Ocean Pollution's Impact On Marine Life

Ocean pollution is a pressing issue that poses a serious threat to the health of our planet and its ecosystems. Oceans cover over 70% of the Earth's surface and are home to most of the life on the planet, from microscopic algae to the blue whale, the largest animal on Earth. Unfortunately, human activities have led to the ocean being flooded with various forms of pollution, including chemicals and trash. Marine ecosystems are being drowned in trash, noise, oil, carbon emissions, and chemical contamination, causing severe damage to the environment and the health of all organisms. This paragraph will discuss the impact of pollution on marine life and highlight the urgent need to address this global issue.

Fish and other marine animals

Marine pollution is a pressing issue that poses significant risks to fish and other aquatic organisms. The delicate balance of marine ecosystems is disrupted by contaminants, such as heavy metals, oil spills, pesticides, and plastic waste. These pollutants have detrimental effects on the health and survival of fish populations.

One of the primary threats to fish comes from the ingestion of toxic substances. Oil spills, for instance, can cause gill damage, fin and tail rot, reproductive issues, and even death among fish. Similarly, pesticides and heavy metals released into the water through industrial activities or agricultural runoff can lead to deformities and mortality in fish.

Plastic pollution is another significant concern for fish and other marine life. Plastic waste, which can take hundreds of years to decompose, is often mistaken for food by marine animals. Ingesting plastic can lead to intestinal injuries and death, as seen in cases of whales, sea turtles, and birds with plastic in their stomachs. Additionally, plastic debris can entangle and restrict the growth of fish, causing further harm.

The impact of pollution on fish goes beyond direct physical harm. Pollutants can reduce oxygen levels in the water, creating "dead zones" where fish and other organisms suffocate due to a lack of oxygen. This occurs when excess nutrients, such as nitrogen and phosphorus from agricultural runoff, promote excessive algae growth. When the algae die and decompose, they consume oxygen, leading to oxygen depletion in these areas.

Pollution also indirectly affects fish by damaging their habitats. Certain contaminants can encourage the growth of fungus, bacteria, and algae, which can overtake and hinder the growth of plants that marine life depends on. Large mats of algae or moss can block sunlight and nutrients from reaching plants and fish, disrupting the delicate balance of the ecosystem.

Furthermore, plastic pollution contributes to the spread of pathogens in the ocean. Corals that come into contact with plastic have a significantly higher chance of contracting diseases compared to those that don't. This poses a threat not only to coral reefs but also to the fish and other organisms that rely on these ecosystems for shelter and food.

The consequences of marine pollution extend beyond the immediate harm to fish. Pollutants accumulate in the food chain, affecting larger fish, marine mammals, and ultimately humans who consume contaminated seafood. Microplastics, for example, can be ingested by small organisms and gradually move up the food chain, ending up in the seafood we eat.

Addressing the impact of pollution on fish and other marine animals requires a multifaceted approach. While prevention and cleanup are crucial, it is equally important to advocate for better waste management practices, promote recycling, and push for regulations that limit or ban the use of certain harmful substances and single-use plastics.

Seabirds

Adult seabirds often mistake plastic debris for prey and return to their nests with plastic, which their chicks then ingest. As the plastic takes up room in their stomachs, the chicks are less likely to survive to adulthood due to starvation. In addition, the presence of plastic in the birds' stomachs can impact kidney function, leading to higher concentrations of uric acid and negatively affecting cholesterol and enzymes.

Another way pollution affects seabirds is through bycatch, or accidental hooking or entanglement in fishing gear. Seabirds are attracted to fishing vessels and operations due to the availability of "free food" in the form of offal and bait. This puts them at risk of getting hooked or entangled in fishing gear, especially in longline fisheries. This can be a serious threat to endangered seabird species, such as the Short-tailed Albatross.

To address these issues, various statutes, strategic initiatives, and multilateral agreements have been put in place to include seabirds in efforts to reduce bycatch. The National Seabird Program, led by NOAA Fisheries, works domestically and internationally to protect and conserve seabirds.

Whales and dolphins

Marine Debris

Marine debris, such as discarded fishing nets, plastic bags, and microplastics, poses a significant threat to whales and dolphins. These animals often mistake plastic for food, leading to intestinal blockage and starvation. For example, scientists estimate that approximately 56% of the world's dolphins and whales have ingested plastic. In one tragic case, a pregnant pygmy sperm whale in Melbourne beached itself due to a stomach full of plastic that blocked its digestive system.

Additionally, young marine mammals are especially susceptible to entanglement in floating debris, causing a slow and painful death as their growing bodies become restricted. Entanglement in discarded fishing gear, or "ghost gear," often results in death for dolphins and other animals.

Oil Spills and Chemical Pollutants

Oil spills and chemical pollutants, such as industrial pollutants like PCBs, have detrimental effects on dolphin and whale populations. For instance, the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 led to a decline of over 50% in the local dolphin population over ten years. The contaminated air from the oil spill caused respiratory ailments and immune dysfunction, resulting in increased mortality, failed pregnancies, and a higher risk of diseases and infections.

Fertilizer runoff is another chemical pollutant that impacts dolphins and whales. It causes algal blooms, known as red tides, which produce toxic effects. Dolphins and whales are affected by these toxins through inhalation or ingestion of contaminated fish, leading to bioaccumulation.

Noise Pollution

Noise pollution from ship engines, military sonar, oil drills, and other human activities also poses a threat to whales and dolphins. These marine mammals rely on echolocation to navigate their environment, and noise pollution interferes with their ability to do so effectively. Additionally, loud noises can cause panic, leading to rapid dives that result in fatal decompression sickness.

Toxins

Toxins from sources like automobiles, air conditioners, and household products enter the marine environment through land-based runoff, air pollution, and ocean dumping. These toxins accumulate in the blubber of whales and dolphins, leading to immune system suppression, reproductive failure, and increased susceptibility to infections and diseases. For example, high levels of toxins have been linked to morbillivirus infections in dolphins, which can cause distemper or measles-like symptoms.

Humans

Direct Health Effects

The health effects of ocean pollution on humans are only beginning to be understood. The most common route of exposure is through the consumption of contaminated seafood, which can contain toxic chemicals such as mercury, lead, pesticides, and other heavy metals. These chemicals can cause a range of health issues, including hormonal issues, reproductive issues, nervous system damage, and kidney damage. In addition, microplastics, which are ingested by fish and other marine organisms, can end up in the human food chain and have unknown risks to human health.

Economic Losses

Ocean pollution also has economic impacts on humans. The pollution can affect the fishing industry, with fish stocks declining due to the presence of toxic chemicals and microplastics in the water. This can lead to a decrease in the availability of seafood, which is a major source of protein for humans. Additionally, ocean pollution can impact tourism, as contaminated beaches and waters can deter visitors.

Other Effects

Other effects of ocean pollution on humans include the disruption of cultural and recreational activities, as well as the potential migration of communities due to the loss of livelihood and food sources. Climate change, which is exacerbated by ocean pollution, can also lead to rising sea levels and extreme weather events, further impacting human communities.

Algae

An overgrowth of algae is known as an algal bloom. Algal blooms can occur in fresh, marine (salt), and brackish (a mixture of fresh and salt) water. They are often triggered by an excess of nutrients such as nitrogen and phosphorus, which act like fertiliser and promote the growth of algae. This excess typically enters waterways via agricultural runoff, leaked waste from animal feedlots, stormwater runoff, and discharges from wastewater treatment facilities.

Algal blooms can have negative impacts on aquatic ecosystems, humans, and coastal economies. They can produce toxins that are detrimental to fish and other animals, including humans. These toxins can move up the food chain, impacting larger animals like sea lions, turtles, dolphins, birds, and manatees. Even non-toxic algal blooms can harm aquatic life by blocking out sunlight and clogging fish gills, reducing their ability to find food and causing populations to leave an area or even die.

The decomposition of dead algae can also lead to the formation of "dead zones" or hypoxic areas, where oxygen levels are too low to support aquatic life. These dead zones have been observed in various locations, including the Gulf of Mexico and the Chesapeake Bay.

Harmful algal blooms (HABs) are influenced by factors such as geography, runoff amounts, tides, currents, water temperatures, and the presence of other organisms. Human activities, such as coastal development and the use of agricultural fertilizers and lawn care products, can contribute to an increase in HAB occurrences and severity.

One of the well-known HABs in the US occurs almost annually along Florida's Gulf Coast, caused by the microscopic algae Karenia brevis. This HAB produces toxins that can kill fish or marine mammals and make shellfish dangerous to eat. It is commonly referred to as a "red tide" due to the reddish colour it turns the water.

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