Underwater Noise Pollution: A Growing Threat to Marine Life 

Underwater noise pollution is a growing concern in the marine environment. It refers to the increased levels of noise caused by human activities, such as shipping, oil and gas exploration, military sonar, and construction. This noise can have detrimental effects on marine life, including whales, dolphins, and other marine species that rely on sound for communication, navigation, and survival. 

Underwater noise is still a relatively unknown problem for public authorities, certain industrial companies and the general public. This is because noise propagating beneath the surface of the water is not noticeable to humans, which has long allowed manufacturers to remain discreet on the subject of underwater noise pollution. However, for more than 25 years now, scientific studies have been demonstrating the harmful effects on marine life, and in particular the correlations between seismic campaigns, the use of military sonar and pile-driving operations and the mass stranding of mammals. 

How Does Underwater Noise Pollution Affect Marine Life? 

The effects of underwater noise pollution on marine life can be far-reaching. Some of the most common problems include: 

• Communication problems: Many marine animals, such as whales and dolphins, use sound to communicate with each other. Underwater noise can interfere with this communication, making it difficult for animals to find mates, stay in touch with their pod, or warn each other of danger. 
  
  
• Hearing loss and auditory damage: The noise from shipping, sonar, and other human activities can be very loud, and it can cause hearing loss and other auditory damage in marine animals. This can make it difficult for animals to hear their prey, avoid predators, or navigate their environment. 
  
  
• Changes in behavior and stress: Underwater noise can also cause changes in behavior and stress in marine animals. Animals may become more aggressive, less active, or avoid areas where the noise is loud. This can lead to problems with reproduction, feeding, and overall health.
   
• Trouble to navigate and find food: Underwater noise can also interfere with the ability of marine animals to navigate and find food. This is because many animals use sound to echolocate, or bounce sound waves off objects to create a mental map of their surroundings. When the noise is too loud, it can make it difficult for animals to echolocate, which can lead them to become lost or starve. 

Biofouling 

Biofouling is the accumulation of living organisms on a surface. In the maritime industry, biofouling is a major problem that can significantly increase the drag of a ship, decrease its fuel efficiency, and increase its maintenance costs. Biofouling can also damage the hull of a ship and make it more susceptible to corrosion. 

There are two main types of biofouling: microfouling and macrofouling. Microfouling is the accumulation of small organisms, such as bacteria, algae, and diatoms. Macrofouling is the accumulation of larger organisms, such as barnacles, mussels, and seaweed. 

Biofouling is a problem for ships because it increases the drag of the hull. The drag is the force that resists the motion of a ship through water. As the drag increas, the ship uses more fuel to maintain its speed. This can lead to significant increases in fuel costs. 

Biofouling can also damage the hull of a ship. The organisms that make up biofouling can secrete chemicals that can corrode the hull. This can lead to holes in the hull, which can allow water to leak into the ship. 

In addition to the economic and safety risks, biofouling can also have a negative impact on the environment. The organisms that make up biofouling can be invasive species. These are species that are not native to the area and can disrupt the local ecosystem. 

To combat biofouling, the maritime industry uses a variety of methods. These methods include: 

• Cleaning the hull of a ship regularly 
• Using antifouling paints 
• Using biocides 
• Using electric fields 
• Using ultrasonic waves 

Biocorrosion 

Biocorrosion is the process of metal degradation caused by the action of living organisms. It is a major problem for the maritime industry, as it can significantly reduce the lifespan of ships and other marine structures. 

Biocorrosion is caused by a variety of organisms, including bacteria, algae, and fungi. These organisms produce chemicals that can attack the metal surface. The chemicals can cause the metal to corrode, which can lead to holes and cracks in the metal.  Biocorrosion is a major problem for the maritime industry because it can significantly reduce the lifespan of ships and other marine structures. In addition, biocorrosion can be a safety hazard, as it can weaken the structural integrity of a ship.

Collisions with Cetaceans: A Growing Problem 

Marine vessel collisions with cetaceans (whales, dolphins, and porpoises) are a significant and growing problem. In recent years, there has been an increase in the number of collisions, and the severity of the impacts has also increased. 

There are several factors that contribute to these collisions. One of the main reasons is the increasing amount of shipping traffic in the world’s oceans. As the demand for goods increases, so does the number of vessels on the water. This increased traffic can lead to a higher probability of cetaceans being struck by ships, especially in areas where they are known to migrate or feed. 

Other factors that contribute to collisions include: 

• Vessel speed: Ships that travel at high speeds are more likely to collide with cetaceans, as they have less time to react. 
  
  
• Vessel noise: Ship noise can mask the sounds that cetaceans use to communicate and navigate, making it more difficult for them to avoid collisions. 
  
  
• Vessel lighting: Poor vessel lighting can make it difficult for cetaceans to see ships at night, increasing the risk of a collision. 
  
  
• Cetacean behavior: Cetaceans are often curious about ships and may approach them closely, increasing the risk of a collision. 

The consequences of collisions with cetaceans can be severe. Cetaceans that are struck by ships can be killed or injured, and even if they survive, they may suffer from long-term health problems. It is also important to note that the occurrence of collisions can vary depending on the geographical area, and the species of cetacean.  

In addition to the consequences mentioned above, collisions with cetaceans can also have several other impacts, including: 

• Financial losses due to a ship damage and / or vessel’s immobilization time
  
  
• Safety of the crew, especially for racing boats or small boats 
  
  
• Damage to the marine ecosystem 
  
  
• Negative image 

Marine Life Disruption by Nautical Activities 

Nautical activities, such as jet skiing, kayaking, and recreational boating, can have a significant impact on marine life. These activities can destroy underwater habitats, disturb protected species, alter water quality, generate noise pollution, and cause stress and behavioral changes in marine animals. 

• Destruction of Underwater Habitats:
  One of the most significant impacts is due to the anchorage of recreational boats and yachts in coastal areas. Indeed, they can also physically damage coral reefs and seagrass beds, which provide essential habitat for many marine species. 
  
  
• Disturbance of marine ecosystems:
  Nautical activities can also disturb protected species. For example, jet skis and boats can frighten dolphins, whales, and sea turtles, causing them to abandon their habitat or even beach themselves. In some cases, these activities can even lead to injuries or deaths of marine animals. The stress caused by nautical activities can also lead to behavioral changes in marine animals. For example, fish may avoid areas where there is a lot of boat traffic, and dolphins may stop feeding or socializing. In some cases, the stress can even lead to death.
  
  
• Alteration of Water Quality:
  Nautical activities can also alter water quality. Boats and jet skis can discharge wastewater, fuel, and oil into the water, which can pollute the environment and harm marine life.  
  
  
• Generation of Noise Pollution :
  Underwater noise from nautical activities can also be a major source of disturbance for marine animals. Noise pollution can disrupt the communication and feeding patterns of marine animals, and it can also cause stress and anxiety. In some case, noisy activities can also disturb avifauna species.

Water Turbidity Impact of Port Dredging 

Port dredging is a necessary activity to maintain and expand shipping channels and harbors. However, it can have a significant impact on the marine environment. One of the most serious impacts is the increase in water turbidity. 

Turbidity is the cloudiness of water caused by suspended particles. Suspended particles can include sediment, organic matter, and pollutants. When sediment is disturbed by dredging, it can be suspended in the water column, reducing visibility and making it difficult for marine organisms to find food and mates. 

Turbidity can also have a negative impact on the growth and development of marine plants and animals. Some organisms, such as coral reefs, are very sensitive to turbidity and can be killed or damaged by even small increases in suspended sediment. 

In addition to increasing turbidity, dredging can also release pollutants into the water. These pollutants can come from the sediment itself, or from the dredging equipment. Pollutants can harm marine organisms in a variety of ways, including by poisoning them, disrupting their metabolism, or interfering with their reproduction. 

Overall, port dredging can also have other negative impacts on marine life, such as: 

• Destruction of the habitat of marine ecosystems: Dredging can destroy important marine habitats, such as seagrass beds, coral reefs, and oyster reefs. These habitats provide food and shelter for a variety of marine organisms. 
  
  
• Resuspension of polluted particles: Dredging can resuspend polluted particles that have been deposited on the seabed. These particles can contain harmful contaminants, such as heavy metals and pesticides. 
  
  
• Disturbance of marine animals and ecosystems: Dredging can disturb marine animals and their habitats. This can lead to stress, injury, and death. 
  
  
• Reduction of light availability: Turbidity caused by dredging can reduce the amount of light that reaches the seabed. This can have a negative impact on marine plants and animals that need sunlight to survive
  
  
• Alteration of water quality: Dredging can alter the water quality in a variety of ways. This can include changes in pH, salinity, and oxygen levels. These changes can be harmful to marine organisms. 

The environmental impacts of port dredging can be significant. By taking measures, it is possible to reduce the impact of port dredging on marine life and protect the valuable ecosystems that support these organisms.