the ocean. On this cruise, the CTD is mounted on a carousel of vertically mounted water sampling bottles (Niskins), called a rosette. The closing of the Niskin bottles is triggered from an on-board computer, so water samples can be obtained from specific depths, from which biological and chemical parameters can be measured. To find out more about CTD’s click here

Moving Vessel Profiler (MVP)
We will be using an MVP to measure near vertical profiles from the ship when it is moving, typically to 300m depth at a speed of 10 knots. Parameters measured include depth, temperature, conductivity (used to calculate salinity or saltiness), oxygen concentration, chlorophyll concentration and light intensity. For more information click here



Eddy Correlation System
The EC lander is an instrument which we will place on the seabed, using the ROV, to measure small-scale turbulence and oxygen concentrations with high frequency in the same point just above the seabed. Combining these two measurements will allow us to calculate the oxygen exchange between the seabed and overlying water over a relatively large ‘footprint’ upstream the EC lander. So, by placing the EC lander downstream of the cold-water coral reefs, we can estimate the oxygen uptake rates of the reef





Corers
We will be collecting sediment from the ocean floor, to examine all the creatures which live hidden away. To do this, we will use corers, which work by pushing or grabbing sediment into containers.

Gravity Coring is the simplest method of obtaining a sediment sample from the seabed. A Corer consists of a weight with steel tube sections attached to it. The weight can vary between 100kg to 1000kg. The length of sample tube is selected according to the type of sediment being sampled and is generally between one and four meters. The end of the corer is fitted with a tapered cutter section and a catcher to retain the sample. The corer is lowered down to the sea bed on the end of a wire, stopping a set distance above. It is then lowered at a set speed into the sediment. The Corer is then raised to the surface, dismantled and the liner encasing the sample is removed.

Box corers are designed to take square undisturbed soft sediment samples from the ocean floor, which will allow us to examine the micro- and macro-fauna on the sediment surface. On this cruise we will use two types of corer. Firstly, the SMBA Box Corer, which is designed to take a 600 mm square, undisturbed sediment sample up to a maximum depth of around 450mm. The corer consists of a gimballed sample box and spade assembly. The SMBA box corer is lowered onto the sea bed on a wire at a controlled rate until its frame rests on the bottom. The sample bucket is forced into the sediment by the weight of the corer. As the Corer is slowly pulled out of the sediment, a mechanism allows the spade to swing below the sample box sealing in the sediment. Simultaneously, spring loaded flaps above the sample box are closed to prevent the sample being disturbed during recovery.

Secondly we will use a NIOZ Box Corer, which works on a similar principal to the SMBA Box Corer. The difference is the NIOZ has two spades which operate from either side of the sample box. This design results in a more balanced "pull out" of the corer, reducing the risk of disturbing the sediment during sampling. More information on coring can be found here.

Sediment Profile Imagery (SPI) System

SPI is a high resolution camera system which can be used to look at biological activity on and below the surface of the sediment at the ocean floor, and examine changes over space and time. Basically, we can use SPI to see what animals in the surface sediment are doing, and when and how they are doing it. This camera system acts like an upside-down periscope; a camera faces downwards into a 45-degree mirror and images a cross section of sediment. The system is made up of 2 frames which are lowered through the water. Once the outer frame hits the seafloor, the inner frame continues and the wedge is driven into sediment, aided by 90 kg of steel weights. A "passive" hydraulic piston ensures that the prism enters the bottom slowly and does not disturb the sediment-water interface. On impact with the bottom, a trigger activates a time-delay on the camera shutter release and a photograph is taken when the prism comes to rest. A series of images can be obtained by successively dropping the SPI camera, or the prism can take successive pictures while deployed in time-lapse (t-SPI) mode.
More information can be found at CEFAS

Acoutic surveys and mapping
The RRS James Cook is equipped with a range of sonar equipment, which uses sound pulses to map the seabed. Sound waves use pressure to move through gases, liquids and solids. In air, sound moves at around 340 meters per second but in seawater it zooms along at around 1500 meters per second! A multibeam echosounder (MBES) will be used to show us the varying depths of the ocean, and can actually tell us about the shape of the seabed. A single beam echosounder can also be used to gain information about the sub-surface i.e. deep or shallow sediment. The ship also has an ADCP – Acoustic Doppler Current Profiler which is fitted to the hull of the ship. It measures the speed and direction of the water beneath the ship by sending out a 'ping' sound wave, then measuring the time it takes to return and its frequency. For more information on these instruments, click here.

Stand-alone Pumps
To collect large volumes of seawater, and examine the miniscule plants and animals which live at specific depths in the oceans, we will be using stand-alone pumps or SAPs. They are battery powered water pumps that suck water through various filters leaving the elements of interest on the filter for analysis. SAPs are programmed with a delay time (the time to get them to their target depth – sometimes hours) and a pump time and then deployed clamped to a hydrographic wire.

Spreaders

Spreaders are structures used for underwater incubation experiments. Their major parts are a polycarbonate cylinder (diameter: 25 cm, height: 30 cm) and an acetal plastic lid. On the lid a handle is attached for the spreader’s transport from the ROV. There is also a plastic cartridge containing isotopically-labeled substrates (e.g. algae) and a plunger. The plunger is pushed from the ROV arm and the metallic blade that is attached at the end of the plunger tears the holding membrane of the cartridge, releasing the substrates. At the bottom of the spreader, a plastic collar is attached that prevents the spreader from “over-sinking” in the sediment.

Optodes
To understand how animals are coping with stressful conditions, we can monitor their respiration, which is the chemical process by which animals release energy from food. As oxygen is used in this reaction, we can determine the rate an animal is respiring by measuring how much oxygen they take in. On this cruise, we will be using optodes, which optically measures oxygen concentration using a chemical reaction. We will measure how much oxygen corals and sponges take up, in sealed chambers, under carefully controlled environmental conditions.

Feeding Chambers

Specially designed chambers will be used to look at the feeding habits of the cold-water corals that we collect. These chambers have stirrers which controls how fast the water is moving around the corals. By adding some food that corals normally eat, like zooplankton, and taking water samples at the beginning and end of a set time, we can calculate how much food the corals are actually eating.

Microbial Sampler

Studying microbes, such as bacteria and viruses, associated with cold-water corals requires the use of special equipment to prevent contamination with microbes living in other environments such as seawater, sediment, and even different corals. Much like a surgeon who strives to prevent bacteria from entering the body during an operation, a similar effort must be applied to thwart the unwanted introduction of foreign microbes to the samples of coral collected from the ocean's depths. To do this, the ROV Holland I has been outfitted with a custom-designed sampling unit. In a nutshell, this sampling unit is composed of a rigid box that houses six individual canisters made of a very strong, insulating plastic. Each canister holds fragments of coral collected from an individual Lophelia colony and protects these samples from contamination and accidental loss. Making the box and containers was relatively easy, but designing a lid for the containers was not. The lids are perhaps the most critical aspect of the entire sampling unit because they block the only portal into the container. As such, they must be strong enough to prevent accidental seepage of seawater into the container yet relatively easy to remove and replace using the ROV's robotic arms. Furthermore, the lids must enable equalization of the pressure inside each container with the pressure in the surrounding water column. The solution: magnets and plumbing valves! Complimentary magnetic rings were welded to the top of each plastic container and the bottom of each lid, thereby ensuring the lids strongly adhere to the containers and remain in place during transport. Also, in a manner similar to the way a SCUBA diver's first stage seats against the valve on a compressed air tank, an o-ring was inserted at the base of each lid to mate against the opening of each container. The o-ring serves to provide the necessary watertight seal and prevent accidental seepage of seawater into the container. Special one-way check valves are attached to each lid to equalize the pressures inside and outside the containers. Without this ability to equalize, the containers would be crushed like a grape by the enormous amount of pressure at our extreme operating depths. Controlled by a skilled pilot hovering 1000 meters above, the ROV's robotic arms remove the lid from each container, acquire fragments of coral, deposit the coral fragments into a dedicated container, and replace the lid to prevent contamination and/or loss. The use of this custom sampling unit ensures that our observations reflect, as accurately as possible, the natural composition of microbial communities associated with Lophelia in the northeast Atlantic.