A consortium developed a prototype for a global and disruptive ocean monitoring system using underwater cables, capable of operating at different depths. There’s a lot we don’t know about our oceans and the K2D project advances a solution to light up these grey areas. The new generation of SMART cables can be used to detect earthquakes earlier, monitor wildlife, and charge AUVs, giving them more autonomy.

It’s very likely that, due to climate change, hurricanes and earthquakes will become more intense and have (even) more devastating impacts on coastline populations. What if there was a way to detect some decisive seconds earlier these natural disasters? The answer may be at the bottom of the ocean, unnoticed by almost everyone in the world: submarine cables. Scientists monitor the global ocean with the help of satellites, drones, sensors, or buoys, to study and forecast phenomena like hurricanes or earthquakes, but there’s vital information on the deep ocean that can be extremely valuable to broaden the monitoring process and expand what we know about our oceans.

These thin fiber optic cables run for thousands of miles along the seabed and connect continents, but are mainly used for communication purposes – they basically keep the internet running. A Portuguese-American consortium set out to take advantage of the already existing widespread infrastructure of submarine communications to develop a network for continuous, real-time detection of vital signals from the earth and, in particular, the oceans, developing analysis models based on geoinformatics and Artificial Intelligence.

“The main goal of the K2D project was to assess the possibility of expanding the capabilities of cables that are traditionally just for communication, transforming them into an information gateway. Basically, the key idea was to take advantage of fiber optic repeaters, installed a few tens of kilometers apart, to place not only sensors but also connection points for robots and technologies”, explains Nuno Cruz, a senior researcher at the Institute for Systems and Computer Engineering, Technology and Science (INESC TEC), one of the researching institutes of the consortium. The project had its final demonstration in Portugal, where it showcased these new capabilities successfully.

Presenting a new generation of SMART cables

The K2D (Knowledge and Data from the Deep to Space) project, led by dstelecom in co-promotion with the University of Minho and INESC TEC, took on a novel cable concept called SMART - Science Monitoring And Reliable Telecommunications – and took it a step forward. But what is this new generation of SMART cables all about? “In this new concept, each repeater can be used for more than sensors: we can, for instance, create a hub for docking stations for AUVs to charge batteries and exchange information, or localization beacons for AUV navigation”, outlines the researcher. This can be crucial to give a clearer picture of a layer of the ocean with plenty of grey areas, expanding the roaming possibilities of AUV’s: with these docking stations, it’s easier to send them on long missions and explore the ocean depths away from the cable line.

Let’s look at a practical example: in a cable connecting Porto to Boston, repeaters are already used to regenerate optical signals – using electrical energy that is carried in additional conductors inserted into the cables –, but with “SMART 2.0” cables these repeaters can become access points to the energy and communications infrastructure, allowing AUV’s to charge, reroute missions or simply having a platform to analyse data.

Nuno Cruz explains: “Besides increasing autonomy, we will now have a lane of observation instead of a line along the cable. The robots now know they have a service station there. From a macroscopic point of view, we have something different, we have range. And as we get more cables, we extend the range and start to see the whole sea.”

To test these possibilities, a full operational demonstrator was deployed in Sesimbra, on the west coast of Portugal. Using a 2 km cable, and at depths up to 100 meters – with the support of the Portuguese Navy – the researchers validated the solution. The experimental installation included temperature, pressure, pH, and turbidity sensors, hydrophones, and accelerometers, using three signal repeaters installed along the cable. In addition to regenerating the signals passing through the optical fiber, the repeaters also featured a set of standardised connectors that translated into improved expandability. The cable was connected to the shore, allowing real-time data processing and access.

More than meets the eye

This solution developed for the seabed can also have an impact many meters above sea level. These sensors can detect earthquake patterns seconds earlier and "this aspect of anticipation is very important," says Nuno Cruz. Thanks to the expansive capacity of these cables (they can create real connection trees), the epicenter can be determined more reliably and earlier. These cables can also play an important role in the Defense sector and safety: these SMART cables in the vicinity of subsea installations such as oil and gas pipelines or offshore platforms, can report anomalies and guarantee the integrity of systems. These cables can also be good bodyguards... for the cables themselves: after all, they account for 95% of the world's international voice and data traffic, and cables with these technologies can serve as self-protection, stopping interference attempts.

There are also advantages to environmental and biodiversity monitoring. Measuring background noise, temperature, salinity, acidity, and other fundamental ocean variables can provide critical clues for understanding and protecting marine species.

With more offshore wind farms in business, the turbine vibrations can also have implications underwater: the first generation of SMART cables capture this vibration, but the additional layers developed could produce data to analyse how it’s affecting the acoustic soundscape and creating noise that could disrupt migratory routes.

The consortium is confident that the prototype developed can not only appeal to the wide range of communities that depend on information from the underwater environment but also create value for cable manufacturing and installation companies, "which is why this combination is expected to have a high potential for dissemination".

K2D is a flagship project of the MIT Portugal program – part of the international partnerships that the Portuguese Government established with North American research institutions –, and it received €1.4M funding. The project started in 2020, with dstelecom, University of Minho, INESC TEC, CINTAL, University of the Azores, Air Centre, Alcatel Submarine Networks, and M.I.T.