An Army of Sensors Coupled with Marine Animals to Explore the Ocean

Despite occupying 70 percent of the Earth’s surface and housing nine out of ten living beings, the sea remains the great unknown of our planet. The army of buoys, beacons, radars and satellites that we have deployed only allows us to see the skin of the ocean, the first ten meters of depth, explains oceanographer Carlos Duarte.

To know what happens in the deep sea it is necessary to make expeditions with oceanographic vessels or use autonomous underwater vehicles. Both possibilities are very expensive and limited to very specific areas of the ocean.

For that reason, for some time now, researchers have been looking for ways to explore the oceans and see what happens under the surface of the sea, as every day the sea creatures that go through it do. And they use marine animals to which they attach sensors to know their behaviour and the environment in which they live. However, this technique encounters several problems, one is the weight and price of the sensors and the other the transmission of data in animals that do not rise to breathe to the surface.

Now an international team of researchers, led by Duarte, director of the Red Sea Research Center, belonging to the King Abdullah University of Science and Technology (Saudi Arabia), has designed a new generation of revolutionary sensors , which are millimeter, painless to the carrier, biodegradable, cheap and able to take the data, analyze it and transmit the results in real time.

“Our intention is to achieve a revolution in the sea, similar to the one that supposed the passage of the telephone to the smartphone”, explains Duarte, who a few weeks ago was at the Oceanogràfic of Valencia testing these sensors in controlled conditions in turtles, sharks, dolphins, lobsters and other crustaceans and molluscs .

The idea is that these sensors, whose size have been reduced up to 100,000 times to get the thickness of a plaster or even the head of a pin, are coupled to the body of the animal and are able to transmit data by Bluetooth or transmission optics to mini-antennas that would be released massively in the ocean , because they can be printed and are biodegradable. When a marked animal comes into proximity with one of these antennas (which will be protected in cubes 2 centimetres high by 1 centimetre wide) it transfers all the collected data, explains Rory Wilson, a marine biologist at the University of Swansea (United Kingdom). Kingdom), who leads this project with Carlos Duarte.

When it comes to animals that do not come to the surface to breathe -such as squids and fish, for example- it can be equipped with antennas to the submarine autonomous vehicles that already exist, and that move vertically between 200 and 2,000 meters, so that transfer the information collected by the sensors. Other resident animals – such as adult whale sharks in the Arabian Gulf that drop to 1,000 meters in depth – can also be used as a data receiving station, which they will then transmit when they rise to the surface.

And it is that the animals could transmit to each other the collected data. Not in vain, the University of Science and Technology Rey Abdalá where Duarte works has now the world recórd of submarine data transmission, an achievement that was published last year in «Nature Photonics», where «with optical data transmission techniques, we get the equivalent of downloading a movie in 2 seconds at 20 meters distance under the water, “says Duarte.

At a later stage, the oceanographer explains, “we will fly drones over the field of antennas that will receive the data from the sensors, so we may not need any type of satellite and the cost of acquiring data will be very low”. Right now, the cost of a contract with the Argos satellite system to transmit data in a small project with one or two animals can be about 10,000 euros, “which makes it impossible to have a synoptic picture of the ocean,” says Duarte.

Impact of seismic surveys

The 18 types of sensors that have been developed measure at least the temperature of the water, salinity, pressure, and have a built-in gyroscope and an accelerometer, to know in detail the movements of the animal. In addition, there are hydrogel ones, which are loaded with nanoparticles with a compound that reacts to levels of some hormones that indicate the reproductive status of the animal or the level of stress, for example. The latter will allow us to know the impact that seismic surveys have on the location of hydrocarbons in animals or how they are affected by the increasingly frequent heat waves in the oceans, says Duarte.

In addition, work is being carried out on pH and carbon dioxide sensors, to evaluate changes in the oceans in key parameters that are being affected by the climate system and CO2 emissions, and later they could also measure pollutants.

The 18 types of sensors that have been developed measure at least the water temperature, salinity or pressure,

The next step will be to implement with these sensors a coral reef in the Red Sea, which will be the first test in free animals and in open waters. They hope to do so in the coming months, and next year they hope to deploy the project in open waters in Australia.


Source: ABC Natural