The researcher Michel André, director of the LAB of the Polytechnic University of Catalonia
Michel Andre he was in Antarctica when the world went into lockdown. He was collecting data to perform the first acoustic archive of the biodiversity of the Antarctic Ocean and measure the impact of noise pollution associated with cruise ships to be able to propose solutions, but like so many other scientific expeditions it had to be interrupted.
Cruise ships are the only industrial activity allowed in a region in which "although international regulations are very strict regarding the use of the land and the number of people who can disembark, it does not contemplate noise", explains the marine biologist, for whom the acoustic records that he can obtain in Antarctica are extremely important to use as a reference and to see their future evolution. “With the data we analyze, the idea is to propose to the International Association of Antarctica Tour Operators (IAATO) a series of measures that allow that, in a few years, even if there is less ice, the ecosystem is not so affected”, indicates the marine biologist, to whom the frozen continent produced mixed feelings. “The speed at which the ice disappears is scary. You have a feeling that you are going to be the last to see Antarctica as we know it.”
André, who is the director of one of the leading centers for the acoustic study of biodiversity, the Bioacoustic Applications Laboratory (LAB) of the Polytechnic University of Catalonia (UPC) and the promoter of such interesting initiatives as LIDO (Listening to the Deep Ocean Environment) , it was one of the first scientists to make us see that our noises have consequences on life in the sea.
You may remember that a few weeks ago we talked to him to inform us about the effect of our confinement on the levels of noise pollution in the sea. From that long conversation we want to highlight today, International Oceans Day, some of his reflections and the solutions provided by his studies on noise pollution, since the acoustic technology developed by André's laboratory stands out right now as a particularly valuable tool for detecting imbalances and threats to biodiversity and, therefore, to our Health.
Noise pollution from the sea is invisible and inaudible to humans. "Until we had the technology to hear like a dolphin, we didn't notice its existence. We discovered it late, but it is as old as the other types of pollution. In 15 years we have collected data that reveals that what we have done in the last half a century has consequences. And now it is everyone's responsibility –industries, scientists, NGOs, administrations, society– to reduce our impact on the oceans”, Andre explains.
The good news is that if the noise is turned off, the pollution disappears: "Unlike other sources of pollution, when the noise is turned off its effects also disappear, something that does not happen, for example, with plastic, whose consequences will be inherited by the following generations." And this means that we can take steps to reduce all that unnecessary noise.
MUFFER THE NOISE, LOWER THE VOLUME
Efforts have always been made on ships so that passengers are not bothered by noise from the engine room, but it had never been taken into account that we are pouring that noise to the bottom of the sea and therefore we have not isolated the hulls. In old boats solving the problem is more complicated, since they would have to be dismantled to introduce the improvements, but in new boats the solutions are as simple as they are varied. “Isolate the engine rooms, avoid the use of steel plugs, use other materials that do not transmit sound…”, enumerates bioacoustics and simplifies the challenge: “It is about separating the sources associated with human contamination that do not provide any benefit to said activity and Look for solutions alternatives". Or, to put it another way, a noisy ship is no better than a quiet one, nor does driving a screw making noise make the screw work any better.
For example, work is being done on the quieter propeller design. “At a certain speed, the rotation of the propellers produces what is known as cavitation effect, which is the generation of micro bubbles that, when they explode (actually implode), make a lot of noise. So they are already building propellers that do not cavitate”.
And to alleviate the noise generated in the construction of underwater wind farms, methods such as “placing air bubble curtains around the pillars that, due to the physical capacity of sound, produce a mirror effect that dampens noise, or use membranes absorb it”, explains André.
More complicated are the acoustic sources that are voluntarily introduced into the medium to extract some information, such as military sonars, oil platform probes to search for and extract oil or those of pleasure boats to locate the seabed… “Until we find alternative technologies that allow these industries to obtain the same results, we cannot ask them to stop their activity. What we can do is demand that they take the maximum measures to detect the species that could suffer the acoustic impact generated by their operations and stop them for as long as the animals need to get far enough away”, proposes André, whose job consists of not only in providing scientific studies but also solutions.
Despite the increase in initiatives to dampen marine noise, building ships that are quieter and more respectful of marine fauna is for now a voluntary decision. "At the moment** there are no regulations or directives that oblige boats, whatever their type, to reduce the noise** that it introduces into the water, although there is to control the noise inside the boat itself," André informs us. .
ALARMS TO SAVE TIME
With the same methodology and protocol for real-time analysis of acoustic sources that they use in the ocean, Michel André and his team have been working for a few years in the Amazon where they are carrying out a really ambitious project: record the entire biodiversity of the Amazon. “We do not know the life that exists below the canopy of the trees. We can know the exact number of trees that are felled or burned from satellite images or drones, but we have no idea of the life that exists under the vegetal cover”, acknowledges the scientist and remember when, seven years ago now, they went to the Mamirauá reserve, in the Brazilian state of Amazonas, where the rising river floods the land for six months of the year, to study the botos (pink dolphins) and the effects of overfishing and human activity. “Once there, the researchers from the Mamirauá Institute confirmed what we already knew: the Amazon jungle is so impenetrable that it was impossible for them to collect reliable data and they were forced to work with the partial values collected in the first few meters. So we got to work and started taking the sensors out of the water to put them in the jungle.”
The application of bioacoustic measurements , which spread further than any image and do not require specific lighting or weather conditions, was a complete success and since 2016, with the financial support of the North American Gordon & Betty Moore Foundation, they are spreading the sensor network throughout the Amazon rainforest. And when we say all, it is all. “This network, which has already been active in the reserve since 2018, is allowing us to build the echo-acoustic indices, which are the ones that will indicate the state of conservation of each area and indicate the changes in the face of external pressures. At the end of the project, scheduled for 2025, we will have installed a thousand sensors, covering the entire Amazon, and we will be able to have, for the first time, a complete record of this biodiversity and its state of conservation”, he summarizes in a biologist. The ultimate goal is, as in all his other projects, locate and alert about the threats that weigh on life and offer alternatives and solutions to be able to prevent before having to cure.