Fact Check: This is how noise affects water mammals

Dead whale

In this past photo, a 14-metre long sperm whale, weighing at least five tonnes found dead at the shores of Zote beach in Waa, Kwale County.

Photo credit: File I Nation Media Group

Towards the end of last month, a young humpback whale washed up on a shore in New Jersey, USA. It was just two months since the deaths of eight other whales.

Locals and lawmakers suspected that the construction of an offshore wind farm was to blame for the deaths and called for the construction to stop, even as a preliminary necropsy showed that the whale had died because of blunt trauma injuries.  

On social media, an enraged tweep posted: “The current solutions to climate change do not work. Wind farms kill whales … You are destroying the earth you are trying to save. #climateHoax #climateScan”

Soon after, the National Oceanic and Atmospheric Administration and the Bureau of Ocean Management said claims that wind farms had killed the whales were false.

They attributed the deaths to injuries and trauma from boat strikes, a claim that is only partly true. 

However, the claim that the current solutions to climate change do not work is false, because solutions such as climate smart agriculture, renewable energy and tree planting have also borne fruit in helping people mitigate the effects of climate change.

Climate smart agriculture, which refers to agricultural practices that allow a farmer to adapt to and mitigate negative effects of climate change have been shown by research to boost crop yields and increase food security.

“Climate-smart agriculture helps to build resilience and adapt to the effects of climate change, and contributes to climate change mitigation by reducing or removing greenhouse gas emissions.

Climate-smart practices can focus on ways to reduce emissions in livestock production, to reduce farm inputs (such as fuels, energy, pesticides, mineral fertilisers) for more resource-efficiency, or to keep carbon stored in the soil. Making farming systems more diverse can also make them more resilient in the face of climate change,” says the Agricultural European Innovation Partnership(EI-Agri). 

Renewable energy, including solar, wind and geothermal and hydroelectric energy have been proven to be beneficial for the planet, because they are cheaper, healthier and generate very low levels of carbon dioxide.

“Cheap electricity from renewable sources could provide 65 per cent of the world’s total electricity supply by 2030. It could decarbonise 90 per cent of the power sector by 2050, massively cutting carbon emissions and helping to mitigate climate change,” noted the United Nations.

Other solutions like planting of trees has resulted in more greening of the earth, which has mitigated surface warming of the earth.

In a study published in Science Advances titled Biophysical impacts of Earth Greening Largely Controlled by Aerodynamic Resistance, the earth surface “would have been much warmer without the cooling effect of increased green cover during the recent decades”.

“The greening of the lands during the first 15 years in the 21st century represented an additional heat dissipation from the surface equivalent to five times the total energy produced and used by humans in 2015. This greening-induced cooling effect was 25 times stronger than the warming effect caused by tropical deforestation,” says the study. 

Marine deaths

As regards noise pollution and marine deaths, there are studies that have shown that noise pollution affects all marine species, and may lead to death, as most of them depend on sound for survival.

“Whales and dolphins live in a world of sound. For humans, our primary sense (for the most part) is sight. It is the main way we observe our surroundings. For whales, it is sound. Sound is a much more effective medium in the ocean: it travels much faster in water than in air and can travel over vast distances. But this also causes problems. Humanity is filling the ocean with sound. And because these sounds travel far, there is nowhere for whales to hide. Noise pollution undoubtedly represents one of the biggest threats that whales face today,” says Ocean Alliance.

It explains that noise pollution impacts whales through short and loud noises, that can cause loss of hearing and stranding, and constant quieter noises.

Earth.Org states in an article titled The Impacts of Noise Pollution in the Ocean that marine mammals such as whales rely on sound for communication, hunting, safety from predators, navigation and defending of their territories.

Ocean noises, which come from ships, construction, sonar devices, construction work and explosions, can cause temporary and permanent hearing loss, change in behaviour, injury and death.

“Very loud sounds can truly harm marine mammals. If the animal is too close to the source of the sound, they panic and ascend too quickly to escape the noise. This has been known to cause decompression sickness, which can lead to tissue damage from gas bubble lesions. Loud man-made noises have also been linked to mass breaching events around the world,” says Earth.Org.

“Sonar has been recorded to alter the feeding behaviour of endangered blue whales. In an experiment conducted in Southern California, blue whales were tagged to see how they responded to active sonar. Even though the sound levels were much lower than those of military sonars, the blue whales still stopped feeding, increased their swimming speed and moved away from the sound source. This can have significant impacts on the whales’ individual fitness, foraging ecology, and population health.”

“Noise pollution can interfere with the detection of acoustic signals in the marine environment. This means that the sound we are creating in the ocean is masking the sounds produced by marine wildlife. This can lead to changes in individual and social behavior, altered metabolisms and hampered population recruitment which in turn can affect the health and service functions of marine ecosystems.”

Another study titled Wind Turbine Underwater Noise and Marine Mammals: Implications of Current Knowledge and Data Needs states that construction of wind turbines can generate “high sound pressure levels, disrupt the behaviour of marine mammals at ranges of many kilometres, and have the potential to induce hearing impairment at close range.

“The reported noise levels from operating wind turbines are low, and are unlikely to impair hearing in marine mammals. The impact zones for marine mammals from operating wind turbines depend on the low-frequency hearing-abilities of the species in question, on sound-propagation conditions, and on the presence of other noise sources such as shipping. The noise impact on marine mammals is more severe during the construction of wind farms than during their operation,” says the article.
Generally, anthropogenic noise is recorded to have the ability to change the behaviour of marine mammals, including causing less feeding and producing fewer calls.

Noise caused by ships is also linked to causing stress, which is linked to suppression of growth, lower fertility and poor performance of the immune system.

In Greenland, researchers seeking to understand what happened to marine mammals after loud noises attached tags with suction cups on whales, which would record their heart rates, breathing and position as a ship that had seismic air guns passed by.

They noticed that after a sound pulse, the whales began to dive faster than normal, as opposed to gliding to save their energy.

“This increase in exercise would normally cause their hearts to beat faster, but instead it led to the heart slowing down to less than 10 beats per minute. The narwhals were breathing up to one and a half times as much as normal, with the researchers suggesting that the panic induced by the noise may have caused the diving response to become unbalanced. As a result, the energy costs of diving increased significantly, with startled narwhals using over twice as much energy as animals in the control group,” explains the Natural History museum on its website.

“Acute noise pollution can prove even more damaging. Military sonar can reach volumes of more than 200 decibels, while seismic air guns can reach up to 250 decibels – louder than the largest rocket ever built taking off. At this level, the force of the vibrations is enough to kill zooplankton, with the number of dead plankton tripling within the surrounding kilometre of ocean. While larger animals are not killed directly by the sound waves, anti-submarine sonar has been linked to whale deaths caused by strandings and decompression sickness, which is caused by the animals surfacing too quickly,” says the Natural History museum.

The museum, however, notes that some companies seek to adopt technologies to combat noise pollution, as scientists continue to research the effects of anthropogenic marine noise.

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This fact check was produced by Nation with support from Code for Africa’s Pesa Check, International Fact Checking Network, and African Fact Checking Alliance Network