Marine robotics capability
We now live in a digital age characterised by intelligent instrumentation. Remotely controlled and autonomous vehicles can help researchers sample parts of the ocean and atmosphere that were previously inaccessible, and can increase the geographic coverage of poorly sampled areas like the Southern Ocean.
RRS Sir David Attenborough acts as a central platform for the deployment and operation of a range of state-of-the-art autonomous and remotely operated vehicles in polar regions. It also incorporates enhanced communications and data handling capabilities to enable real-time data delivery and remote UK-based instrument operation.
Autonomous underwater vehicles
Autonomous underwater vehicles (AUV) are robots capable of travelling underwater without direct control from the ship. They usually travel along a pre-programmed path to survey locations that may be dangerous or impossible for humans to reach, including underneath ice shelves and at the calving fronts of glaciers.
The Autosub range of AUVs was developed by the National Oceanography Centre (NOC). They are outfitted with the latest oceanographic sensors, battery technology and advanced satellite communications.
Before being launched from the ship, the AUV’s computers are programmed with instructions of where to go, what to measure and what depths to dive to. With no link to the main ship, all communications with the AUV are limited to using acoustics while the AUV is underwater. Satellite communications can only be used when the Autosub is at the ocean surface.
NOC have a number of different Autosub models, including the latest version – Autosub Long Range. This vehicle is also known as Boaty McBoatface and was first deployed in the Antarctic aboard RRS James Clark Ross in March 2017 as part of a DynOPO research cruise.
Underwater gliders are a type of robotic underwater vehicle that uses an expandable oil-filled bladder to move instead of using a conventional propeller. As the liquid is pumped into or out of the bladder, the volume of the glider changes but its mass remains the same. As a result, its density changes, allowing the device to rise or sink through the water. Its wings turn this vertical motion into forwards motion.
Gliders are extremely energy-efficient, making them a useful tool for gathering long-term data from the oceans. Depending on the sensors and instruments used, gliders can be deployed for six to nine months. They can be directed via two-way satellite communications link while at the ocean surface.
Remotely Operated Vehicles
Unlike AUVs, Remotely Operated Vehicles remain connected to the ship via a cable. This allows an operator on board to directly control and manoeuvre the ROV. The cable acts as an “umbilical cord”, providing the ROV with power and relaying data such as video footage and data collected by the vehicle.
ROVs allow researchers to explore and sample the seafloor in a more targeted and precise manner than was previously possible. They can reach depths that are extremely risky and difficult to access for piloted craft and minimise disturbance to the study site.
The National Oceanography Centre currently operates one ROV, named Isis. It is capable of taking seafloor samples, drilling sediment cores and relaying high-definition still and video imagery from depths of up to 6,500m. Isis can be deployed from the RRS Sir David Attenborough‘s aft deck.
The Southern Ocean is an important region to study; it influences ocean currents and plays a key role in regulating the Earth’s climate. Water that is cooled here sinks to the bottom of the ocean, driving the large-scale ‘conveyor belt’ circulation. It also absorbs about three-quarters of the anthropogenic heat that is absorbed by the ocean, and approximately half of the carbon dioxide.
We don’t yet fully understand many of the processes regulating the exchange of heat and carbon between the atmosphere and ocean. Marine robotics are transforming how scientists observe the ocean by extending the reach of research vessels, supplementing and enhancing the data collected from manned platforms. This technology is therefore instrumental in furthering scientific knowledge in the data-poor Southern Ocean.
Exploring previously inaccessible regions
Marine robotics are opening up new areas of the Southern Ocean to scientific research missions. As they are unmanned they have the ability to visit previously unexplored environments including ocean cavities under ice shelves and hydrothermal vents.
As part of the DynOPO project, the Autosub Long Range AUV, also known as Boaty McBoatface, was deployed from RRS James Clark Ross, on three missions to measure ocean currents and turbulence near the seabed around Orkney Passage, at up to 4000 m depth. While the researchers on the ship were conducting measurements at discrete sites using the ship’s conductivity-temperature-depth (CTD) probe and free-falling vertical microstructure profilers (VMPs), Autosub traversed this area of extremely steep underwater topography, staying close above the seabed. In total the AUV covered 188 km in 75 hours, its longest mission to date. Read more here.
Data collected shows the patterns of deep currents at a resolution that cannot be measured using traditional methods. Read more about the results from the AUVs debut Antarctic mission here.
Enhancing sampling capability and data collection
Remotely operated vehicles (ROVs) and AUVs greatly increase our ability to study the vast Southern Ocean. Using these technologies, data can be collected from larger areas, in finer detail and over longer periods of time. This is crucial for understanding how the Southern Ocean interacts with global systems.
Ocean gliders, for example, are designed to sample very densely, providing high-resolution data that is crucial for examining structures in the Southern Ocean, known as steep fronts and eddies. While they have limited capabilities compared with a large research vessel, gliders can sample specific areas in greater detail for longer periods of time.
As part of the £8.4m ORCHESTRA project, four underwater gliders and one waveglider (an autonomous surface vehicle that uses waves on the sea surface to propel itself) were deployed from RRS James Clark Ross. These gliders spent two months in the Drake Passage, off the coast of the Antarctic Peninsula, conducting surveys to study ocean characteristics and the interaction between the ocean and the atmosphere at the surface. An example of the type of data collected is found below:
Large ROVs such as ISIS have a unique capability to explore ecosystems on the seabed. They are piloted from the surface via a tether that sends power and commands to the vehicle while transmitting data and video back in real-time. This allows biologists to study the undisturbed seabed, or even collect targeted samples. New species are still being discovered in the depths of the oceans, and these platforms allow us to see them in the context of their natural environment.