Ocean Pollution: Devastating Impact On Marine Life

Marine life is under threat from a range of human activities, from commercial fishing to climate change. However, one of the most pressing issues is ocean pollution. The oceans cover 71% of the Earth's surface and are home to a vast array of species, but they are extremely vulnerable to the harmful substances that humans are releasing into them. Marine pollution takes many forms, from plastics to chemical and noise pollution, and it is having a devastating impact on marine animals.

Plastic ingestion

Marine animals are suffering the consequences of plastic pollution in the ocean. Plastic ingestion is a pressing issue, with plastic being consumed by marine animals of all kinds, from fish to turtles, seals, crustaceans, microorganisms, and more.

The issue of plastic ingestion is not limited to larger marine animals. Microplastics, tiny particles of plastic that result from the breakdown of larger plastics, are easily consumed by wildlife. These microplastics can absorb and transfer toxins to the fatty tissues of the organisms that ingest them. As microplastics are a recent discovery, their long-term impacts are yet to be fully understood. However, their presence in the food chain is indisputable, and they have been found in drinking water, salt, beer, and even in the soil where we grow our vegetables.

The impact of plastic ingestion on marine life is not limited to direct consumption. Humans are also affected by this issue as toxic contaminants accumulate on the surface of plastics and are then transferred to humans through the consumption of seafood. This poses health risks, including potential acute and chronic toxicity, carcinogenicity, and developmental toxicity.

Entanglement in debris

Marine animals, such as whales, dolphins, seals, sea lions, and sea turtles, are vulnerable to entanglement in fishing gear and marine debris as they swim or while on the beach. This includes lost or abandoned fishing gear, as well as other types of ropes, lines, and trash, such as plastic bags.

Entanglement can cause drowning, starvation, physical trauma, and infections, as the gear cuts into the flesh of the animals and restricts their movement. It can also increase the risk of vessel strikes as entangled animals are unable to avoid ships. Smaller marine animals, such as sea turtles, seals, and porpoises, may drown immediately if entangled in large or heavy gear.

Entanglement is considered a primary cause of human-induced mortality in many whale species, including right whales, humpback whales, and gray whales. According to the International Whaling Commission, 300,000 whales, dolphins, and porpoises die from entanglement each year.

Long-term effects of entanglement include deteriorating health, fatigue, decreased reproductive ability, and starvation. It can also lead to deformities or amputations. One well-known case involved a dolphin named Winter, who lost her tail fluke due to ischemic necrosis after becoming entangled in crab fishing gear.

The problem of entanglement can be mitigated through public awareness campaigns, safer fishing practices, and support for ocean conservation programs that focus on removing and reporting marine debris. It is crucial that only trained professionals attempt to disentangle marine animals to ensure the safety of both the animals and the rescuers.

Habitat damage

Marine debris can damage the habitats of marine animals in a variety of ways. Firstly, it can physically crush or smother sensitive plants and corals, reducing their access to light and oxygen, which are essential for their survival. This is particularly detrimental to coral reefs, which are extremely biodiverse ecosystems. The slow growth rate of corals means that even small amounts of damage can take a long time to recover from. Abandoned vessels can also damage coral reefs by releasing fuel, anti-fouling paints, and other chemicals that are toxic to corals and encourage the growth of algae, which competes with corals for space.

Marine debris can also entangle and trap marine animals, leading to injury or death. This is a significant issue for dolphins and whales, which are often entangled in discarded fishing nets. It is also a problem for sea turtles, which can mistake plastic bags and clear containers for food, leading to choking and internal injuries. In addition, plastic debris can alter the temperature of the sand on beaches, impacting the reproduction rates of sea turtles that nest there.

Marine debris can block the movement of water and decrease water quality, which is detrimental to mangroves, which are habitats for both land and aquatic wildlife. It can also trap and kill wildlife, such as the mangrove seedlings, and release contaminants into the surrounding water. Large pieces of plastic and microplastics can be found in the roots, branches, and sediments of mangrove habitats, posing a threat to the wildlife that lives there.

Salt marshes, which are coastal wetlands made of grasses and shrubs, are also susceptible to damage from marine debris. Debris can shade or crush plants, block areas where grasses would normally grow, and smother marsh soils and vegetation, preventing them from getting the nutrients they need to survive. Heavy debris, such as tires or wire crab pots, can scrape and break the stems of salt marsh grasses, disrupting their growth.

Seagrasses, which are flowering marine plants that grow on the seafloor, can be damaged by derelict fishing gear that becomes stranded in seagrass meadows. This can reduce light and impede the plants' ability to photosynthesize. Derelict traps can also break or scrape seagrass blades and crush them into the sediment, suffocating them. Lost or abandoned vessels can also cause damage or erosion to seagrass habitats if they remain stranded for extended periods.

Overall, marine debris poses a significant threat to the habitats of marine animals, leading to physical damage, entanglement, and the release of toxic contaminants. These issues can have long-lasting impacts on marine ecosystems and the animals that depend on them.

Noise pollution

Impact on Marine Mammals

Marine mammals, such as whales, dolphins, and porpoises, are highly dependent on sound for critical activities such as communication, locating prey and mates, navigation, and territory defence. Noise pollution interferes with these natural behaviours and can cause stress, disorientation, and hearing loss. For animals that rely on echolocation, like dolphins and toothed whales, excessive noise can disrupt their signals, causing them to become disoriented and unable to hunt successfully.

Additionally, very loud noises can induce panic in these animals, causing them to ascend too quickly and resulting in decompression sickness and skin damage from gas bubble lesions. In some cases, loud sounds can lead to hearing loss or even strandings and death. Noise pollution has been linked to mass stranding events around the world, particularly among beaked whales.

Impact on Other Marine Life

Impact on the Marine Ecosystem

The complex and interconnected nature of marine ecosystems means that the effects of noise pollution on one species can have indirect consequences for others. For instance, if a whale strands on a beach due to sudden, intense noise from human activity, its body may provide a key food source for seafloor-dwelling animals. When the whale dies on land instead of at sea, these animals lose access to this food source.

Mitigation Efforts

Currently, there are no international legal regulations on noise pollution, but organisations like the International Maritime Organization (IMO) have established guidelines for the reduction of underwater noise from shipping. Local governments and individual ports have also implemented their own regulations, such as the Port of Vancouver, which offers discounts to vessels that voluntarily comply with environmental guidelines. However, a growing public awareness of this issue is leading to increased advocacy for stronger legislation and the development of quieter technologies to reduce noise pollution in the ocean.

Chemical pollution

Marine pollution is a combination of chemicals and trash, most of which comes from land sources. Chemical pollution, or nutrient pollution, occurs when human activities, such as the use of fertilizers on farms, lead to the runoff of chemicals into waterways that flow into the ocean. The increased concentration of chemicals, such as nitrogen and phosphorus, in the coastal ocean promotes the growth of algal blooms, which can be toxic to wildlife and harmful to humans.

Algal blooms, also known as "red tides", grow rapidly and produce toxic effects that can affect marine life and sometimes even humans. Excess nutrients entering a body of water can result in hypoxia or dead zones, where there is so little oxygen in the water that nothing can survive. The resulting low-oxygen environment forces marine life to leave the area or perish.

Clams and oysters, which are important sources of food and livelihoods for many coastal communities, are also affected by chemical pollution due to their filtering behaviour. The toxins and harmful substances they absorb can stay in their bodies for long periods, leading to death and depletion of the species.

Additionally, microplastics, which are small plastic particles less than 5mm in size, can adsorb toxins, which can then be transferred to the fatty tissues of organisms that ingest them. Microplastics have been detected in a range of marine species, including plankton, whales, fish, and seabirds. As these small organisms are eaten by larger animals, the toxic chemicals migrate up the food chain, eventually becoming part of the food that humans consume.

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