Marine acoustic pollution The ‘evil’ of the oceans that influences the species it houses: sound pollution becomes one of the most important dangers for the marine environment. The sounds that are produced by ships, industrial activities and oil car visits will seriously harm communication and feeding marine animals.
Fisheries Overexploitatie or chemical pollution are traditionally identified as important pressure on the biodiversity of marine.
However, there are other pressure noise pollutionthat together with the Seam forms one of the The most important emerging problems.
There is scientific evidence that the sound generated by human activities in the sea (eg navigation, infrastructure construction, seismic campaigns) causes negative effects on marine fauna.
Most studies have been aimed so far Marine mammalsperceive that underwater noise It can cause direct damage to tissues and body systems (due to aerembolism) and indirect damage such as the interruption of acoustic communication between samples, condition for the ability to detect predators or other hazards, changes in diving and swimming patterns or to raise or raise in breathing speed or in the speed of breathing or in the speed of speed respiratory speed.
Although there are a lower number of studies for other groups of Marine Fauna, they indicate that Submarine sound also causes the consequences of fish (eg barotraum.
Finally, There is recent scientific evidence that underwater sound can also lead to changes in marine flora (in roots and nutrition processes) as Oceanic Posidonia.
A propeller of a broken ship, his helmet breaks the waves and slides through the ocean. More in the background, a canyon drives a bubble for seismic prospects that explodes. Far, it fills in the seabed, 30 meters deep, a concrete pillar that will serve to build some structure.
Perhaps the ashes of a mill also rotates at another point in the ocean and generates energy. The common denominator: The sound that generates and what Travel, through waterAt a speed of approximately 1500 meters per second. Sometimes for hundreds of kilometers. Faster and far than through the air.
The ocean is not quiet But human activity generates extra sound –HeyTend Pollution– That floods the seas and breaks into the activities of its inhabitants. «People are deafCompared to marine mammals, to capture the nuances of noise, “he says Nose Pérez GimenoUnderwater Acoustic research technique in the Acoustic Engineering Laboratory of the Marine Research Institute of the University of Cádiz (inmar).
These nuances are recorded by frequency, a characteristic of the sound measured in Hercios (HZ) and determines whether it is more acute or more serious – more tools, sharper a sound. «The whale -likeFor example, They have much more variation that us in the Frequency rangeAlso in the reaction to sound, “says Neus.
How it affects sound pollution to life at sea
Sound can influence the communication or orientation of marine mammalsthat are highly dependent on their auditory systems. This expert says that there are two types of damage that they can suffer: firstly, the “temporary disorders”: “Like when you go to a concert, with speaker exposure you keep deaf, but you recover. The same with them, the sound Can cause temporary damage ». «You have changed the medium, generated and caused a change in behavior injury Small and repairable »account.
The biggest problem comes with permanent injury. A very strong acoustic shock in a short period can cause serious damage: “For example, if there is an animal under a seismic campaign – a prospecting to look for resources or to investigate the seabed – that generates more than 200 decibels,” he says.
“Timpanos and membranes have been broken, there may even be bleeding”. He says that when this type of damage is produced, «Mass -Varities can«. “Throughout history there have been various events of this type, coupled with seismic and military campaigns, nowadays we still have to control it,” although, he says, “technology has improved to minimize the acoustic impact.”
Pérez Gimeno also refers to the Adjustment capacity of these animals, which are one of the most intelligent in the world. “There are many studies that show that they can adapt to environments with ships sound,” he says, although he points out that “masking can occur, that is, that shifts Confuse the sound of ships – of low frequency, such as the one broadcast by whales – with those of other animals and performance clash«.
Stephanis Renaud He has been working in the Gibraltar street for 30 years and is director of Circe, an organization that focuses on the preservation of cetaceans. He believes that, although acoustic pollution is « A problem, “we don’t have to” oversized “.
“The street is an area full of noise, and there are still many cinnaments because they can adjust,” says the researcher. It tells a case in which the sound disturbs the cetaceans in the area: «Some dolphins hunt tuna for passive acoustics, They make some clicks that function as a sónar And find the dams. If a lot of noise is done, you can disrupt this process ».
Although marine mammals, because of their greatest dependence on sound, are the most sensitive to anthropogenic noise – process of human activity – a lot Other species They can suffer from the consequences. “The sound is energy that is transferred, vibrates,” says the expert of the inmar, and “also influences Types without auditory systems; Marine molluscs, Flora … “Moreover,” that does not have the possibility to adjust the cetaceans. “
It is too The least studied consequence From a research field that is young in itself: “The consequences in Flora and Fauna started to look around 10 years further than sea mogers.” Over the Fuentes of Marien noise, says Pérez Gimeno that «Maritime Traffic is the King«.
Maritime traffic, the largest contamination with a lower control capacity
According to the UN body for trade and development (Unctad), 80% of world trade passes the seas. Tens of thousands of metal mastodons cross the oceans of the world without peace. Their propellers, engines … Most marine noise pollution.
Francisco Javier Rodrigo Saura He is Director Operations of Saes, a company specialized in underwater electronics. The engineer, who has published various studies on sound pollution, talks about the sound of ships that «What makes the most noise is propeller (less at low speeds, such as in port areas). The vibrations of the helmet (generated by the engine and other machines of the ship) also generates sound pollution ».
The sound that is emitted by the ships is low frequency. Saura says that “it is the one who comes to the aquatic environment.” It is the same type of frequency they use The great cetaceans – What can messages send hundreds of kilometers – to communicate. Therefore, The sound of the ships can interfere in their communication.
The technician explains that the measures to relieve these effects through space and time limitations are currently going through, he says, “limit traffic in certain areas according to his ecological activity” as breeding areas at certain times. Apart from that, the only brake on marine sound is the limitations for the construction of ships that, Saura says, “over the years, just like any other vehicle, age and ultimately make more noise.”
Limiting the sound pollution generated by ships when navigating is complicated. Nose Pérez says that «The sea, at the legislative level, is a cocoa ». “There are international water areas, others shared …”, he says, “like the street of Gibraltar, who controls Spain, England and Morocco.”
“There like laws?” He asks. Another problem is The pavilion in which the ship is registered: “A ship of Somalia or Cabo Verde will not have the same requirements as those of a European country, and can navigate through every sea,” he explains.
Bubbles in the depths: Seismic prospects and other sound sources
There are human activities at sea that one noise pollution opposite, Temporary and traumatic. As the Seismic studies.
These studies serve to know what is under the seabed. A ship drags an air cannon that at some point generates a pressure change and forms a bubble that exploits and exploits and Low frequency waves. These waves penetrate the bed and let them know if, for example, there are gas or oil sacks under the ground. The sound generated by these guns exceeds 200 decibelabove the threshold in which you can damage the auditory systems of animals.
Carla Álvarez Chicot She is one of the founders of Submon, an NGO that develops projects for the preservation, study and distribution of the marine environment. Chicote, who collaborated in the elaboration of a guide To reduce the effects of Marine Acoustic PollutionTell that There are various measures This can be assumed to prevent damage to cetaceans.
First, the preventive measures“, He explains that they continue” the teams calibrate well, make sure that other campaigns are done in the area … “. Then a”modeling“That is, a study in which” it is determined which noise will do the activity to know how far you can generate temporary damage to the whale. “Then, based on this area,” an exclusion zone “is determined”. ” Cetaceans are sought by visual observation and sounds, if present, stop until they pass, “says Álvarez, who has participated in this type of campaign.
Another sources of Marien sound is BuildFor which they are nailed in the pillars of the seabed that generate a sound that is comparable to that of prospects. According to the expert, the take To reduce this type of pollution are «Similar to those used in seismic campaignsWith the difference that, as static, there are more ways to reduce noise, such as the use of bubble curtains that block sound ».
About the sound generated by the facilities magazines wind Marine says “it is shown to generate noise” but that “It is not clear“To what extent is a risk for the environment:” It is something that is still being studied. “